ORGANIC FARMING

Organic farming is a production system where all kinds of agricultural products are produced organically, including grains, meat, dairy, eggs, fibres like cotton, flowers & processed food products.

Organic farming avoids or largely excludes the use of synthetic fertilizers, pesticides, growth regulators & livestock feed additives.

1. Components of organic farming

It largely relies upon crop rotations, crop residues, animal manure, legumes, green manure, on/off-farm organic wastes, mechanical cultivation, mineral-bearing rocks & aspects of biological control of pests & diseases to maintain soil productivity & tilth to supply plant nutrients. Organic manures, biological pest & disease management & non-chemical weed control are components of organic farming.

Scope

• A sustainable agricultural system which maintains & improves soil fertility to guarantee adequate food security in the future.
• It relies upon resources from its own area which is not dependent much on imported resources.
• It helps maintain the stability of the natural ecosystem.

Concepts

• Building up of biological soil fertility.
• It recycles all wastes & manure within the farm.
• Control of pests, diseases & weeds through the development of an ecological balance within the system & by the use of bio-agents & various cultural techniques.

Eco-farming: Farming about ecosystem. It is the farming mutually reinforcing ecological approaches to food production. It aims at the maintenance of soil chemically, biologically & physically the way nature would do if left alone. Soil would then take proper care of plants growing on it. Feeding the soil, not the plant is the watchword & slogan of ecological farming.

Biological farming: Farming about biological diversity.

Biodynamic farming: Farming which is biologically organic & ecologically sound & sustainable farming.

Principles:

The three interrelated principles of organic farming are:

• Mixed farming
• Organic cycle optimization
• Crop rotation

Differences between organic & inorganic fertilizers

2. Permaculture

• It is defined as a design system for creating a sustainable human environment. It uses ecology as the basis for designing integrated systems of food production, housing, appropriate technology & community development.
• Bill Mollison, an Australian ecologist with his student David Holmgren coined the term “Permaculture which is also known as permanent agriculture”.
• Permaculture is built on an ethic of caring for the earth & interacting with the environment in mutually beneficial ways.
• A central theme in Permaculture is the design of ecological landscapes that produce food. Emphasis is placed on multi-use plants, cultural practices like sheet mulching & trellising & the integration of animals to recycle nutrients & graze weeds.

Characteristics

• It is one of the most holistic, integrated system analysis & design methodologies found in the world.
• It can be applied to create productive ecosystems from the human-use standpoint or to help degraded ecosystems recover health & wildness.
• It values & validates traditional knowledge & experience.
• Incorporates sustainable agriculture practices & land management techniques & strategies from around the world.
• It is a bridge between traditional cultures & emergent earth-tuned cultures.
• It promotes organic agriculture which does not use pesticides.
• It aims to maximize symbiotic & synergistic relationships between site components.

3. Integrated Farming System

Integration of farm enterprises like cropping systems, animal husbandry, fisheries, forestry etc, for optimal utilization of resources bringing prosperity to the farmer.

According to the availability of land, type of land, water, capital, resources, technical skill of the farmer, market facilities etc & the components of the farming system are to be chosen & adopted for better results.

Benefits of Integrated Farming System

• Steady income other than income from regular cropping.
• Employment opportunity.
• Risk coverage due to subsidy allocation in the event of unexpected crop failures.
• Higher productivity
• Easily adopted by marginal & sub-marginal farmers.
• Augmented returns & recycling of organics.
• General uplift of farm activities.
• Better utilization of land, labour, time & available manures in the farm.

Elements Required in Plant Growth:

Macro Nutrients: Based on the relative abundance in plants- Nitrogen (N), phosphorus (P), Potassium (K), Sulfur (S), Calcium (Ca), and Magnesium (Mg).

Micro Nutrients: Their concentration is very small. They are also referred to as minor elements. Iron (Fe), Zinc (Zn), Manganese (Mg), Copper (Cu), Boron (B), Chlorine (Cl) and molybdenum (Mo). In some plants, other than the above, Sodium (Na), Cobalt (Co), Vanadium (Va), Nickel (Ni) and silicon (Si) are considered essential micronutrients.

Nitrogen (N): N is an essential constituent of proteins & is present in many other compounds of great physiological importance in plant metabolism. N is an integral part of chlorophyll, which is a primary observer of light energy needed for photosynthesis. N imparts vigorous vegetative growth & dark green colour to plants.

Phosphorous (P): P is an essential part of the enzymes which help the crop to fix light energy. It forms an integral part of nucleic acids, the carriers of genetic information & is important in stimulating root growth.

Potassium (K): Potassium (K) is involved in processes which ensure carbon assimilation & the transportation of photosynthates throughout the plant for growth & the storage of sugars & proteins. The potassium ion is important for water regulation & uptake. The presence of potassium in sufficient amounts ensures resistance to frost, drought & certain diseases.

Magnesium occurs in chlorophyll & also an activator of enzymes.

Sulphur forms part of two essential amino acids which are among the many building blocks of protein. It is found in vitamin B1 & several important enzymes.

Calcium is required for plant growth, cell division & enlargement. The growth of root & shoot tips & storage organs is also affected by calcium as it is a component of cell membranes. Calcium is vital for pollen growth & to prevent leaf fall.

4. Manures

Manures are plant & animal wastes that are used as sources of plant nutrients. They release nutrients after their decomposition. Manures can be grouped into bulky organic manures & concentrated organic manures.

Role of manures:

• Organic manures bind the sandy soil & improve its water-holding capacity.
• They open the clayey soil & help in aeration and better root growth.
• Organic manures should be incorporated before the sowing or planting because of the slow release of nutrients.
• They add plant nutrients in small percentages & also add micronutrients which are essential for plant growth the microbial activity is increased which helps in releasing plant nutrients available for bulky organic manures.

Fertilizers: Fertilizers are industrially manufactured chemicals containing plant nutrients. The nutrient content is higher in fertilizers than in organic manures & nutrients are released almost immediately.

Classification of Organic Manures:

1. Farm yard manure: This is the traditional manure & is mostly readily available to the farmers. Farmyard manure is a decomposed mixture of Cattle dung & urine with straw & litter used as bedding material & residues from the fodder fed to the cattle.
2. Compost Manure: Compost is well-rotted organic manure prepared by the decomposition of organic matter. Composting is largely a biological process in which micro-organisms of both types, aerobic & anaerobic, decompose the organic matter & lower down the C: N ratio of refuse. The final product of composting is well-rotted manure known as compost.
3. Sheep and goat droppings: It is a valuable organic manure. It contains about 0.5-0.7% N, 0.4-0.6% P₂O₅, 0.3—1% K₂O. It is effective for all types of crops.

Concentrated Organic Manures

Oil Cakes:

• Oil cakes are quick-acting organic manure. Though they are insoluble in water, their nitrogen became quickly available to plants in about a week or in 10 days after application.
• There are many varieties of oil cakes which contain not only nitrogen but also some P and, K along with a large percentage of matter. These oil cakes are of two types.

1. Edible oil cakes: suitable for feeding cattle.
2. Non-edible oil cakes: not suitable for feeding cattle.

Bone Meal: Bones from slaughterhouses, and carcasses of all animals & from the meat industry constitute bone meal which is the oldest phosphatic fertilizer used. It contains some N.

Green Manuring: It is a practice of ploughing in the green plants grown in the field or adding green plants from outside & incorporating them into the soil to improve the physical structure as well as the fertility of the soil. Examples: Sun hemp, Dhaicha, Pillipesara, Shervi, Urd, Mung, Cowpea etc.

Fish Meal: Fish manure or meal is processed by drying non-edible fish, carcasses of fish & wastes from the fish industry. It contains 4.0-10% nitrogen, 3.0-9% phosphorus & 0.3-1.5% K. Fishmeal is quick-acting organic manure & is suitable for application to all crops on all soils.

Green leaf Manuring: Green leaf manuring refers to adding the green leaves & green twigs from legume plants or trees to a field & then incorporating them into the soil by ploughing. Examples: Glyricidia, wild Dhaicha, Karanj, Leucaena.

5. Bio-fertilizers

Bio-fertilizers are preparations containing live or latent cells of efficient strains of nitrogen-fixing, phosphate solubilizing or cellulolytic micro-organisms used for application to seed or composting areas to increase the numbers of such micro-organisms & accelerate those microbial processes which augment the availability of nutrients that can be easily assimilated by plants.

Bio-fertilizers harness atmospheric nitrogen with the help of specialized micro-organisms which may be free living in soil or symbiotic with plants.

Nitrogen Fixers:

Symbiotic: Rhizobium, inoculants for legumes.

Non-symbiotic: For cereals, millets & vegetables.

Bacteria:

1. Aerobic: Azatobacter, Azomonas, Azospirillum
2. Anaerobic: Clostridium, chromium
3. Facultative anaerobes: Bacillus, Escherichia.

Blue-green algae:

1. Phosphate solubilizing micro-organisms
2. Cellulolytic & ligninolytic micro-organisms
3. Sulphur dissolving bacteria
4. Azolla

Integrated Nutrient Management

• Judicious combination of organic, inorganic & bio-fertilizers which replenishes the soil nutrients which are removed by the crops is referred to as Integrated Nutrient Management system.
• To sustain the productivity of different crops & cropping systems, an efficient, economical & integrated system of nutrient management for realizing high crop productivity without diminishing soil fertility.

6. Weeds

Weeds are unwanted & undesirable plants that interfere with the utilization of land & water resources & thus adversely affect crop production & human welfare. They are gregarious in nature compared to crop plants.

Harmful effects of weeds

• Weeds compete with the main crop for space, light, moisture & soil nutrients thus causing a reduction in yield.
• Affect quality of farm produce, livestock products like milk & skin.
• Act as an alternate host for pests & pathogens.
• Increase cost of cultivation due to weeding problem.
• cause health problems to human beings like parthenium causing the allergy.
• Aquatic weeds transpire large quantities of water, obstructing the flow of water.
• Some weeds are poisonous to livestock.
• Reduce the land value.

Beneficial effects of weeds

• Manure
• Weeds as soil binders
• Human food
• Fodder
• Weed as fuel
• Weed as mats & screens
• Weed as medicine: Many weeds have great therapeutic properties & used as medicine.
• Example: Phyllanthus neruri- Jaundice, Eclipta alba- Scorpion sting, Centella asiatica- Improves memory, Cynodon dactylon- Asthma, piles, Cyperus rotundus- stimulates milk secretion.
• Genetically modified crops are plants, the DNA of which has been modified using genetic engineering techniques which are then used in agriculture.

Watershed Management: A watershed is an area of land & water bounded by a drainage divide within which the surface runoff collects & flows out of the watershed through a single outlet into a larger river/lake.

Micro Irrigation: Micro irrigation is defined as the method in which a low volume of water is applied at low pressure & high frequency. The system has an extensive network of pipes operated at low pressure. At pre-determined spacing, outlets are provided for emission water generally known as emitters.

Sprinkler Irrigation: In the sprinkler method of irrigation, water is sprayed into the air & allowed to fall on the ground surface somewhat resembling rainfall. The spray is developed by the flow of water under pressure through small nozzles.

Drip Irrigation: Drip irrigation is called trickle irrigation & involves dripping water onto the soil at very low rates from a system of small-diameter plastic pipes fitted with outlets called emitters. Water is applied close to plants so that only part of the soil in which the roots grow is wetted, unlike surface & sprinkler irrigation, which involves wetting the whole soil profile.

Terracing: A terrace is an embankment or ridge of earth constructed across a slope to control runoff & minimize soil erosion. It reduced the length of the hillside slope, thereby reducing sheet & rill erosion & preventing the formation of gullies.

7. Soil

Soils are a thin layer on top of most of the earth’s land surface. This thin layer is a basic natural resource & deeply affects every other part of the ecosystem. Soils are composed of three main ingredients- minerals of different sizes, organic materials from the remains of dead plants & animals, and open space that can be filled with water or air.

Good soil for growing most plants should have about 45% minerals with a mixture of sand, silt & clay, 5% organic matter, 25% air & 25% water.

With sufficient time, a mature soil profile reaches a state of equilibrium. Feedback mechanisms involving both abiotic & biotic factors work to preserve the mature soil profile. The relative abundance of sand, silt & clay is called soil texture.

Soils develop in response to several factors:

• Parent Material: This refers to the rock & minerals from which the soil derives. The nature of the parent rock, which can be either native to the area or transported to the area by wind, water or glacier has a direct effect on the ultimate soil profile.
• Climate: This is measured by precipitation & temperature. It results in partial weathering of the parent material, which forms the substrate for soil.
• Living Organisms: These include the nitrogen-fixing bacterial Rhizobium, fungi, insects, worms, snails etc that help to decompose litter & recycle nutrients.
• Topography: This refers to the physical characteristics of the location where the soil is formed. Topographic factors that affect a soil’s profile include drainage, slope direction, elevation & wind exposure.

Soil Components

• Clay: Very fine particles. Compacts easily. Forms large dense clumps when wet. Low permeability to water, therefore upper layers become waterlogged.
• Loam: About equal mixtures of clay, sand, silt & humus. Rich in nutrients. Holds water but does not become waterlogged.
• Sand: Sedimentary material coarser than silt. Water flows through too quickly for most crops. Good for crops & plants requiring low amounts of water.
• Gravel: Coarse particles. Consists of rock fragments.
• Silt: Sedimentary material consisting of very fine particles between the size of sand & clay. Easily transported by water.

Soil is a natural body of mineral & organic constituents differentiated into horizons usually unconsolidated of variable depth which differ among themselves as well as from the underlying parent material in morphology, makeup, chemical properties & composition & biological characteristics.

Soil Profile: The vertical section of the soil showing the various layers from the surface to the unaffected parent material is known as a soil profile. The various layers are known as horizons. There are 5 major horizons in the soil profile. Not all soil profiles contain all 5 horizons, soil profiles differ from one location to another.

The 5 master horizons are represented by the letters: O, A, E, B, and C.

O: The O horizon is a surface horizon that is comprised of organic material at various stages of decomposition. It is most prominent in forested areas where there is an accumulation of debris falling from trees.

A: The A horizon is a surface horizon that largely consists of minerals & with appreciable amounts of organic matter. This horizon is predominantly the surface layer of many soils in grasslands & agricultural lands.

E: The E horizon is a subsurface horizon that has been heavily leached. Leaching is the process in which soluble nutrients are lost from the soil due to precipitation or irrigation. The horizon is typically light in colour. It is generally found beneath the ‘O’ horizon.

B: The B horizon is a subsurface horizon that has accumulated from the layer above. It is a site of deposition of certain minerals that have leached from the layers above.

C: The C horizon is subsurface. It is the least weathered horizon. Also known as the saprolite, it is unconsolidated, loose parent material.

R:  Unweathered rock exists below the parent material.

Soil Texture: Soil texture refers to the relative proportion of particles or it is the relative percentage by weight of the three soil separates like sand, silt & clay or simply refers to the size of soil particles.

Loam: A type of soil texture with good water-holding capacity & drainage suitable for the cultivation of a variety of crops.

Soil Structure: The arrangement & organization of primary & secondary particles in a soil mass is known as soil structure.

Saline soils: Saline soils are characterized by a higher amount of water-soluble salt due to which the crop growth is affected.

Sodic soils: Sodic soils are characterized by the predominance of sodium in the complex with the exchangeable sodium percentage exceeding 15% & the pH of more than 8.5%.

Acid Soils: Acid soils are characteristically low in pH (<6). Predominance of H+ & Al₃+ causes acidity resulting in a deficiency of P, K, Ca, Mg, Mo & B.

Sandy Soils:

• Sandy soils contain predominant amounts of sand resulting in higher percolation rates & nutrient losses.
• Alkaline soil: A soil with a pH above 7, usually above 8.5 is considered alkaline. Alkaline soils often occur in arid regions that receive less than 25 inches of rain per year.
• Calcareous soil: Soils with calcium carbonate abundance are considered as calcareous soil.
• Alfisol: Soils with grey to brown surface horizons, medium to high supply of bases & B horizons of alluvial clay accumulation. These soils formed mostly under forest or savanna vegetation in climates with slight to pronounced seasonal moisture deficit.
• Aridisol: Mineral soils that have an acidic moisture regime. These are desert soils.

Podsolization:

• It is a process of soil formation resulting in the formation of podsols & podzolic soils.
• Podsolization is the negative form of calcification. The calcification process tends to concentrate calcium in the lower part of the B horizon, whereas podsolization leaches the entire solution of calcium carbonates.
• The other bases along with calcium are also removed & the whole soil becomes distinctly acidic. The process is essentially one of the processes of acid leaching.

Lateralization: The term laterite is derived from the word ‘meaning brick or tile’ & was originally applied to a group of high clay Indian soils found in the Malabar hills of Kerala, Tamil Nadu, Karnataka & Maharashtra. Lateralization is the process that removes silica, instead of sesquioxides to concentrate in the solum.

Gleization: It is a process of soil formation resulting in the development of a Glei (Gley formation) in the lower part of the soil profile above the parent material due to poor drainage conditions & where water-logged conditions prevail.

Salinization: It is the process of accumulation of salts such as sulphates & chlorides of calcium, magnesium, sodium & potassium in soils in the form of a salty horizon. It is common in arid & semi-arid regions. Salt accumulation may result from irrigation or seepage in areas of impeded drainage.

Desalinization: It is the removal of excess soluble salts by leaching from horizons or soil profiles that contain enough soluble salts to impair the plant growth by ponding water & improving the drainage conditions by installing an artificial drainage network.

Alkalization: This process involves the accumulation of sodium ions on the exchange complex of the clay, resulting in the formation of sodic soils. All cations in solutions are engaged in a reversible reaction with the exchange sites on the clay & organic matter particles. This process is also known as Alkalization.

Solodization: This process refers to the removal of Na+ from the exchange sites. This process involves the dispersion of clay. Dispersion occurs when Na+ ions become hydrated. Much of the dispersion can be eliminated if Ca++ & Mg++ ions are concentrated in the water, which is used to leach the soonest. This Ca & Mg ion can replace the Na on exchange complex & the salts of sodium are leached out. This process is also known as Dealkalization.

Desertification:

• Productive potential of arid/semiarid land falls by at least 10% due to human activity & climate change.
• Loss of native vegetation; increased wind erosion; salinization; drop in water table; reduced surface water supply.
• Remediation: Reduce overgrazing; reduce deforestation; reduce destructive forms of planting, irrigation & mining. Plant trees & grasses to hold soil.

Salinization: Water that is not absorbed into the soil & evaporates leaves behind dissolved salts in topsoil. Stunted crop growth; lower yield; and eventual destruction of plant life. Take land out of production for a while; install underground perforated drainage pipes; flush soil with freshwater into separate lined evaporation ponds; plant halophytes (Salt-loving plants) like barley, cotton, sugar beet, semi-dwarf wheat.

Water logging:

• Saturation of soil with water resulting in a rise in the water table is considered as water logging.
• Saline water envelops deep roots killing plants, lowering productivity, and eventually destruction of plant life are the results of water logging.
• Remediation: Utilize conservation tillage farming, switch to less water-demanding plants in areas susceptible to water logging, plant water logging-resistant trees with deep roots, take & out of production for a while, install pumping stations with drainage pipes that lead to catchment-evaporation basins.
• If the topsoil is brown or black, it is rich in nitrogen & is good for crops. If the topsoil is grey, yellow or red, it is low in organic matter & poor for crops.
• Loam soils generally contain more nutrients & humus than sandy soils, have better infiltration & drainage than silty soils & are easier to till than clay soils.

Soil Erosion:

Soil erosion is the wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents like water, ice, snow, air, plants & animals.

Stages:

• Splash Erosion: Splash erosion is the first stage of the erosion process. It occurs when raindrops hit bare soil. The explosive impact breaks up soil aggregates so that individual soil particles are splashed onto the soil surface.
• Sheet Erosion: Sheet erosion refers to the uniform movement of a thin layer of soil across an expanse of land devoid of vegetative cover. Raindrops detach soil particles, which go into solutions as runoff occurs & are transported downstream to a point of deposition.
• Rill Erosion: When sheet flows begin to concentrate on the land surface, rill erosion occurs. While sheet erosion is generally invisible, rill erosion leaves visible scouring on the landscape. This type of erosion occurs when the duration or intensity of rain increases & runoff volumes accelerate.
• Gully Erosion: Rill erosion evolves into gully erosion as the duration or intensity of rain continues to increase & runoff volumes continue to accelerate. A gully is generally defined as a scoured-out area that is not crossable with tillage or grading equipment.
• Ammonification: production of ammonia as a result of the biological decomposition of organic nitrogen compounds.
• Border Cropping: Border cropping is the growing of crops on the border areas of the plot or field. Examples include safflower as a border crop in potatoes.
• Border strip irrigation: It is an efficient method of irrigation of close-growing crops. In this method, the field is divided by low flat levels into a series of strips, each of which is flooded separately.
• Allelopathy: It is defined as the direct or indirect harmful effect of one plant over the other crop species through the exudation of toxic substances from the roots or the decomposition of crop residues.
• Carbon: Nitrogen ratio: The ratio of the weight of organic Carbon to the weight of total Nitrogen in the soil.
• Check Basin: It is a method of irrigation with beds & channels for retaining water to form a pond.
• Heaving: Injury to plants caused by lifting upward of the plant along with soil from its normal position in temperate regions where snowfall is common.
• Contour Farming: Contour farming is the practice of ploughing across a slope following its elevation contour lines.
• Cover Crops: Crops which are grown to cover the soil to reduce the loss of moisture from the soil due to leaching & erosion.
• Critical Stage of Irrigation: The period or the stage of development of the lifecycle of the crop when it is most sensitive to moisture stress, results in yield loss.
• Hard Pan: It is a hard & impermeable layer formed in the soil profile by the accumulation of materials like salts, clay etc which impedes drainage.
• Growth Regulators: Organic substances which in minute amounts may participate in the control of growth processes like auxins, and cytokinins.
• Heliophytes: Sun-loving plant species require intense light for normal development. Example: rice, wheat, cotton, sugarcane.
• Sciophytes: Plants which are shade-loving & require less light intensity.
• Heliotropism: It is the movement of the plant parts towards the sun. (sunflower)
• Geotropism: A growth movement in response to gravity. Example: groundnut penetration into the soil.
• Herbicide: A chemical used for killing or inhibiting the growth of unwanted plants.
• Insecticide: It is the chemical used for killing the insects. (Endosulfan)
• Hidden Hunger: It is the condition where plants do not exhibit visual symptoms of deficiency for the short supply of particular nutrients but will result in yield losses.
• Humus: A brown or black organic substance consisting of partially or wholly decayed vegetable or animal matter that provides nutrients for plants & increases the ability of soil to retain water.
• Mulching: Practice covering the soil surface with materials like plant residues, straw, leaves or plastic film to reduce evaporation, restrict weed growth & maintain the soil temperature.
• Puddling: It is the ploughing operation carried out in stagnated water conditions to create an impervious layer below the plough pan.
• Shifting Cultivation: It is the old practice of cutting & clearing forests for cultivation crops for a certain period as long as the soils have fertility.
• Subsidiary Farming: Settled farming in river banks & streams in addition to gathering & hunting.

Sustainable Sugarcane Initiative (SSI):

• Sustainable Sugarcane Initiative (SSI) is an innovative set of agronomic practices that involves using fewer seeds, raising seeds in s nursery & following new planting methods, with wider seed spacing & better water, and nutrient management to increase the cane yields significantly.
• SSI methods can increase sugarcane yields by at least 20% with 30% less water & 25% reduction in chemical inputs.
• The SSI method of sugarcane cultivation evolved from the principles of “More with Less” followed in SRI & introduced in India by the WWF-ICRISAT collaborative project in 2009.

System of Rice Intensification (SRI):

• System of Rice Intensification (SRI) emerged in the 1980s as a synthesis of locally advantageous rice production practices encountered in Madagascar.
• SRI is a combination of several practices which include changes in nursery management, time of transplanting water & weed management.
• It emphasizes altering certain agronomic practices of the conventional way of rice cultivation. All these new practices are together known as System Rice Intensification (SRI).
• SRI is not a fixed package of technical specifications, but a system of production with four main components soil fertility management, planting method, weed control & water management.
• Rice yield increased with less water & with a reduction in chemical inputs.