Effects of perennial grass on soil physical properties
The effects of Russian wildrye, smooth brome and crested wheatgrass, as well as oat were planted in Saibei Working station. The effects of perennial and annual grasses on soil physical properties were studied after 3 years. The results indicated that after a period of growing season in the third year, soil bulk density decreased 9. 29% ,8. 64% ,6. 38% in depth of 0 ~ 10 cm,10 ~ 20 cm,20 ~30 cm, respectively. Soil water content was clearly higher in perennial grass plots than that in oat plots. Soil total porosity in perennial grass plots increased 6. 45% in 0~10 cm soil, while reduced1. 04% in oat plots. In 10 ~20 cm soil, total porosity increased 7. 15% in perennial grass plots and 1. 49% in oat plots. The soil total number of ≥ 0. 25 mm aggregates in 0 ~ 30 cm was 8. 45% higher in perennial grass plots (averagely 73. 89%) than that in oat plots(averagely 65. 44%).