Original Articles

Changes in a Doveton clay loam after 12 years of direct-drill maize production

Published in: South African Journal of Plant and Soil
Volume 4, issue 4, 1987 , pages: 188–192
DOI: 10.1080/02571862.1987.10634972
Author(s): J.B. Mallett, Republic of South Africa, P.M. Lang, Republic of South Africa, A.J. Arathoon, Republic of South Africa


After 8 years of direct-drill maize production at Cedara on a Hutton/Doveton clay loam (Typic Plinthustult) it was found that the top 120-mm layer had become somewhat denser and that organic carbon levels in the top 20 mm were higher than in conventionally tilled plots. Direct-drill plots also displayed superior soil water conservation properties and this was reflected in better maize grain yields during seasons of below average rainfall. After a further 4 years the plots were again the subject of a detailed investigation and it was found that soil dry bulk densities had stabilized while surface organic carbon levels had increased in the interim from 3,8 to 4,7% in the direct-drill plots but had remained unchanged in the conventionally tilled plots at around 3,3%. Surface pH levels in the direct-drill plots had dropped further while P, K and Al levels were higher in the direct-drill than conventionally tilled plots. Earthworm counts were significantly higher in the direct-drill plots.

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