PENETRATION RESISTANCE AND ROOT-GROWTH OF OATS IN TILLED AND UNTILLED LOESS SOIL
PENETRATION RESISTANCE AND ROOT-GROWTH OF OATS IN TILLED AND UNTILLED LOESS SOIL
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DOI：
10.1016/0167-1987(83)90027-2
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发表时间：
1983-01-01
影响因子：
6.5
通讯作者：
BOHM, W
中科院分区：
文献类型：
--
作者：
EHLERS, W;KOPKE, U;BOHM, W
在耕作和未耕作灰褐色灰壤中，对燕麦的入渗阻力、容重、土壤含水量和根系生长进行了研究。未翻耕土壤表层的容重和贯入阻力均高于翻耕土壤。在后者中，25 - 30 cm土层中存在一个交通盘，该土层的容重和贯入阻力比未耕作土壤的任何一层都高。以上的交通潘，生根密度（厘米根长每厘米3的土壤）较高，但低于潘低于在同一深度的未耕土壤。根系生长与渗透阻力呈线性关系。在两种耕作处理中，已耕作的Ap-horizon中根系生长的极限渗透阻力为3.6 MPa [兆帕斯卡]，而未耕作的Ap-horizon和底土中的极限渗透阻力为4.6 - 5.1 MPa。土壤强度-根系生长关系的这种差异可以用蚯蚓和前茬作物的根系在未耕土壤中形成的连续孔隙系统来解释。这些占土壤体积小于1%的生物孔隙可被后茬作物的根系利用，作为土壤强度相对较低的通道。大量土壤的沟化可以抵消在免耕系统中经常观察到的土壤强度增加可能产生的根系限制效应。
Penetration resistance, bulk density, soil water content and root growth of oats were intesnively studied in a tilled and an untilled gray brown podzolic loess soil. Bulk density and penetration resistance were higher in the top layer of the untilled soil compared with the tilled soil. In the latter, a traffic pan existed in the 25-30 cm soil layer which had higher bulk density and penetration resistance than any layer of the untilled soil. Above the traffic pan, rooting density (cm root length per cm3 of soil) was higher but below the pan it was lower than at the same depth in the untilled soil. Root growth was linearly rated to penetration resistance. The limiting penetration resistance for root growth was 3.6 MPa [megapascals] in the tilled Ap-horizon but 4.6-5.1 MPa in the untilled Ap-horizon and in the subsoil of both tillage treatments. This difference in the soil strength-root growth relationship is explained by the build up of a continuous pore system in untilled soil, created by earthworms and the roots from preceding crops. These biopores, which occupy < 1% of the soil volume, can be utilized by roots of subsequent crops as passages of comparatively low soil strength. The channeling of bulk soil may counteract the possible root restricting effect of an increased soil strength which is frequently observed in the zero tillage system.