THE ROLE OF SOIL MULCHING AND TILLAGE SYSTEM ON YIELD OF BROAD BEAN UNDER WATER STRESS CONDITION AND WEED COMPETITION

Abstract

To determine the role of wheat straw and tillage system on yield of broadbean and companying weed at water stress, a field experiment was carried outduring winter season of 2016-2017 in field of Wasit University , collage ofagriculture (180 k south of Baghdad , Iraq, on latitude 45 - 490and longitude32.30 and 19 m above sea level) in silty loam texture of soil. Randomizedcompletely block design (RCBD ) within split –split plot arrangement and threereplicate was used . Two treatments of tillage systems (tillage and withouttillage) were represented on whole plots, and three treatments of water stresswere represent the sub plots ( 50% as control, 60% and 71% decrease fromavailable water). Sub-sub plot treatment included wheat straw as cover crop andanother without cover treatment. The results showed a superiority of the soilcovered treatment with yield of broad bean compared with uncovered soiltreatment, as it was recorded yield under stress conditions (71% available- waterdepletion) and no tillage, not significant different from non-covered treatment atnormal irrigation (50% available- water depletion) and tillage. Soil coveragetreatment have also shown a high efficiency of the conservation agriculturesystem in reducing the density of the weeds, reducing its competition for the cropand improving productivity of crop. As well as reducing tillage , which reducesthe cost of agricultural production and gives an economic yield under stressconditions with the possibility of saving the amount of water available forirrigation and increasing cultivated areas.