Influence of Irrigation Water Deficit on Forage Yield, and Water Utilization Efficiency for Sorghum and Cowpea Forage Crops

Abstract

The present study was carried out at Sakha Agricultural Research Station (clayey soils) during 2018 and 2019 to find out the role of water deficit on yield and some water relations for sorghum and cowpea summer forage crops. Three irrigation levels were executed; 100% (full irrigation), 90% (10% deficit) and 80% (20% deficit). Results showed that increasing water deficit, markedly led to decreasing fresh, dry yield and plant height at the three cuts in the two seasons. Regarding water relations, irrigation level with 90% (10% deficit) resulted in several advantages; almost same yield as recorded under full irrigation, 10% water saving as well as the highest values of water productivity (WP) and productivity of irrigation water (PIW). The mean values of fresh sorghum forage yield can be arranged in descending order as; 2917.0 > 2857.5 > 2561.0 kg.plot-1, while the corresponding values of the dry weight were; 381.6> 367.8> 319.6 kg.plot-1. Plant height for cowpea slightly affected with different irrigation treatments. On the contrary, both fresh and dry yields were significantly affected with water level or deficit irrigation. Moreover, the effect was highly significant in connection with the combined analysis. In this regard, mean values of fresh yield descending arranged as; 1502.5> 1447.0> 1321.5 kg.plot-1 for treatments A(control), B (90%) and C (80%), respectively. The corresponding values regarding dry yield are 253.5, 241.0 and 215.4 kg.plot-1. Comparing the deficit treatments with the control irrigation (Trt. A), overall mean decrease in fresh yield was 3.7% for treatment B (90%) and 12% for treatment C (80%). While, the corresponding decrease in dry yield were 4.9% and 15.0%.We can conclude that forage yield of sorghum and cowpea  not affect by water irrigation deficit about 10% at Middle North Nile Delta area.