横垄覆膜对丹江口库区土壤净氮矿化的影响

以丹江口库区五龙池小流域玉米黄棕壤为例,利用原位矿化试验,通过与横垄无覆膜土壤比较,研究横垄覆膜对土壤净氮矿化的影响。结果表明:玉米苗期中期和拔节期前期,横垄覆膜土壤净氮矿化量与无覆膜土壤相比分别降低7.8%~57.0%和2.2%~52.8%;玉米拔节期后期、抽穗期和成熟期,横垄覆膜土壤净氮矿化量比无覆膜土壤分别提高352.9%~703.3%,52.5%~311.0%和15.2%~334.8%。横垄覆膜土壤净氮矿化量在玉米苗期、拔节期、抽穗期和成熟期与土壤含水量、温度和全氮间均存在较强度关联关系(0.6灰色关联度≤0.8)。逐步回归分析表明,横垄覆膜土壤净氮矿化量在玉米苗期与土壤温度间呈最优线性关系(F=7.205,P=0.023);在玉米拔节期与土壤含水量和温度间呈最优线性关系(F=36.861,P=0.001);在玉米成熟期与土壤含水量间呈最优线性关系(F=42.438,P=0.007)。

Effects of Cross Ridge Covered with Plastic Film on Soil Net Nitrogen Mineralization in Danjiangkou Reservoir Area, China

A field plot experiment was conducted to explore the effects of cross ridge covered with plastic film on soil net nitrogen mineralization in Wulongchi small watershed during maize growing period.Results showed that the soil net nitrogen mineralization contents under cross ridge covered with plastic film were significantly lower than those of non-mulched treatment at the mid-term stage of seedling and the early stage of jointing,and the decreases were 7.8％～57.0％ and 2.2％～52.8％,respectively.While at the later stage of jointing,heading stage and maturity stage,the former were significantly greater than the latter and the increases were 352.9 ％ ～ 703.3 ％,52.5 ％ ～ 311.0％ and 15.2 ％ ～ 334.8 ％,respectively.The higher correlations existed between the soil net nitrogen mineralization contents under cross ridge covered with plastic film and the soil moisture,temperature and total nitrogen contents at the seedling stage,jointing stage,heading stage and maturity stage (0.6＜Grey correlation degree≤0.8).The soil net nitrogen mineralization contents under cross ridge covered with plastic film showed a significant linear relationship,with soil temperature at the seedling stage (F=7.205,P=0.023),with soil moisture and temperature at the jointing stage (F=36.861,P=0.001),and with soil moisture at the maturity stage (F=42.438,P=0.007).