Agronomy

What is Agriculture?

• Agriculture is the backbone of our Pakistani Economy.
• Agriculture is a very broad term encompassing all aspects of crop production, livestock farming, fisheries, forestry, etc.
• Agriculture is the most important human economic activity.
• Agriculture is the activity of man for the production of food, fiber, fuel, etc. by the optimum use of terrestrial resource i.e. land & water.

Definition of Agriculture:

• The word agriculture comes from the Latin words ager, means the soil & cultura, means cultivation.
• “Agriculture can be defined as the cultivation and/or production of crop plants or livestock products.”
• Agriculture includes Crop Production, Animal Husbandry & Dairy Science, Agriculture Chemistry & Soil Science, Horticulture, Agril Economics, Agril Engineering, Botany, Plant Pathology, Extension Education and Entomology, which develops its separate and distinct branches of agriculture occupying now a days place in several Agril Universities in the country.

Conventional Agriculture:

• “Conventional Agriculture is the term for predominant farming practices and systems of crop production adapted by farmer in a particular region”

Agriculture can be termed as a science, an art & business altogether.

Science: because it provides new and improved strain of crop and animal with the help of the knowledge of breeding and genetics, modern technology of dairy science.

Art: because it is the management whether it is crop or animal husbandry.

Commerce (Business): because the entire agril produce is linked with marketing, which brings in the question of profit or loss.

Scope of Agriculture

Proverbially, India is known as “Land of Villages”. Near about 67% of India’s population live in villages. The occupation of villagers is agriculture. Agriculture is the dominant sector of our economy & contributes in various ways such as:

• National Economy: In 1990 – 91, agriculture contributed 31.6% of the National Income of India, while manufacturing sector contributed 17.6%. It is substantial than other countries for example in 1982 it was 34.9% in India against 2% in UK, 3% in USA, 4 % in the Canada. It indicated that the more the more the advanced stage of development the smaller is the share of agriculture in National Income.
• Total Employment: Around 65% population is working & depends on agriculture and allied activities. Nearly 70% of the rural population earns its livelihood from agriculture and other occupation allied to agriculture. In cities also, a considerable part of labor force is engaged in jobs depending on processing & marketing of agricultural products.
• Industrial Inputs: Most of the industries depend on the raw material produced by agriculture, so agriculture is the principal source of raw material to the industries. The industries like cotton textile, jute, paper, sugar depends totally on agriculture for the supply of raw material. The small scale and cottage industries like handloom and power loon, ginning and pressing, oil crushing, rice husking, sericulture fruit processing, etc are also mainly agro based industries.
• Food Supply:  During this year targeted food production was 198 million tons & which is to be increased 225 million tons by the end of this century to feed the growing population of India i.e. 35 corer in 1951 and 100 corers at the end of this century. India, thus, is able to meet almost all the need of its population with regards to food by develop intensive program for increasing food production.

• State Revenue:  The agriculture is contributing the revenue by agriculture taxation includes direct tax and indirect tax. Direct tax includes land revenue, cesses and surcharge on land revenue, cesses on crops & agril income tax. Indirect tax induces sales tax, custom duty and local octri, etc. which farmer pay on purchase of agriculture inputs.

• Trade: Agriculture plays and important role in foreign trade attracting valuable foreign exchange, necessary for our economic development. The product from agriculture based industries such as jute, cloth, tinned food, etc. contributed to 20% of our export. Around 50 % of total exports are contributed by agril sector. Indian agriculture plays and important role in roads, rails & waterways outside the countries. Indian in roads, rails and waterways used to transport considerable amount of agril produce and agro based industrial products. Agril products like tea, coffee, sugar, oil seeds, tobacco; spices, etc. also constitute the main items of export from India.
  
  History of Agriculture as a science
  1. In pre scientific agriculture six persons could produce enough food for themselves and for four others. In years of bad harvest they could produce only enough for themselves, with the development of science and application of advanced technology five persons are able to produce enough food for nine others.
  2. Van Helmet (1577-1644Ad): Experiments pertaining to plant nutrition in systematic way and   concluded that the main “Principle” of vegetation is water.
  3. Jethre Tull (1674-1741AD): Conducted several experiments and published a book “Horse Heeing Husbandry”. These experiments mostly on cultural practices and they led to the development of seed drill & horse drawn cultivation.
  4. Aurthur young (1741-1820Ad): Conducted pod culture experiments to increase the yield of   crops by applying several materials like poultry dung, litter, gun power, & publish his work-in 46 volumes at “Annals of agriculture”.
  5. In 1809 soil science begin with the formulation of the theory of hums.
  6. Research in plant nutrition & physiology was started in 18th century.
  7. Sir Humphrey Davy published book “Elements of agri chemistry” in 1813
  8. Sir John Bennet was begun to experiment on the effects of manures of crops.
  9. Justus Libey on agriculture chemistry and physiology launched systematic development of agriculture in 1840.
  10. 1842, Initiated the systematic fertilizers Industry by the patented process of hearting phosphate rock to produce super phosphate.
  11. Gregor Johann Mendel (1866) discovers the law of heredity and the ways to mutations laid to modern plant breeding.
  12. Charles Darwin Published the results of the experiments on cross and self ferlization in plants.
  13. 1920, the application of genetics to develop new strains of plants and animals brought major charges of agriculture.
  14. The first successful tractor was built in U.S in 1882 from implements & machinery was manufactured industrially on a large scale by 1930.
  15. Due to economic pressure and decrease in labor availability, the application of electricity to agriculture was in 1920.
  16. The first successful large scale conquest of a pest a chemical means was the control of grapevine powdery mildew in Europe in 1840.
  17. The key date in history of argil research at education is 1862. When the US congress set up departments of agriculture & provided for colleges for agriculture in each state.
  18. Scientific agriculture began in India when Sugarcane, cotton, & Tobacco were grown for purpose.
      What is Agronomy?
      The term agronomy is derived from Greek words “AGRO” meaning field & “NOMO” meaning to manage.
      Definition of agronomy:
      1. Agronomy is branch of agril science which deals with principles & practices of soil, water & crop management. 2. It is branch of agril science that deals with methods which provide favorable environment to the crop for higher productively, 3. It deals with the study of principles and preaches of crop production and field management. 4. It is the study of planet in relation to soil and climate. It deals essentially with all aspects of soil, crop and water management to increase productively of crops.
      Principles of agronomy deal with scientific facts in relations to environment in which crop are produced
      Scope of agronomy:
      Agronomy is a dynamic discipline with the advancement of knowledge and better understanding of planet & environment, agril. Practices and modified of new practices developed for high productively as follows:
      1. Proper methods of filling the lands.
      2. Suitable period for its cultivation.
      3. Keeping farm implements in good shape and managing field crops in a efficient manner as experienced farmer.
      4. Management of crops, live stock & their feedings.
      5. Care and disposal of farm & animal products like milk & eggs.
      6. Proper maintenance of accounts of all transactions concerning farm industry.
      7. Availability of chemical fertilizers has necessitated the generation of knowledge on the method.
      8. Availability of herbicides for control of weeds has led to development for a vast knowledge about selectivity, time & method of its application.
      9. Water management practices.
      10. Intensive cropping.
      11. New technology to overcome the effect of moisture stress under dry land condition.
      12. Packages of practices to explore full potential of new varieties of crops.
      Restoration of soil fertility, preparation of good seedbed, use of proper seed rates, correct dates of sowing for each improved Variety, proper methods of conservation & management of soil moisture & proper control weeds are agronomic practices to make our finite land water resources more productive.
      With the growth of other allied agril sciences, the present day agronomy not only embodies the act of soil management of crop production and obtaining maximum production at minimum cost but also establishing new facts and applying scientific knowledge to practical problems.
      The emphasis of agronomy is now more towards the scientific study of the behavior of plant under the different environmental conditions like varing soils and climate, irrigation, fertilization etc. by conducting well laid out experiments in the fields, pots & laboratories.
      It is also involves application of research in the field or forming suitable packages of practices under a given set of conditions.
      Relationship of Agronomy with other Sciences
       Agronomy is having relationship with both basis and applied sciences.
      1. Basic sciences are those which reveal the facts or secrets of nature and comprise subjects like chemistry, physics, math’s, botany, zoology.
      2. Applied sciences are those in which the theories and laws propounded in basic sciences are applied to problems in agriculture and other fields. Agril chemistry comprising, soil, planet, fertilizer, and dairy chemistry developed from basic science of chemistry.
      3. Agril Botany covers planet nutrition, plant physiology and planet breeding developed from botany & chemistry.
      4. Planet pathology & economic entomology developed from botany & Zoology.
      5. Agril extension developed from psychology, sociology and anthropology.
      6. Agronomy is essentially an applied science and is largely dependent on basic and other applied science.
      7. Knowledge of all the science is necessary to learn the basic facts, regardless, of whether they would be of any practical value of agriculture.
      8. All the applied sciences are important for advancement of agriculture, which are closely related to each other and no branch can progress without to help of allied science branches.
      9. Agronomy is synthesis of several disciplines like soil science, agril chemistry, crop physiology, planet ecology, biochemistry & economics. Agril chemistry & soil science deals with: a) Management of acidic, saline & alkali soils. b) Application of fertilizers. c) Effects of physical, chemical changes (modifications) on soil environment.
      1. Physiology deals to meet their requirement.
      2. Breeding deals with evolution of new verities & exploitation of hybrid vigor.
      3. Economics deals for economically crop production.
      4. Pathology & entomology deals with effective control of diseases & pests.
      Coordinated Approach:
      1. Since the applied sciences are so interrelated the specialists cannot work in isolation but have to work in coordination with each other to solve the problems of agriculture rapidly and efficiently.
      2. For Example: the Planet breeder while evolving a HYV (High yielding Variety) of any crop must take the help of planet pathologist to test the resistant or susceptibility of the new strain to diseases, physiologist to make sure that the new strain has not developed any undesirable qualities and of the agronomist to test the behavior of variety under field condition.   
                

Agronomist

An agronomist is called as an expert of agriculture except veterinary science. Also known as doctor of plant

Agronomist is a specialized scientist in agronomy, which deals with the science of utilizing plants for food, fuel, feed & fiber.

Agronomist are involved with many issues including food, feed & fuel production without impact on environmental.

Agronomist should be specializing in areas such as crop rotation, irrigation & drainage, planet breeding, soil science, weed control & disease & pest control.

Role of Agronomist:
1. Agronomist aims at an obtaining maximum production at minimum cost by exploiting the exploiting the knowledge developed by basic and allied/applied science.
2. In a board sense he is conceder with production of food and fiber to meet the needs of the growing population.
3. He has to test the suitability of research finding of others specialists in the field and accept them finally and also judge the reaction of the farming community.
4. He is a coordinator of different subject matter specialist and act as a physician who concern with other SMS.
5. He carries out research on scientific cultivation of crops taking into account the effect of factors like soil climate, variety of crops production techniques suitably depending on the situation.
6. He is person with working knowledge of all agril disciplines and coordinator of different subject matter specialists.    

Introduction to Principles of Agronomy

“Principles of agronomy deals with basic concepts & common agronomic principles & much more than crop to crop management approaches”

This principle of agronomy is useful for the application with many crops.

The principle of agronomy is based on two major purposes:
1. To develop an understanding of the important principles underlying the management.
2. To develop the ability to apply these principles to production situations

Major Principles to Agronomy:

1. Agrometerology: study of climatic factors in related to agriculture.

2. Soils & Tillage: Tillage is the agricultural preparation of the soil by ploughing, ripping, or turning it. There are two types of tillage: primary and secondary tillage. Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics.

3. Soils & Water conservation: Water conservation refers to reducing the usage of water and recycling of waste water for different purposes like cleaning, manufacturing, agriculture etc.

4. Dry land Agriculture: Dry land farming is an agricultural technique for cultivating land which receives little rainfall.

5. Mineral Nutrition of plants, Manures & Fertilizers: Plant nutrition is the study of the chemical elements that are necessary for plant growth.

6. Irrigation & water management: Water management is the activity of planning, developing, distributing and optimum use of water resources under defined water polices and regulations

7. Weed Management: Management of unwanted plant in field.

8. Cropping & Farming systems.

9. Sustainable Agriculture: Sustainable agriculture refers to the ability of a farm to produce fertile soil and cows, without causing severe or irreversible damage to ecosystem health

Agronomy Definition:
Agronomy is the science and technology of producing and using plants for food, fuel, fiber, and reclamation. Agronomy encompasses work in the areas of plant genetics, plant physiology, meteorology, and soil science. Agronomy is the application of a combination of sciences like biology, chemistry, economics, ecology, earth science, and genetics. Agronomists today are involved with many issues including producing food, creating healthier food, managing environmental impact of agriculture, and creating energy from plants.^[1] Agronomists often specialize in areas such as crop rotation, irrigation and drainage, plant breeding, plant physiology, soil classification, soil fertility, weed control, insect and pest control.

Outline of Agronomy - Agriculture Science

Agronomy is the branch of agriculture sciences dealing with principles and practices of crop production and field management. Agronomy is mainly based on following basic principles Agrometerology, Soils and Tillage, Soil and Water Conservation, Dryland Agriculture, Mineral Nutrition of Plants, Manures and Fertilizers, Irrigation Water Management, Weed Management, Cropping and Farming Systems, Sustainable Agriculture.

Agrometerology: Agrometerology is the branch of meteorology, which investigates the relationship of plants and animals to the physical environment. Agrometerology describes Agrometerological Observatory, Atmosphere, Wind, Clouds and Precipitation, Solar Radiation, Air Temperature, Soil Temperature, Humidity and Evaporation, Weather Hazards and their Mitigation, Weather and Crop Productivity, Weather Relations of crops, Weather Forecasting and Classification of Climate and Agroclimate in relation to agriculture.

Soils and Tillage:  Soils and tillage are necessary to know how soils should be managed and conserved for sustainable crop production. Under this principle of agronomy we can learn Physical Properties of Soil, Chemical Properties of Soil, Biological Properties of Soil, Soil Organic Matter, Salt Affected Soils, and Tillage.

Soil and Water conservation: We must conserve soil and water because these are the most critical resources. In this principle we will touch to Soil Erosion, Water Erosion, Wind Erosion, Soil and Water Conservation Measure.

Dryland Agriculture: Dryland farming is cultivation of crops in regions with annual rainfall more than 750 mm. Under this we need to read History of Dryland Agriculture, Problems of Dryland Agriculture, Monsoon and Length of Crop Growing Season, Drought, Moisture Conservation in Drylands, Water Harvesting and Protective Irrigation, Crops and Cropping Systems, Mitigating Adverse Effect of Aberrant Weather, Alternate Land Use Systems, Watershed Management and Improved Dryland Agricultural Implements.

Mineral Nutrition, Manures and Fertilizers: Nutrient Management is one of the most important principles in agronomy which includes Essentials in Plant Nutrition, Nutrient Uptake by Plants, Soil Fertility Evaluation, Manures, Fertilizers in Indian Agriculture, Nitrogen Fertilizers, Phosphatic Fertilizers, Potassic Fertilizers, Calcium, Magnesium and Sulphur, Micronutrients, Mixed Fertilizers, Fertilizer Application, and Fertilizers & Environment.

Irrigation Water Management: Irrigation Water Management is very important for success of agriculture. In irrigation management we need to read Irrigation in Indian Agriculture, Water Resource & Their Development, Systems of Irrigation, Soil – Water Relationships, Plant – Water Relationship, Evapotranspiration, Water Requirements of Crops, Measurement of Irrigation Water, Scheduling Irrigation, Methods of Irrigation, Irrigation & Water Use Efficiency, Irrigation Practices for Major Crops, Quality of Irrigation Water, Drainage, Cropping Pattern in Command Areas, Pricing Irrigation Water.

Weed Management: Weed is a plant grown at place & time which is not desire. Understanding of Common Weeds, Losses and Benefits, Weed Ecology & Classification, Crop – Weed Association & Competition, Methods of Weed Control, Classification of Herbicides, Herbicide Formulation, Herbicide Application, Absorption & Translocation of Herbicides, Mode of action of Herbicide, Selectivity of Herbicide, Herbicide Combination, Rotations & Interactions, Persistence of Herbicides in Soils, Herbicide Resistance, Chemical Weed Control in Different Crops, Parasitic & Aquatic Weed Control.

Cropping Systems: Cropping systems is gaining more importance in this day and includes Various Terminology, Major Cropping Systems, Agronomy of Rainfed Cropping Systems, Agronomy of Irrigated Cropping Systems, Evaluation of Cropping Systems, Farming Systems and Farming Systems Research

Sustainable Agriculture: Sustainable agriculture can be define as the form of agriculture aimed at meeting the food and fuel needs of the present generation without endangering the resource base for the future generations. It includes study of Impact of Improved Crop Production Technology, Factors Affecting Ecological Balance, Evaluation of Sustainable Agriculture, Components of Sustainable Agriculture, Sustainable Utilization of Land Resources, Sustainable Utilization of Water Resources, Sustainable utilization of Biodiversity, Integrated Nutrient Management, Integrated Nutrient Management, Integrated Plant Protection, Enhancing Sustainability of Dryland Agriculture, Enhancing Sustainability of Irrigated Agriculture, Agricultural Sustainability and Farming Systems.

Divisions of Plant Kingdom

A crop is an organism cultivated & harvested for obtaining yield.

• According to the natural system the plant kingdom has been divided into two divisions. I.e.     Cryptogams & Phanerogams.
• Phanerogams divided into two sub division i.e. Angiosperm & Gymnosperm.
• Angiosperm further divided into two classes i.e. Monocots & Dicots.
• Classes again divided into orders, orders into families, families into genera & species, some times species into varieties.

Classification of Crop Plants

Importance of classifying the Crop Plants:

1. To get acquainted with crops.
2. To understand the requirement of soil & water different crops.
3. To know adaptability of crops.
4. To know the growing habit of crops.
5. To understand climatic requirement of different crops.
6. To know the economic produce of the crop plant & its use.
7. To know the growing season of the crop
8. Overall to know the actual condition required to the cultivation of plant.

Classification based on climate:

1. Tropical: Crops grow well in warm & hot climate. E.g. Rice, sugarcane, Jowar etc
2. Temperate: Crops grow well in cool climate. E.g. Wheat, Oats, Gram, Potato etc.

Classification Based on growing season:

1. Kharif/Rainy/Monsoon crops: The crops grown in monsoon months from June to Oct-Nov, Require warm, wet weather at major period of crop growth, also required short day length for flowering. E.g. Cotton, Rice, Jowar, bajara.
2. Rabi/winter/cold seasons crops: require winter season to grow well from Oct to March month. Crops grow well in cold and dry weather. Require longer day length for flowering. E.g. Wheat, gram, sunflower etc.
3. Summer/Zaid crops: crops grown in summer month from March to June. Require warm day weather for major growth period and longer ay length for flowering. E.g. Groundnuts, Watermelon, Pumpkins, Gourds.

Use/Agronomic classification:

1. Grain crops: may be cereals as millets cereals are the cultivated grasses grown for their edible starchy grains. The larger grain used as staple food is cereals. E.g. rice, Jowar, wheat, maize, barley, and millets are the small grained cereals which are of minor importance as food. E.g. Bajara.
2. Pulse/legume crops: seeds of leguminous crops plant used as food. On splitting they produced dal which is rich in protein.  E.g. green gram, black gram, soybean, pea, cowpea etc.
3. Oil seeds crops: crop seeds are rich in fatty acids, are used to extract vegetable oil to meet various requirements. E.g. Groundnut, Mustard, Sunflower, Sesamum, linseed etc.
4. Forage Crop: It refers to vegetative matter fresh as preserved utilized as food for                                  animals. Crop cultivated & used for fickler, hay, silage. Ex- sorghum, elephant grass, guinea grass, berseem & other pulse bajara etc.
5. Fiber crops: crown for fiber yield. Fiber may be obtained from seed. E.g. Cotton, steam, jute, Mesta, sun hemp, flax.
6. Roots crops: Roots are the economic produce in root crop. E.g. sweet, potato, sugar beet, carrot, turnip etc.
7. Tuber crop: crop whose edible portion is not a root but a short thickened underground stem. E.g. Potato, elephant, yam.
8. Sugar crops: the two important crops are sugarcane and sugar beet cultivated for production for sugar.
9. Starch crops: grown for the production of starch. E.g. tapioca, potato, sweet potato.
10. Dreg crop: used for preparation for medicines. E.g. tobacco, mint, pyrethrum.
11. Spices & condiments/spices crops: crop plants as their products are used to flavor taste and sometime color the fresh preserved food. E.g. ginger, garlic, chili, cumin onion, coriander, cardamom, pepper, turmeric etc.
12. Vegetables crops: may be leafy as fruity vegetables. E.g. Palak, mentha, Brinjal, tomato.
13. Green manure crop: grown and incorporated into soil to increase fertility of soil. E.g. sun hemp.
14. Medicinal & aromatic crops: Medicinal plants includes cinchona, isabgoli, opium poppy, senna, belladonna, rauwolfra, iycorice and aromatic plants such as lemon grass, citronella grass, palmorsa, Japanese mint, peppermint, rose geranicem, jasmine, henna etc.       

Classification based on life of crops/duration of crops:

1. Seasonal crops: A crop completes its life cycle in one season-Karin, Rabi. summer. E.g. rice, Jowar, wheat etc.
2. Two seasonal crops: crops complete its life in two seasons. E.g. Cotton, turmeric, ginger.
3. Annual crops: Crops require one full year to complete its life in cycle. E.g. sugarcane.
4. Biennial crops: which grows in one year and flowers, fructifies & perishes the next year? E.g. Banana, Papaya.
5. Perennial crops: crops live for several years.  E.g. Fruit crops, mango, guava etc.

Classification based on cultural method/water:

1. Rain fed: crops grow only on rain water. E.g. Jowar, Bajara, Mung etc.
2. Irrigated crops: Crops grows with the help of irrigation water.  E.g. Chili, sugarcane, Banana, papaya etc.

Classification based on root system:

1. Tap root system: The main root goes deep into the soil. E.g. Tur, Grape, Cotton etc.
2. Adventitious/Fiber rooted: The crops whose roots are fibrous shallow & spreading into the soil.  E.g. Cereal crops, wheat, rice etc.

Classification based on economic importance:

1. Cash crop: Grown for earning money. E.g. Sugarcane, cotton.
2. Food crops: Grown for raising food grain for the population and & fodder for cattle. E.g. Jowar, wheat, rice etc.

Classification based on No. of cotyledons:

1. Monocots or monocotyledons: Having one cotyledon in the seed.  E.g. all cereals & Millets.
2. Dicots or dicotyledonous: Crops having two cotyledons in the seed. E.g. all legumes & pulses.

Classification based on photosynthesis’ (Reduction of CO2/Dark reaction):

1. C3 Plants: Photo respiration is high in these plants C3 Plants have lower water use efficiency. The initial product of C assimilation in the three ‘C’ compounds. The enzyme involved in the primary carboxylation is ribulose-1,-Biophospate carboxylose.  E.g. Rice, soybeans, wheat, barley cottons, potato.
2. C4 plants: The primary product of C fixation is four carbon compounds which may be malice acid or acerbic acid. The enzymes responsible for carboxylation are phosphoenol Pyruvic acid carboxylose which has high affinity for CO2 and capable of assimilation CO2 event at lower concentration, photorespiration is negligible. Photosynthetic rates are higher in C4 than C3 plants for the same amount of stomatal opening. These are said to be drought resistant & they are able to grow better even under moisture stress. C4 plants translate photosynthates rapidly.  E.g. Sorghum, Maize, napter grass, sesame etc.
3. Cam plants: (Cassulacean acid metabolism plants) the stomata open at night and large amount of CO2 is fixed as a malice acid which is stored in vacuoles. During day stomata are closed. There is no possibility of CO2 entry. CO2 which is stored as malice acid is broken down & released as CO2. In these plants there is negligible transpiration. C4 & cam plant have high water use efficiency. These are highly drought resistant.  E.g. Pineapple, sisal & agave.

Classification based on length of photoperiod required for floral initiation:

Most plants are influenced by relative length of the day & night, especially for floral initiation, the effect on plant is known as photoperiodism depending on the length of photoperiod required for floral ignition, plants are classified as:
1. Short-day plants: Flower initiation takes plate when days are short less then ten hours.  E.g. rice, Jowar, green gram, black gram etc.
2. Long day’s plants: require long days are more than ten hours for floral ignition. E.g. Wheat, Barley,
3. Day neutral plants: Photoperiod does not have much influence for phase change for these plants. E.g. Cotton, sunflower. The rate of the flowering initiation depends on how short or long is photoperiod. Shorter the days, more rapid initiation of flowering in short days plants. Longer the days more rapid are the initiation of flowering in long days plants.

Seeds and Sowing

Seed is  any material used for planning & propagation whether it is in the form of seed (grain) of food, fodder, fiber or vegetable crop or seedlings, tubers, bulbs, rhizomes, roots, cuttings, grafts or other vegetatively  propagated material.

Seed is a fertilized ovule consisting of intact embryo, stored food (endosperm) and seed coat which is viable & has got the capacity to germinate.

As we say, “Reap as you sow”, the good quality seed must have following characters:

1. Seed should be genetically pure & should exhibit true morphological & genetical characters of the particular strain (True to type).
2. It should be free from admixture of seeds of other strains of the same crop or other crop, weeds, dirt and inert material.
3. It should have a very high & assured germination percentage and give vigorous seedlings.
4. It should be healthy, well developed & uniform in size.
5. It should be free from any disease bearing organisms i.e. pathogens.
6. It should be dry & not mouldy and should contain 12-14% moisture.

Seed is the basic input in the crop production which should be of good quality.

Seeds and sowing - Seed Germination

Seed Germination: Means the resumption of growth by embryo & development of a young seedling from the seed. Germination is an activation of dormant embryo to give rise to radical (root development) and plumule (stem development).Germination is the awakening of the dormant embryo. The proce4ss by which the dormant embryo wakes up & begins to grow is known as Germination.

Seed Emergence Means actually coming above and out of the soil surface by the seedling.

Changes During Germination:
1) Swelling of seed due to imbibition of water by osmosis.
2) Initiation of physiological activities such as respiration & secretion of enzyme.
3) Digestion of stored food by enzymes.
4) Translocation & assimilation of soluble food.

When seed is placed in soil gets favorable conditions, radical grows vigorously & comes out through micro Pyle & fixes seed in the soil. Then either hypo or epicotyls begins to grow.

Types of germination:

1. Hypogeal germination: The cotyledons remain under the soil. E.g.: cereals, gram.
2. Epigeal germination: The cotyledons pushed above the soil surface. E.g.: mustard, tamarind, sunflower, castor, onion.

Sowing Of Seed:  

 For cultivation of any field crop, one must follow the recommended practices of seeds and sowing to harvest maximum yield of the crop.

A. Seed Rate
B. Seed Treatment
C. Sowing Time
D. Depth of Sowing
E. Spacing & Plant Population
F. Methods of Sowing

Seed rate: The seed rate per unit area depends on germination of the seed, size of the seed, growing habit of the crop, etc. Extremes from the recommended seed rate (i.e. too high or too low) affect the plant population & then yield of crop. E.g. higher seed rate will influence higher plant population/unit area. It results in heavy competition within the crop plants and suppresses the crop growth. Lower seed rate will result lower plant population thereby lowers the yield/unit area. The seed rate is governed by the ultimate stand desired. Most crops are seeded at smaller rates under dry land than under irrigated condition. Seed rate depends on size, germination, growing habit, type of farming, time of sowing, variety, etc.

Sowing Of Seed – Seed Treatment 

Seed treatment: It is a process of application of chemicals or protectants (with fungicidal, insecticidal, bactericidal or nematocidal properties) to seeds that prevent the carriage of insect or pathogens in or on the seeds.

Objects of seed treatment: Some seeds need treatment with some specific objectives before sowing.

1.To control disease: There are some seed borne or soil borne diseases, seeds are treated with fungicides or organo mercurial compounds like Thirum, captain, carbendazim, agrosan, cereson, etc. E.g. to control paddy blast, seed is to be treated with agrosan @ 3 g per kg (3g/kg) of seed).

2.To have convenience in sowing: Difficulties are encountered in sowing certain crops due to special characteristics of the seed like fuzz of cotton seeds, coriander seeds, small seeds of chilli, ragi, bajara, etc. E.g.: coriander seed is to be splitted by rubbing it against hard surface. Seed of chilli, Sesamum, bajara are mixed with fine sand or soil.

3. To have quick germination: Germination of certain leguminous crops is delayed due to thick seed coat which restricts water absorption. Such seed coats are broken to some extent by mixing them with coarse gritty sand & trampling or pounding it lightly in a morter with a wooden pestle for breaking the thick seed coat. Sometimes seeds are soaked in water for a specified time. E.g.: cotton seed or paddy seed is soaked in water before actual sowing. Seed of Lucerne and Indigo is pounded with pestle
.
4. To increase nitrogen fixation in legumes: Legume seeds are inoculated with a particular Rhizobium culture. This is mixed with jaggery solution & applied to seed and dried in shade. It increases nodulation & thereby N fixation.

5. To protect the seed against insect pests: There are some insect pests like ants, white ants, in the soil which attack on seed and eat. Sometimes, seed may be picked up by birds after sowing. To avoid this, seed is treated with repellents like campor, kerosene or soil drenching with insecticides like BHC, heptachlor, etc. E.g.: the carbofuran treatment in Jowar.

6. To induce earliness (Vernalization treatment): This is an important for breeding programme by vernalization treatment. As a result of this, life span is reduced. In this, seed is soaked in water & incipient germination is induced in the form of awakening of the dormant embryo & commencing the changes favoring germination in the endosperm. Such seeds are kept in cold storage for a specified time in which germination power remains intact but the process of germination is temporarily halted. Thus, the plant spends part of its vegetative period or phrase in the form of sprouted seed and the seed so treated as a dormant plant. The period from sowing to flowering is thus greatly reduced & with such adjustment, a variety which is normally a long duration one, can be made to flower early.

7. To induce variation: Seed is treated to induce variation in its morphological & general structure by ‘X’ ray treatment. It changes the genetical make up & helps in selection of desired types.E.g. Sonora, a wheat variety, is the result of Sonora-64 treated with gamma rays.

8. To break dormancy: Some crops are having seed dormancy in fresh harvested produce. Dormancy is the state of rest period of a seed in which it does not germinate even if all the favorable conditions are available for germination. Due to dormancy of seed we cannot use the fresh harvested produce for sowing. It is desirable if the crop get rains at maturity. E.g.: groundnut varieties. This dormancy is broken by treating seed with chemicals. E.g. Thiourea 1% treatment to potato tubers.

9. Seed treatment for special purpose: In vegetatively propagated crops, planting material is treated with growth promoting hormones like colchicines, Gibberellic acid (GA), Indole acetic acid (IAA), Seradix, sometime cattle urine. These promotes sprouting & growth of plant. E.g.: onion bulbs or potato tubers are treated with Malic Hydrazine (MH) for avoiding sprouting and growth of sprouts and thereby reducing losses due to sprouting.

Seed treatment in important crops:

1) Sorghum: Thirum or 300 mesh sulphur: Seed is coated in seed dressing drum or earthen pot @ 3.4 g/kg seed against smut disease.
2) Bajara: Brine solution treatment is given @ 20% against eat got and to discard light & diseased seed.
3) Paddy: Seed is treated with brine solution @ 3% against blast of paddy and to discard unfilled seed.
4) Cotton: a) Cow dung slurry treatment: Seed is rubbed with cow dung slurry in 1:1 proportion of dung and soil for convenience in sowing or Seed is delinted by treating the seed with conc. H2SO4 for 2 min. for convenience in sowing. b) Seed is treated with organo mercurial compound like ceresin, agrosan @ 3 g or Thirum @ 5g against seed borne disease like anthracnose.
5) Coriander & Garlic: Seed is rubbed to split the seed for even sowing.
6) Small seeded crops like Sesamum, bajara, tobacco, etc: Seed is mixed with fine sand or soil for even sowing of seed in the field.
7) Potato: a) Seed is dipped in 1% Thiourea solution for breaking the seed dormancy.
b) Seed is dipped in streptomycin solution @ 200 g in 100 lit. Water for 1 hour against Ring rots disease.
8) Legume crops like Mung, Udid, Soybean, Etc.
a) Seed is treated with Thirum @ 3 g/kg seed against seed borne disease.
b) Seed is treated with Rhizobium culture @ 250g/10kg seed for ‘N’ fixation & better nodulation.
9) Sugarcane: a) Hot water treat (500C) or hot air treat. (540C) is given to sets for 2 hrs. Against grassy shoot & other diseases.
b) Sets are treated with OMC 6% @ 500g in 100 lit. Water by dipping for 5 min. against smut & increase germination.
Or Bavistin @ 200g in 100 lit. For 5 min.
10) Wheat & Oilseed crops: Seed is coated with Thirum or Bavistin @ 5 g/kg seed against seed borne diseases.

System Approach- Types of Cropping

1. Mixed cropping: It is growing of two or more crops simultaneously intermingled without any row pattern. It is a common practice that the seeds of different crops are mixed in certain proportion and are sown. E.g.: Kharif Groundnut + Jowar, Cotton + Mesta (Ambadi), Jowar + Mustard or Wheat + Mustard.

2. Sequence cropping: It is growing of two or more crops in sequence on the same piece of land in a farming year. It Amy is doubles (2 crops), triple (3 crops) or quadruple (4 crops). E.g.: Cotton – Groundnut, Jowar – Wheat, Mung – Rabi Jowar, and Hy. Jowar – Gram. Etc.

3. Relay Cropping: It refers to planting of succeeding crop before harvesting the preceding crop like a relay race where a crop hands over the land to next crop in quick succession. Ratoon cropping or rattooning refers to revising a crop with regrowth coming out of roots or stalks after harvest of the crop. E.g.: Sugarcane or Jowar rattooning.

4. Efficient cropping systems: for a particular farm depend on farm resources, farm enterprises & farm technology. The farm resources include land, labour, water, capita; and infrastructure. When land is limited, intensive cropping is adopted to fully utilize available waer & labour. When sufficient and cheap labour is available, vegetable crops are also included in the cropping system as they require more labour. Capital intensive crops like sugarcane, banana, turmeric, ginger, etc. find a place in the cropping system when capital is not a constraint. In low RF (less than 750 mm/annum) monocropping is followed & when RF is more than 750 mm intercropping is practiced. With sufficient irrigation water, triple, quadruple cropping is adopted when other climatic factors are not limiting. When the farm enterprise includes dairy the cropping system should contain fodder crops as a component.

Weeds and Their Control

There are 3 serious pests of the crop plants which causes loss of yield, i.e.

1. Insect-pests,
2. Diseases,
3. Weeds.
The estimated losses in crop yields range from 5% in clean cultivated fields over 70% in neglected fields depending upon the degree of weed infestation. They compete with crop plants for nutrients, water, light and space. The loss of ‘N’ through weed is as high as 150 kg/ha.

WEED:  Any plant not sown in the field by farmer is out of place, called weed.

The term, ‘weed’ used by Jethro Tull for the first time, suggested an useless and harmful plant that persistently grows where it is quite unwanted.

According to Robinson: Weeds are that species of plants which grow unwanted or are not useful, often prolific, persistent, interfere with agricultural operations, increase labour cost and reduce the crop yields.

Weed is a plant growing where it is not wanted, unwanted plant, out of place, extremely noxious, useless, and poisonous.
Characteristics of weeds: Weeds are like any other crops plants in size, form, morphological & physiological characters but possess the following characteristics, on account of which they are considered as enemy of crops by the farmer.
1. The weed seeds germinate early and the seedlings grow faster. They being hardy, compete for light, moisture and nutrients.
2. They flower earlier, run to seed in profusion and mature ahead of the crop. They are difficult to control and it may be even impossible to eradicate some weeds completely.
3. They are non-useful, unwanted & undesirable.
4. They are harmful to crops, cattle and human beings.
5. They can thrive even under adverse conditions of soil, climate, etc.
6. They are prolific and have a very high reproduction capacity. E.g.: A plant of satyanashi (Argemone mexicana) produces over 5000 seeds while a plant of striga produces over half a million seeds.
7. Viability of weed seeds remains intact, even if they are buried deep in the soil. In some cases, the seeds may remain viable even after passing through the digestive tract of the animals.
8. The seeds may have special structures like wings, spines, hooks, sticky hair, etc. on account of which they can be easily disseminated over long distances.
9. Many weeds like Cynodon dactyl on are vegetatively propagated  and spread rapidly all over the field even under adverse conditions.

Manures and Fertilizers

Plant requires food/nutrients/elements for its growth and development which are absorbed through soil. The nutrient supplying sources are manures and fertilizers. Application of manures and fertilizers to the soil is one of the important factors which help in increasing the crop yield and to maintain the soil fertility. N, P and K are the 3 major elements required for the crop growth.

Manure: It is a well decomposed refuse from the stable and barn yards including both animal excreta and straw or other litter. Or

The term manure implies to the any material with the exception of water which when added to the soil makes it productive and promotes plant growth.
Fertilizers: These are industrially manufactured chemicals containing plant nutrients. Or
It is an artificial product containing the plant nutrients which when added to soil makes it productive and promotes plant growth.

Classification Of Manures And Fertilizers

Manures and fertilizers may be: 
1. Natural or
2. Artificial.

1. Natural Or Organic Manures: Natural manures are those which are bulky in nature and supply nutrients in small quantities and organic matter in large quantities.
These are two types:
1. Bulky organic and
2. Concentrated org. manures.
1. Bulky OM: These are those which contain small percentage of nutrients and are applied in large quantities. E.g.: Farm Yard Manure (FYM), compost, Night soil, sludge and sewage, sheep and goat manure (Folding), Poultry dropping, Green manures, etc.
2. Concentrated OM: These are those which are organic in nature and contain higher percentage major plant nutrients like N, P and K as compared to bulky OM. These are made from  materials of animal and plant origin. The examples of manures of plant origin are oilseed cake which may be edible or non-edible. Edible oil seed cakes are Groundnut cake, Linseed cake, Sesamum cake, Safflower cake (decort). Non-edible oil seed cakes are castor cake, Neem cake, Safflower cake (undercoat). The examples of manures of animal origin are Bone meal, Fish meal, Meat meal and blood meal.
A. Bulky Organic Manures:
a) Farm Yard Manure (FYM): FYM  is a mixture of cattle dung, urine, litter or bedding material, portion of fodder not consumed by cattle and other domestic wastes like ashes, etc. collected and dumped into a pit or a heap in the corner of the back yard. Or
FYM refers to the decomposed mixture of dung and urine of farm animals along with the litter (bedding material) and left over material from roughages or fodder fed the cattle.
Because of the varied nature of the material, the composition of the manure itself varies widely but on an average well rotted FYM contains 0.5% N, 0.2%, P2O5 and 0.5% K2O. It also influences by various factors.

Soil Fertility And Productivity

Soil fertility: is the capacity/ability of the soil to supply the plant nutrients required by the crop plants in available and balanced forms. Or

It is the capacity of soil to produce crops of economic value to man and maintain the health of the soil for future use. Or

The soil is said to be fertile when it contains all the required nutrients in the right proportion for luxuriant plant growth.
Plants like animals and human beings require food for growth and development. This food is composed of certain chemical elements often referred to as plant nutrients or plant food elements. These nutrients are obtained from soil through roots.
Plants need 16 elements for their growth and completion of life cycle. In addition to these, 4 more elements viz. sodium, vanadium, cobalt and silicon are absorbed by some plants for special purposes.

Classification and source of nutrients:
Class                    Nutrient                                      Source
Basic                    C, H, O                                     Air and water
Macro                  N, P, K, Ca, Mg, S                     Soil
Micro                   Fe, Mn, Zn, Cu, B, Mo & CI     Soil

Four more recognized nutrients are NA, Co, VA & SI.
Basic nutrients (C, H, and O) constitute 96% of total dry matter of plants. Macro (Major) nutrients (primary-N, P, K, and secondary-Ca, Mg, S) are required in large quantities while Micro nutrients (Trace elements-Fe, Zn, Cu, B, Mo, Cl, and Mn) are required in small quantities. These trace elements are very efficient and minute quantities produce optimum effect. On the other hand, even a slight deficiency or excess is harmful to plants.

Function of the plant:

1. Elements that provide basic structure to the plant – C, H, O.
2. Elements useful in energy storage, transfer and bonding – N, S & P. these are accessory structural elements which are more active and vital for living tissues.
3. Elements necessary for change balance – K, Ca & Mg, act as regulators and carrier.
4. Elements involved in enzyme activation and electron transports. Fe, Mg, Cu, Zn, B, Mo & Cl are catalysers and activators.

Criteria of Essentlailty: Armon and Stout (1939) proposed criteria of essentiality which was refined by Arnon (1954) as:

1. The plant must be unable to grow normally or complete its life cycle in the absence of the element.
2. The element is specific and cannot be replaced by another.
3. The element plays a direct role in metabolism and
4. The deficiency symptoms of the element can be corrected or prevented by application of that element only.

In general, an element is considered as essential, when plants can’t complete vegetative or reproductive stage of life cycle due to its deficiency when this deficiency can be corrected or prevented only by supplying this element and when the element is directly involved in the metabolism of the plant.

Nicholas (1961) proposed the term functional nutrient for any mineral nutrient that functions in plant metabolism whether or not its action is specific. E.g.: Na, Co, Va and Si.

Soil fertility denotes the capacity of the soil to produce crops of economic value and maintain the health of the soil for future use.                                                                          Or

It is the capacity of soil to supply essential nutrients to normal plants in adequate amounts and in a balanced proportion.
                                                                 Or                                   
It is better to cultivate small piece of fertile land than large nutrient needs of the crop. Or The soil is said to be fertile when it contains all sixteen of the required nutrients in the right proportion for luxuriant plant growth.

Dry Land Farming

Indian agriculture is traditionally a system of Rainfed agriculture. Out of 143 million hectares of net cropped area, about 72% is Rainfed production about 45% of food grains and 75 - 80% of pulses and oil - seeds and a number of important industrial crops. Considering the present rate of development of irrigation facilities and also water potentiality of the country, express estimate that at any point of time 50% of cropped area in India will remain under Rainfed farming system.
Such vast areas as of now consume hardly 25% of total fertilizer consumption of the country. Due to poor level of management, crop productivity is also very low resulting in socio - economic backwardness of the people.

Dry lands: Areas which receive an annual rainfall of 750 mm or less and there is no irrigation facility for raising crops.

Dry land Agriculture: Scientific management of soil and crops under dry lands with out irrigation is called dry land agriculture.

Dry land crops: It refers to all such crops which are drought resistant and can complete their life cycle without irrigation in areas receives an annual rainfall less than 750 mm.

Drought: It is an condition of insufficient moisture supply to the plants under which they fail to develop and mature properly. If may be caused by soil, atmosphere or both.

Dry farming : In the country with low and precarious rainfall two types agricultures are usually met, one crop production on aerable farming land other animal husbandry, including management of grazing areas.
Definiuons:
The different definitions of dry farming given by various express are described below.
1. Dry farming is an improved system of cultivation in which maximum amount of moisture is conserved in low and untimely rainfall for the production of optimum Quantities of crop on economic and sustames basis.
2. Dry farming in short, is a programme of soil and water management designed to conserve the maximum quantity of water on a particular piece of land.
By Anand
3. Dry farming is the profitable production of useful crops without irrigation on land that receive annually a rainfall of 500 mm or less.
By Anonymous
4. In a more specific way dry farming may be defined as an efficient system of soil and crop management in the regions of low land and uneven distributed rainfall.
By Anonymous
Dry land Vs Rainfed farming.

Zero tillage

Zero tillage refers to tillage systems in which soil disturbances is reduced to sowing generals and traffic only and where weed country must be achieved by a genital nears. It can be considered as a men extreme form of minimum tillage 2010 tillage maintains more corposiders than any other tillage  soil surface and it protect the grout against wind and water evasion.

Primary tillage it commonly avoided and secondary tillage restricted to Seedbed Corporation in the row zone only. It is also known no till and is resorted to who soil are subjected to wind & water erosion Zero tilled soil are homogenous in structure with high population earthworms. Organic matter content increases due to less mineralization.
Control of weeds is the main problem in zero tillage. Incomplete weed control is the main ebstoute to the further adoption. Zero tillage a widely used in humid areas.
Erosion losses and polities are minimized by zero tillage. Zero tillage will be useful concept where than.
i. Soils are subject to wind and water erosion eg. in sloppy bare compacted soils with high gilt fine sand.
ii. Timing of tillage operation 15 foods difficult.
iii. Conventional tillage to not yield more.
iv. Requirement of energy and labour too high.
v. In medium to fine textured soils use of heavy implements can result in formation of hard puncturing wet conditions. Much more research information is needed on cartilage.

Types of Sprayers

A) Knapsac Sprayers:

Loaded on the back of worker during operations.  Tanks may be plastic or metal. Common Knapsack sprayers are

i) Hydraulic

ii) Manual pneumatic and

iii) Motorized pneumatic.

i) Hydraulic Knapsac Sprayers:

Manually operated, tank capacity is 15 liters, mechanical or hydraulic agitation, worked with a hand lever to maintain constant pressure, particularly used for spot treatment small holding farmer and hand treatment. Equipped with a boom. It is good for blanket application.

Drawbacks:

These sprayers are mounted on back of man. One hand to lever and other to lance with a lance, one sprays 0.4 ha/day and with a boom 0.8 ha/day. It is high volume spray but low volume nozzles can be fitted. Spray potential is 12 kg/cm2. It sprayed at 3 to 4 kg cm2 to prevent spray drift.

ii) Pneumatic or compressed system Knapsac:

Do not require pumping during operation / spraying. The tank is pressurized after filling the liquid to 2/3rd capacity with a built in hand pump. Undesirable for weedicide spray pressure lower after some time spraying resulting into uneven spray. Tank cleaning is difficult. Used limited to spray on weeds in paddy and jute.

iii) Motorised Pneumatic sprayers:

As a low volume sprayer suitable for spraying concentrated spray liquid. A blast of air flows through spraying jet of delivery hose and nozzle tube and ejects spray liquid in this blast. Air blast atomizes spray liquid in to fine droplets. Air acts as carrier. Faster the air is pressured, more the atomization. These sprayers are also used as blowers. Mist blower cause considerable loss of herbicide by winds. The main advantages of Knapsac blower are:
1. Low volume spray. Loss of time in refilling tanks.
2. Portable working.
3. Fast spraying. Suited to post emergence translocated type. Herbicides as low volume
Spraying is not so uniform with Knapsac blowers.
Liquid – 60 liters / ha swath 7 to 8 m.

B. Foot Sprayer / Pedal Pump Sprayers:

Popularly applied for pesticide application operated with foot. It has provision of 1 – 2 long delivery hoses. Fitted with either lance or 2-6 nozzle booms. Its potential spray pressure is 17 to 21 kg / cm2 output with lance is 1 ha/day. It can spray high volume spray and covers more area.

C. Traction Pneumatic Sprayer:

Indian Institute of Sugarcane Research, Luck now has developed bullock drawn sprayer with size nozzle boom that of powered from the wheels of the frame. It is efficient, easy to operate and simple in its construction. It uses two pneumatic pumps and develops maximum pressure of 2-8 cm2 which his suited to minimize spray drift. Area covered 2-3 ha/day equipment.

D. Tractor mounted sprayers:

With spray pressure of 1.4 to 2.8 kg cm2 and fitted with multi nozzle boom are very useful in herbicide application for large holding of farmers. Tractor mounted sprayer fitted with booms are used to spray road side vegetation. Tractor run sprayers have.

1. High uniformity of sprayers.

2. High working efficiency.

3. Full utilization of tractor during idle time.

E. Acrial sprayers:

Herbicide application from air is limited to treat aquatic weeds like water hyacnth, paddy fields, large sugarcane plantation. Presence of obstacles like trees and diversified farming in India are bottle necks in its use.

 

Problems, Planning and Objections in Weed Research

In planning, weed control research the various weed problems and their magnitude needs to be denotified. Problem should be handled as per priority basis. The worst weeds of cereals like Lavala should be controlled immediately. The scope and study of weed control should be clearly defined to avoid confusions and ambuiquity lateion
.
Objectives of Conducting a Weeds Control Trial:

1. To determine the herbicidal activity of a new unestablished compound on a particular weed or crop specied.

2. To determine the optimum rate, time and method of application of a herbicide a specific weed species flora in a crop.

3. To study the harmful or beneficial impacts of herbicide on a weed control practice on the yield and quality of particular crop in a mix or rotation.

4. To study the persistence activity and residual problem of any of a herbicide.

5. To determine the effect of a herbicide in different formulations.

6. To improve the activity of a herbicide in combination with adjuvants and other herbicides.

7. To study the changes on weed flora due to continuous use of a herbicide or weed control
practice.
8. To determine the suitability of the herbicide for a weed control in a particular crop situation.

9. To determine the duration of weed competition and the time of weeding of weed control in crop.
The successes of achieving the set objectives depend upon a number of factors:

1) Environmental factors.

2) Agronomic factor.

3) Application of treatments.

4) Plant morphology and growth.

5) Composition of tolerant stress to a susceptible weed.

6) Composition of tolerant stress to a susceptible weed.

7) Method of evaluation of plant response.

8)  Data collection etc.

Types of Field Experiments:

Most of weed control experiments are testing and evaluation of herbicides which are conducted in the form of multi stage trials.

1. Screening Trials:

Primary screening of herbicides and second screening of herbicides.

2. Advanced Trials:

Once secondary screening is completed, the most promising herbicides or treatment are included in advanced trails with objective like yield, herbicide residue weed shifts, cost benefits, formulation, spray volume, regional studies, cultivars etc.

i) Yield Trials to Determine:

(a) Direct effect of herbicides.

(b) Indirect effect of herbicides. These are carried out for economic evaluation of herbicides

ii) Residue Trials:

These trails are conducted in field or green houses which are useful to determine the duration of herbicides activity and effect of the following crops in rotation and weed species infesting latter.

iii) Weed Shift:

These studies can include investigation of new or established herbicide or even a recommended practices.

iv) Herbicide Formulations:

Herbicides are available in different formulations and they can be compared at equivalent rates on the basis of active ingredients.

v) Spray Volume:

Optimum spray volume varies with the herbicide, species of weed infestation. Generally the foliage applied contract herbicides require greater volumes than the translocated herbicides.

vi) Regional Trials:

Regional trials are followed with the objective of screening up the performances of a herbicide or a treatment under diverse condition (agro climatic), soil type and cropping practices.

vii) Cultivars:

Crop cultivars differ in their tolerance to herbicides.

viii) Demonstration Trial:

To display the performance of selected herbicide.

ix) Special Trial:

Weed competition on study the competitiveness of weed spp. These are essential for recommendations of new herbicides.

x) Application Techniques:

Weed research is also conducted to standardize herbicides application technique.

a. Optimum spray delivery.

b. Proper sprays nozzles.

c. Optimum sprays volumes.

d. Proper herbicides application.

xi) Other Studies:

Special studies are required to determine the interaction of herbicides of weed control practices with soil fertility and nutrient levels, plant population, row spacing, soil moisture and condition crop varieties, insect and disease of occurrence.

Plant Interactions and Its Types

Plant Interactions:

The interaction between different components crops: In intensive cropping, when crops are grown in association (intercropping) or sequence (sequential cropping) interaction between different component crop species occurs, which is essentially a response of one species to the environment as modified by the presence of another species (commonly referred to as interference or interaction).

Interference can be divided into two

a) Removal Reactions of One Plant on its Environment and

b) Additive Reactions when Something is Added.

When some factor is removed from the environment, the resulting response of neighboring species can be negative, positive or neutral. Competition among plants is one example for removal interactions. Some such additive interactions are allelopathic and symbiosis. When crops are grown in sequence, residual effect of the preceding crop influences the succeeding crop this may be harmful or helpful. The toxic chemicals (allelopathic chemicals) left in the soil by the roots of sunflower crop inhabit germination of the succeeding crop. The stubbles of sorghum with high C: N ration causes immobility of nitrogen, thus causing nitrogen deficiency in early stages of the succeeding crops. The roots of legume crops and their residues add nitrogen to soil.

The interaction may be:

1. Competitive

2. Non-competitive and

3. Complementary.

1. Competitive Interaction: - One species may have greater ability to use the limiting factor and will gain at the expense of the other and this is called as competitive interaction or interference. Or when one or more growth factors are limiting, the species that is better equipped to use the limiting factors(s) will gain at the expense of the other and this is called as competitive interaction. In mixed crop communities, if the associated species are to share their growth from a limited pool of recourses such as light water or nutrients, then it is non-competitive interaction or interference.

2. Non-competitive:- If the crops are grown in association and the growth of either of the concerned species is not affected, such type of interaction is called non-competitive interaction or interference. Or if these resources (growth factors) are present in adequate quantities as a result of which the growth of either of the concerned species is not affected, then it is non-competitive interaction or interference.

3. Complementary: - If one species is able to help the other it is known as complementary interaction. Or if the component species are able to exploit to supply of growth factors in different ways (temporal or spatial) or if one species is able to help the other in supply of factor (like legumes supplying part of N fixed by symbiosis to non-legumes), it is complementary interaction or interference. This also referred to as Annidations.

Interaction in Inter-Cropping: Competition between the associated crops in mixed crop communities has been discussed by Donald (1963), Trenbath (1976) and Willey (1979).

Faulty Agriculture Practice

Various farming operation improperly carried out lead to adverse effects such as loss of topsoil though water and wing erosion. Due to improper management of irrigation water, stabilization and alkalization of soil takes place. An area of 6 m ha of lands is affected by water logging and another 7 m ha is stalinized due to faulty irrigation practices. Water logging due to inadequate drainage, depletion of ground water due to excessive extraction, pollution of surface and ground water with pesticide and fertilizer residues, loss of biological diversity and erosion of germ plasma resources though removal of natural fauna and flora are the adverse effects of faulty practices.

Alternative land use system: Crop production in dry land is gamble with monsoon in most of water shed situation substantial. Percentage of land is found to be degraded thus resulting in poor productivity. Of late, due to population explosion, more and more marginal and sub marginal lands are being brought under cultivation. Apart from being uneconomical in the long run, cultivation of such land can lead to serious imbalance of ecosystem. Therefore, for such lands an efficient land use system would be more appropriate. In addition to this day by day demand for food, fodder, and fuel increasing can fulfill such demands. According to national remote sensing agency, cultivable wastelands in India occupy 38.8 million hectare. Income from dry land could be increased though alternate land use system is applicable to all classes of land of land to generate assured income with minimum risk through can be practiced and beyond that arable farming is considered as a risky proposition. Suitable farming system as per land capability class is proposed as follows:

1. Food class- II and III- Alley cropping, Agri- horticulture, inter- cropping with nitrogen fixing trees.
2. Fodder- class IV and V- Horti- pasture, silvi- pasture, Ley farming, pasture management.

Ley Farming:

ley farming or ley rotation is one of the alternate land use systems aimed to increase the food and fodder production and to enhance soil fertility concurrently, in this system, grasses and or legumes are grown in rotation with arable crops. The objective of the system is tonnage production of fodder and enhancing soil fertility. Ley farming is more productive as well as sustainable against climate economic risk than than cropping alone. Considerable amount of organic matter is added through roots and above ground biomass and legumes. There is reduction in weds, pest and disease since ley provides a break in the crop sequence. Yield of grain and Stover of sorghum increased when it is after four years of continuous cultivation of stylosanthes hamata.

Alley Cropping:

Food crops are grown in alley formed by hedgerows of trees or shrubs in arable lands. it is also known as hedgerow intercropping. Among them, forage alley cropping is recommended as an alternate land use system for semi- arid region with main benefit of green fodder production during dry season.

Alley cropping is an agro- forestry system in which fast growing N- fixing shrubs are planted as hedgerows. Food crops are grown in alleys formed by hedge of trees and shrubs. This system is most suitable for marginal and sub- marginal lands.
The essential feature of this is that hedge rows are cut back at about one meter height at panting and kept pruned during cropping to prevent shading and to reduce competition with field crops. In semiarid region, alley cropping provide fodder during dry period since mulching the crop with hedge row pruning usually do not contribute to increase crop production.

Advantages of this System are as Follows:

1. Provision of green fodder during lean period of the year.
2. Higher biomass production per unit area then aerable year.
3. Efficient use of off- season rainfall in the absence of the crop.
4. Additional employment during off- season.
5. it serves as a barrier to surface runoff leding to soil and water.
6. Conservation based on objectives following three types of alley.
7. It improves soil fertility and is more remunerative under rain fed condition.
8. System is recognized:
a) Forage alley cropping.
b) Forage cum mulch system
c) Forage cum pole system.

a. Forage Alley Cropping:

In this system both yield of crop and forage assume importance. Leucaena (Subabul), sesbania are recommended for hedgerow. Pigeon pea or casters are suitable for growing in the allies. Crop yields decreases with increase in the row width.

b. Forage Cum Mulch System:

 In this system hedgerows are used for both forage and mulch lapping are used for mulching during the crop season.

c. Forage Cum Pole System:

Leucaena alleys are established at 5 meter interval along the contours. Hedge rows are established by direst seeding and topped every two months at 1.0m height during crop season and every four months during the off season. A Leucaena plant at every 2 meter is allowed too grow in to a pole. Crop yields are usually reduced due to competition from hedgerow.

Irrigation

Definition: irrigation is artificial application of water to soil for the purpose to access the crop production. It is supplied supplementary to water available from rainfall & ground water.

Types of irrigation – (classification)

1. Flood
2. Surface
3. Sub surface
4. Sprinkle
5. Drip irrigation.

Surface irrigation:

Water is applied directly to the soil from channel located at upper ridge of the field proper land preparation adequate control of water is necessary for uniform distribution of water border. The entire field is divided into strips separated by low ridge of the strip to lower in form of sheet guided by the low ridges. Border should have uniform gentle slope in direction of irrigation. Each strip is independently by turning stream of water at upper ridge. Suitability-suitable for close growing crops some row crop & orchards under favorable soil & topographic condition. Not recommended for extremely low or extremely high infiltration rate soils.

Advantage:

1. Easy construct & operate
2. Person can irrigation more compares to check basin.
3. If properly designed use uniform distribution & high water use efficiency.
4. Large streams can be effectively used.
5. If can provide excellent drainage (surface) if have proper outlet facility at the lower end.

Disadvantages:

1. Required precise land leveling
2. Required large irrigation streams.

Check basin:

It is used in extreme condition of soil. It is well known method generally used for heavy soils with low infiltration rate or high permeable soil like deep sand. Used for orchards grain & folder production.

Disadvantages:

1. Labor requirement for land preparation is high.
2. Operation cost is more.
3. The ridges cause hindrances to implements by field operations.

Furrow method:

Furrow is preferably used for row crops like maize, sugarcane, potato, groundnut & other vegetable crops. Water is applied in small furrows betureoil the row crops. Water infiltrated into soil & spread within the root zone. Large as well as small sized stream can be effectively used for irrigation. It also acids for safe disposal of excess water i.e. facilitates drainage. Only 1/5 to ½ of land surface is in contact with water (wet). There by reducing the evaporation losses. Method is specially situated to crops like maize which are sensitive to water in contact with their strength. The cost of land preparation is reduced & there is no wastage of land under field channels. In clay or deep clay soils shadow furrow are made along with guiding ridge to take care of soil cracking behavior such furrow are called corrugated furrow.

Subsurface irrigation:

Water is applied below the ground surface by maintaining artificial water table at some depth depends upon the soil characteristic & root zone of crop. Water moves through capillaries within soil to meet plant requirement deep trenches & underground piper are the two ways for sub-surface irrigation.

Adaptability: Soils having low W.H.C. soil having very high-high infiltration rate. Soils surface method is not possible where sprinkle method of irrigation proves to be expensive.

Advantage:

1)  Evaporative losses are minimum.

Disadvantage:

1)  Salty water can not be used.

Definitions & Terms used in Irrigation 

• Hydroscopic Water: That water is adsorbed from an atmosphere of water vapour because of attractive forces in the surface of particles.
• Hysteresis: It is the log of in one of the two associated process or phenomena during reversion.
• Indicator Plant: It is the plant, which reflects specific growing condition by its presence or character of growth.
• Infiltration Rate: It is the maximum rate at which a soil under given condition and at given time can absorb water when there is no divergent flow at borders
• Intake Rate or Infiltration Velocity: It is the rate of water entry into the soil expressed as a depth of water per unit area applicable or divergence of flow in the soil.
• Irrigation Requirement: It refers to the quantity of water, exclusive of precipitation, required for crop production. This amounts to net irrigation requirement plus other economically avoidable losses. It is usually expressed in depth for given time.
• Leaching: It is removal of soluble material by the passage of water through the soil.
• Leaching Requirement: It is the fraction of water entering the soil that must pass through the root zone in order to prevent soil salinity from exceeding a specific value.
• Oasis effect: It is the exchange of heat whereby air over crop is cooled to supply heat for evaporation.
• Percolation: It is the down word movement of water through the soil.
• Permanent Wilting Point (PWP): Permanent wilting point is the moisture content in percentage of soil at which nearly all plants wilt and do not recover in a humid dark chamber unless water is added from an outside source. This is lower limit of available moisture range for plant growth ceases completely. The force with which moisture is held by dry soil this point corresponds to 15 atmospheres.
• Permeability: Permeability is the property of a porous medium to transmit fluids It is a broad term and can be further specified as hydraulic conductivity and intrinsic permeability.
• PF: It is the logarithm of height in cm of column of water which represents the total stress with which water is held by soil.
• PH: It is the negative logarithm of hydrogen ion concentration.
• Potential Evaporation: It represents evaporation from a large body of free water surface. It is assumed that, there is no effect of addictive energy .It is primarily a function of evaporative demand of climate.
• Potential Evapo-transpiration: It is the amount of water evaporated in a unit time from short uniform green crop growing actively and covering an extended surface and never short of water. Penman prefers the term potential transpiration.
• Seepage: It is the water escaped through the soil under gravitational forces.
• Agricultural Drainage: It is removal of excess water known as free or ravitational water from the surface or below the surface of farm land to create favorable condition for proper growth and development of the plot.
• Surface Drainage: when the excess water saturates the pores spaces removal of water of water by downward flow through the soil is called subsurface drainage.