施用稻壳炭对黄棕壤氮磷淋失及微生物生物量碳氮含量的影响

【目的】为减少农田氮磷淋失,提高土壤肥力,探究高孔隙度的稻壳炭在增强黄棕壤对养分元素吸附的特征。【方法】采用室内土柱淋溶试验,研究不同稻壳炭施用量(质量占比分别为0、1%、4%、8%、12%)条件下,黄棕壤总氮(TN)、硝态氮(NO^-₃-N)、铵态氮(NH⁺₄-N)、总磷(TP)、磷酸根(PO^3-₄)及可溶性有机碳(DOC)的淋失变化,并对黄棕壤氮磷养分和土壤微生物生物量的变化进行分析。【结果】随着施用量的增加,稻壳炭对黄棕壤TN、NO^-₃-N、NH⁺₄-N、DOC淋失的抑制效应增强,最佳施用量为12%时,TN、NO^-₃-N、NH⁺₄-N及DOC的淋失量与对照相比分别减少了85.41%、85.16%、92.61%、32.02%; 随其施用量的增加,稻壳炭对黄棕壤中P淋失的抑制效应不显著,TP和PO^3-₄的淋失量反而增加,TN、NO^-₃-N、有效磷(AP)及土壤微生物生物量碳氮(SMBC、SMBN)含量增高,而NH⁺₄-N含量减少。【结论】稻壳炭可以有效抑制黄棕壤氮素及DOC的淋失,对磷素的淋失抑制效果不显著。

Effects of rice husk biochar application on nitrogen and phosphorus leaching and microbial biomass carbon and nitrogen content in yellow brown soil

Objective] This study was conducted to explore whether rice husk biochar application affects nitrogen and phosphorus leaching in soil,due to its high porosity and adsorption.Methods] A soil column leaching laboratory experiment was used to investigate the efficacy of biochar in reducing soil nutrient leaching.The application rates of rice husk biochar were 0％,1％,4％,8％ and 12％ (w/w).Results] The leaching of total nitrogen,nitrate nitrogen and ammonium nitrogen decreased with the increase of the biochar application rate.Compared with the control,biochar application at 12％ had the best inhibitory effect by reducing the leaching of total nitrogen,nitrate nitrogen,and ammonium nitrogen by 85.41％,85.16％ and 92.61％,respectively,and reducing the leaching of DOC by 32.02％.The effect on phosphorus leaching was not significant.With the increase of the biochar application rate,the leaching of total phosphorus and phosphate increased.Soil total nitrogen,nitrate nitrogen,phosphorus,and microbial biomass carbon and microbial biomass nitrogen content increased,but ammonium nitrogen decreased.Conclusion] The application of rice husk biochar could reduce the leaching of nitrogen and DOC,but it does not have a significant effect on phosphorus leaching.