Effects of soil tillage systems on the water use and on common bean yield

The objective of this work was to compare water use efficiency and yield of two common bean cultivars with different plant architectures under no-till age system, using two amounts of straw in relation to other soil tillage sy stems. The experiment was carried out during four years on a Dark Red Latos ol, in Santo Antonio de Goias, GO, Brazil. The experimental design was a sp litplot strip block with four replications. The A strips, parallel to a spr inkler line source, consisted of five irrigation levels. The four year-aver age water amounts applied to each strip were: 399.8, 307.0, 216.8, 128.0, a nd 54.0 mm. The B strips, across to sprinkler line source, consisted of fiv e soil tillage systems: no-tillage, no-tillage plus mulch, harrowing, moldb oard ploughing, and chisel ploughing. Cultivars Safira and Apore were plant ed in the splitplots. The magnitude of common bean yield response to irriga tion levels varied with bean cultivar and soil tillage systems. No-tillage with adequate mulch provided higher water economy than the other soil tilla ge systems.