Composting or stockpiling of feedlot manure in Nebraska: Nutrient concentration and mass balance1

When feedlot pens are scraped in the spring and summer, manure is often stored before land application can occur in the fall. Manure stockpiled or composted was evaluated for nutrient losses in 2 experiments for 104 (Exp. 1) and 111 d (Exp. 2). Stockpiles (n = 2 in Exp. 1 and n = 3 in Exp. 2) and compost windrows (n = 6 in Exp. 1 and n = 4 in Exp. 2) were constructed with feedlot manure scraped from pens and sampled upon construction and throughout the storage period. In Exp. 1, N loss was 3 times greater (P < 0.01) for compost compared with stockpile on d 104 (43.6 and 14.3%, respectively). Loss of C was 34.7% greater (P < 0.01) for compost compared with stockpile on d 104 (54.4 and 40.4%, respectively). Total mass loss (water + DM) was not different (P = 0.30) among storage methods on d 104 (20.0 and 15.8% for compost and stockpile, respectively). In Exp. 2, N loss from compost was 42.1% greater (P < 0.01) compared with stockpiling on d 111. Carbon losses in Exp. 2 were not different (P = 0.77) among storage methods on d 111 (38.4 and 37.5% for compost and stockpile, respectively). Total mass loss in Exp. 2 was less compared with Exp. 1 and was not different (P = 0.23) among storage methods (5.7 and 3.6% for compost and stockpile, respectively). When evaluated on a nutrient basis, stockpiled manure had greater N and C concentrations compared with composted manure.