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Dynamics of Nitrogen and Phosphorus in Paddy Field Water Under Agricultural Residue Applications in Chengdu Plain |
Received:November 01, 2014 |
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KeyWord:agricultural residues;paddy field water;nitrogen;phosphorus;dynamic changes |
Author Name | Affiliation | E-mail | LI Han | College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, China Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | DENG Ou-ping | College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, China Key Laboratory of Soil Environmental Protection in Sichuan Province, Chengdu 611130, China | | HU Jia | College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, China Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | DENG Liang-ji | College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, China Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China Key Laboratory of Soil Environmental Protection in Sichuan Province, Chengdu 611130, China | auh6@sicau.edu.cn | ZHANG Shi-rong | College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, China Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China Key Laboratory of Soil Environmental Protection in Sichuan Province, Chengdu 611130, China | |
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Abstract: |
Applying agricultural residues has improved soil fertility and thus crop yields. However, little information is available about the risk of nitrogen and phosphorus pollution caused by agricultural residue applications in paddy fields. In this study, an experiment with three agricultural residue application rates was conducted to study the dynamics of nitrogen and phosphorus in paddy field water. The concentrations of total N(TN), dissolved total N(DTN), ammonium(NH4+-N) and nitrate(NO3--N) under different treatments all reached their peak values 2~3 days after applying residues, and then decreased rapidly. The concentrations of different forms of N showed no significant difference between different treatments 21 days after treatments. The concentrations of total P(TP) and dissolved P(DTP) under different treatments attained their peak values on the 1st day after treatments, and then declined. However, TP and DTP significantly increased 5~7 days after swine manure treatment. In comparison with chemical fertilizer, wheat straw did not have significant effects on the concentrations of different N and P forms. High rates of swine manure significantly decreased ammonium concentrations and ammonia volatilization potential in paddy field water, but significantly enhanced P loss. The applications of agricultural residues had no significant effects on rice yields and P contents in brown rices. Considering food production and environmental risks resulted from applying agricultural residues in Chengdu Plain, we suggest that under the whole wheat straw returning the paddy field carrying capacity for swine manure per 667 m2 during rice growing season should be less than the amount of excretion by three swines during half year. |
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