Seasonal drainage characteristics and total nitrogen and total phosphorus losses of strawberry hydroponic farms in Gyeongnam

Abstract

This study aimed to evaluate the nutrient utilization efficiency in strawberry hydroponics and assess the actual nutrient discharge status under a non-circulating hydroponic system. Water samples from both supply and drainage were collected three times monthly, at approximately 10-day intervals, from October to May of the following year, across five farms in Gyeongnam. A total of 18 parameters, including total N (T-N), total P (T-P), electrical conductivity (EC), and pH, were analyzed. The average drainage rate observed during the study period was 49.5%. The utilization efficiencies of macronutrients by the plants were 47.5% for T-N, 51.4% for T-P, 56.3% for K, 36.9% for Ca, 40.2% for Mg, and 33.5% for SO4 2-. Micronutrients such as Fe, Mn, B, and Mo demonstrated utilization efficiencies exceeding 50%, excluding Cu and Zn. During the survey period, the average total discharge amounts of using October data (the highest T-N and T-P discharges), these total discharges were calculated to 2.12 kg (T-N) and 0.67 kg (T-P) of average daily emissions per hectare, which shows the nutrient loads to be managed to mitigate the environmental pollution. This study established the foundation for reducing environmental pollution from non-circulating hydroponic systems by providing fundamental data on supply, drainage, and nutrient utilization efficiency. It highlights the need for further research into the reduction and reuse of drainage.