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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #260928
Title: Tillage and Composting Strategies to Maximize Potentially Mineralizable Nitrogen in Maize-based Cropping Systems

Author
item BROWN, KIM - Iowa State University
item MITCHELL, DAVID - Iowa State University
item CASTELLANO, MIKE - Iowa State University
item Singer, Jeremy

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/2/2010
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Cereal crop yields vary drastically between developed and developing nations. In developing nations, a lack of synthetic nitrogen (N) fertilizer often limits yields. Low-cost soil management strategies that increase biologically available soil organic matter can reduce farmer reliance on synthetic N fertilizer. We evaluated the cumulative 12-year impact of tillage and manure compost on biologically mineralizable carbon (C) and N pools. No-tillage, conventional tillage, no-compost and compost management strategies were compared in a fully-factorial design with three replicates. Biologically available C and N were measured as the cumulative amount of C and N mineralized during a 28 day laboratory incubation. We hypothesized that a combination of no-tillage and compost would increase potentially mineralizable organic C and N. We rejected this hypothesis. No treatments affected potentially mineralizable C. No-tillage had significantly more mineralizable organic N (73.3 kg ha-1) than conventional tillage (36.5 kg ha-1), but compost did not affect mineralizable N. Average annual compost additions of 3910 kg C ha-1 and 292.83 kg N ha-1 did not increase biologically available C or N pools. These data suggest compost C and N inputs were: 1) stored in pools that are not easily mineralizable 2) removed from the system in grain (N only) or 3) lost to the environment. Mineralizable C was not affected by tillage, suggesting that soil organic C in these no-tillage systems may be stored in pools that are not easily mineralizable or affected by processes other than tillage. No-tillage may be an effective low-cost strategy to increase crop-available mineralizable N. Mineralizable N can promote yield amount and yield resilience to climate variability.