Index variations of structure and quality of black soil with a long-term located monitoring

The index variations of structure and quality of black soil with a long-terrrx located monitoring are analyzed．The results show that a long-terrll utilization of organic manure increases the microaggregate of the fraction，i．e．0．05～0．02mm，0．02～0．O02mm and the waterstable capability of soil aggregate(>0．25mm)．and may facilitate the microag-gregate tO form lots of stable clay-particles．The soil bulk density of single use of N disposal is the largest in all the fertilized treatments，the soil structure of CK is markedly degenerated and the soil aggregate waterstable is low ，while the soil aggregate waterstable capability of fallow is markedly higher compared with others，thus indicating that the organic materials play a determ inative role in the shape and conservation process of soil structure．