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

Abstract

Pre-vs. post-turning sampling of the active treatment was also compared. Mean daily temperature was warmest at the bottom windrow location (53.6ºC) and coolest at the top (46.4ºC) in the active treatment, but warmest at the top (44.1ºC) and coolest at the bottom (33.9ºC) in the passive treatment. Final compost from the passive treatment had significantly higher total N (TN), total C (TC), electrical conductivity (EC), Na, and Cl than the active treatment. There were no significant treatment effects on C:N ratio, NH 4 -N, NO 3 -N, total P (TP), Kelowna-extractable P (KEP), pH, Ca, Mg or K. Both treatments showed substantial and non-significantly different C (71-80%) and N (44-58%) losses. Pre-versus post-turning sampling showed significant differences for some compost parameters, notably soluble salts. After the thermophilic phase, the passive treatment appeared only partially composted. Additional disadvantages of the passive treatment included lower windrow temperatures, which may fail to reduce pathogens, and higher EC, which could potentially limit the end use of passively aerated compost.

Effects of diet and manure storage method on carbon and nitrogen dynamics during storage and plant nitrogen uptake

“…The slurry treatment had an increasing C:N ratio over the first 5 weeks after which it stabilized, while the solid manure storage treatment had a decline in the C:N ratio over time. A decline in C: N ratio during the composting of cattle manure has also been observed in other studies (e.g., Larney and Olsen, 2006;Larney et al, 2008).…”

“…Literature values of C losses during storage of solid cattle manure in static piles range from 13 to 47%, with C losses increasing with storage length (Petersen et al, 1998;Larney and Olsen, 2006;Luebbe et al, 2011). The values from the present study fall within this range and are similar to the longer term storage losses of 47% seen in studies with manure stored for 6 months.…”

“…The mass loss of N over the storage period was similar between the slurry (47%) and static pile (45%) treatments. Literature values of N losses during storage of solid cattle manure range from 7 to 39% (Petersen et al, 1998;Sommer, 2001;Larney et al, , 2008Larney and Olsen, 2006;Luebbe et al, 2011). However, greater loss estimates have been reported.…”

Nutrient and trace element changes during manure composting at four southern Alberta feedlots

“…Larney and Olson (2006) found that composting resulted in increased concentrations of soluble Na and K.…”

“…Composting decreases manure volume (Larney et al 2000), and eliminates pathogenic bacteria , human parasites (Van Herk et al 2004) and weed seed viability (Larney and Blackshaw 2003). Despite its benefits, like most manure-handling or storage practices, composting is associated with N and C losses (Larney et al 2006a(Larney et al , 2008Larney and Olson 2006). Most N is volatilized as NH 3 , but some is emitted as N 2 O, a greenhouse gas, while C losses as greenhouse gases (CO 2 , CH 4 ) also occur (Hao et al 2001(Hao et al , 2004.…”