Title: Assessing the risks to water bodies from nitrogen vs. phosphorus based broiler litter strategy Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2008
Publication Date: June 2, 2008
Citation: Adeli, A., Brooks, J.P., Jenkins, J.N. 2008. Assessing the risks to water bodies from nitrogen vs. phosphorus based broiler litter strategy [abstract]. Mississippi 38th Water Resources Conference Proceedings. p. 53. Technical Abstract: The large amounts of poultry manure in localized areas and the high cost of implementing effective Best Management Practices (BMP’s) often favor disposal rather than utilization of manure. Continual application of poultry manure at rates providing more N and P than removed by crops can increase soil N and P to levels that are of environmental rather than agronomic concern. Over application can enhance potential movement of N as NO3 to ground water and P in surface runoff. This study was conducted in 2007 at R.R. Foil Plant Science Research Center, Mississippi State University on a Mariate silt loam soil to investigate how N- vs. P-based poultry manure to perennial forage crops affects nitrate and P leaching from the crop root zones, N and P in surface runoff, crop removal and soil accumulation of the nutrients. An experimental field with bermudagrass has been established. Treatments included poultry manure was applied to meet the N or P requirements of bermuda grass; fertilizer N and P at the recommended rate, and control treatments serve as comparison purposes. Treatments were replicated three times. Pen lysimeters were used to collect leachate for determining nitrate and P leaching losses. Runoff collection devices was installed for estimating runoff losses of N and P. A rainfall simulator was used to simulate precipitation events. Following each rain event, runoff samples were collected for nutrient analysis. After 24 h of rain events, leachate samples were collocted for N and P concentrations. Phosphorus-based broiler litter application resulted in significantly greater P uptake than N-based treatment, indicating greater P use efficiency for lower P application rate. Runoff and leachate from N-based broiler litter and commercial fertilizer plots had nitrate concentrations significantly greater than P-based broiler litter application. Runoff losses of P followed the same pattern as runoff losses of N However, P losses in the leachate samples was negligible and no significant difference in P concentration in the leachate samples was obtained among the treatments. No significant difference in dry matter production was obtained between N and P-based treatments but N-based resulted in greater P accumulation into the soil surface. Such data will provide much needed information for devising and effective decisions on how best to manage the vast amount of poultry manure nutrients for protecting waters while sustaining animal agriculture.