Plant-Available Nitrogen from Poultry Manure as Affected by Time of Application
Appropriate poultry manure management is essential to ensure maximum crop N utilization and reduce risk of negative environmental impact. This study was conducted to evaluate the effect of three application times (late fall, winter, and spring preplant) on N availability from two sources of poultry manure [chicken (Gallus domesticus) and turkey (Melleagris gallopavo)] for corn (Zea mays L.) production. Manure was applied based on total N, intending to supply 84 and 168 kg total N ha−1 Urea fertilizer was applied at the same time as the manure at six rates (0, 34, 67, 100, 134, 168 kg N ha−1). Soil classification used for the study was primarily Clarion (fine-loamy, mixed, superactive, mesic Typic Hapludolls) and Nicollet (fine-loamy, mixed, superactive, mesic Aquic Hapludolls). Effect of application timing was determined by response in grain yield, grain N uptake (GNU), leaf chlorophyll meter (CM) reading, and soil NO3−–N measured in early June. Soil NO3−–N concentrations were greater for manure and fertilizer N applied in spring compared with fall and winter application, but the same for both poultry manure sources. Grain yield, GNU, and CM reading response to manure N were not different among either poultry manure sources or application timings. Furthermore, estimated manure plant N availability was not different among poultry manure sources or time of application. Overall first year crop-available N from poultry manure, based on fertilizer N equivalence, using grain yield, GNU, and CM readings was estimated at 43 to 53% of total N. The supply of available N to corn was not affected by poultry manure application timing despite different lengths of time to crop uptake or delayed incorporation with winter application.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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