模拟降水对荒漠草原土壤氮矿化的影响

Effect of Simulated Precipitation on the Soil Nitrogen Mineralization of Desert Steppe

在短花针茅荒漠草原设置不同模拟降水处理(分别为P1减少降水量的50%、P2自然降水、P3增加降水量的50%和P4增加降水量的100%),探讨降水对荒漠草原土壤氮矿化的影响。结果表明:随着降水量的增加,铵态氮和硝态氮含量都出现了显著差异,P4处理下铵态氮含量最大,硝态氮含量整体呈“增加-降低-再增加”的趋势;降水量增加使铵化速率显著降低,而硝化速率则随着降水量的增加而显著增加,但P3与P4硝化速率没有显著差异;土壤净矿化速率随着降水量的增加显著增加,降水量增加到P3时土壤净矿化速率不再发生改变,减少降水没有使土壤净矿化速率发生改变。

In order to explore the effect of precipitation on soil nitrogen mineralization in desert steppe,different simulated precipitation treatments were set in Stipa breviflora desert steppe,which were as follows:reducing precipitation by 50%(P1),natural precipitation(P2),increasing precipitation by 50%(P3)and increasing precipitation by 100%(P4).The results showed that:with the increase of precipitation,the contents of ammonium nitrogen and nitrate nitrogen were significantly different(P<0.05).Under P4 treatment,the content of ammonium nitrogen was the highest,and the content of nitrate nitrogen showed a trend of“increase-decrease-increase again”.With the increase of precipitation,the ammonification rate decreased significantly(P<0.05);while the nitrification rate increased significantly with the increase of precipitation(P<0.05),but there was no significant difference between P3 and P4 treatments.The soil net mineralization rate also increased significantly with the increase of precipitation(P<0.05).When the precipitation increased to P3 treatment level,the soil mineralization rate had no more change,and the decrease of precipitation did not change the soil mineralization rate.