EFFECTS OF MOISTURE REGIMES AND PLASTIC MULCHING ON TOMATO IN SURFACE AND SUBSURFACE DRIP IRRIGATION METHODS

摘要

Tomato is the most important vegetable crops which generally grows under surfacernirrigation method. In this method, the major proportion of irrigation water is lost byrnsurface evaporation and deep percolation, resulting in lower irrigation efficiencies.rnRecentlydue to worldwide aridity and water shortage, there is tendency of farmers tornapply drip irrigation for water saving in agriculture. The objective of this paper isrndetermining the impacts of plastic mulching, drip irrigation methods and differentrnamount of applied water and their interactions on yield, water use efficiency andrnquality characteristic of tomato. This study was conducted during 2006-2008 inrnTorogh Agricultural Research Station in Razavi Khorasan Province. The soil texturernwas silty loam and loam in 0-40 and 40-80 cm, respectively. Experimental design wasrnrandomized complete blocks design in split split plot with three replications.rnTreatments included different amount of applied water (60, 80 & 100% waterrnrequirement) in main plot, drip irrigation methods (surface and subsurface) in sub plotrnand mulching (without mulching & plastic mulch) in sub-sub-plot. Results showed thatrnirrigation moisture regime, irrigation method and mulch treatments had significantrneffectson yield and WUE (P≤ 0.01). Yield in 60, 80 and 100% of water consumptionrnwas 31.14, 54.58 and 62.27 ton/ha, respectively. This difference was significant. Thernhighest WUE (7.88 kg/m~3) was obtained at 80% moisture regimes and followed by 60rnand 100% of moisture regimes with 5.93 and 7.23 kg/m~3, respectively. However,rnthere was a significant difference between yield in surface and subsurfacerndripirrigation methods (43.38 and 55.27 ton/ha, respectively). WUE in subsurfacerndripirrigation was 7.93 kg/m~3 and greater than surface drip irrigation (6.12 kg/m~3).rnYield in plastic mulching and without mulching treatments were 55.64 and 42.71rnton/ha, respectively. Application of mulch increased WUE about 30%. Also, whenrnwater saving vegetable growth, yield and economics return were taken into account,rnthen an irrigation level of 80% through subsurface dripirrigation along with plasticrnmulch will be considered optimal.