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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #146070
Title: MANURE APPLICATION, TILLAGE, AND FURROW IRRIGATION MANAGEMENT EFFECTS ON RUNOFF NUTRIENT LOSSES

Author
item Lentz, Rodrick
item Westermann, Dale
item PECKENPAUGH, RONALD - USDA-ARS (RETIRED)

Submitted to: Sustainable Land Application Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2003
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Dairy industry expansion in southern Idaho has increased manure production, raising concerns that its application to irrigated crop land may increase nutrient contamination of surface waters. We hypothesized that nutrient losses in furrow irrigation runoff are a function of tillage and the timing of irrigations and manure application. Two or three irrigations were monitored on fields i) with and without a current-year, disked-incorporated, manure application (23-Mg/ha, moisture-free) and ii) in which manure was disk-incorporated in summer and either irrigated in fall, or irrigated the following spring after being roto-tilled or moldboard plowed. We measured furrow irrigation inflows and outflows and determined runoff sediment, nitrate-N, ammonium-N, dissolved-reactive-P, and total-P. Flow-weighted runoff-nutrient concentrations from the field with manure applied in the current-year were 5 to 8 times those of the nonmanured field. Ammonium-N losses in furrow irrigation runoff were 20x greater from the field with current-year manure application relative to nonmanured plots. Spring tillage and irrigation reduced nitrate-N and ammonium-N runoff losses by 90 to 95%, but had no effect on total-P or dissolved-reactive-P losses, relative to fall-irrigation values. Soluble nutrient concentrations (excluding total-P) trended higher in plowed irrigation furrows, relative to roto-tilled, but furrow runoff rates for roto-tilled fields were 1.4x greater than for plowed plots. Consequently, nutrient runoff mass losses did not differ between spring tillage treatments. Tillage and the timing of irrigation and manure applications can affect runoff nutrient losses from furrow irrigated fields.