Shankar IAS Summary: Agriculture - 3 | Environment for UPSC CSE PDF Download

Organic Farming

Organic farming is a production system encompassing various agricultural products like grains, meat, dairy, eggs, cotton, flowers, and processed foods, all produced organically. This approach deliberately avoids or significantly minimizes the use of synthetic fertilizers, pesticides, growth regulators, and livestock feed additives.

Components of Organic Farming

Organic farming relies on practices such as crop rotations, crop residues, animal manure, legumes, green manure, on/off-farm organic wastes, mechanical cultivation, mineral-bearing rocks, and biological control of pests and diseases. These methods are employed to maintain soil productivity, enhance tilth, and supply plant nutrients.

Scope of Organic Farming

1. It serves as a sustainable agricultural system that maintains and improves soil fertility, ensuring future food security.
2. Reliance on resources from the local area, minimizing dependence on imported resources.
3. Contribution to maintaining the stability of natural ecosystems.

Concepts in Organic Farming

1. Building up biological soil fertility is a fundamental concept.
2. Control of pests, diseases, and weeds through ecological balance and the use of bioagents and cultural techniques.
3. Recycling all wastes and manure within the farm.

The key components include organic manures, non-chemical weed control, and biological pest and disease management.

Principles of Organic Farming

1. Mixed farming.
2. Crop rotation.
3. Optimization of the organic cycle.

Eco-farming

Eco-farming involves mutually reinforcing ecological approaches to food production, aiming for the maintenance of soil in a manner consistent with natural processes. The guiding principle is "feed the soil, not the plant," emphasizing the importance of ecological balance in farming.

Comparison: Organic vs. Inorganic Fertilizers

Permaculture

Bill Mollison, an Australian ecologist, along with his student David Holmgren, introduced the term "permaculture" in 1978, derived from "permanent agriculture" or "permanent culture."

Permaculture is defined as a design system aimed at creating sustainable human environments, utilizing ecology as the foundation for integrated systems covering food production, housing, appropriate technology, and community development.

• This approach is grounded in an ethic of caring for the earth and fostering mutually beneficial interactions with the environment.
• A key focus of Permaculture is the design of ecological landscapes for food production, emphasizing multi-use plants, cultural practices like sheet mulching and trellising, and the integration of animals to recycle nutrients and control weeds.

Characteristics

• Permaculture stands out as one of the most holistic and integrated systems for analysis and design globally. Its application can create productive ecosystems for human use or aid in the recovery of health and wildness in degraded ecosystems, irrespective of their condition.
• The approach values traditional knowledge and experience, incorporating sustainable agriculture practices and land management techniques from various cultures worldwide.
• Acting as a bridge between traditional and emerging earth-tuned cultures, Permaculture advocates for organic agriculture without the use of pesticides. It seeks to maximize symbiotic relationships between site components and tailors its design to be site-specific, client-specific, and culture-specific.

Integrated Farming System

The integration of various farm enterprises, such as cropping systems, animal husbandry, fisheries, forestry, etc., aims at optimizing resource utilization and bringing prosperity to farmers. The choice and adoption of farming system components depend on factors like land availability, type of land, water resources, capital, farmer's technical skills, market facilities, etc.

Benefits of Integrated Farming System

• Provides a consistent income in addition to earnings from regular cropping.
• Offers risk coverage through subsidiary allocations in case of unexpected crop failures.
• Generates employment opportunities.
• Enhances overall productivity.
• Facilitates increased returns and the recycling of organics.
• Readily adopted by marginal and submarginal farmers.
• Leads to the general uplift of farm activities.
• Optimizes the use of land, labor, time, and available manures on the farm.

Elements Required in Plant Growth

1. Macronutrients:

• Nitrogen (N)
• Phosphorous (P)
• Potassium (K)
• Sulfur (S)
• Calcium (Ca)
• Magnesium (Mg)

2. Micronutrients:

• Iron (Fe)
• Zinc (Zn)
• Manganese (Mg)
• Copper (Cu)
• Boron (B)
• Chlorine (Cl)
• Molybdenum (Mo)
• Sodium (Na)
• Cobalt (Co)
• Vanadium (Va)
• Nickel (Ni)
• Silicon (Si)

Role of Manures

1. Organic manures enhance water-holding capacity in sandy soil and promote better root growth in clayey soil.
2. They contribute plant nutrients and essential micro-nutrients.
3. Microbial activity is increased, aiding in the release of nutrients for plants.

Classification of Organic Manures

• Farm Yard Manure: A decomposed mixture of cattle dung, urine, straw, and litter.
• Compost Manure: Well-rotted organic manure prepared by decomposing organic matter.
• Sheep and Goat Droppings: Valuable organic manure containing nitrogen, phosphorus, and potassium.
• Concentrated Organic Manures: Includes oil cakes, bone meal, and fish meal.

Green Manuring

• It involves ploughing green plants into the soil to enhance physical structure and fertility, e.g., Sannhemp, Dhaicha, Pillipesara, etc.

Bio-fertilizers

• Preparations containing live or latent cells of microorganisms to increase nutrient availability, e.g., nitrogen-fixing Rhizobium, phosphate-solubilizing microorganisms, etc.

Integrated Nutrient Management (INM)

• The judicious combination of organic, inorganic, and biofertilizers to replenish soil nutrients and sustain crop productivity.

Weeds

Weeds are plants that are unwanted and interfere with land and water resources, negatively impacting crop production and human welfare. They exhibit gregarious behavior compared to crop plants.

Harmful effects of weeds

1. Weeds compete with the main crop for space, light, moisture, and soil nutrients, leading to reduced yield.
2. They affect the quality of farm produce and livestock products, such as milk and skin.
3. Weeds act as alternate hosts for pests and pathogens.
4. Some weeds can cause health problems for humans, such as allergies induced by Parthenium.
5. Weeds increase the cost of cultivation due to weed-related issues.
6. Aquatic weeds transpire large quantities of water and obstruct the flow of water.
7. Presence of weeds like cynodon and parthenium can reduce the land value.
8. Some weeds are poisonous to livestock.

Beneficial effects of weeds

• Weeds can act as soil binders.
• They can be used as manure.
• Some weeds serve as human food.
• Weeds can be used as fodder.
• Weeds are utilized as fuel.
• Some weeds can be woven into mats and screens.
• Certain weeds possess medicinal properties and are used in traditional medicine.
• Weeds can serve as indicators of soil quality.

Genetically modified crops (GM crops)

These are plants whose DNA has been modified using genetic engineering techniques for agricultural purposes.

• A watershed is an area of land and water bounded by a drainage divide. Watershed management involves controlling surface runoff within this area to prevent soil erosion and maintain water resources.

• Micro irrigation is a method where a low volume of water is applied at low pressure and high frequency. It utilizes an extensive network of pipes and emitters for efficient water distribution.

• In this method, water is sprayed into the air and falls on the ground surface, resembling natural rainfall. It is achieved through nozzles or orifices under pressure.

• Also known as trickle irrigation, it involves dripping water onto the soil at low rates through small-diameter plastic pipes fitted with emitters. Water is applied close to plants, wetting only the root zone.

• Terracing is the construction of embankments or ridges across a slope to control runoff, minimize soil erosion, and reduce the formation of gullies. It shortens the length of hillside slopes.

Soil

Soils cover Earth's land surface and play a crucial role in the ecosystem. Composed of minerals, organic materials, and open spaces, soils should ideally have about 45% minerals (sand, silt, clay), 5% organic matter, 25% air, and 25% water for optimal plant growth.

Factors influencing soil development

1. Parent material: The rock and minerals influencing soil composition.
2. Climate: Precipitation and temperature leading to partial weathering.
3. Living organisms: Inclusive of various organisms aiding in nutrient recycling.
4. Topography: Physical characteristics of the location affecting soil profile.

A mature soil profile, consisting of horizons labeled O, A, E, B, and C, reaches equilibrium over time. The composition of these horizons varies, and not all profiles contain all horizons.

Soil Components

• Clay: Very fine particles, compacts easily, low permeability to water.
• Gravel: Coarse particles consisting of rock fragments.
• Loam: Balanced mixture of clay, sand, silt, and humus, rich in nutrients.
• Sand: Coarser than silt, suitable for crops requiring low water.
• Silt: Fine particles between sand and clay, easily transported by water.

Soil Texture and Structure

• Soil texture refers to the relative proportion of sand, silt, and clay, while soil structure is the arrangement of particles in a soil mass.

Types of Soils

• Saline soils: High water-soluble salt content affecting crop growth.
• Sodic soils: Predominance of sodium with an exchangeable sodium percentage exceeding 15%.
• Acid soils: Characteristically low pH, leading to nutrient deficiencies.
• Sandy soils: Contain predominant sand with high percolation rates.
• Alkaline soil: Soil with a pH above 7, common in arid regions.
• Calcareous soil: Contains kankar nodules in the plough zone and subsoil.
• Alfisol: Soils with grey to brown surface horizons, formed under forest or savanna vegetation.
• Aridisol: Mineral soils with an aridic moisture regime, found in desert areas.

Processes of Soil Formation

• Laterization: Formation of laterite soils with a hard, brick-like horizon.
• Gleization: Development of a glei horizon due to poor drainage conditions.
• Salinization: Accumulation of salts in soils, common in arid regions.
• Desalinization: Removal of excess soluble salts from the soil profile through leaching.
• Solonization or Alkalization: Accumulation of sodium ions, forming sodic soils.
• Solodization or dealkalization: Removal of sodium ions, involving clay dispersion.

Environmental Issues Related to Soil

• Desertification: Productive potential reduction in arid or semi-arid land due to human activity or climate change.
• Salinization: Accumulation of dissolved salts in topsoil, affecting crop growth.
• Water logging: Saturation of soil leading to a rise in the water table.

Additional Information

• Loam soils generally contain more nutrients and humus than sandy soils.
• Topsoil color indicates its richness in nitrogen; brown or black is good for crops, while gray, yellow, or red is poor.

Stages of Soil Erosion

Splash Erosion

• Splash erosion marks the initial stage, triggered when raindrops impact bare soil, breaking up soil aggregates and splashing individual particles onto the surface.

Sheet Erosion

• Sheet erosion involves the uniform movement of a thin soil layer across vegetation-deprived land. Raindrops detach soil particles, which dissolve in runoff and are transported downstream.

Rill Erosion

• Rill erosion follows as sheet flows concentrate, leaving visible scouring on the landscape. It becomes apparent with increased rain duration or intensity.

Gully Erosion

• Rill erosion progresses into gully erosion with continued rain intensity, forming scoured areas impassable with regular equipment.

Ammonification

• Ammonification is the production of ammonia resulting from the biological decomposition of organic nitrogen compounds.

Border Cropping

• Border cropping involves growing crops on the border areas of a plot or field, for example, using safflower as a border crop in potato cultivation.

Border Strip Irrigation

• Efficient irrigation method dividing the field into flooded strips, suitable for closely spaced crops.

Allelopathy

• Allelopathy refers to the harmful effects of one plant on another through the exudation of toxic substances from roots or decomposed crop residues.

C:N Ratio

• The C:N ratio represents the weight ratio of organic carbon to total nitrogen in the soil.

Check Basin

• Check basin is an irrigation method using beds and channels to retain water, forming a pond.

Hard Pan

• Hard pan is an impermeable layer in the soil profile, formed by the accumulation of materials like salts and clay, impeding drainage.

Growth Regulators

• Growth regulators are organic substances, such as auxins and cytokinins, participating in the control of growth processes.

Heliophytes and Sciophytes

• Heliophytes are sun-loving plants (e.g., Rice, Wheat), while sciophytes are shade-loving plants requiring less light intensity.

Heliotropism

• Heliotropism is the movement of plant parts toward the sun, as seen in sunflowers.

Geotropism

• Geotropism is a growth movement in response to gravity, like the groundnut peg's penetration into the soil.

Herbicide and Insecticide

• Herbicides are chemicals used to kill or inhibit unwanted plants (e.g., Atrazine), while insecticides are chemicals for killing insects (e.g., Endosulfan).

Hidden Hunger

• Hidden hunger occurs when plants show no visual deficiency symptoms but experience nutrient shortages, leading to yield losses.

Humus

• Humus is a brown or black organic substance from partially or wholly decayed plant or animal matter, providing nutrients and enhancing soil water retention.

Mulching

• Mulching involves covering the soil with materials like plant residues or plastic film to reduce evaporation, suppress weed growth, and maintain soil temperature.

Puddling

• Puddling is a plowing operation conducted in waterlogged conditions to create an impervious layer beneath the plow pan.

Shifting Cultivation, Subsidiary Farming, and Subsistence Farming

Shifting cultivation involves clearing forest for temporary crop cultivation based on soil fertility. Subsidiary farming is settled farming in river banks in addition to gathering and hunting. Subsistence farming is growing crops only for family needs, not commercially.

Miyawaki Method for Creating Forests

The Miyawaki method, pioneered by Akira Miyawaki, builds dense native forests by planting dozens of native species in the same area. It ensures rapid plant growth and a dense plantation, becoming maintenance-free after the first three years.

System of Rice Intensification (SRI)

SRI, emerging in the 1980s, combines practices like changes in nursery management, transplanting timing, and water management to intensify rice production. It follows the principle of 'More with Less,' increasing yield with less water and reduced chemical inputs.