HR: 0800h
AN: H41C-0648    [Abstracts]
TI: Quantifying runoff water quality characteristics from nurseries and avocado groves subjected to altered irrigation and fertilizer regimes
AU: * Samant, S A
EM: shraddha_samant@yahoo.com
AF: San Diego State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AU: Beighley, R E
EM: beighley@mail.sdsu.edu
AF: San Diego State University, Civil and Environmental Engineering, 5500 Campanile Drive, San Diego, CA 92182, United States
AB: In agriculture, improper, excessive or poorly timed irrigation and fertilizer applications can result in increased pollutants in runoff and degraded water quality. Specifically, the cultivation of salt sensitive plants and nurseries require significant irrigation and fertilizer that leads to high nutrient leaching. In southern California, a large producer of Avocados and nursery plant, waterways are often subjected to elevated nutrient concentrations, which stress the aquatic ecosystem. In this research, the specific objectives are to determine optimal irrigation and fertilizer application rates for minimizing nutrient and sediment export from avocado groves and nurseries. Altered irrigation and fertilizer application experiments will be implemented and monitored at the San Diego State University's Santa Margarita Ecological Reserve, which contains a 12 ha avocado grove and newly constructed 0.4 ha nursery. The study will last for twelve months, with runoff from natural rainfall or irrigation sampled and analyzed for nutrient concentrations on a monthly basis. The growth rate, leaf nutrient content and plant yield will also be monitored monthly. The nursery site is divided into eight plots (13.5-m x 13.5-m), with each plot containing 1200 plants consisting of four commonly used landscaping varieties in southern California. The avocado grove of the Hass variety is divided into four 1-ha plots. The experimental plots represent combinations of irrigation and fertilization practices with different methods and rates. In all cases, irrigation is fully automated based on soil moisture. To assess the effectiveness of the altered irrigation and fertilizer strategies, runoff water quality and plant yield will be compared to controlled treatments. This research is intended to provide a better understanding of how irrigation and fertilizer management can be used for the long-term reduction of nutrients in the Santa Margarita Watershed, which in turn will lead to improved surface water quality, aquatic habitats, and overall stream health. Preliminary results for runoff water quality (N and P) and plant growth characteristics from two months of monitoring are presented.
UR: http://spatialhydro.sdsu.edu
DE: 1842 Irrigation
DE: 1852 Plant uptake
DE: 1866 Soil moisture
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2007 Fall Meeting