Nutrient, Carbon, and Mass Loss during Composting of Beef Cattle Feedlot Manure

Abstract

Quantification of nutrient and mass loss during composting is needed to understand the composting process, to implement methods for nutrient conservation, and to reduce potential adverse environmental impact. Beef cattle feedlot manure was composted in a windrow on an open concrete area in 1992, 1993, and 1994 to determine the amounts of nutrient, C, and mass loss during composting. The area was enclosed on all sides with a 0.2 m high metal sheet to direct runoff to a fiberglass tank (4000 L) during rainfall. Nutrients in runoff represented combined runoff and leaching losses. Nutrients, C, and mass loss during composting was determined by the difference between the amounts at the beginning and at the end of the composting. Nitrogen loss during composting ranged from 19 to 42% and was related to the initial manure N content. Ammonia volatilization (calculated by difference) accounted for >92% of the N loss whereas combined runoff nitrate and ammonium loss was <0.5%. Mass loss was relatively low (15–20%) while loss ranged from 46 to 62% and was basically all through bio‐oxidation. Phosphorus runoff loss, the main mechanism for P loss, was low (<2%). Manure N/P ratio decreased during composting, indicating a greater soil P buildup potential with compost application. Potassium and Na losses in runoff were high (>6.5% each) 1992 and 1993; they were low (<2% each) in 1994 due to fewer rainfall. Calcium and Mg losses were <6% each year. Nutrient and salt loss during composting resulted in reduced electrical conductivity of the composted manure. Ammonium and P concentrations in runoff would create surface water pollution if runoff was not diluted with fresh water.

Winter and growing season nitrogen mineralization from fall-applied composted or stockpiled solid dairy manure

“…By the end of the 2004 season in Field B, however, the apparent N mineralization rate was positive, reflecting a net gain in buried bag inorganic N relative to total N applied in every amended treatment ( Table 9). The apparent N mineralization rate where composttreated was very low, reflecting compost's generally recalcitrant organic compounds (Eghball et al 1997). The apparent N mineralization rate of the Manure2 treatment, similar to that of Manure1, exceeded that of both compost treatments.…”

Soil salinity and sodicity after application of fresh and composted manure with straw or wood-chips

“…Composting should increase soluble salts as dry matter losses increase during composting and the salts become more concentrated in the final product. However, leaching and runoff losses from compost windrows can offset this concentration effect and result in lower soluble salts in the composted manure (Eghball et al 1997). Eghball et al (1997) reported in a 3-yr study that K, Na, Ca, and Mg were generally higher in composted than fresh beef cattle manure, and that EC was generally lower in composted manure or similar to fresh manure.…”

“…However, leaching and runoff losses from compost windrows can offset this concentration effect and result in lower soluble salts in the composted manure (Eghball et al 1997). Eghball et al (1997) reported in a 3-yr study that K, Na, Ca, and Mg were generally higher in composted than fresh beef cattle manure, and that EC was generally lower in composted manure or similar to fresh manure. We calculated the SAR and PAR from Eghball's data, and there was no trend in SAR, and the PAR was higher for composted than fresh manure in 2 of 3 yr. Larney et al (1999) reported that active composting of beef cattle manure for 99 d increased concentrations of Na, SO 4 , and Cl, reduced concentrations of Ca, Mg, and K, and EC values remained unchanged.…”

Windrow temperatures and chemical properties during active and passive aeration composting of beef cattle feedlot manure

“…Although C and N losses during active (turned) manure composting have been documented (Eghball et al 1997;Michel et al 2004;Larney et al 2006a), they have not been generally compared with losses during passive composting. During the thermophilic phase, there were significantly higher C mass losses for the active treatment (77% of initial) than the passive treatment (45%) ( Table 3).…”