Nitrogen- vs. Phosphorus-Based Manure and Compost Management of Corn
- Amir Sadeghpoura,
- Quirine M. Ketterings *a,
- Gregory S. Godwina and
- Karl J. Czymmeka
Animal manure is typically applied to meet the N needs of crops. This can lead to overapplication of P and K. We evaluated the impact of a change from N-based applications of manure and compost without incorporation to a P-based (crop-removal) management system with immediate incorporation of manure on (i) silage corn (Zea mays L.) yield and quality, and (ii) soil test NO3, P (STP), and K (STK). A 5-yr field study was conducted with annual spring applications of composted dairy solids (46 and 74 Mg ha–1), liquid dairy manure (68 and 196 kL ha–1), and inorganic N fertilizer (0 and 112 kg ha–1). Shifting from N- to P-based manure and compost management reduced the corn yield by 7 to 13% and protein by 8 to 9%, suggesting that fertilizer N is needed for P-based management. Shifting from N- to P-based manure management reduced soil NO3–N at silage harvest by 39% vs. 21% for compost. After 5 yr, STP increased four- and sixfold and two- and fourfold for N- and P-based manure and compost management, respectively, reflecting positive P balances (lower than anticipated yields). Soil test K increased three- and twofold with N- and P-based manure and compost management, respectively. Both STP and STK remained unchanged with inorganic N fertilization. We conclude that a shift from N- to P-based compost and manure management, with immediate incorporation of manure, leads to reduced soil P and K buildup and, for manure, also soil NO3, but supplemental inorganic N fertilization is required to ensure that crop N needs are met.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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