不同水分模式对山东茶园土壤氮素动态的影响

以山东茶园土壤为研究对象,采用室内好气培养法,分析了恒定湿润和干湿交替模式下土壤氮素转化特征.结果表明:(1)至培养结束时,恒湿模式下60％WHC处理土壤净矿化量和净硝化量较高;脲酶和亚硝酸还原酶活性较强.20％WHC处理下土壤净矿化速率、净硝化速率严重受到抑制.(2)干湿交替模式下复水后土壤净矿化量、净硝化量以及酶活...

Effects of Water Regimes on Soil Nitrogen Dynamics in Tea Garden in Shandong Province

In this study, the characteristics of nitrogen transformation in tea garden soil of Shandong Province were analyzed by indoor aerobic culture. Soil N transformation and enzymes activities in constant wet and dry/wet cycle conditions were measured. The results showed that: (1) The net mineralization quantity and net nitrification quantity, the activities of urease and nitrite reductase were the highest in the 60%WHC treatment at the end of incubation. The net mineralization and net nitrification rates were seriously inhibited in 20%WHC treatment. (2) In dry/wet cycle treatment, net mineralization quantity, net nitrification quantity and enzymes activities increased and the change of pulse pattern appeared. (3) N₂O emission was greater than NH₃ volatilization in both models. N₂O emission was directly proportional to soil water content, while NH₃ volatilization was inversely proportional. Dry wet alternation enhanced N₂O and NH₃ emissions. (4) The structural equation model revealed that soil water content affected soil N transformation (p<0.001); urease significantly improved soil N transformation in constant wet treatment (p<0.001), while nitrate reductase inhibited N transformation (p<0.001) in constant wet and dry/wet cycle models. These results might help to better regulate soil management and the use of N fertilizer in the tea garden ecosystem under different water supply conditions.