Soil properties following long-term application of stockpiled feedlot manure containing straw or wood-chip bedding under barley silage production.

摘要

The influence of long-term land application of stockpiled feedlot manure (SM) containing either wood-chip (SM-WD) or straw (SM-ST) bedding on soil properties during the barley ( Hordeum vulgare L.) silage growing season is unknown. The main objective of our study was determine the effect of bedding material in stockpiled manure (i.e., SM-WD vs. SM-ST) on certain soil properties. A secondary objective was to determine if organic amendments affected certain soil properties compared with unamended soil. Stockpiled feedlot manure with SM-WD or SM-ST bedding at 77 Mg (dry wt) ha -1 yr -1 was annually applied for 13 to 14 yr to a clay loam soil in a replicated field experiment in southern Alberta. There was also an unamended control. Soil properties were measured every 2 wk during the 2011 and 2012 growing season. Properties included water-filled pore space (WFPS), total organic C and total N, NH 4-N and NO 3-N, water-soluble non-purgeable organic C (NPOC), water-soluble total N (WSTN), denitrification (acetylene inhibition method), and CO 2 flux. The most consistent and significant ( P鈮?.05) bedding effects on soil properties in both years occurred for total organic C, C:N ratio, and WSTN. Total organic C and C:N ratio were generally greater for SM-WD than SM-ST, and the reverse trend occurred for WSTN. Bedding effects on other soil properties (WFPS, NH 4-N, NO 3-N, NPOC) occurred in 2012, but not in 2011. Total N, daily denitrification, and daily CO 2 flux were generally unaffected by bedding material. Mean daily denitrification fluxes ranged from 0.9 to 1078 g N 2O-N ha -1 d -1 for SM-ST, 0.8 to 326 g N 2O-N ha -1 d -1 for SM-WD, and 0.6 to 250 g N 2O-N ha -1 d -1 for the CON. Mean daily CO 2 fluxes ranged from 5.3 to 43.4 kg CO 2-C ha -1 d -1 for SM-WD, 5.5 to 26.0 kg CO 2-C ha -1 d -1 for SM-ST, and from 0.5 to 6.8 kg CO 2-C ha -1 d -1 for the CON. The findings from our study suggest that bedding material in feedlot manure may be a possible method to manage certain soil properties.