www.sciencemag.org SCIENCE VOL 327 26 FEBRUARY 201

There is a global concern about the increase in atmospheric concentrations of greenhouse gases. One method being discussed to encourage greenhouse gas mitigation efforts is based on a trading system whereby carbon emitters can buy effective mitigation efforts from farmers implementing conservation tillage practices. These practices sequester carbon from the atmosphere, and such a trading system...

Targeting of agricultural conservation practices to the most effective locations in a watershed can promote wise use of conservation funds to protect surface waters from agricultural nonpoint source pollution. A spatial optimization procedure using the Soil and Water Assessment Tool was used to target six widely used conservation practices, namely no-tillage, cereal rye cover crops (CC), filter...

Soil quality appears to be an ideal indicator of sustainable land management. Soil is the foundation for nearly all land uses. Soil quality, by definition, reflects the capacity to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. By reflecting the basic capacity of the soil to function, it integrates across many potential use...

surface. the development of gullies causes the loss of a great amount of soil and could be considered as one of the principal causes of geo-environmental degradation. in this research fazi model introduced for gully erosion zonation in arid and semiarid area considered to calibration and validation in kahkiloeh and boyerahmad province. therefore, the abgandi watershed were selected by considera...

Relations between riverine export (load) of total nitrogen (N) and total phosphorus (P) from 133 large agricultural watersheds in the United States and factors affecting nutrient transport were evaluated using empirical regression models. After controlling for anthropogenic inputs and other landscape factors affecting nutrient transport-such as runoff, precipitation, slope, number of reservoirs...

In order to maintain a proper balance between development pressure and water resources protection, and also to improve public participation, efficient tools and techniques for soil and water conservation projects are needed. This paper describes the development and application of a web-based watershed management spatial decision support system, WebWMPI. The WebWMPI uses the Watershed Management...

soil erosion in a given area depends on natural characteristics of the place as well as the rate of  human impact. in iran, the mediterranean precipitation regime and relatively high erosivity of rain, wide area of erodible soils/lithological formations, sparse natural vegetation in many regions and mountainous topography are main natural factors that affect soil erosion by water. accelerated s...