Effect of irrigation and mulching practices on maize crop and some water relations

The experiments were conducted at the experimental farm of Giza Agricultural Research Station, Egypt, during the summer seasons of 2014 and 2015 to study the effect of different irrigation regimes (I₁=Irrigation at 25-30%, I₂ = 50-55% and I₃ 75-80% of available soil moisture depletion (ASMD) and mulching treatments white plastic film mulch (PFM), Rice straw mulch (RSM), and No mulching (NM) on (Zea mays L.). A split plot design with three replicates was used. The most important results can be summarized as follows:
The highest value of the irrigation water applied (IWA), was found to be (3451 and 3444 m³/fed.), due to (I₁) treatment in both growing seasons, respectively. Water consumptive use (WCU) was increased in the case of frequent irrigation as in 25-30% (ASMD) than the two irrigation treatments. Also, average water use efficiency (WUE) was increased by using 25-30% of (I₁), with plastic mulch and recorded (1.64 kg/m³), followed by 50-55 with plastic mulch (1.59 kg/m³), and 75-80% (ASMD) treatments with plastic mulch (1.42 kg/m³) in both seasons. The maximum value of water utilization efficiency (WUtE), was 1.06 and 1.12 kg /m^-3 in 2014 and 2015 seasons, respectively, and was obtained from (I₂) 50-55% with plastic mulch treatments compared with no mulching treatments in the both seasons. The highest significant values of ear diameter (cm), ear length ,100-grain weight (g) and grain yield of maize were obtained when irrigation was done at 25-30% (ASMD) compared with other treatments 50-55% and 75-80% (ASMD) in both seasons. The mulching with plastic gave the highest significant values of ear length and diameter (cm) as well as 100-grain weight (g) and grain yield of maize compared without mulching in both seasons. Also, results revealed that the highest significant values of ear length and diameter (cm) as well as 100-grain weight (g) and grain yield of maize were obtained by  I₁ 25 -30 % with plastic mulching treatment in both seasons. The highest net return (L.E.fed^-1 3726/fed.), and (L.E.fed^-1 3100/fed.), were found for 25-30% (ASMD) application with plastic or straw mulch. The study thus reveals that (ASMD) 25-30% with mulch has an explicit role in increasing the yield and net return of maize