This paper analyzes virtual water trade flows through food products between India and its trading partners. It relies on the gravity model of trade and estimates a panel data fixed effect regression to identify drivers of virtual water trade. Our results show that India was the net exporter of virtual water in food products during 1990–2013; however later it turned out to be its net importer. Further our analysis shows distance between trading partners as the primary driver of virtual water trade. India prefers trading with its neighbours to reduce transportation costs. The availability of arable land and water used in crop production are limiting factors for production of food crops and thus act as essential factors in deciding the virtual water trade flows. These findings indicate that resource endowment factors influence bilateral virtual water trade flows.

The authors of the recently completed Comprehensive Assessment of Water Management in Agriculture (CA) concluded that there are sufficient water resources to produce food for a growing population but that trends in consumption, production and environmental patterns, if continued, will lead to water crises in many parts of the world. Only if we act to improve water use will we meet the acute fresh water challenge. Recent spikes in food prices, partially caused by the increasing demand for agricultural products in non-food uses, underline the urgent need to invest in agricultural production, of which water management is a crucial part. The world experienced similar pressure on per capita food supplies and food prices in the 1960s and 1970s, but the challenges now are different than those we experienced 50 years ago. The world's population is substantially larger, there are many more people living in poverty, and the costs of many agricultural inputs are much higher. The current situation and the long-term outlook require a fresh look at approaches that combine different elements such as the importance of access to water for the poor, providing multiple ecosystem services, rainwater management, adapting irrigation to new needs, enhancing water productivity, and promoting the use of low-quality water in agriculture. This special issue highlights the analysis behind a number of policy options identified by the CA, a five-year multi-disciplinary research program involving 700 scientists. This introductory article sets the background and context of this special issue, introduces the key recommendations from the CA and summarizes the papers in this issue.

Residual resources in agriculture provide prime raw material for bioenergy production whose optimization has potential to promote agricultural economy while mitigating environmental side-effects. Food, energy, water, and land resources are intertwined in agricultural systems. Effective management of bioenergy production, considering the nexus of these resources, is needed for the sustainable development of agriculture, which is challenging because of the uncertainties involved therein. This study proposes an optimization-assessment approach (input/output relationship) for sustainable bioenergy production in agricultural systems. The approach is capable of (1) providing decision makers with the ability to determine optimal policy options among water, land, energy, and livestock, considering the tradeoff between economic and environmental impacts for bioenergy production; (2) helping decision makers identify the level of sustainability of agricultural systems and where the effort should be made for various regions; and (3) dealing with the uncertainties to provide decision alternatives. The proposed approach is applied to a case study in the particular context of northeast China, which is predominantly an agricultural region with large bioenergy potential. The changing range of bioenergy production potential, system costs, and environmental impacts were obtained, based on different schemes for the allocation of agricultural resources among different regions. Economic-environmental impact and sensitivity analyses were conducted, and agricultural system sustainability was assessed in a changing environment. Considering the complexity due to uncertainty, the proposed approach can help manage bioenergy production in agricultural systems in a sustainable way, and will be applicable for similar agriculture-centered regions.

This article attempts to evaluate the comparative socioeconomic benefits of funding performance-based private sector social enterprises and posits that the social rate of return of such investments is significant and exceeds expectations for similar investment portfolios. Using the case study of the Securing Water for Food Grand Challenge for Development, we perform a social rate of return analysis on 16 water conservation technologies (WCTs) in 10 nations. Through using an extensive benefit cost ratio, we obtain the Marginal Internal Rate of Return whereby the discounted value of future benefits is equal to the reinvestment cost of capital for the SWFF portfolio. This allows the impact of SWFF to be comparable to other investments and serve as a benchmark. The resulting social rate of return metrics exceed the conservative expectations of impact investment funds as well as comparable foreign aid investments. The reasons behind this high rate of social impact are further explored and recommendations are provided accordingly for an alternative performance-based investment model of foreign aid disbursement that prioritizes scalable small and medium-sized social agribusiness enterprises in developing nations.

Smallholder irrigation is an important pathway towards better livelihoods and food security in sub-Saharan Africa. This article assesses the contribution of farmer-friendly soil and water monitoring tools, and agricultural innovation platforms, towards household income and food security in two small-scale irrigation schemes in Tanzania. Quantitative and qualitative data from farmer’s field books, household surveys and focus groups were used to assess the impacts of the two interventions. The two interventions together contributed to enhancing smallholders’ food security and household income in the two schemes, as did the agricultural innovation platform on its own.