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Abstract: Soil water plays an important role in muskmelon (Cucumis melo L.) production, especially inside greenhouse. The object of this study was to determine the soil water content criteria at which growth and yield production of muskmelon would be optimal based on soil water measured by Time Domain Reflectometry (TDR) inside a plastic greenhouse when using drip irrigation. Four soil water content lest thresholds (relative to the percentage of field water capacity) for starting the irrigation (45%-I45, 55%-I55, 65%-I65, 75%-I75) were compared inside plastic greenhouse experiment in 2009. Amount of applied irrigation water for four treatments varied from 120.1 to 178.6mm. The results showed that muskmelon plant development, fruit production and quality were significantly affected under different irrigation water amounts. Higher soil water content enhanced vegetative growth through increasing the plant height and stem diameter. Variation in soil water content not only had effects on fruit size, but also had effects on fruit yield. The highest fruit yield and irrigation water use efficiency (IWUE) were obtained from the treatment employing the greatest irrigation thresholds and quantity of irrigation (I75). When the thresholds of soil water content were below 65% field water capacity during the whole growth period, the mean fruit weight and yield decreased significantly. Irrigation water amount significantly affected the flesh thickness and fruit total soluble solids (TTS), soluble sugar (SS), vitamin C (Vc), soluble protein (SP) and free amino acid (FAA) content. In conclusion, treatment I75 was the optimum irrigation schedule for muskmelon grown inside plastic greenhouse. [Copyright &y& Elsevier]

Abstract: The experiments were conducted to evaluate the effects of different amount of irrigation water on the growth and yield of cucumber under a rainshelter from May to October for two seasons in Yamaguchi University, Japan. For spring experiment, the amount of irrigation water applied was 0.50, 0.75, and 1.00 times of water surface evaporation (Ep) measured by a standard 0.2m diameter pan, regimes were denoted as Ep0.50, Ep0.75, and Ep1.00. Same method for autumn experiment, regimes were denoted as Ep0.75, Ep1.00, Ep1.25, Ep1.50, and Ep1.75. The results showed that amount of irrigation water significantly affected plant growth and fruit production. Plant height and biomass increased, but specific leaf weight (SLW, g/m2) decreased with increasing amount of irrigation water. The SLW and leaf blade water content were directly response to the applied irrigation water and soil water content, and the SLW of cucumber was decreased with the leaf blade water content increasing. The amount of irrigation water had significant effects on decreasing the leaf temperature, and the largest differences in leaf temperature with Ep1.75 regime were 2.1, 2.6, 4.7, and 5.8°C for Ep1.50, Ep1.25, Ep1.00, and Ep0.75 regimes at noon. Plant biomass (dried stem and leaves), the number of lateral branches and production were highest for spring regime Ep1.00 and autumn regime Ep1.75 that the plant received the most amount of irrigation water. During the cucumber growth period of 5 months from May to September for the plant and fruit growth, the crop coefficient K should be more than 1.00 that is a guideline and it is better between 1.00 and 1.50, and the average irrigated water of 4.0–5.5mm/day is necessary for plant and fruits growth. Therefore, applying water by drip irrigation in relation to the amount of water evaporated from a standard 0.2m diameter pan is a convenient, simple, easy, and low cost method under a rainshelter. [Copyright &y& Elsevier]