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

Geomorphology, soils and palaeosols of the Chencha area (Gamo Gofa, south western Ethiopian Highlands)

The landscape of the Chencha Highland (south western Ethiopia) is characterized by flat plateau bordered by steep slopes affected by landslides and dissected by concave valleys and gullies. Coalescing alluvial fans are found along the eastern piedmont at the transition to the Lake Abaya shores. A major rift-plateau escarpment, with minor synthetic and antithetic faults, is located along the eastern slopes of the highlands. Soil erosion is a widespread process and the soil cover is usually thin and discontinuous. Immature Cambisols formed on colluvial deposits containing lithic tools, pottery fragments and charcoal represent the most recent phase of soil formation. They are related to the clearance of the original forest cover and the introduction of extensive agricultural and pastoral practices. On the slopes these soils locally unconformably overlie reddish, strongly weathered buried Nitisols and Luvisols that can be classified as Palaeoedlisols with formation of saprolite. Thicker and better preserved Palaeoeldisols can be found on the summit plateau, due to reduced runoff erosion. Different generations of clay illuviation indicate that they underwent polycyclic processes, recording soil processes probably older than Holocene. Along the slopes, gully erosion exhumed a palaeo-gully system infilled by colluviums of soils and buried soils containing Middle Stone Age artifacts suggesting that important slope degradational processes occurred also during the Late Pleistocene. Buried brownish soils in these infillings show moderate clay illuviation that indicates short-lived climatic amelioration and phases of slope stability

Pedodiversity of three experimental stations in Estonia

The soil cover composition and properties of three experimental stations of Estonia - Jõgeva (JEA), Kuusiku (KEA) and Olustvere (OEA) - were analysed in detail (by soil type subdivisions - species and varieties) in relation to soil forming ecology and land management practices. The arable soil covers' pedodiversity and taxonomical conversion of Estonian Soil Classification into the World Reference Base for Soil Resources system were analysed on the basis of seven arable land parcels. The soil cover of JEA was relatively homogenous by soil species. The soil cover of KEA was much more heterogeneous, with five contrasting soil species in terms of soil genesis and with four stages in soil moisture regimes. OEA's soil cover consisted predominantly from Glossic Retisols with topsoils' texture - sandy loam. The texture of JEA is predominantly loamy and has, therefore, optimal agronomical properties. The texture of OEA is of a lower quality, by approximately one stage. The texture of KEA varies considerably (from sand to loam). Clay-rich textures are absent in all three EAs. In terms of soil species and properties, JEA is a representative of Central Estonian, OEA of South Estonian and KEA of North Estonian pedo-ecological conditions. All three field experimental areas are representative of the arable soils of the eastern part of the North European plain. The detailed research on soil cover is a good base for further researches on soils' humus and agrochemical status, productivity and suitability for crops, and for the evaluation of soils' environmental protection ability