(a) Write down the physical environmental factors affecting the crop production. Discuss the effects of changing rainfall pattern…

Crop production in India is fundamentally constrained by physical environmental factors, with rainfall variability posing the most acute threat to food security.

(a) Physical Environmental Factors and Rainfall Variability The primary physical factors governing crop growth include temperature, light, humidity, wind, and edaphic conditions such as soil texture, structure, depth, and moisture-holding capacity. Temperature dictates metabolic rates and phenology, while light intensity and duration drive photosynthesis. Humidity influences transpiration and disease pressure, and wind affects pollination and physical damage. Soil properties determine water and nutrient availability.

Changing rainfall patterns significantly disrupt these dynamics. A delayed monsoon onset, as seen in recent years, compresses the kharif sowing window, leading to reduced crop duration and yield. Spatially uneven distribution causes simultaneous drought in some regions and waterlogging in others. For instance, erratic rainfall has caused kharif crop failures in Maharashtra and Andhra Pradesh, while excess rainfall in the Northeast leads to lodging and disease. Conversely, deficit rainfall during the rabi season induces moisture stress in wheat and chickpea, reducing grain fill. Extreme events like cyclones and unseasonal rains further exacerbate losses, necessitating climate-resilient agronomy.

(b) Improved Cultivation Practices of Chickpea Chickpea (Cicer arietinum) is a vital rabi pulse. Its improved cultivation involves:

(i) Improved Varieties: Selection depends on the type. Desi types, such as JG 16, are known for high yield potential and early maturity. Kabuli types, including KAK 2 and JGK 1, are preferred for their larger seed size and specific market preferences. Both groups now include varieties with resistance to Fusarium wilt and Ascochyta blight, enhancing stability under stress.

(ii) Seed Rate and Spacing: The standard seed rate is about 75–80 kg/ha for desi types and 100–125 kg/ha for bold-seeded kabuli types. Spacing varies by type to optimize light interception and air circulation. Desi chickpea is typically sown at 30 cm row-to-row and 10 cm plant-to-plant spacing. Kabuli chickpea, having a larger canopy, requires wider spacing, often 30 cm row-to-row and 15 cm plant-to-plant, to prevent overcrowding and disease incidence.

(iii) Nutrient Management: Chickpea is a legume but requires basal application of phosphorus and potassium. The recommended dose is 20 kg N, 40 kg P₂O₅, and 20 kg K₂O per hectare. Since the crop fixes its own nitrogen, only a small starter dose is given; excess nitrogen suppresses nodulation. Sulfur (20 kg/ha) is also beneficial for protein synthesis.

(iv) Weed Management: Weeds compete for moisture and nutrients. Pre-plant incorporated herbicides like Fluchloralin (1.0 kg a.i./ha) are applied before sowing and incorporated into the soil. Pre-emergence herbicides such as Pendimethalin (1.0 kg a.i./ha) can be applied within two days after sowing. Hand weeding at 30–45 days after sowing is often necessary for complete control.

(v) Insect-Pest and Disease Management: Integrated Pest Management (IPM) is crucial. The major pest, Helicoverpa armigera (pod borer), is managed by pheromone traps, bird perches, and selective insecticide sprays (e.g., Emamectin benzoate) only when the economic threshold is crossed. Fusarium wilt, a soil-borne disease, is managed by growing resistant varieties, crop rotation with non-hosts like maize or wheat, and soil solarization.

(c) Cropping Patterns: Middle Gangetic Plain vs. Western Plateau and Hills Middle Gangetic Plain (agro-climatic zone IV: eastern Uttar Pradesh and Bihar): fertile alluvial soils, about 1,000–1,500 mm rainfall and good groundwater support intensive cropping. Rice–wheat is the dominant system; rice–lentil/chickpea, rice–rabi maize (especially in Bihar), maize–wheat and sugarcane-based sequences (north Bihar, eastern Uttar Pradesh) are also common, with jute in the wetter eastern districts and vegetables near towns. Floods and waterlogging in north Bihar make boro rice and flood-escape practices locally important.

Western Plateau and Hills (zone IX: parts of Maharashtra, Madhya Pradesh and Rajasthan): black and red soils with about 600–1,000 mm rainfall and a small irrigated area, so the region is mostly rainfed. Kharif sorghum, cotton, soybean, groundnut and pigeonpea dominate, followed by rabi sorghum, chickpea and wheat on residual moisture or well irrigation. Typical systems are soybean–chickpea/wheat, cotton + pigeonpea intercropping, sorghum–chickpea and groundnut-based systems. Cropping intensity is lower than in the Gangetic plain, and moisture conservation (mulching, ridge–furrow, broad bed and furrow) is central.