The following points highlight the eight major principles of agronomy. The principles are: 1. Sustainable Agriculture 2. Cropping System 3. Cropping Scheme 4. Crop Rotation 5. The Integrated Intensive Farming System 6. Agrometerology 7. Soils and Tillage 8. Dryland Agriculture.
Sustainable agriculture is the act of farming using principles of ecology, the study of relationship between organisms and their environment. Sustainable agriculture can be defined in many ways, but ultimately it seeks to sustain farmers, resources and communities by promoting farming practices and methods that are profitable environmentally sound and good for communities.
i. Satisfy human food and fibre needs.
ii. Enhance environmental quality and the natural resource based upon which the agriculture economy depends.
iii. Enhance the quality of life for farmers and society as a whole.
iv. Sustain the economic viability of farm operation.
Some of the most common sustainable agriculture techniques are employed by farmers today to achieve the key goals of weed control, pest control, disease control, erosion control and high soil quality.
i. Crop Rotation
ii. Cover Crops
iii. Soil Enrichment
iv. Natural Pest Predators
v. Biointensive Integrated Pest Management
System means a set of components that are interrelated and interaction among themselves. The objective of any cropping system is efficient utilisation of all resources viz., land, water and solar radiation. Maintaining stability in production and obtaining higher net returns.
The objective of cropping system are as follows:
i. By increasing the area of cultivation.
ii. By increasing the productivity.
iii. To increase the production per unit time.
iv. To increase the production per unit space.
Modern scientific cropping system has three pillars:
(i) Geometry of Planting:
For cropping system geometry of planting includes:
a. Shape of planting pattern on the land surface.
b. Space of the area available for the individual plants.
(ii) Genotype means genetic make-up of seed.
(iii) Management Practice:
For the cropping systems management includes:
i. Type and arrangement of crops in time
ii. Choice of variety
iii. Method of stand establishment
iv. Pest management and harvest
‘System of cropping is the way in which different crops are grown sometimes a number of crops are grown together or they are grown separately at short intervals in the same field.’
The cropping system may be divided into two main groups:
Mixed cropping is the process of growing two or more crops together in the same piece of land based on their mixed cropping may be classified into following groups, method of sowing.
(a) Mixed Crops – In this groups the seeds of different crops are mixed together and then sown either in lines of by broadcasted.
(b) Companion Crops – Under this method the seeds of different crops are not mixed together but different crops are sown in different row, e.g., between two rows of mustard five to eight rows of wheat.
(c) Augmenting Crops – When sub-crops are sown to supplement the yield of the main crop, the sub-crops are called as augmenting crops.
The most important points given below for the selection of crops:
a. Tall growing habit crops should be sown with short growing habit crops, e.g., maize with urd.
b. Legumes should be sown with non-legumes, e.g., arhar with jowar.
c. Tap rooted crops should be sown with shallow rooted crops.
d. Erect growing crops should be sown with bushy crops.
e. Mixture should consists short and long duration crops.
a. To get handy installments of cash returns especially in irrigated crops.
b. To achieve better distribution of labour throughout the year.
c. To utilise available space and nutrients to maximum extent possible.
d. To safeguard against hazards of weather, diseases and pest.
e. To secure daily requirements like pulses, oilseeds, fibres, etc.
f. To get balanced cattle feed.
When the area is limited and the number of crops to be grown is increases within a definite period of time, this cropping method is termed as intensive cropping.
The following methods have been developed to make intensive cropping a success:
(a) Multiple Cropping:
Multiple cropping may be defined as a cropping system in which two or more crops are grown in succession within year.
Multiple cropping made successful by adopting the following cropping systems:
(I) Relay Cropping:
Its concept has been derived from relay race in which four runners run in the field having flag in their hand. The first runner passes on its flag to the succeeding partner and 2nd to 3rd and 3rd to 4th runner. Relay cropping can be defined as growing two or more crops simultaneously during the part of the life cycle of each. Succeeding crops planted before harvesting the preceding crop. Generally 2nd crop is planted after the first crop has reached its reproductive stage of growth, but before it is ready for harvest, e.g., potato is planted before the harvesting of maize,
i.e., Moong → Maize → Potato → Wheat.
(II) Overlapping System of Cropping:
In this system, the crop is harvested in phases and the vacated area is sown by next crop viz., in case of forage Sorghum, part of the crop is harvested for feeding to the cattle and vacated area is sown with berseem or lucerne.
This is a process of growing two or more crops simultaneously on the same piece of land with a definite row arrangement or in a fixed ratio is called Intercropping, e.g.,
Wheat + Mustard =9:1
Setaria + Red gram =5:1
The main object of this type of cropping is to utilise the space left between two rows of main crop and to produce more grain per unit area.
The principles of intercropping are as follows:
i. The crop grown in association should have complementary effects rather competitive effects.
ii. The component crops should have similar agronomic practices.
iii. Erect growing crops should be intercropped with cover crops like pulses, so that, the soil erosion and weed population could be checked.
iv. The component crops should have different root depths, so that, they do not complete for nutrients, water and root respiration among them.
v. Component crops of similar pest and disease pathogens and parasite infestations should not be chosen.
vi. The planting method and management should be simple, less time taking, less combustive, economical and profitable so that, it may have wider adaptability.
Intercropping may be divided into the following four groups:
(i) Parallel Cropping:
Under this cropping two crops are selected which have different growth habits and have a zero competition between each other and both of them express their full yield potential. e.g., black gram, green gram and maize.
(ii) Companion Cropping:
In companion cropping, the yield of one crops is not affected by the other. In other words, the yield of both the crops is equal to their pure crop. e.g., mustard, potato, onion and sugarcane.
(iii) Multistoried Cropping:
Cultivation of two or more than two crops of different heights simultaneously on a certain piece of land in any certain period. e.g., sugarcane, mustard, onion and potato.
(iv) Synergetic Cropping:
The yield of both crops, grown together are found to be higher than the yield of their pure crops on unit area basis. e.g., sugarcane and potato.
i. The main objective of intercropping is to get higher productivity per unit area in addition to stability in production.
ii. Intercropping utilises resources efficiently.
The advantages of intercropping are as follows:
i. Total bio-mass production (unit area) period of time is increased because of fullest use of land as the inter row space will be utilised which otherwise would have been used for weed growth.
ii. The fodder value in terms of quantity and quality become higher when a non-legume is intercropped with legume viz. Napier + Cowpea.
iii. It provides crops yield in installments which reduces the marketing risks.
iv. It offers best employment and utilisation of labour, machine and power throughout year.
v. A cereal-legume mixture is beneficial because of an efficient fixation of atmospheric nitrogen into the soil.
The cropping scheme is a plan to which crops are grown on individual plots of a farm during a given period of time with the object of obtaining maximum return from each crop without loss of soil fertility.
The cropping scheme is related to the most profitable use of resources, land, labour, capital and management so that maximum net income may be obtained from the farm as a whole with proper restoration from the farm as a whole with proper restoration of soil fertility.
These principles are as follows:
i. Area under building and layout.
ii. Number of plots.
iii. Selection of crops depends upon the situation of farm.
iv. Facilities available on the farm.
v. Area under individual plots.
vi. Area allotted to crops for calculation of cropping intensity and rotational intensity.
(i) Cropping Intensity (CI):
Cropping intensity is the ratio of total cropped area to net cultivated area which is multiplied by 100 and represented in percentage.
(ii) Rotational Intensity (RI):
This is calculated by counting the number of crops grown in a rotation and is multiplied by 100 and then divided by the duration of the rotation.
Principle # 4. Crop Rotation:
It refers to recurrent succession of crops on the same piece of land either in a year or over a longer period of time. It is a process of growing different crops in succession on a piece of land in a specific period of time, with an objective to get maximum profit from least investment without impairing the soil fertility.
The principles of crop rotation are as follows:
i. It should be adapted to the existing soil, climatic and economic factors.
ii. The sequence of cropping adapted for any specific area should be based on proper land utilisation. It should be so arranged in relation to the fields on the farm that the yields can be maintained and soil losses through erosion reduced to the minimum.
iii. The rotation should contain a sufficient acreage of soil improving crops to maintain and also build up the content of the soil.
iv. In areas where legumes can be successfully grown, the rotation should provide for a sufficient acreage of legumes to maintain the nitrogen supply of the soil.
v. The rotation should provide roughage and pasturage for the livestock, kept on farm.
vi. It should be so arranged as to help in the control of weeds, plant disease and insect-pests.
vii. It should be provided for the acreage of the most profitable cash crops adapted to the area.
viii. The rotation should be arranged as to make for economy in production. More exhaustive crops should be followed by less exhaustive crops, e.g., potato, sugarcane, maize, etc. need more inputs than oilseeds and pulses.
ix. The crops with tap roots should be followed by those which have fibrous root system.
x. Selection of crop should be problem based.
xi. An ideal crop rotations is one which provide maximum employment to the family and farm labourer, the machines and equipment are efficiently used, so all the agriculture operations are done timely.
The advantages of crop rotation are as follows:
i. There is an overall increase in the yield of crops due to maintenance of proper physical condition of the soil Inclusion of crops having different feeding zones and different nutrient requirement help in maintaining a better balance of nutrients in the soil.
ii. Diversification of crop reduces the risk of financial loss from unfavorable weather conditions and damage to insect and pest.
iii. It facilitates more even distribution of labour.
iv. There is regular flow of income over the year.
v. The incidence of weeds, pests and diseases is reduced and can be kept under control.
vi. Proper choice of crops in rotation help to prevent soil erosion.
vii. It supplies various needs of farmers and his cattle.
viii. Agricultural operation can be done timely for all the crops because of less competition.
Principle # 5. The Integrated Intensive Farming System:
Even after three decades of green revolution, India could not build a platform for the next phase of agriculture transformation.
It’s time that we seriously implemented several new strategies for achieving the second phase of green revolution, i.e., the evergreen revolution. But we must ensure this evergreen revolution does not result in social, economic and ecological imbalance. Agricultural systems now need to use new tactics to attain sustainability in agriculture.
(i) Reduce the reliance on chemical fertilisers and pesticides.
(ii) Diversify farming systems.
(iii) Promote better management of natural resources.
(iv) Enhance soil fertility and develop agroforestry.
There are six pillars for successful implementation of such a system.
These are described below:
Soil health care is fundamental of sustainable agriculture Ideal soil health care includes provisions of optimum soil reaction, soil moisture content and addition of organic matter. All these factors aid in improving soil fertility and hence, lead to the evergreen revolution. Green manures, biofertilisers and vermiculture enhance soil fertility and maintain its sustainability.
There should be an integrated policy for appropriate use of rain, river, ground, sea and other water resources. For achieving these goals integrated water management is the right approach.
It include following tries:
It is a method of irrigation in which water is applied to the roots zone of the crops at slow speed, under low pressure and a measured rate; it helps in fertigation and chemigation. It includes; drip, sprinkler, trickle and micro spar methods.
(b) Rain Water Harvesting:
Rain water is the biggest and ultimate source of freshwater on the Earth. The distribution of annul precipitation varies from less than 50 mm to more than 200 mm in low to high rainfall areas. Hence, it is necessary to develop suitable techniques for its storage and efficient use.
(c) Water Shed Management:
Water shed management is holistic approach to bringing about development of integrated farming systems on water shed basis. Its aims at optimising use of land, water and vegetation in an area to alleviate drought, moderate floods, prevent soil erosion, improve water availability and increase fuel, fodder and agricultural production on sustainable basis.
INM is a flexible approach to minimise the use of chemicals and maximise the efficiency of production. The concept is for optimisation of the effects of all available sources of plant nutrients to improve soil fertility. The gap in nutrient removal and addition can be bridged only by practising INM.
i. Assessment of the basic soil fertility and climate.
ii. Nature of crop, not in isolation but as a part of the cropping system and yield target.
iii. At least 30% of the total nutrient level of NPK to be in organic form. These principles help estimate the fertiliser level, from and time of application to the crop.
i. Intensified cropping
ii. Vermin compositing
iii. Green manuring
iv. Chemical fertilisers
It refers to an ecological approach in pest management in which all available necessary techniques are consolidated in a unified programme so that pest population can be managed in such a manner that economic damage is avoided and adverse side effects are minimised. The management of pest population in man’s agro-ecosystem is the theme of IPM. Therefore, ecologically sound and environmentally acceptable control tactics include a combination of components viz.
(a) Mechanical Method:
I. Hand pulling
II. Nets and traps
(b) Physical Methods:
I. Heating and cooling
II. Electricity and radiant energy
(c) Cultural Method:
I. Crop diversification
II. Soil cultivation
III. Use of resistant varieties
IV. Pruning and thinning
(d) Chemical Methods:
I. Insecticides and antifeedants
II. Attractants and repellants
(e) Biological Methods:
I. Natural enemies parasitoids, predators, pathogens
(f) Legal Methods:
I. Quarantine control thus the system based with the essential and suitable techniques applied for reducing the pest population below the level of economic injury is termed as IPM.
Even agro-forestry is the important pillar of sustainable agriculture. It is the cordial balance between agriculture and forestry. Technically, it is a sustainable land management tool resulting into increased production. Agro-forestry is a broad-based term which includes the systems like-Agri-silviculture, silui pastoral farming, Silviapiculture, Silvilac culture etc.
The essential aim of the components of agro-forestry is to conserve and improve the site and to optimise the combined production. Agro-forestry is beneficial both on short and long-term basis. It is essential for maintaining the nitrogen content of the soil.
The different types and components of agro-forestry are:
a. Agri-silviculture – Agricultural crops + forest crops (silviculture)
b. Sylvo-pastoral Systems – Silviculture (forest crops) + pasture (grass) management.
c. Agro-sylvo-pastroal Systems – Agriculture crop + forest crops + pasture management
d. Agri-horti-silvicultrue Systems – Forestry for the multipurpose benefits or uses.
(vi) Integrated Farming:
A majority of Indian farmers are small and marginal. To improve their socio-economic condition, integrated farming system is considered suitable. The concept of integrated farming is an integration of different interdependent enterprises are interacting, the byproducts of one enterprise is utilised as raw materials for other and vice-versa.
Millennium integrated farming can solve all problems through:
a. Increased productivity per unit of land.
b. Better utilisation of resources.
c. Recycling of farm wastes.
A branch of meteorology that examines the effects and impacts of weather and climate on crops, rangeland, livestock and various agricultural operations. The branch of agricultural meteorology dealing with atmospheric biospheric processes occurring at small spatial scales and over relatively short time periods is known as micrometeorology, sometimes called crop micro- meteorology for managed vegetative ecosystems and animal biometeorology for livestock operations.
i. The branch that studies the processes and impacts of climatic factors over larger time and spatial scales is often referred to as agricultural climatology.
ii. Weather and climate is a resource and considered as basic input or resources in agricultural planning, every plant process related with growth development and yield of a crop is affected by weather.
For determining crop growing season, solar radiation, air temperature, precipitation, wind, humidity etc., are important climatic factors on which the growth, development and yield of a crop depends Agro-meteorology considers and assess the suitability of these parameters in a given region for maximum crop production and economic benefits.
To reduce risk of crop failure on climatic part, so as to get stabilised yields even under weather adversity, suitable crops/cropping patterns/contingent cropping planning can be selected by considering water requirements of crop, effective, rainfall and available soil moisture.
(iii) Crop Management:
Management of crop involves various farm operations such as, sowing fertiliser application. Plant protection, irrigation scheduling, harvesting etc., can be carried out on the basis of specially tailored weather support. For this the use of operational forecasts, available from agromet advisories, is made.
(iv) Crop Monitoring:
To check crop health and growth performance of a crop, suitable meteorological tools such as crop growth models. Water balance technique or remote sensing, etc., can be used.
(v) Crop Modeling and Yield:
Climate relationship Suitable crop models, devised for the purpose can provide information or predict the results about the growth and yield when the current and past weather data is used.
Agro-meteorology can help to understand crop-climate relationship so as to resolve complexities of plant process in relation to its micro climate.
(vii) Climate Extremities:
Climatic extremities such a frost floods, droughts, hail storms, high winds can be forecasted and crop can be protected.
(viii) Climate as a Tool to Diagnose Soil Moisture Stress:
Soil moisture can be exactly determined from climatic water balance method, which is used to diagnose the soil moisture stress, drought and necessary protective measures such as irrigation, mulching application of antitranspirant, defoliation, thinning, etc., can be undertaken.
(ix) Livestock Production:
Livestock production is a part of agriculture. The set of favourable and unfavorable weather conditions for growth, development and production of livestock is studied in Agri-meteorology. Thus to optimise milk production poultry production, the climatic normal are worked out and on the suitable breeds can be evolved or otherwise can provide the congenial conditions for the existing breeds.
(x) Soil Formation:
Soil formation process depend on climatic factors like temperature, precipitation, humidity, wind, etc., thus climate is a major factor in soil formation and development.
Conservation agriculture makes use of soil biological activity and cropping systems to reduce the excessive disturbance of the soil and to maintain the crop residues on the soil surface in order to minimise damage to the environment and provide organic matter and nutrients.
i. Provide and maintain optimal conditions in the root zone (maximum possible depth for crop roots) in order to enable them to grow and function effectively and without hindrance in capturing plant nutrients and water.
ii. Ensure that water enters the soil so that plants have sufficient water to express their potential growth and excess water passes through soil to groundwater and stream flow, not over the surface as runoff where it can cause erosion. There is greater potential for increased cropping efficiency as more water is held in the soil profile than under conventional systems.
iii. Increase beneficial biological activity in the soil in order to maintain and rebuild soil architecture for enhanced water entry and distribution within the soil profile compete with potential soil pathogens, contribute to decomposition of organic materials to soil organic matter and various grades of humus and contribute to the capture, retention and gradual release of plant nutrients avoid physical or chemical damage to roots and soil organisms that would disrupt their effective functioning.
i. Tillage was used to soften the soil and prepare a seed bed that allowed seed to be placed easily at a suitable depth into moist soil using seed drills or manual equipment. This results in good uniform seed germination.
ii. Wherever crops grow, weeds also grow and compete for light, water and nutrients. Every gram of resource used by the weed is one less gram for the crop. By tilling their fields, farmers were able to shift the advantage from the weed to the crop and allow the crop to grow without competition early in its growth cycle with resulting higher yield.
iii. Tillage helped release soil nutrients needed for crop growth through mineralisation and oxidation after exposure of soil organic matter to air.
iv. Previous crop residues were incorporated along with any soil amendments (fertilisers, organic or inorganic) into the soil. Crop residues, especially loose residues, create problems for seeding equipment by raking and clogging.
i. Dry land farming has evolved as a set of techniques and management practices used by farmers to continually adapt to the presence or lack of moisture in a given crop cycle. In marginal regions, a farmer should be financially able to survive occasional crop failures, perhaps for several years in succession.
ii. Survival as a dryland farmer requires careful husbandry of the moisture available for the crop and aggressive management of expenses to minimises losses in poor years.
iii. Dryland farming involves the constant assessing of the amount of moisture present or lacking for any given crop cycle and planning accordingly.
iv. Dryland farmers know that to financially succeed they have to be aggressive during the good years in order to offset the bad years.