“Trap-dams”: Artificial Subsurface Storage of Water
To secure and increase the availability of clean drinking water in arid and semi-arid regions of the world, construction of sediment filled dams for artificial subsurface storage of water could provide very cost efficient solutions.
Managed Aquifer Recharge
Water scarcity can be caused primarily by a shortage in the total amount of water available, or to temporal imbalances between supply and demand. In many areas of the world, periodic water shortages can be alleviated by storing water available during rainy periods (or other times of excess supply) for later use during dry periods. The storage and recovery cycle could be seasonal or inter-year with water stored in years with higher than normal rainfall for use during subsequent dry years. Even in arid lands, where the average annual total supply of water is inadequate to meet all demands, seasonal or inter-year storage of water may still be of value by capturing water that would otherwise not be available for beneficial use. Mutiso (2003) observed that in most arid and semiarid lands, the quest for water does not depend on the absolute amount of precipitation, but on the fraction retained.
Spatial distribution of root lesion nematodes (Pratylenchus spp.) in a long-term no-till cropping system and their relationship with soil and landscape properties
The Cook Agronomy Farm of Washington State University is a long-term precision agriculture study site. Since 2000, the farm has been in various three-year no-till rotations with winter wheat, spring wheat, and various rotation crops such as barley, canola, peas, lentils, and chickpea. The spatial distribution of root lesion nematodes (Pratylenchus spp.) and their relationships with soil and terrain variables were studied by collecting soil samples at 127 and 124 geo-referenced points in two 12-ha fields during the spring of 2010 and 2011, respectively. Pratylenchus spp. were detected in more than 85% of the sampled locations in both fields. Nematode densities spatially mapped using ArcGIS software occurred in an aggregated pattern. Previous rotation crops had no effect on the spatial distribution. Classification and regression tree analysis (CART) using soil and terrain variables, and nematode density, explained 61 and 34% of the variability associated with nematode density in 2010 and 2011, respectively. Soil edaphic factors, such as organic matter, were stronger predictors of nematode populations than rotation effects.