Effect of mulching on plant water status, soil salinity and yield of squash under summer-fall deficit irrigation in salt affected soil

Field studies were conducted for two consecutive seasons (summer and fall) under sub-temperate climatic conditions at southwest of Cairo, Egypt (29° 35′ N 30° 23′ E) in saline soil (ECe 12.6 dS m−1) to investigate the effect of different mulches (without mulch, WM as a control, farmyard manure: FYM, rice straw: RSM and white polyethylene: PM) on soil salinity, plant water status, water-use efficiency (WUE), and yield of squash under three levels of irrigation (I100 = 100%, I85 = 85% and I70 = 70% of crop evapotranspiration). Under full irrigation, seasonal water use by squash was 479 over 86 days in summer and 306 mm over 91 days in fall season, respectively. Plant water status (as evaluated by relative water content, canopy temperature), fruit quality yield and water use efficiency (WUE) were significantly (P ≤ 0.05) affected by season and both irrigation quantity and mulching materials. Photosynthesis efficiency, total soluble sugars (TSS), leaf area index, harvest index (HI), yield and WUE were not significantly affected by interaction between growth season and both irrigation and mulching treatments. All mulching materials effectively reduced salt accumulation in the root zone. Mulching treatments markedly increased WUE and yield in the order of FYM > RSM > PM > WM. Results showed that, under different mulches, the I85% strategy studied here could be successfully applied during summer and fall seasons in commercial squash production allowing water savings of 15% without any detrimental effect on plant growth or yield.