Evaluation of Replacement Ratio of Mixed Oilcake for Basal Application of Inorganic Fertilizers in Watermelon Cultivation at the Plastic Film House Soil

Abstract

The objective of this study was analyzed the replacement ratio of mixed oil cakes(MC) for basal application of inorganic fertilizers. The fields were selected the plastic film house soils for watermelon cultivation. The MC were applied at 50(MC50+N50), 100(MC100), and 150(MC 150) % level of the basal amount of nitrogen fertilizer in soil testing recommendation. And these were compared to NPK treatment and -N(PK) treatment except nitrogen as inorganic fertilizer. The yields of watermelon in MC50+N50, MC100, and MC150 were similar to NPK treatment, but sugar contents as watermelon quality in MC50+N50, MC100, and MC150 were higher than NPK. In MC100 and MC150 treatments, nitrate nitrogen and electrical conductivity were lower than MC50+N50 treatment. Relative nitrogen efficiency of watermelon ranged 109 - 128%. These results suggest that MC application with the 100 - 150% level of nitrogen input as the basal dressing could be best to prevent a nutrient accumulation of soil and to increase the yield and commercial quality for watermelon. Changes in watermelon yield according to replacement ratio of basal amount of nitrogen fertilizer. ( ) mean relative yield of watermelon to NPK treatment. N, P, K, and MC mean nitrogen, phosphate, potash fertilizers, and mixed oil cakes, respectively. Treatment Fruit weight (g plant-1) Sugar contents (Brix) Weight of leaf, stem, and fruit (ton ha-1) -N (PK) 5,312(78)b† 10.0b 45.1b NPK 6,768(100)a 10.1b 58.0a MC 50+N50 6,866(101)a 11.1a 58.6a MC 100 6,963(103)a 11.5a 61.1a MC 150 6,960(103)a 11.7a 63.7a † Numbers with the same letter within a column are not significantly differed (Duncan's test, p < 0.05).