转移矩阵法评价土壤团聚体的稳定性

团聚体稳定性是土壤的基本性质,反映了土壤肥力的高低。在3个合理假设的基础上,通过建立干筛和Yoder法湿筛结果之间的转移矩阵,并通过不同径级团聚体的保存率构造了团聚体稳定性指数。该稳定性指数与文献结果具有良好的一致性,说明了转移矩阵方法可用于土壤团聚体稳定性的评价。同时利用该方法分析了不同径级团聚体抗破裂能力大小,发现降雨模拟、干湿循环(1次)、干湿循环(10次)和Yoder湿筛法影响的团聚体粒径并不相同。>0.25 mm水稳性团聚体含量虽然在整体上与团聚体的稳定性具有良好的相关性,但并不是随着>0.25 mm水稳性团聚体含量的增高,每个径级范围的团聚体稳定性增强。该方法可充分利用团聚体分析所得的信息,为进一步认识土壤团聚体的稳定性提供方法支撑。

Using Transition Matrix to Evaluate Stability of Soil Aggregates

Soil aggregate stability is a key property of soil,and reflects soil fertility.Soil aggregate stability index(ASI) was formed through the transition matrix between dry sieving results and Yoder method results,and conserving-probability of each size aggregate on the basis of 3 reasonable assumptions.The ASI is identical to the result by references,which shows that the transition matrix can be used to evaluate the soil aggregate stability.The transition matrix was then used to analyse anti-break ability of different size aggregates.Results show that there are difference effects for each size aggregate with 4 methods of simulation rainfall,wetting-drying cycles one time,wetting-drying cycles ten time,and Yoder wet sieving.There is a good linear relationship between content of more than 0.25 mm water stable aggregate and ASI in a total tendency,but not all size aggregate stability heightenes with >0.25 mm water stable aggregate content increasing.The transition method utilizes all information of aggregate analysis,and can be a better tool to understand soil aggregate.