Author
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ALVA, ASHOK |
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Submitted to: American Water Resources Association Summer Specialty Conference
Publication Type: Abstract Only Publication Acceptance Date: 3/18/2005 Publication Date: 7/1/2006 Citation: Alva, A.K. 2006. Optimizing irrigation scheduling to minimize leaching losses by using capacitance probes. American Water Resources Association Summer Specialty Conference. On CD. Interpretive Summary: Technical Abstract: Soils with low retention capacity for nutrients and water, and shallow-rooted crops increase the potential for N leaching. Potatoes are grown in the irrigated area of the US Pacific Northwest (PNW) as a major cash crop. This production occurs under irrigation systems, predominantly center pivots, and mostly on low organic matter sandy soils. Improved N management practices combined with careful irrigation scheduling are necessary to increase crop water and nutrient uptake efficiencies and minimize N losses to groundwater. Real time, continuous monitoring of soil water content within and below the root zone is necessary to fine tune irrigation scheduling to minimize the leaching loses below the root zone, while supplying adequate water for the plants to minimize the effects of water stress, which can have significant negative effects on the tuber production and quality. Capacitance probes were used in Potato fields to monitor the soil water content at 15, 30, 60, 90, and 120 cm depth. Depth integrated soil water content (0-60 cm depth soil. i.e. predominant root zone) corresponding to field capacity soil water content (Full point), 30 percent depletion of the available soil water content (Refill point), and at wilting point (Driest point) provided the set points for basing the irrigation. During the crop growing season, the soil water content in the 0-60 cm depth should be maintained between the “Full point” and the “Refill point” to minimize excess soil water content, which could leach below the root zone, and minimize the water stress effects on the crop. |
