Effect of closed circuits drip irrigation system and lateral lines length on growth, yield, quality and water use efficiency of soybean crop

Abstract

Field experiment was conducted for one grow-ing season (2012) in clay loam soil at the Ex-perimental Farm of Faculty of Agriculture, Sou-thern Illinois University at Carbondale (SIUC), USA on soybean crop to study the effect of: 1) the closed drip irrigation system: closed circuits with one and two a manifolds for lateral lines (CM1DIS; CM2DIS) and traditional drip irrigation system (TDIS) as a control; and 2) lateral lines length (LLL): LLL1, LLL2 and LLL3 (40, 60, 80 m) on soybean growth, yield, oil, protein content and water use efficiency. Plants were drip irri-gated every 4 days. N, K 2 O and P 2 O 5 fertilizers were added via irrigation water. Data obtained could be outlined as follows: 1) According to the mean values of soybean crop growth (leaf area; plant height), yield (grain and straw), both oil and protein content and water use efficiency, the treatment used could be ranked in the following ascending orders: TDIS < CM1DIS < CM2DIS and LLL3 < LLL2 < LLL1; 2) Differences in the means of the studied data among treatments used were significant at the 1% level; 3) The effects of the DIC × LLL on the data obtained were significant at the 1 % level; And 4) the highest values of the obtained data and the lowest ones were achi-eved in the following interactions: CM2DIS × LLL1; TDIS × LLL3, respectively.