Characteristics of NO_3~--N and NH_4~+-N Mineralization from Different Organic Fertilizers

Aerobic incubation was conducted to study the characteristics of NO3——N and NH4+-N mineralization from different organic fertilizers.Results indicated that mineralization rates of NO3——N increased rapidly after 10 d,10 d and 30 d,respectively for chicken manure,pig manure and cattle manure.The mineralization rates of composts for chicken manure,cattle manure and pig manure increased after 10 d,60 d,60 d,respectively.The mineralization rates of organic fertilizer with composting treatment were significantly lower than that with not composting products and mineralization peak postponed.The mineralization rate of NO3——N became slower after 90 d,while after 120 d the rate of chicken manure,cattle manure and pig manure was 42.6%,24.0%,22.6%,respectively;that of chicken manure compost,cattle manure compost and pig manure compost was 23.4%,16.0%,18.0%.With the extension of incubation,NH4+-N content decreased rapidly applying organic fertilizer to soil.At the fifth day,it was lower than the control and nearly to or slightly higher than the control after 15 d.Applying organic fertilizer to soil mainly increased NO3-N content,had a little influence on NH4+-N.