The effect of wheat straw, corn straw and tobacco residues on denitrification losses in a field planted with wheat

摘要

A field experiment was conducted to determine the effects of different organic residues (OR) (e.g., wheat straw, maize straw and tobacco residues) on nitrogen mineralization and denitrification loss (N2O-N) using application rates recommended to local farmers. Nitrate and ammonium analyses were carried out on periodically collected soil samples from a wheat field. In-situ denitrification loss was determined using the acetylene inhibition technique (AIT). The results revealed that OR application increased N mineralization significantly. In the favourable conditions for nitrification and intensive mineralization period, NO3--N accumulation at 0-60 cm depth peaked at 163.0, 177.7 and 226.6 kg N ha-1 in plots with wheat straw, maize straw and tobaccowaste, respectively. In-situ denitrification measurements showed that intensive mineralization, depending on temperature and humidity conditions, significantly increased denitrification losses. The denitrification values measured showed a variation between 7.58 and 17.40 kg N2O-N ha-1. The results also showed that the effect of organic substrates on N loss via denitrification was highly dependent on the type of organic substrate used, and the C:N ratio of the organic substrate played an important role in N loss by denitrification.