中文摘要：

容许土壤流失量（T值）是进行水土流失治理的定量标准,目前以专家经验确定为主,缺乏定量研究。本文以我国重要的粮食生产基地东北黑土区为研究区,实地调查区内21个黑土土种典型剖面的厚度,采集分层土壤样品测定理化性质后,利用修订的生产力指数模型计算了21个土种的T值,并分析其影响因素。结果显示：21个土种的T值变化于68～358t/km2×a,平均141t/km2×a。按亚类T值为白浆化黑土（漂白滞水湿润均腐土）106t/km2×a,黑土（简育湿润均腐土）129t/km2×a,草甸黑土（斑纹简育湿润均腐土）为184t/km2×a。土壤厚度和土壤侵蚀脆弱性指数是影响T值的主要因素,它们与T值的相关系数分别为0.750和0.605。草甸黑土厚度明显高于其它两个土壤亚类,脆弱性指数与黑土接近,其T值较黑土T值大42.6%。白浆化黑土厚度较黑土厚度大22.1%,但T值却比黑土T值小21.7%,因为白浆化黑土有明显的障碍层存在。因此确定不同土种或亚类的T值,更能反映土壤剖面特性,对于指导水土流失治理更具实际意义。

英文摘要：

Soil Loss Tolerance（T） is a quantitative criterion for soil conservation,and it is determined empirically at present due to limited quantitative researches.The black soil region of Northeast China,one of the major grain production bases in China,was selected as the study area.Soil depths were investigated and physicochemical properties of soil profiles were analyzed for 21 black soil species in the study area.T values of the 21 black soil species,calculated by using a modified productivity index model,varied from 68 t/km 2 ×a to 358 t/km 2 ×a,and 141 t/km 2 × a in average,and 106 t/km 2 × a for albic black soils（Albic Stagni-Udic Isohumosols） ,129 t/km 2 × a for black soils（Hapli-Udic Isohumosols） ,and 184 t/km 2 × a for meadow black soils（Mottlic Hapli-Udic Isohumosols） .Soil depths and soil erosion vulnerability index were two key factors influencing T values.The correlation coefficients of these two factors with T were 0.750 and 0.605 repectively.The meadow black soils had the largest soil depth and similar erosion vulnerability index close to that of black soils,and its T value was 42.6% larger than that of black soils.The soil depth of Albic black soils was 22.1% larger than that of black soils,and its T value was 21.7% smaller than that of black soils.This is due to the existence of obstacle horizon for Albic black soils.Therefore,determination of T values for different soil species or families is more practical for soil conservation in terms of soil profile properties.