This study conducted to evaluate catchment storage and command relationship and water use strategies under supplemental irrigation for sustainable rainfed agriculture in the semi-arid regions of Rajasthan, India. In southern Rajasthan, a small category of farmers is above 78%, the potential evapotranspiration is greater than the average rainfall with prevailing arid conditions, and rainfed agriculture is a challenging task. An agricultural micro watershed of 2.0 ha evaluated to establish a catchment storage command area (CSC) relationship and micro irrigation system as an effective water use strategy. The significant results indicate that a farm pond with a storage capacity of 560 m³ with permanent lining (cement + brick) is sufficient to harvest runoff water from a 2.0 ha catchment under the rainfall conditions of below normal (up to 50% deficit), long-term average, and wet years. Harvested rainwater can be used to irrigate a command area of even up to 1.0 ha, with supplemental irrigation of 5 cm in both the seasons of kharif as well as rabi. The two crops, maize (Zea mays) in the kharif season and coriander (Coriandrum sativum) in the rabi season, were significantly profitable with supplemental irrigation by adopting a drip irrigation system.

Rainfall deficits and erratic dry spells pose major challenges in rainfed ecosystem. In-situ moisture conservation practices (MCP) like ridge–furrow methods, improve soil moisture but are inadequate during 2–3 week dry spells at critical crop stages (flowering and maturity), leading to yield loss. Supplemental irrigation (SI) using an ex-situ rainwater harvesting (RWH) pond can mitigate these effects, but optimizing the pond design is challenging due to limited runoff and storage losses. This study aims to design RWH pond for small farm holders with a 1.0 ha area and evaluate its efficient use for SI during intermittent dry spells and critical crop stages. The design volume was estimated using the SCS-CN method based on daily rainfall data (1974–2010) for the northeast monsoon. A pond with a capacity of 487.5 m³, constructed for a 1 ha micro-watershed, was used to observe the runoff for design validation. The harvested runoff can be used as SI for a cultivable area of 0.4 ha, based on the watershed-to-cultivable area ratio. Statistical analysis of observed and estimated runoff data from 2011 to 2023 revealed a strong correlation (r = 0.87), confirming the pond design. Harvested rainwater, applied through micro-irrigation (rain gun) at a depth of 50 mm during moisture stress periods, significantly improved cotton productivity. The combined use of harvested rainwater and MCP increased yield in the range of 3.8 to 25.3%, improved rainwater use efficiency (1.52 to 3.13 kg ha⁻¹ mm⁻¹), and had a higher benefit-cost ratio (1.15 to 2.43) over a 13-year period. This study concludes that integrating in-situ MCP with ex-situ RWH with micro-irrigation significantly improves rainfed crop productivity in vertisols.

1. India receives an annual precipitation about 4000 billion cubic meters (BCM) which is highly variable with space and time. The annual flow to river systems in India is about 1953 BCM and repleni...

The performance of stone cover on infiltration, runoff, erosion and sediment yield during overland flow were quantified using a hydraulic tilting flume under two different discharges with four different slopes (0.1, 1.0, 3.0, and 5%). Two surface conditions were tested: bare soil and partial stone-cover (50%) arranged in two strips. Stone cover reduced flow velocity, decreased outflow, increased infiltration and reduced soil erosion compared to bare soil. Stone cover was most effective at reducing discharge when the flow depth was less than the median particle diameter, but was effective at reducing sediment yield for both flow depths. Stone cover prevented rill erosion above 3% slope. Infiltration decreased with increasing slope due to lower ponding depths on steeper slope. Sediment concentration increased with an increase in slope even with stone cover. In the case of bare soil, sediment concentration showed an exponential increase with increase in slope. Stone cover was effective in increasing infiltration rate of overland flow by decreasing flow velocity, but only when flow depth was less than or equal to median particle diameter. By contrast, stone cover reduced erosion and sediment load at both flow depths. Models of infiltration rate and sediment transport capacity were calibrated with the observed data for use in other modeling applications.

A field experiment was conducted at AICRPDA centre Rewa, during 2008 to 2017 to establish the rainfall-runoff relationship for rainwater gathering aimed at enhancing production. The daily rainfall pattern in the catchment region was analysed over 30 years specifically from 1995 to 2024. The rainfall exhibits variability over the 30 year period. Based on analysis of rainfall data, optimum size of farm pond for Kymore plateau regions is 1000 m3 with a minimum catchment area of 1.0 ha and can supplement to command area 1.0 ha. If 5.0 cm irrigation to two times is to be supplemented, which can cover an area of 1.00 ha of command area. Harvested water can also be used during dryspells under variable rainfall conditions during Kharif season and as a supplemental irrigation during rabi season for crops like chickpea and other pulses etc., This technology ensures a sustainable yield in kharif major crops by addressing dryspells and enhance production of rabi crops like chickpea and other pulses.