Effect of growing cotton in rotation with different crops on structure of black cotton soil

Abstract

Results of an investigation carried out to study the effect of growing cotton in rotation with juar and groundnut on the structure of black cotton soil are presented and discussed. The rotations studied were:- (a) Cotton grown continuously year after year; (b) Cotton and juar grown in alternate years; and (c) Cotton-juar-groundnut in three course rotation. Determinations made for evaluation of structure and the ranges of values obtained were:- (i) Degree of aggreation - 64.4-69.3 (ii) Single value figure for surface area - 587.6-595.7 (iii) Dispersion coefficient - 805-9.0 (iv) Volume weight - 1.11-1.14 (v) Total pore space - 58.3-60.1% (vi) Volume of large pores - 20.2-21.6% (vii) Rate of percolation through undistrubed soil core samples - 1.9-3.9 inch per hr. (viii) Rate of percolation through distrubed soil samples - 2.7-2.9 inch per hr. No significant differences in the structural condition of the soil were observed in plots under the three different rotations, both in 0-6" and 6-12" layers. The lower 6-12" layer did not show any structural difference from the surface 0-6" layer. None of the standing crops of the year,i.e., cotton, juar and groundnut showed any pronounced effect on the structure of the soil.