Abstract
Comparative studies of the influence of crop rotation and residue management on soil shrinkage in irrigated cotton (Gossypium hirsutum L.) based cropping systems in Australian Vertosols are sparse. Our objective was to quantify soil shrinkage in beds under four cotton-based cropping systems sown on permanent beds in an irrigated Vertosol with subsoil sodicity. The experimental treatments were: cotton monoculture; cottonvetch (Vicia benghalensis L.) rotation; cottonwheat (Triticum aestivum L.) rotation; and cottonwheatvetch rotation, with wheat stubble retained as in-situ mulch and a summer fallow. Vetch in the cotton-vetch sequence was sown immediately after cotton picking and bed renovation in May and slashed/sprayed out during September whereas that in the cotton-wheat-vetch sequence was sown during February and slashed/sprayed out during August. The experiment was laid out in 3 RCB. Soil shrinkage was evaluated in clods (4) extracted from 4 locations in each plot during late September 2009. Specific volume was determined after coating soil clods with paraffin wax and plotted against the corresponding soil water content to derive shrinkage curves. The shapes of the curves and the shrinkage parameters suggested that surface compaction was present in the cotton phases of the rotations that included a wheat crop, and confirmed by the pore size distribution. Compaction was probably caused by trafficking on beds during wheat harvest. Until 2010 wheel and axle widths of the wheat harvester used in this site were incompatible with the cotton systems 1-m bed configuration.
| Original language | English |
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| Pages (from-to) | 61, 66pp |
| Journal | 2nd Australian Cotton Research Conference 2015: Science securing cotton's future |
| Publication status | Published - 2015 |
| Event | 2nd Australian Cotton Research Conference 2015 - University of Southern Queensland, Toowoomba Duration: 1 Jan 2015 → … |