이탈리안라이그라스 재배지의 비료⋅퇴비 사용실태와 토양화학성, 수량 및 양분흡수 특성 간 상관관계 = Relationships among Fertilizer and Compost Use, Soil Chemical Properties, Yield, and Nutrient Uptake in Italian Ryegrass Fields

다국어 초록 (Multilingual Abstract)

This study examined fertilizer and compost use, soil chemical properties, yield, and nutrient uptake in Italian ryegrass (IRG) fields across Korea to quantify nutrient dynamics and provide baseline data for developing soil test–based fertilization guidelines. A total of 52 IRG-producing farms were surveyed over a two-year period (2021–2022), and soil and plant samples collected from each site were analyzed. Livestock manure compost was used by 78.8% of farms, with an average application rate of 2,758 kg 10a-1. Soil test results showed that organic matter (57.7%) and available P₂O₅ (28.8%) commonly exceeded the recommended ranges (NAS, 2019), indicating long-term nutrient accumulation caused by repeated applications of organic amendments. After excluding the basic compost rate, the calculated fertilizer inputs averaged N–P₂O₅–K₂O = 19.5–11.0–20.9 kg 10a-1, reflecting substantial over-application of K relative to the standard fertilization recommendation for IRG. Dry matter yield across farms ranged from 831 to 2,104 kg 10a-1 (average 1,153 kg 10a-1). Nutrient uptake followed the order K₂O (42.0 kg 10a-1) > N (20.0 kg 10a-1) > P₂O₅ (6.7 kg 10a-1), consistent with the known luxury consumption of K by IRG. Plant N concentration showed significant positive correlations with soil NO₃-N and NH₄-N, whereas plant P and K concentrations exhibited strong positive correlations with available P₂O₅ and exchangeable K, respectively, demonstrating that nutrient accumulation in IRG closely reflects actual soil nutrient status. Dry matter yield and nutrient uptake were more strongly influenced by soil properties—including pH, NO₃-N, available P₂O₅, and exchangeable K and Mg—than by fertilizer application levels. The results provide nationally representative baseline information for IRG production systems and highlight the need to mitigate the excessive accumulation of P and K caused by livestock manure-based fertilization. These findings offer practical evidence for establishing soil test–based nutrient management strategies that enhance nutrient-use efficiency and support balanced and sustainable soil fertility in IRG cultivation.