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a USDA-ARS, Mississippi State, MS 39762
b USDA-ARS, Bowling Green, KY 42104
c USDA-ARS, Stoneville, MS 38776
* Corresponding author (htewolde{at}ars.usda.gov).
Inefficient extraction of litter-derived N and its loss to the immediate environment is a concern when poultry litter is used as a fertilizer. This research determined the magnitude of N extraction by cotton (Gossypium hirsutum L.) fertilized with broiler litter with or without supplemental inorganic N. Extraction of N by cotton fertilized with litter rates of 2.2, 4.5, and 6.7 Mg ha1 in combination with 0, 34, or 67 kg ha1 N as ureaammonium nitrate (UAN) was determined on two farms, one at Cruger and another at Coffeeville, MS, in 2002 to 2004. The treatment that received 4.5 Mg ha1 litter plus 67 kg ha1 UAN-N was among the treatments that had the largest N extraction with an average across years of 233 kg N ha1 total extraction at Cruger and 183 kg N ha1 at Coffeeville. These extractions were more or only slightly less than the total applied N. An average of 56% of extracted N at Cruger and 62% at Coffeeville was partitioned to seed and lint, which represents an amount that would be removed from the field. The remainder is bound in plant parts with little or no risk of becoming released to the immediate environment until the plant parts decompose. These results demonstrate cotton is efficient at extracting N supplied by as much litter as 6.7 Mg ha1 when supplemented with inorganic N. The risk of N detrimentally affecting the immediate environment when cotton is fertilized with litter plus inorganic N is no greater than when fertilized with 100% inorganic N fertilizers.
Abbreviations: DAP, days after planting NEE, nitrogen extraction efficiency NTPA, applied total plant available nitrogen STD, farm standard fertilization UAN, ureaammonium nitrate.
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