(a) Give an account of greenhouse gas (GHG) emissions from agriculture. State the mitigation strategies for reducing greenhouse…

(a) Greenhouse gas emissions from agriculture and mitigation strategies (20 marks)

Emissions. Agriculture releases mainly methane and nitrous oxide, with some carbon dioxide, and accounts for roughly one-seventh of India's national emissions.

• Methane (CH4), with a warming effect about 28 times that of CO2 over a century: from enteric fermentation in ruminants (the largest agricultural source in India, given the very large cattle and buffalo population), from flooded rice fields where anaerobic decomposition of organic matter produces it, and from manure storage.
• Nitrous oxide (N2O), about 270 times as potent as CO2: from nitrification and denitrification of soil nitrogen, chiefly synthetic nitrogen fertiliser (mostly urea), manure and crop residues, and from waterlogged soils.
• Carbon dioxide: from burning of crop residues (also releasing black carbon and methane), oxidation of soil organic matter under intensive tillage, fossil fuel use in pumps and machinery, fertiliser manufacture, and land-use change such as deforestation.

Mitigation strategies:

• Rice: alternate wetting and drying, the system of rice intensification, direct-seeded and aerobic rice, mid-season drainage, low-methane varieties, and use of ammonium-based or sulphate-containing fertilisers.
• Livestock: better feed and balanced rations, fodder improvement, feed additives and supplements that reduce enteric methane (such as the anti-methanogenic supplement developed by ICAR), genetic improvement to raise productivity per animal and reduce numbers of unproductive animals, and biogas plants for manure.
• Nutrients: the 4R approach (right source, rate, time and place), soil-test-based use (Soil Health Card), neem-coated urea, nano fertilisers, nitrification inhibitors, split application, and legumes to replace fertiliser nitrogen.
• Residues and soil: in-situ management using Happy Seeder and incorporation, or ex-situ use for fuel, fodder and biochar rather than burning; conservation agriculture (zero tillage, mulch, cover crops) to build soil carbon.
• Agroforestry, and shelterbelts, for carbon sequestration; renewable energy (solar pumps under PM-KUSUM) and efficient irrigation, and energy-saving machinery.
• Policy: national programmes such as the National Mission for Sustainable Agriculture, climate-resilient agriculture research (NICRA) and the Green Credit Programme, with capacity building and monitoring of emissions. Many measures also raise productivity and farm income, giving mitigation with adaptation and food security.

(b) Precision farming in India (20 marks)

Scope. Precision farming is site-specific management that applies inputs at the right place, time and rate, guided by spatial and temporal variability in field conditions, using technology. Its components are the Global Navigation Satellite System (GPS), geographic information systems, remote sensing (satellite and drone imagery), soil and crop sensors, variable rate technology, yield monitors, Internet of Things devices, decision support systems and artificial intelligence. In India its scope covers:

• Soil and nutrient management through grid soil sampling, fertility mapping and variable-rate fertiliser application.
• Water management using drip irrigation and fertigation, sensor-based scheduling and soil moisture monitoring.
• Crop monitoring, growth-stage and stress detection, pest and disease forecasting, and yield estimation using drones and satellites; and spraying by drones (for example, under the Namo Drone Didi scheme).
• Suitable crops and systems: high-value horticulture, plantation crops, sugarcane, protected cultivation and vertical farming, cotton, and rice-wheat systems in irrigated tracts.
• Support from digital public infrastructure such as the Digital Agriculture Mission, Agri Stack and Krishi-DSS.

Benefits: higher input-use efficiency and savings in fertiliser, water, seed and pesticide; higher yield and quality; lower environmental pollution and emissions; reduction in production risk; better records and traceability; saving of labour; and improved farm profit.

Limitations in the Indian scenario: small and fragmented holdings (average about 1.1 hectares), which make machinery and sensors uneconomic; high initial cost and low affordability; low awareness, digital literacy and skill of farmers; poor rural connectivity and power; lack of local soil, weather and crop data and maps; weak extension and service providers for maintenance; unsuitability of some imported technology; and tenancy and uncertainty of land rights. Custom-hiring centres, farmer producer organisations, subsidy, training and low-cost indigenous technologies can extend its reach.

(c) GIS in land use analysis and micro-watershed planning (10 marks)

Land use analysis. GIS integrates spatial data in layers. Satellite images (such as IRS-LISS, Sentinel) are classified into land use and land cover, and change detection of successive dates shows shifts, for example loss of farmland or forest, expansion of built-up area and degradation. Overlay of soil, slope from a digital elevation model, climate, water and land-capability layers gives land suitability analysis and identifies wasteland and unused land for cropping, forestry or pasture; it supports crop planning, monitoring and policy-making.

Micro-watershed planning. GIS delineates watershed and micro-watershed boundaries and the drainage network from the elevation model, computes morphometric parameters such as stream order, drainage density and slope, and prioritises sub-watersheds by erosion risk (using the Universal Soil Loss Equation) and by runoff (curve number method). Overlays then select suitable sites for check dams, farm ponds, contour bunds and afforestation; and repeated imagery monitors treatment impact on vegetation, groundwater and soil moisture. The results support participatory planning under watershed programmes such as PMKSY, with data available from Bhuvan and the National Remote Sensing Centre.