6Unger P W. Straw mulch rate effects on soil water storage and sorghum yield [J] Soil Science Society of America Journal, 1978,42: 486- 491.
7Blevins R L, Smith M S, Thomas G W, et al. Influence of conservation tillage on soil properties[J]. Soil Water Conserv, 1983,38:301-305.
8Goss M J, Ehlers W, Boone F R, et al. Effect of soil management production on soil physical conditions affecting root growth[J]. J Agric Eng Res, 1984,30: 131 -140.
9All maras R R, Nelson W W. Corn (Zea may L. ) root configuration as influenced by some row-interrow variants of tillage and straw mulch management[J]. Soil Sci Soc Am Proc, 1971,35:974-980.
10Anderson W B, Kemper W D. Corn growth as affected by aggregate stability, soil temperature, and soil moisture [J]. Agron J,1964,56;453-456.