水蚀对千岛湖消落带土壤氮素影响的数值模型分析  

Water erosion and soil nitrogen at the water-level-fluctuation zone of Qiandao Lake

作　　者：余敏芬[1] 方佳[1] 何勇清[1] 林太本 郑炳松[1] 王强[3] 

机构地区：[1]浙江农林大学亚热带森林培育建国家重点实验室培育基地,浙江临安311300 [2]浙江省森林资源监测中心,浙江杭州310020 [3]浙江大学宁波理工学院,浙江宁波315100

出　　处：《浙江农林大学学报》2013年第6期805-813,共9页Journal of Zhejiang A&F University

基　　金：国家自然科学基金资助项目(30470330);浙江省科技计划项目(2009C33070)

摘　　要：水蚀作用影响消落带土壤氮素的分布进而对库区水环境产生影响。以千岛湖消落带为研究对象，依据湖水水位变化时间与空间特征和土壤基质的差异性，设置13条代表性土壤样本采集带。采用国家林业行业标准（全氮采用凯氏定氮法GB7173—1987，碱解氮采用碱解扩散法LY/T1229—1999，硝态氮采用酚二磺酸比色法LY/T1230—1999）测定方法，分别测定样本消落带及林地上层（0～30cm），中层（30-50cm），下层（50-75cm）土壤中全氮、碱解氮和硝态氮的质量分数。通过建立拟合最小二乘、BP神经网络和偏微分扩散方程3种数值模型，对土壤样本测定所得数据分别进行计算分析。其中，拟合最小二乘法模型计算结果表明：水蚀作用对千岛湖消落带土壤中全氮和碱解氮流失贡献分别为80．13万t和10．95万t；硝态氮在消落带综合富积量为913．39t。从对千岛湖案例的分析中可见，消落带水土流失较为严重，需要加强对消落带区域的生态环境保护及治理。To analyze the effects of water erosion on soil nitrogen at the water-level-fluctuation zone of Qiandao Lake, Zhejiang Province, 13 representative soil bands and 26 sample transects were set up to determine based on the temporal and spatial characteristics of the water level and differences in the soil matrix. Soil total nitrogen, hydrolytic nitrogen, and nitrate nitrogen for depth of 0-30 crn, 30-50 cm, and 50-75 cm in the water-level-fluctuation zone and in a woodland were analyzed respectively using the national forestry industry standards （GB 7173-1987）, （LY/T 1229-1999）, and （LY/T 1230-1999）. Each soil sample was measured three times, and resulted the average value. Results showed that soil total N and hydrolytic N for the water-lev- el-fluctuation zone were decreased than those for the woodland, whereas nitrate N for the water-level-fluctua- tion zone was increased than that for the woodland. The numerical least square method models for the water- level-fluctuation zone to the lake showed losses of total N 801 277.54 t and hydrolysis N 109 465.28 t with sedimentation of nitrate N from the lake to the water-level-fluctuation zone of 913.39 t. The BP neural network numerical models were soil total N 712 593.85 t, hydrolytic N 97 823.34 t, and nitrate N 849.30 t. Partial differential diffusion equation numerical models were soil total N 921 058.79 t, hydrolytic N 123 125.13 t, and nitrate N 1 028.35 t. The least square method models better explained the effects of water erosion at the water-level-fluctuation zone of Qiandao Lake, and zone need to be strengthened.

关 键 词：土壤学 消落带 水土流失 氮素 千岛湖 

分 类 号：S714.8[农业科学—林学]