Effects of Deficit Irrigation and Fertigation on Growth, Yield and Water Productivity of Greenhouse-Grown Cucumber

Low water productivity has caused the wastage of water in agricultural production. Water productivity can be increased by using drip irrigation for vegetables on raised beds in greenhouses. For this purpose, a greenhouse study was conducted on sandy loam soil at the Experimental Research Station of the Asian Institute of Technology, Thailand. The experiment was designed in randomized complete block design having ten treatments using three irrigation levels [100%, 80%, 60% of actual evapotranspiration (ETc)] and three recommended dose of fertilizer (RDF) levels [100%, 80%, 60%]. Furrow irrigation with 100% of RDF was used as a control treatment. Data of crop and water productivity were recorded; the results showed that treatment T5 (W80%ETc F80%RDF) under deficit irrigation and fertigation recorded the highest mean fresh fruit yield of 66.71 t/ha while the full irrigation treatments T1 (W100% ETc F100% RDF) and T2 (W100%ETc F80%RDF) recorded the lowest mean fresh fruit yield of 12.9 t/ha and 13.9 t/ha, respectively, as against 9.6 t/ha for the control plot. Also, T5 recorded the highest water productivity of 14.47 kg/m3 while full irrigation treatments (T1 and T2) recorded the lowest water productivity of 2.52 kg/m3 and 2.73kg/m3, respectively, as against 1.37 kg/m3 for the control plot. A deficit irrigation level of 80% of ETc with a fertilizer level of 80% of RDF was found most suitable for sandy loam soil to improve crop growth, yield and water productivity for greenhouse-grown cucumber under the drip irrigation system. The results also suggest that a 20% deficit irrigation and fertilizer approach may be a good strategy for increasing water productivity when full irrigation is not possible due to limited water supplies.