Effect of Agronomic Intervention on the Productivity of Khadin Cultivated Rabi Crops in Arid Region for Enhancing Farm Income: A Case Study from Jodhpur (Rajasthan, India)

Khadin is a traditional runoff farming system practiced in the Indian Thar Desert, designed to facilitate cultivation of at least one crop annually in regions receiving approximately 200 mm of annual rainfall. Strategic selection of high-value crops and use of collected rainwater for supplemental irrigation are considered vital for enhancing farm income and water productivity (WP) in khadin systems. The present study aimed to: (i) develop a facility for providing supplementary irrigation to test crops using solar energy; (ii) identify most remunerative crop under prevailing khadin conditions; (iii) determine optimal irrigation levels for maximizing water productivity; and (iv) validate research findings through measurements of soil-water content and crop physiological characteristics. A water storage structure with a capacity of 3.2 million liters was constructed within the khadin for surplus runoff collection and lined with 300-micron HDPE sheet to enable supplementary irrigation. Experiments were conducted with three crops-mustard (B. juncea), barley (H. vulgare), and gram (C. arietinum)-under three levels of supplementary irrigation to identify the most profitable crop. Standard methodologies were employed to assess soil-water content and crop physiological responses. Results revealed that gram with supplemented irrigation produced the highest gram equivalent yield (GEY) of 2047 kg ha-¹, which was 32% and 20% higher than barley and mustard, respectively. The highest economic water productivity (EWP) of Rs. 122.54 m-³ was recorded for gram, representing an Rs. 31.65 m-³ advantage over barley. Additionally, a single supplementary irrigation increased gram grain yield by 479 kg ha-¹ and farm income by Rs. 28,740 ha-¹ compared to farmer-managed gram cultivation. Enhancing existing khadin systems with supplementary irrigation at critical crop growth stages and selecting suitable crops can significantly improve productivity and farm profitability in semi-arid and arid regions of India.