The spectrum of this study was research on the closed hydroponic cultivation of netted melons (Cucumis melo L.) using coir substrate, analyzing the impact of this cultivation method on melon yield, fruit quality, and the efficiency of water and nutrient usage. The experimental results showed that the average fruit weight of the melons grown in a closed system was 71.4 g higher than that of the open system, and the fruit width was on average 0.2 cm larger, showing a statistically significant difference. However, there was no difference in the average sugar content of the fruit flesh and height. Although there is no substantial commercial difference, it is conjectured that the change in the macronutrients ratio in the irrigation has played a role in the statistically significant increase in fruit weight, which is attributed to changes in the crops' nutrient uptake concentrations. This necessitates further research for a more comprehensive understanding. In terms of the productivity of irrigation required to produce the fruit, applying the closed system resulted in an increase of 7.6 kg/ton compared to the open system, saving 31.6% of water resources. Additionally, in terms of nutrients, cultivating in a closed system allowed for savings of approximately 59, 25, 55, 83, 76, and 87% of N, P, K, Ca, Mg, and S, respectively, throughout the entire cultivation period. As the drainage was reused, the ratios of NO3 - and Ca2+ increased up to a maximum of 9.6 and 9.1%, respectively, while the ratios of other ions gradually decreased. In summary, these results suggest that closed hydroponic cultivation can effectively optimize the use of water and fertilizer while maintaining excellent fruit quality in melon cultivation.

This study aimed at improving the method of oil cake application in maize. The experiment was conducted during 2 years at NAS (National Institute of Agricultural Sciences) experimental field, located in Wanju-kun, Jeollabuk-do. Growth factors and nutrient use efficiency were evaluated depending on oil cake application depth, placement, and application rate. Difference in oil cake application method and depth was tested in 2012 and different placements of oil cake application were compared in 2013. Plant height, SPAD value, and dry weight of stem and corn were investigated. SPAD value, dry weight of stem and corn were significantly higher in oil cake banding treatment (OB5, 5 cm depth) as compared to others application methods, i.e. spreading (OS0), deep banding (OB10) and banding + spreading (OB5S). In addition, dry weight of stem and corn of banding treatments (OBL, OBLL) on rhizosphere and in between row (OBR) were higher than spreading treatment (OSP). Furthermore, in case of reduced application rate in additional fertilization did not decrease dry weight of corn and increased nutrient use efficiency. Therefore, it is concluded that banding application in 5 cm-depth and rhizosphere can improve growth and nutrient use efficiency in maize production.