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通过室内培养实验,研究了氮、硫输入对闽江河口湿地土壤有机碳矿化和土壤理化性质的影响.结果表明:NH_4Cl(N1)、NH_4NO_3(N3)、K_2SO_4(S)和NH_4Cl+K_2SO_4(NS1)处理显著促进了湿地土壤有机碳矿化速率(p<0.05),较对照分别提高了76.57%、60.09%、83.20%和52.59%,并且不同处理下土壤有机碳矿化速率均表现为随培养时间的增加而递减.氮、硫输入在不同时间对湿地土壤有机碳矿化的影响不尽一致,在前6 d各处理的促进作用最明显.湿地土壤有机碳累积矿化量在不同处理下均表现为随培养时间逐渐增加,其增长速率在培养初始阶段较快,而后逐渐减慢;不同培养时间有机碳累积矿化量在N1、N3、S和NS1处理下与对照处理间均存在显著差异(p<0.05).短期培养结束后,N3、NS1处理显著增加了湿地土壤DOC含量(p<0.05);N1、N3、NS1和NH_4NO_3+K_2SO_4(NS3)处理均显著增加了土壤NH_4~+-N含量(p<0.05);KNO_3(N2)、N3、NS2和NS3处理均显著增加了土壤NO_3~--N含量(p<0.05);S、NS1、NS2和NS3处理均显著增加了土壤SO_4~(2-)含量(p<0.05).不同处理下湿地土壤Cl-、pH、EC具有微弱的波动变化特征,但在不同处理组间均不存在显著差异(p>0.05).多元回归分析显示,DOC、NH_4~+-N和SO_4~(2-)是氮、硫输入处理下影响闽江河口湿地土壤有机碳矿化速率的主要控制因素.
The effects of nitrogen and sulfur inputs on soil organic carbon mineralization and soil physical and chemical properties in Minjiang estuary wetlands were studied by laboratory culture experiments.The results showed that: NH_4Cl (N1), NH_4NO_3 (N3), K_2SO_4 (S) and NH_4Cl + K_2SO_4 NS1) significantly increased the organic carbon mineralization rate (76.57%, 60.09%, 83.20% and 52.59%, respectively) in wetland soils, and the rates of soil organic carbon mineralization varied with And the incubation time decreased.The input of nitrogen and sulfur had different effects on the mineralization of organic carbon in the wetland at different times and the promotion was the most obvious in the first 6 days.The cumulative mineralization of organic carbon in the wetland was significantly different under different treatments Under the condition of N1, N3, S and NS1, the accumulative amount of mineralization increased with the increase of culture time, and its growth rate was faster at the initial stage of culture and then gradually slowed down. (P <0.05). After the short-term culture, N3 and NS1 significantly increased the DOC content of wetland soils (p <0.05), while the treatments of N1, N3, NS1 and NH4NO3 + K2SO4 (NS3) + -N content (p <0.05); KNO_3 (N2), N3, NS 2 and NS3 significantly increased soil NO_3 ~ - N content (p <0.05), while SO_4 ~ (2-) content of soil increased significantly (P <0.05) under treatments of S, NS1, NS2 and NS3 Cl-, pH and EC in wetland soil fluctuated slightly, but there was no significant difference among different treatment groups (p> 0.05) .Multiple regression analysis showed that DOC, NH_4 ~ + -N and SO_4 ~ (2- ) Is the main control factor affecting the rate of mineralization of soil organic carbon in the Minjiang estuary wetlands under nitrogen and sulfur input.