Agriculture and Environment: UPSC Previous Year Questions (Environment and Ecology)

Explanation

Methane (CH₄) and nitrous oxide (N₂O) are the two most important GHGs after carbon dioxide (CO₂). The most rapid increase in CH₄ emission was found in natural wetlands and rice fields due to increased rice cultivation area and climate warming. N₂O emission increased substantially in all the biome types and the largest increase occurred in upland crops due to increasing air temperature and nitrogen fertilizer use. Rice paddies are considered one of the most important sources of CH₄ and N₂O emissions, which have attracted considerable attention due to their contribution to global warming.

Explanation

The System of Rice Intensification involves cultivating rice with as much organic manure as possible, starting with young seedlings planted singly at wider spacing in a square pattern; and with intermittent irrigation that keeps the soil moist but not inundated, and frequent inter cultivation with weeder that actively aerates the soil. SRI is not a standardised, fixed technological method. It is rather a set of ideas, a methodology for comprehensively managing and conserving resources by changing the way that land, seeds, water, nutrients, and human labour are used to increase productivity from a small but well-tended number of seeds. Advantages of SRI Disadvantages of SRI Higher yields - Both grain and straw Higher labour costs in the initial years Reduced duration Difficulties in acquiring the necessary skills Reduced seed requirement Not suitable when no irrigation source available Lesser chemical inputs Less water requirement Reduced electricity consumption Less chaffy grain rain weight increased without change in grain size Higher head rice recovery Withstand cyclonic gales Cold tolerance Soil health improves through biological activity Reduced methane production

Explanation

Permaculture is a totally integrated design system that’s modelled on nature.

Statement 1 is correct: Permaculture farming promotes multi-cropping and integrated farming systems. While chemical farming is more suitable for monoculture cropping due to the use of crop-specific inputs like irrigation, chemical fertiliser and harvesting methods.

Statement 2 is correct: Conventional farming usually alters the natural environment, increases soil salinity, and eliminates biodiversity. Such problems are not seen in permaculture farming as it relies on organic fertilizers.

Statement 3 is incorrect: Chemical farming is based on the intense use of inputs like chemical fertilizers and irrigation that make the soil less fertile over time, thus restricting its practice in semi-arid regions. Thus, conventional farming is not suitable for semi-arid regions. Permaculture involves well-designed systems that don’t produce waste and permaculture tries to imitate well-designed systems. Thus, it can work in arid climates as well.

Statement 4 is correct: Mulching is an important component of Permaculture systems for promoting maximum efficiency.

Explanation

Climate-Smart Agriculture (CSA) is a strategy to assist those in charge of managing agricultural systems in efficiently adapting to climate change. The CSA approach pursues the triple objectives of:

Sustainably increasing productivity and incomes Adapting to climate change Reducing greenhouse gas emissions where possible

Statement 1 is correct: The Climate-Smart Village project in India is a CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

Statement 2 is correct: Climate Change, Agriculture and Food Security (CCFAS) is carried out under CGIAR (formerly the Consultative Group for International Agricultural Research).

Statement 3 is correct: ICRISAT is a CGIAR Research Center. It is a non-profit, non-political public international research organization that conducts agricultural research for development in Asia and sub-Saharan Africa with a wide array of partners throughout the world.

Explanation

Fertigation is a technique for applying fertilizer where the drip irrigation system incorporates the fertilizer into the irrigation water. In this technology, irrigation is used to evenly disperse fertiliser solutions. Fertigation is practised extensively in commercial agriculture and horticulture. Fertigation is used to supplement nutrients that are already present or to make up for nutrient shortages found during plant tissue analysis.

Statement 1 is correct: Drip irrigation also avoids water spill-age on the field which could have promoted weed growth or increased soil alkalinity due to water logging.

Statement 2 is incorrect: Rock phosphate is not water-solu-ble and thus not suitable for fertigation. Only water-soluble fertilizers are effectively used in fertigation systems.

Statement 3 is correct: Accurate placement of nutrient, where the water goes the nutrient goes as well. Thus, increased nutrient absorption by plants.

Statement 4 is correct: Fertigation mixes fertilizers into irrigation water so that plants receive small, measured amounts of nutrients regularly, which minimizes the risk of nutrient losses through leaching.

Explanation

The practice of sowing seed without tillage or preparation of soil is called Zero-tillage or No-till farming. In some cases it may reduce labour, fuel, irrigation and machinery costs. Another possible benefit is that because of the higher water content, instead of leaving a field fallow it can make economic sense to plant another crop instead. No-till farming decreases the amount of soil erosion tillage causes in certain soils, especially in sandy and dry soils on sloping terrain.

Statement 1 is correct: Zero tillage is the process where the crop seed will be sown through drillers without prior land preparation and disturbing the soil where previous crop stubbles are present.

Statement 2 is correct: Direct Seeded Rice (DSR) is a viable option to reduce the unproductive water flows, with increasing shortage of water, dry-DSR with minimum or zero tillage further enhances the benefits of this technology by saving labour.

Statement 3 is correct: Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide to mitigate climate change. No-tillage farming has been claimed to increase soil organic matter, and thus increase carbon sequestration.

Explanation

Sustainable Agriculture is farming in such a way to protect the environment, aid and expand natural resources and to make the best use of nonrenewable resources. Options 1, 2 and 3 are correct:

Mixed cropping or diverse cropping: When two or more crops are cultivated concurrently on a field, it is known as mixed cropping or diversified cropping. In the unlikely event that one crop fails, the other crops will mitigate the risk of a complete crop failure. Legume intensification: A category of plants known as leguminous plants (legume) contain edible roots or knobs that help nitrogen-rich soil grow vegetables or other meals. A leguminous crop is typically cultivated alongside the primary crop. Legumes contribute to increased soil fertility by fixing nitrogen from the atmosphere. Crop Rotation: It entails the methodical planting of various crops in a specific order over the course of several years in the same growing space. It contributes to the preservation of soil nutrients, the reduction of soil erosion, and the prevention of pests and disease in plants. Tensiometer: A tensiometer is a device used to measure soil moisture levels, helping in precision irrigation. Farmers and other irrigation managers can use tensiometers to help them decide when to water the land. It helps in reducing excessive water use and promotes water conservation in agriculture. Option 4 is incorrect: Vertical farming is the process of raising crops in vertical layers and frequently combines soilless farming methods and controlled-environment agriculture, which attempts to maximise plant development.

Explanation

Biochar is a high-carbon, fine-grained residue that is currently produced through modern pyrolysis processes (direct thermal decomposition of biomass in the absence of oxygen and preventing combustion). The extremely porous nature of biochar is found to be effective at retaining both water and water-solu-ble nutrients. When applied to soil, biochar can improve water retention, increase soil fertility, and enhance microbial activity, leading to better crop yields.

Statement 1 is correct: The use of biochar in vertical farming, part of the growing medium, can increase output significantly. As biochar migrates vertically through the soil profile, therefore can be used as a part of the growing medium in vertical farming.

Statement 2 is correct: Its presence on the earth can improve water quality, increase soil fertility, raise agricultural productivity, and reduce pressure on old-growth forests. Using biochar in the soil promotes the growth of nitrogen-fixing microorganisms.

Statement 3 is correct: Biochar is hygroscopic. Thus it is a desirable soil material in many locations due to its ability to attract and retain water.

Explanation

In India, pesticides must be registered with the Ministry of Agriculture & Farmers Welfare’s Directorate of Plant Protection, Quarantine & Storage before they can be used. A 2015 report by the Anupam Verma Committee recommended banning 27 pesticides, including some commonly used chemicals mentioned above:

Carcinogenic: Oxyfluorfen, Pendimethalin (causes Thyroid follicular cell adenoma) Endocrine disruptor: Dicofol, Carbofuran, Oxyfluorfen Eco-toxic: Carbofuran, Monocrotophos, Carbofuran, Oxyfluorfen.

Explanation

Carbon fertilisation is the artificial enrichment of the atmosphere of greenhouses with carbon dioxide, an essential nutrient for plants and vegetables. It also goes by the name of "Carbon Dioxide Fertilization." It can be used to grow nearly any form of vegetable (asparagus, celery, lettuce, tomatoes, aubergines, etc.), greenhouse fruit (strawberries), and ornamental plants, and is especially suited for cold climates.

Option (a) is correct: Carbon fertilisation results in an increase in the instantaneous rate of photosynthesis in C3 plants; and increases the transpiration efficiency of the leaf (C3 and C4 plants). During high concentration of carbon dioxide, plants maintain narrow openings of leaf surface which protects them from water loss. Faster plant growth enhances food production and allows for the sequestration of more carbon dioxide. Plants distribute a greater proportion of photosynthate to roots under high concentrations of atmospheric carbon dioxide. The reproductive biomass growth, as well as vegetative biomass growth, is usually increased by elevated carbon dioxide.