Soil nitrogen response to coupling cover crops with manure injection

Abstract

Coupling winter small grain cover crops (CC) with manure (M) application may increase retention of manure nitrogen (N) in corn (Zea mays L.), -soybean [Glycine max (L.) Merr], cropping systems. The objective of this research was to quantify soil N changes after application of liquid swine M (Sus scrofa L.) at target N rates of 112, 224, and 336 kg N ha -1 with and without a CC. A winter rye (Secale cereale L.)-oat (Avena sativa L.) CC was established prior to fall M injection. Surface soil (0-20 cm) inorganic N concentrations were quantified every week for up to 6 weeks after M application in 2005 and 2006. Soil profile (0-120 cm in 5, 20-cm depth increments) inorganic N, total N, total organic carbon and bulk density were quantified for each depth increment in the fall before M application and before the CC was killed the following spring. Surface soil inorganic N on the day of application averaged 318 mg N kg À1 soil in 2005 and 186 mg N kg À1 soil in 2006 and stabilized at 150 mg N kg À1 soil in both years by mid-November. Surface soil NO 3 -N concentrations in the M band were more than 30 times higher in the fall of 2005 than in 2006. The CC reduced surface soil NO 3 -N concentrations after manure application by 32% and 67% in mid-November 2005 and 2006,respectively. Manure applied at 224 kg N ha -1 without a CC had significantly more soil profile inorganic-N (480 kg N ha -1 ) in the spring after M application than manured soils with a CC for the 112 (298 kg N ha -1 ) and 224 (281 kg N ha -1 ) N rates, and equivalent inorganic N to the 336 (433 kg N ha -1 ) N rate. These results quantify the potential for cover crops to enhance manure N retention and reduce N leaching potential in farming systems utilizing manure.

Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands

“…More importantly, these grasslands exhibited depleted soil N after only one growing season, which in turn coincided with high N immobilization in aboveground forage biomass. While these results are consistent with other studies highlighting the importance of cover crops in N retention (Cambardella et al 2010), our results were found in semi-arid grasslands. The high density of fine roots typical of these areas, particularly native grasslands (Coupland and Johnson 1965;Dormaar et al 1995), likely resulted in favorable uptake of N, which in turn led to little to no apparent carryover of elevated soil N. The rapid depletion of soil mineral N may partly reflect favorable plant growth associated with above-normal rainfall during the 1999 growing season immediately following LHM application.…”

Winter Rye Cover Crop with Liquid Manure Injection Reduces Spring Soil Nitrate but Not Maize Yield

“…Similarly, Krueger et al found that soil nitrate was reduced by approximately 35% with a rye cover crop compared with the no-cover control in Minnesota, USA [48]. Cambardella et al found a slightly higher reduction of 41% in Iowa, USA, which has a warmer climate, with a rye/oat mix [54]. In the current study, variability across sites was likely due to differences in rye biomass production as well as site-specific weather and soil conditions.…”

Management of Manure Nitrogen Using Cover Crops

“…It has commonly been suggested that use of a cover crop following manure application will result in N sequestration by the cover crop (Singer et al, 2008; Cambardella et al, 2010) and subsequent mineralization and release to the following crop. Our results indicate that the cover crops were not effective in conserving N in this manner.…”

“…Among the different livestock manures used as nutrient sources for crop production, application of hog manure as a N source for corn production is a common practice (Woli et al, 2013). Cover crops can be used to enhance the retention of applied manure N and minimize N losses (Cambardella et al, 2010). We conducted a study to evaluate the possibility of using different cover crops to immobilize the N from hog manure which was applied in late summer and supposed to release the immobilized N to the following corn crop.…”