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Conference paper2009

Effects of Direct drilling & residue management on Readily Dispersible Clay

Etana, Ararso; Rydberg, Tomas; Arvidsson, Johan


Readily dispersible clay (RDC) was determined in a Swedish long-term tillage experiment, initiated in 1983 at Lanna experimental station (58º21′/13 º8′E). The treatments included: Mouldboard ploughing (MP); Direct drilling with occasional ploughing; and Direct drilling (DD). Straw has been removed or left on the plots as sub-treatments. Soil clods were collected from 0-10 cm and 12-17 cm. In addition, soil columns (20 cm in diam., 20 cm h) were collected. From the soil clods, aggregates of 8-11 mm in diameter were prepared and kept in a wet chamber at 50 mm water suction for a week to get similar water tension. They were then transferred to PVC bottles with 250 ml water and gently turned over to insure aggregate surface-water contact. After settling of particles greater than clay-size, turbidity was measured. Drainage tests were carried out on the soil columns by applying artificial rain and then the turbidity of the outflow was determined. RDC was less in DD than in MP, by 17 % and 48 % for the aggregates from 0-10 cm and 12-17 cm, respectively. Straw incorporation in the MP significantly reduced clay dispersion, but it did not give any significant difference in the DD. RDC of the outflow from drainage tests was also much less in DD than MP. Keywords: direct drilling readily dispersible clay

Published in


18th Conf. ISTRO