COMMON BEAN GROWTH, WATER USE EFFICIENCY AND SOIL SALINITY AS EFFECT TO DEFICIT IRRIGATION AND MULCHING MATERIALS UNDER DRIP IRRIGATION

This study investigated the combined effects of deficit irrigation and mulches on beans yield, water use efficiency (WUE) and soil salinity under drip irrigation. The treatments of the study comprised different combinations of three irrigation treatments (I100% =100%, I85% =85% and I70% = 70% of crop evapotranspiration (ETc) and three mulching materials (no mulch (NM), rice straw mulch (RSM) and farmyard manure mulch (FYM). The results obtained that the irrigation treatments and mulching materials on yield and WUE were significant. The greatest value of bean yield (941.5and 925.7kg fed^-1) were obtained under (I100%) in the first and second season, respectively, while the lowest ones (706.4 and 710.6kg fed^-1) were obtained from (I70%) in the first and second season, respectively. 39.6 and 11.1 % than NM and RSM in 2014 seasons, respectively increased the average GY of FYM treatment. The corresponding values in 2015 season were 39.6 and 9.3 % in the same order. The average of soil salinity value (I70%) was increased by 28.26and 13.50% than those of I100% and I85%, respectively. 21.9 and 19.7 % than those of FYM and RSM treatments, respectively increased the average EC value of NM. The greatest WUE (0.74 and 0.75 kg m^−3) value was obtained under I70% compared to (0.69 and 0.68 kg m^−3) under I100%, in two seasons, respectively. 40.3 and 10.6 % than those of NM and RSM, respectively increased the average WUE values of FYM. It could be considered as a suitable under environmental conditions of study area and similar areas, the treatment (I100 × FYM) is the most suitable for producing high bean crop yield. Under limited irrigation water supply, application of (I85 ×FYM) treatment was found to be favorable to save 15% of the applied irrigation water, with reduction in bean crop yield.