猪场废水灌溉对土壤氮素时空变化与氮平衡的影响

利用地中渗透仪测坑开展了田间灌溉试验,研究了猪场废水和等氮投入清水处理土壤铵态氮、硝态氮含量在时间、剖面上的变化规律,根据氮平衡原理对不同处理氮输入和氮输出项进行对比分析,估算了不同处理的氮矿化量。结果表明:各处理土壤铵态氮和硝态氮含量在时间上的变化规律基本一致,表现为追肥期出现峰值,随后下降的趋势;土壤铵态氮含量随土层深度的增加而迅速下降,土壤硝态氮含量随土层深度的增加变化规律不明显,且易淋移至下层土壤并累积。PWH(猪场废水高氮)处理土壤铵态氮、硝态氮含量在追肥期出现峰值后下降的幅度较慢,而CKH(清水高氮)处理下降的幅度较快。猪场废水高氮处理PWH作物吸氮量及氮矿化量比等氮清水处理CKH分别高6.91%和21.29%,表明该处理有利于土壤有机氮的矿化,但同时硝态氮深层淋溶量也较大,比CKH高出11.82%。

Effect of Piggery Wastewater Irrigation on Temporal-spatial Variation and Balance of Nitrogen

As an alternative water sources, piggery wastewater has attracted more and more attention. Study on piggery wastewater irrigation technology is essential for alleviating agricultural water resource deficit, reducing nitrogen fertilization and protecting eco-environment. Based on a field irrigation experiment in reinforced concrete lysimeters, the effects of piggery wastewater and clean water (equal nitrogen inputs) irrigation on soil NH+4-N and NO-3-N variations in time and profiles were studied. The inputs and outputs of nitrogen and the amount of nitrogen mineralization of different treatments were analyzed according to the principle of nitrogen balance. The results showed that the changes of soil ammonium nitrogen with time showed a similar trend to nitrate nitrogen, which had a peak in top-dressing stage at first, and then decreased. Ammonium nitrogen content was decreased with the increase of soil depth, but there was no significant difference in nitrate nitrogen. It can be easily leached and accumulated. Ammonium nitrogen and nitrate nitrogen were slightly decreased in PWH (piggery wastewater with high nitrogen) treatment after top-dressing stage, while the decrease range was more sharply in CKH (clean water and high nitrogen) treatment. PWH treatment was beneficial to the mineralization of organic nitrogen, and crop nitrogen uptake, nitrogen mineralization and nitrate nitrogen leaching amount in PWH treatment were higher than those in CKH treatment with values of 6.91%, 21.29% and 11.82%, respectively.