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Decentralized rainwater harvesting (RWH) is a promising approach to mitigate drought in the drylands. However, an insufficient understanding of its impact on hydrological processes has resulted in poor resource planning in this area. This study is a meta-analysis of 25 agricultural watersheds representing a range of rainfall and soil types in the semi-arid tropics. Rainfall-runoff-soil loss relationship was calculated at daily, monthly and yearly levels, and the impact of RWH interventions on surface runoff and soil loss was quantified. A linear relationship was observed between daily rainfall and surface runoff up to 120 mm of rainfall intensity, which subsequently saw an exponential increase. About 200–300 mm of cumulative rainfall is the threshold to initiate surface runoff in the Indian semi-arid tropics. Rainwater harvesting was effective in terms of enhancing groundwater availability (2.6–6.9 m), crop intensification (40–100%) and farmers' incomes (50–200%) in different benchmark watersheds. An average of 40 mm of surface runoff was harvested annually and it reduced soil loss by 70% (3 ton/ha/year compared to 1 ton/ha/year in non-intervention stage. The study further quantified runoff at 25th, 50th and 75th percentiles, and found that more than 70% of the area in the Indian semi-arid tropics has high to medium potential for implementing RWH interventions. [ABSTRACT FROM AUTHOR]

Agricultural water management (AWM) interventions play an important role in ensuring sustainable food production and mitigating climate risks. This study was carried out in a watershed located in a low rainfall (400-600 mm) region of western India. The Soil and Water Assessment Tool model was calibrated using surface runoff, soil loss, and reservoir storage levels, between the year 2000 and 2006. The investigation indicated that the various AWM interventions increased groundwater recharge from 30mm/year to 80 mm/year and reduced surface runoff from 250 mm/year to 100 mm/year. The intervention structures were refilled two to three times during the monsoon season depending on rainfall intensity and duration. The interventions have the advantage of building a resilient system by enhancing groundwater availability even in dry years, stimulating crop intensification and protecting the landscape from severe erosion. The results indicate that soil erosion has been reduced by more than 75% compared to the nonintervention situation. Moreover, the AWM interventions led to the cultivation of 100-150 ha of fallow land with high-value crops (horticulture, vegetables, and fodder). Household income increased by several folds compared to the nonintervention situation. The study showed about 50% reduction in downstream water availability, which could be a major concern. However, there are a number of ecosystem trade-offs such as improved base flow to the stream and reduction in soil loss that should be considered. The study is of great importance to stakeholders to decide on the optimal design for AWM interventions to achieve sustainable development goals. [ABSTRACT FROM AUTHOR]

A host of best water and soil management practices (BMPs) hold promise in addressing water scarcity and land degradation to enable sustainable crop intensification in smallholder farming systems. OBJECTIVE This study quantifies the effect of BMPs on crop productivity, income, water saving and water balance components and identifies gaps for future research. This paper synthesizes the performance of BMPs and the existing data gap by reviewing 108 published studies from the Indian subcontinent which capture a diverse range of rainfall and cropping systems. In situ conservation measures helped enhance crop yields by 200–1000 kg/ha, reduced cost of cultivation and enhanced incomes by US$ 10–200/ha/year. The BMPs were helpful in enabling annual water saving in the range of 50 mm to 300 mm by either conserving residual soil moisture or saving irrigation water resulting in enhanced water productivity. Interventions such as direct seeded rice and laser land leveling were found most effective in terms of water saving and in reducing cost of cultivation. On the other hand, ex situ rainwater harvesting interventions helped enhance groundwater recharge by harvesting an additional 50–150 mm of surface runoff which helped increase crop yields, led to sustainable crop intensification and strengthened the number of ecosystem services. Most of the published literature on in situ conservation measures are studies that were carried out at research stations, which show promise of sustainable intensification. However, greater efforts are needed to document learnings from farmer/community scale interventions for effective scaling up. There is also a gap in data availability that hampers a clear understanding of the impact of ex situ rainwater harvesting interventions and ecosystem trade-offs; moreover the data available covers short periods and only covers an area of up to 10 km2. We recommend the monitoring of long-term system-level impact indicators to realize the potential of ex situ rainwater harvesting interventions in a systems perspective and better grasp the ecosystem trade-offs. More importantly, the review revealed the ample scope of integrating in situ and ex situ interventions to build system-level resilience in smallholder farming systems in order to accelerate progress towards achieving the United Nations Sustainable Development Goals (SDGs). [Display omitted] • Direct seeded rice and laser land leveling interventions can reduce irrigation water requirement by 200–300 mm • Raised bed and mulching are found helpful to conserve 50–80 mm moisture • Ex-situ rainwater harvesting interventions enhanced groundwater availability by harvesting 50–150 mm surface runoff • Integration of in-situ & ex-situ practices hold promise to bridge the yield gap while ensuring sustainable intensification [ABSTRACT FROM AUTHOR]

• Shallow aquifer recharge during a wet year served two successive dry years. • Increased water availability converted degraded areas into productive landscape. • Crop productivity increased by 10–70 % and income of rural households by 170%. • Downstream water availability fell by 40% in a normal year but was negligible in a wet year. Rainfall variability and water scarcity continue to hamper the food and income security of smallholder farming systems in poverty-affected regions. Innovations in soil and water management, especially in the drylands, are critical for meeting food security and water productivity targets of Agenda 2030. This study analyzes how rainfed agriculture can be intensified with marginal impact on the landscape water balance. The impact of rainwater harvesting structures on landscape hydrology and associated agricultural services was analyzed in the semi-arid Jhansi district of Bundelkhand region in central India. The Parasai-Sindh pilot watershed was subjected to a 5-year (2012–2016) monitoring of rainfed system improvements in water availability and crop intensification due to surface water storage (haveli system), check dams, and field infiltration structures. Hydrological processes were monitored intensively to analyze the landscape's water balance components. Rainwater harvesting (RWH) structures altered the landscape's hydrology, limiting average surface runoff from 250 mm/year to 150 mm/year over the study period. Groundwater levels increased by 2–5 m (m), alleviating water scarcity issues of the communities in recurring dry years. Nearly 20% of fallow lands were brought under cultivation. Crop yields increased by 10–70% and average household income increased from US$ 960/year to US$ 2700/year compared to that in the non-intervention landscape. The combined soil–water–vegetation efforts strengthened water resilience and environmental systems in agricultural landscape. [ABSTRACT FROM AUTHOR]

Global experiences reveal the positive impact of watershed-based interventions in improving livelihoods and environmental security. In the drylands, increasing forage resources and improving livestock productivity is a critical challenge. The overarching aim of this paper is to analyse the impact of watershed-based interventions on livestock population, productivity, fodder resources, and biomass availability. The paper describes the interrelationship between land, water, crop, and livestock and how the gap in forage deficit can be bridged through a range of watershed interventions. The study was undertaken in the Parasai-Sindh watershed of Central India between 2011 and 2016. A 300-year-old defunct haveli (a traditional rainwater harvesting structure) was renovated and nine check dams along the drainage line were constructed. Nearly 25,000 running-meters of field bunds were constructed. Large fields (2-3 ha) were divided into relatively smaller plots (0.3–0.5 ha) to reduce runoff velocity. The impact of watershed interventions on water availability, livestock productivity, forage yield, and income was studied through hydrological monitoring, primary household survey and principal component analysis (PCA) biplot and hierarchical clustering. The watershed interventions enhanced groundwater availability leading to greater fodder availability, 22% increase in livestock population (ACU) and a 120% increase in milk production over a period of five years. The bovine population recorded a surge of 193% (cattle) and 32% (buffalo) over this period. Mean dry matter (DM, fodder) availability also increased from 10 t/household/year to 16.7 t/household/year owing to improved water availability. Groundnut (rainy season) and wheat (post rainy season) contributed significantly as forage resources. There was an annual forage demand of 5560 t DM for a livestock population of 2175 ACU in 2011 and of 6770 t DM for a livestock population of 2650 ACU in 2016. Annual forage biomass availability was estimated at 4219 t DM in 2011 and 6977 t DM in 2016. There was a deficit of 1341 t DM (24%) in 2011 which turned into a 3% surplus of 210 t DM in 2016 through watershed-based interventions. With increased cropping intensity and milk production, average annual household income increased from US$ 1325 to US$ 2430 over the five-year period. This case study clearly illustrates the impact of watershed-based interventions on livestock population, productivity, forage resources, and biomass availability to bridge the gap in forage deficit. Its findings serve as a guide to widely scale up watershed-based interventions for improved water and biomass availability, and livestock productivity in semi-arid and dryland regions. [Display omitted] • Poor crop and livestock productivity is a critical challenge in drylands and watershed interventions could help build resilience to this • Interlinkages among land-water-crop-livestock sectors and their sustainability have been studied • Watershed based interventions enhanced groundwater availability, which reduced risk of crop failure, increased crop intensification and productivity • Forage availability has improved from deficit to surplus status due to watershed interventions despite significant increase in livestock population • Integrating land-water-crop-livestock interventions in watersheds can provide opportunities to improve rural livelihoods in drylands [ABSTRACT FROM AUTHOR]