氮输入对纳帕海沼泽湿地土壤氨挥发和反硝化的影响

Effects of nitrogen input on marsh wetland soil ammonia volatilization and denitrification in Napahai

选取纳帕海常见湿地植物茭草(Zizania caduciflora)和水葱(Scirpus validus)及其生长土壤为对象,通过培养实验,研究了3个不同氮输入水平[0 g.m-2(对照,N0)、20 g.m-2(N20)、40 g.m-2(N40)]对茭草和水葱湿地土壤氨挥发和反硝化的影响。结果表明:氮输入促进了茭草和水葱湿地土壤氨挥发化作用,增加了湿地土壤氨挥发的累积量。适量的氮输入对湿地土壤氨挥发促进显著。在培养前期适量氮输入下的氨挥发积累量高于高水平氮输入的,随着培养时间的延长,后期适量氮输入下的积累量明显下降;而高水平氮输入处理下氨挥发积累量的明显增加,适量氮输入下茭草氨挥发积累大于水葱。氮输入增强了茭草和水葱湿地土壤反硝化作用,加快了反硝化N2O的排放。适量的氮输入促进茭草反硝化作用和反硝化损失量增加明显,培养的前期的适量氮输入处理下的反硝化作用和反硝化N2O的排放增强不明显,随着培养时间的延长,高水平氮输入处理下的反硝化损失量越明显,并且水葱较茭草更为明显。后期适量氮输入下的反硝化损失速率和反硝化损失量高于高水平氮输入,适量氮输入较高水平氮输入促进明显,高水平的氮输入限制了反硝化损失,反硝化N2O的排放总量下降,土壤中氮富集增大。

This paper taking the typical marsh plant Zizania caduciflora and Scirpus validus and they grow soil in Napahai wetland of Northwest Yunnan as test material, a control experiment was conducted to study their ammonia volatilization and denitrification under effects of different levels of nitrogen input. Three nitrogen fertilization treatment, i.e. 0 g-m^2 （CK）, 20 g-m^2（N20）and 40 g-m^2（N40）, were installed.The result showed that nitrogen input promoted the ammonia volatilization of Zizania caduciflora andScirpus validus wetland soils, increased their accumulation of ammonia volatilization. The ammonia volatilization of Zizania caduciflora and Scirpus validus wetland soils were promoted significantly by moderate nitrogen input. In the training early, the ammonia volatilization accumulation was higher with moderate nitrogen input than high nitrogen input. In the later stage, the ammonia volatilization accumulation declined significantly under moderate nitrogen input and increased obviously under high nitrogen input. The ammonia volatilization accumulation of Zizania caduciflora wetland soil was greater than Scirpus validuswetland soil with moderate nitrogen input. Nitrogen input enhanced the Zizania caduciflora and Scirpus validus wetland soil denitrification, sped up the denitrifying N20 emissions.Moderate nitrogen input promoted Zizania caduciflora denitrifying functionand denitrification accumulation increased obviously. In the training early, it was not obvious in the increment of the denitrification and denitrification N2O emissions with moderate nitrogen input. With training the extension of time, denitrification loss with high nitrogen input increased more obviously. The denitrification loss of Zizania caduciflora wetland soil was more obvious than Scirpus validus wetland soil. In the later stage, denitrification loss rate and denitrification loss amount with moderate nitrogen input weremore than high nitrogen input. Moderate nitrogen input promoted denitrification more obviously than high nitrogen input. High nitrogen input limited the denitrification loss. Denitrifying N2O emission declined and nitrogen accumulation in the wetland soil increased.