丘陵红壤茶园根际氮磷转化对不同强度酸雨胁迫的响应  

Responses of rhizosphere nitrogen and phosphorus transformations to different acid rain intensities in a hilly red soil tea plantation

作　　者：陈希[1] 陈伏生[2] 叶素琼[3] 喻苏琴[2] 方向民[2] 胡小飞[1] 

机构地区：[1]南昌大学生命科学学院,南昌330047 [2]江西农业大学江西省竹子种质资源与利用重点实验室,南昌330045 [3]江西环境工程职业学院,江西赣州341000

出　　处：《应用生态学报》2015年第1期1-8,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(31260199;31160107;31060081);江西省青年科学家培养对象项目(20122BCB23005);江西省教育厅科技计划项目(GJJ12021)资助

摘　　要：南方丘陵红壤茶园长期受到酸沉降的胁迫,但茶树根际氮(N)、磷(P)转化过程对酸雨的响应及其机制尚不清楚.以江西典型丘陵红壤25年茶园为对象,开展p H 4.5、p H 3.5、p H 2.5及对照4种不同强度酸雨处理的原位模拟试验,于试验第3年测定根际和非根际土壤矿质N、速效P和相关酶的活性,并估测土壤N、P矿化速率,计算各变量的根际效应.结果表明:与对照相比,p H 4.5、p H 3.5和p H 2.5处理根际土壤NO3--N含量分别降低了7.1%、42.1%和49.9%,矿质N分别降低了6.4%、35.9%和40.3%,速效P分别降低了10.5%、41.1%和46.9%;根际氨化速率分别降低了18.7%、30.1%和44.7%,N净矿化速率分别降低了3.6%、12.7%和38.8%,P矿化速率分别降低了31.5%、41.8%和63.0%,但不同处理之间根际硝化速率差异不显著;根际土壤脲酶和酸性磷酸酶活性均表现为随酸雨加重呈增强的趋势(P<0.05).非根际土壤除NH4+-N外,其他有效N和P含量未随酸雨加重而改变;不同酸雨处理对非根际土壤氨化、硝化、N净矿化速率和P矿化速率的影响差异均不显著.根际NH4+-N、NO3--N、矿质N、氨化和净矿化速率均随着酸雨强度加重由正效应转变为负效应,而脲酶和酸性磷酸酶活性由负效应转变为正效应,但速效P和P矿化速率始终表现为负效应,硝化速率始终为正效应.综上所述,连续酸雨加重总体上抑制了根际N、P转化,降低其有效性,且不同程度改变其根际效应,从而影响茶园养分循环.Tea （Camellia sinensis） plantation in hilly red soil region has been long impacted by acid deposition, however its effects on nitrogen （N） and phosphorus （P） transformations in rhizo- sphere soils remain unclear. A 25-year old tea plantation in a typical hilly red soil region was selec- ted for an in situ simulation experiment treated by pH 4.5, pH 3.5, pH 2.5 and control. Rhizo- sphere and bulk soils were collected in the third year from the simulated acid deposition experiment. Soil mineral N, available P contents and major enzyme activities were analyzed using the chemical extraction and biochemical methods, and N and P mineralization rates were estimated using the in- door aerobic incubation methods. Our results showed that compared to the control, the treatments of pH 4.5, pH 3.5 and pH 2.5, respectively decreased 7.1%, 42.1% and 49.9% NO3--N, 6.4%, 35.9% and 40.3% mineral N, 10.5%, 41.1% and 46.9% available P, 18.7%, 30.1% and 44.7% ammonification rate, 3.6%, 12.7% and 38.8% net N-mineralization rate, and 31.5%, 41.8% and 63.0% P mineralization rate in rhizosphere soils ; however, among the 4 treatments, rhizosphere soil nitrification rate was not significantly different, the rhizosphere soil urease and acid phosphatase ac- tivities generally increased with the increasing intensity of acid rain （P〈0.05）. In bulk soil, com- pared with the control, the treatments of pH 4.5, pH 3.5 and pH 2.5 did not cause significant chan- ges in NO3--N, mineral N, available P as well as in the rates of nitrification, ammonification, net N-mineralization and P mineralization. With increasing the acid intensity, the rhizosphere effects of NH4＋-N, NO3--N, mineral N, ammonification and net N-mineralization rates were altered from positive to negative effects, those of urease and acid phosphatease showed the opposite trends, those of available P and P mineralization were negative and that of nitrification was positive. In sum, pro- longed elevated acid rain could reduce N and P transformation rates, decrease t

关 键 词：模拟酸雨 氮磷矿化 茶树 根际效应 丘陵红壤区 

分 类 号：S571.1[农业科学—茶叶生产加工]