FertilizerManagementPractices withRice Straw Application forImproving Soil Quality inWatermelonMonoculture Greenhouse Plots

FertilizerManagementPractices withRice Straw Application forImproving Soil Quality inWatermelonMonoculture Greenhouse Plots

Indoor cultivation plots forwatermelon plantmostly have salt-accumulation problembecause of continuous cropping especially with the heavy applications of chemical fertilizers. Thus, this study was conducted to investigate selected soil properties andwatermelon growth condition as affected by the application of different farming practices in the salt-affected soils of greenhouse plots used for continuous watermelon production. Five different practice conditions in the experimental plots were applied, 1) a conventional farming practice (CFP), 2) a nitrogen-phosphorus-potassium (NPK) fertilizer management practice (FMP), and 3) the FMP with different amounts (5, 10, and 15 t ha-¹)of fresh rice straw treatments (FMP-RS), for three years of study. As comparing with CFP plots, soil organic matter content gradually increased during the experimental years,whereas it decreased in the FMP only plot. Soil pHwas not changed in the CFP and FMP plot, but it declined in the FMP-RS plots; however, it increased again fromthe third yearin the FMP-RS plots with applying 10 and 15 t ha-¹ of RS treatments. The concentrations of exchangeable cations, Ca²+ and Mg²+, except K+, and water-soluble anions, NO₃-, Cl-, SO₄²-, andPO₄³-, markedly decreased inFMPandFMP-RS plots. In particular,the application of rice straw tended to significantly decrease the ion concentrations, especiallymost anions, in the first year, but there was no more decrease in the second and third study years. With relation to the ion concentrations, the changes of electrical conductivity (EC) after applying the management practices showed very similar to those of the ion concentrations. In addition, incidence of withered watermelon plant after applying themanagement practices dramatically declined fromapproximately 20%in the CFPplot to 3.5%in the FMP-RS plots. Water melon fruit weight was also improved by the management practices, especially FMP-RS. Therefore, the fertilizer and/or fresh rice straw applicationmanagement practices are beneficial to improve salt-affected soils and watermelon plant growth condition.

Indoor cultivation plots forwatermelon plantmostly have salt-accumulation problembecause of continuous cropping especially with the heavy applications of chemical fertilizers. Thus, this study was conducted to investigate selected soil properties andwatermelon growth condition as affected by the application of different farming practices in the salt-affected soils of greenhouse plots used for continuous watermelon production. Five different practice conditions in the experimental plots were applied, 1) a conventional farming practice (CFP), 2) a nitrogen-phosphorus-potassium (NPK) fertilizer management practice (FMP), and 3) the FMP with different amounts (5, 10, and 15 t ha-¹)of fresh rice straw treatments (FMP-RS), for three years of study. As comparing with CFP plots, soil organic matter content gradually increased during the experimental years,whereas it decreased in the FMP only plot. Soil pHwas not changed in the CFP and FMP plot, but it declined in the FMP-RS plots; however, it increased again fromthe third yearin the FMP-RS plots with applying 10 and 15 t ha-¹ of RS treatments. The concentrations of exchangeable cations, Ca²+ and Mg²+, except K+, and water-soluble anions, NO₃-, Cl-, SO₄²-, andPO₄³-, markedly decreased inFMPandFMP-RS plots. In particular,the application of rice straw tended to significantly decrease the ion concentrations, especiallymost anions, in the first year, but there was no more decrease in the second and third study years. With relation to the ion concentrations, the changes of electrical conductivity (EC) after applying the management practices showed very similar to those of the ion concentrations. In addition, incidence of withered watermelon plant after applying themanagement practices dramatically declined fromapproximately 20%in the CFPplot to 3.5%in the FMP-RS plots. Water melon fruit weight was also improved by the management practices, especially FMP-RS. Therefore, the fertilizer and/or fresh rice straw applicationmanagement practices are beneficial to improve salt-affected soils and watermelon plant growth condition.