2002/05/01 by Pei‐Yuan Qian, P. Qian, J.J. Schoenau +1 · 3 citations
Environmental Science · Agricultural and Biological Sciences · #Phosphorus and nutrient management #Soil and Water Nutrient Dynamics #Soil Carbon and Nitrogen Dynamics
paper · pdf · doi:10.4141/s01-018
Manures behave differently as sources of available N due to differences in the amounts and forms of N in the manure. The C:N ratio is an important factor affecting the rate of mineralization and release of available N from manures in which the majority of N is contained in organic forms. In order to ascertain the effect of manure C:N ratio on N mineralization in manure-amended soils, 13 solid manures with a large range in C:N ratio were applied to two Saskatchewan soils (Haverhill sandy loam and Blaine Lake clay loam) at 100 mg N kg -1 along with control (no manure) treatments. A growth chamber experiment was conducted to evaluate the relationship between manure C:N ratio and canola yield and N uptake, and a laboratory incubation was conducted to measure how the addition of manures with different C:N ratios affected the pattern of N release in the soils as measured by supply rates to anion exchange membrane (PRS TM ) probes placed directly in the soil. Canola (Brassica napus var. Sprint) was grown under the same environmental conditions to maturity, and yield and nutrient contents were determined. A significant increase in canola yield and N uptake was observed over the control in both soils only when amended with poultry manure (C:N 7.6) or a pelletized form of hog manure that was supplemented with fertilizer N (C:N 6.6). A significant negative correlation was found between cattle manure organic C:N ratio and N mineralization. Overall, the manures showed limited release of available N over the short-term (67 d) when the organic C:N ratio was in the range of 13–15 and tended to decrease N availability in the short-term if the organic C:N ratio was over 15. The C:N ratio appears to be a useful parameter to measure when attempting to predict the effects of solid manure amendments on short-term N availability. Key words: Nitrogen availability, mineralization, manure, C:N ratio, anion exchange membrane