Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture

Economic instruments can be used to control groundwater nitrate pollution due to the intensive use of fertilizers in agriculture. In order to test their efficiency on the reduction of nitrate leaching, we propose an approach based on the combined use of production and pollution functions to derive the impacts on the expected farmer response of these instruments. Some of the most important factors influencing nitrate leaching and crop yield are the type of soil and the climatic conditions. Crop yield and nitrate leaching responses to different soil and climaticconditions were classified by means of a cluster analysis, and crops located in different areas but with similar response were grouped for the analysis. We use a spatial economic optimization model to evaluate the potential of taxes on nitrogen fertilizers, water prices, and taxes on nitrate emissions to reduce nitrate pollution, as well as their economic impact in terms of social welfare and farmers' net benefits. Themethod was applied to theMancha Oriental System(MOS) in Spain, a large area with different soil types and climatic conditions.We divided the study area into zones of homogeneous crop production and nitrate leaching properties. Results how spatially different responses of crop growth and nitrate leaching, proving howthe cost-effectiveness of pollution control instruments is contingent upon the spatial heterogeneities of the problem.The study has been supported by the European Community 7th Framework Project GENESIS (226536) on groundwater.Peña Haro, S.; García Prats, A.; Pulido-Velazquez, M. (2014). Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture. Science of the Total Environment. 499:510-519. https://doi.org/10.1016/j.scitotenv.2014.07.029S51051949

Vineyard microclimate and yield under different plastic covers.

The use of plastic cover in vineyards minimizes effects of adverse weather conditions. The northwest of São Paulo State is one of the largest grape producing regions in Brazil; however, few studies investigate the effects of different plastic covers on vineyards in this region. This study compared the effect of black shading screen (BSS) and braided polypropylene film (BPF) on BRS Morena vineyard microclimate, grown on an overhead trellis system in the northwestern São Paulo. The experiments were carried out during three growing seasons (2012 ? 2014). BSS allowed superior incoming solar radiation (SR) transmissivity, resulting in higher net radiation (Rn), and higher ratio between photosynthetically active (PAR) and SR. No differences were observed between the average air temperatures (T) and relative humidity (RH) of covered environments (BPF and BSS) and outside condition (automatic weather station ? AWS), due to high air circulation, despite wind speed (WS) reduction caused by plastic covers. BPF provided better conditions for vineyard growth with higher fruit yield than vineyard under BSS regarding the number of shoots with bunches per plant, bunch and stem weights, longitudinal diameter of berries, quantity of fertile buds per shoot, and yield per shoot and per plant. BPF covers also influenced leaf size and growth speed of plants in vineyards. Keywords Black shading screen . Braided polypropylene film . BRS Morena . Leaf wetness duration . Yiel