Crop water demand estimation and irrigation scheduling for sustainable water management and crop planning in selected watersheds of Meghalaya, India.

Abstract

Understanding crop water requirements is critical for irrigation scheduling and cropping pattern decisions in any environment. Using the CROPWAT model, a study was conducted to estimate the irrigation requirement of major crops cultivated in the humid subtropical climate of Meghalaya from 2001 to 2022 and preparing irrigation scheduling plan for the current scenario. The results showed that the annual ET₀ from 2001 to 2022 at the selected station was 876.7 mm. The lowest monthly ET₀ (46.8 mm) was observed in December and the highest (94 mm) was observed in March. The results also indicated that the seasonal minimum and maximum CWR for rice, maize, ginger, mustard, and potato were 462.5 and 652.2 mm, 314.6 and 455.8 mm, 673.3 and 922.9 mm, 199.8 and 413.4 mm, and 341.5 and 465.3 mm, respectively. The minimum and maximum IR for rice, maize, ginger, mustard, and potato were 152.9 and 378.8 mm, 0 and 30.2 mm, 60.1 and 255.7 mm, 0 and 193 mm, and 0 and 170.8 mm, respectively. The net irrigation requirement (NIR) and gross irrigation requirement (GIR) were calculated using the scheduling option and 70% efficiency for the preparation of the irrigation schedule. For rice (transplant), the effective rainfall partially met its water needs, requiring supplemental irrigation. Maize, Cotton, and Jute relied entirely on effective rainfall, eliminating the need for irrigation. Ginger and Mustard needed both effective rainfall and additional irrigation. These findings delivered a comprehensive understanding of the location-specific water variations for crops in Meghalaya, vital for sustainable water resource management. PRACTITIONER POINTS: CWR are critical for irrigation scheduling and cropping pattern decisions. FAO CROPWAT model was used for crop planning and irrigation scheduling. The net irrigation requirement and gross irrigation requirement for hilly watershed Comprehensive understanding of the location-specific water variations for crops The irrigation needs vary among different crops based on efficiency % and depletion %.