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Nitrogen use efficiency (NUE) is often used to evaluate an agricultural system's relative ability to process nitrogen (N) inputs. However, no universal indicator has simultaneously considered both economic and environmental objectives. We develop Luenberger indicators of NUE that incorporate both economic and environmental objectives to examine spatio-temporal changes in NUE, which we apply to the Upper Mississippi River Basin (UMRB) for the period 2002-2012. We find considerable spatial-temporal variation in NUE, which could be used to inform future agri-environmental policy and conservation targeting decisions in the UMRB. Using this approach could lead to more cost-effective targeting of areas for N reduction in the UMRB. [ABSTRACT FROM AUTHOR]

Irrigation application of effluent from lagoon based systems is an important aspect of animal manure management in swine rearing facilities. This paper describes a procedure for obtaining least-cost components and operational parameters for an irrigation system used to apply liquid manure. The paper employs propositions from hydraulics--affinity laws and Hazen--Williams formula--to derive statistically estimable relationships between pressure, liquid output, power requirement, and impeller speed of an irrigation system. Coefficient estimates are then used in a spreadsheet based decision support system that employs an optimization program to select the least costly irrigation system. A practical application is showcased through simulation of three hypothetical swine farms. Main findings are that the use of this optimization procedure can result in cost savings for swine growers applying manure by irrigation and that the cost savings potentials increase with the farm size. CE Database subject headings: Agricultural wastes; Economic models; Effluents; Irrigation systems; Animals; Waste management.

How off‐farm employment can enhance welfare in terms of food consumption and poverty alleviation is a critical question facing many developing countries. This study addressed that question by pursuing two objectives: (i) to quantify the impact of off‐farm employment on rural households' welfare, food security and poverty; and (ii) to examine the factors that affect their decision to work off‐farm. Using panel data, we estimated a difference‐in‐difference combined with a propensity score matching model. The findings show that off‐farm employment improves income, ensures food security and contributes to poverty alleviation. The results also show that age, marital status, education, labour, financial capital, land, location, market access and losses from natural disasters are significant contributing factors to the decision to participate in off‐farm employment. The findings suggest that to improve the welfare of rural households, the Vietnamese government should proceed with policies that enhance their opportunities for participation in off‐farm employment. [ABSTRACT FROM AUTHOR]

Abstract: An integrated biophysical and economic model is used to determine the effects of using more water efficient irrigation systems and trade in water rights on the environmental performance of irrigation enterprises in the Mooki catchment within the Murray–Darling Basin, Australia. We find that improved water use efficiency increased profit in the presence of modern irrigation technologies and water trading. Salinity risk downstream is reduced due to the fall in saline discharge from the catchment, and irrigation water is traded away from ecologically significant regions. It is important that the institutional setup gives confidence in the security of water supplies. When irrigators can be assured about the security of their water entitlements in the context of water reform policies, incentives emerge for them to invest in water efficient irrigation technologies and to participate in the water market. Environmental performance can thereby be improved without the need for financial support from the government. Further, minimal government intervention is required to address salinity; given the conjunctive nature of secondary salinity and water use it can be cost-efficient to address both environmental flow and salinity mitigation with a single policy instrument. [Copyright &y& Elsevier]

Firms are often confronted with regulations on their productive and commercial activities. In many instances a firm can take various actions to pre-empt regulations. This article determines the optimality of pre-emptive action for a firm subject to natural resource regulation. The regulation may be either fixed or relative to the production history. Dependent on the type of regulation, a firm can pre-empt by terminating its current use of resources and converting to other use or by building up the input use or output history in the period prior to regulation. It is shown that the optimal pre-emption decision depends on the extent and perceived probability of regulation, on the rate of discount and on technological characteristics of the production process including the alternative use of the resource. [ABSTRACT FROM AUTHOR]