An Approach for Estimating a Decay Series for Organic Nitrogen in Animal Manure

Abstract

Animal manures are an important source of N for crop production. Efficient use of manure is necessary to increase N recycling, eliminate excessive purchase of fertilizer N, and reduce N loss to the environment. An estimate of the annual rate of organic N mineralization in manure is a necessary prerequisite to efficient manure N management. A mineralization or decay series for the organic N in dairy manure was estimated for corn (Zea mays L.) production from several field experiments over a 5‐ to 8‐yr period. Four rates of sidedressed fertilizer N (0, 56, 112, and 224 kg N ha−1) were superimposed over several springapplied manure treatments ranging from 0 to 168 Mg ha−1 yr−1. Ammonia volatilization from manure was encouraged, to allow for an assessment of the fertilizer N equivalence of the more stable organic N fraction. Based on silage dry matter yield and N uptake, a decay series of 0.16, 0.10, 0.03, 0.03 and 0.02, and 0.21, 0.09, 0.03, 0.03 and 0.02, respectively, described the fertilizer N equivalence of organic N. The first number in the decay series estimates the fraction of organic N that is available for crop use during the year of application, and the second to fifth numbers are estimates of available N from residual N in Years 2 through 5. An independent set of field data was used to evaluate the accuracy of the decay series. The predicted decay series, based on dry matter yield (R2 = 0.16) was more variable than the corresponding decay series based on N uptake (R2 = 0.72). The non‐N effects of manure were insignificant, and therefore yield and N uptake were directly related to the N contribution.

Net Nitrogen Mineralization from Past Years' Manure and Fertilizer Applications

“…Th e Year 1 and 2 values of Klausner et al (1994) are quite similar to ours, but their Year 3 value was less. Note that Klausner et al (1994) derived net N mineralization (i) using the two spring manure applications from which NH 3 volatilization was encouraged, and (ii) from N uptake data, which is a function of crop growth and infl uenced by other factors such as root distribution, soil water availability, and leaching. Eghball (2000) also estimated decay values from crop N uptake data: 0.39 and 0.18 for the fi rst and second years aft er a 378 kg total N ha −1 cattle manure application to Nebraska soils.…”

“…Research done under cool-winter climates may be more relevant. Our series may be compared with a 3-yr decay series of 0.21, 0.09, and 0.03 reported by Klausner et al (1994) for New York, which was derived from the mean of two dairy manure rates, 250 and 700 kg total N ha −1 compared with our 310 and 970 kg total N ha −1 . Th e Year 1 and 2 values of Klausner et al (1994) are quite similar to ours, but their Year 3 value was less.…”

“…Our series may be compared with a 3-yr decay series of 0.21, 0.09, and 0.03 reported by Klausner et al (1994) for New York, which was derived from the mean of two dairy manure rates, 250 and 700 kg total N ha −1 compared with our 310 and 970 kg total N ha −1 . Th e Year 1 and 2 values of Klausner et al (1994) are quite similar to ours, but their Year 3 value was less. Note that Klausner et al (1994) derived net N mineralization (i) using the two spring manure applications from which NH 3 volatilization was encouraged, and (ii) from N uptake data, which is a function of crop growth and infl uenced by other factors such as root distribution, soil water availability, and leaching.…”

Response of the Illinois Soil Nitrogen Test to liquid and composted dairy manure applications in a corn agroecosystem

“…This decay series is the current recommendation in New York (Ketterings et al 2003) for estimated manure organic-N credits based on work by Klausner et al (1976). For the second comparison, we credited organic-N for three residual years after application at 9, 3, and 3% for manure, based on Klausner et al (1994), and 5, 5, and 3% for compost. The compost decay series was based on composted cattle manure results from Eghball and Power (1999) who estimated 8% N availability in the first residual year after application and by Paul and Beauchamp (1993) who found 2.9% N recovery in the first residual year and 5.5% in the second residual year.…”

Estimates of Gross Transformation Rates of Dairy Manure N Using15N Pool Dilution

“…A smaller number of comparisons have been conducted under field conditions that include climatic variability and crop uptake components (Paul and Beauchamp 1993). Despite common assumptions that up to 35 -50% of manure organic N may be mineralized in the first growing season after application or during an equivalent incubation period (Klausner et al 1994), reports that net mineralization of manure N are zero or near zero, with some manures resulting in net immobilization of N in soil, are common (Eghball 2000;Griffin et al 2000;Griffin et al 2005;Paul and Beauchamp 1993;Van Kessel and Reeves 2002). While valuable, these experiments shed little light on internal cycling of manure N and carbon (C) in the soil, because they account for only changes in N pool size over time without providing any information on the flow of N into and out of soil N pools (Barraclough 1991;Wang et al 2001).…”