소형 라이시미터를 활용한 유기자재에 따른 유기농 논물에서의 무기태질소 동태 = Behavior of Inorganic Nitrogen in Organic Paddy Field Water Depending on Organic Nutrient Sources Using Mini-lysimeters

다국어 초록 (Multilingual Abstract)

Behavior of inorganic nitrogen in organic paddy field water depending on organic nutrient sources was monitored using mini-lysimeters. The mini-lysimeters were placed in National institute of Agricultural Sciences (NAS). 36 undisturbed paddy field soil samples of 30 × 80 cm (diameter × height) was collected by special sampler and installed in mini-lysimeters. After stabilization of lysimeters, several input treatments of organic nutrient sources were applied, including compost, expeller cake and green manures of hairy vetch and rye. Each nutrient source as recommended by the standard amount of fertilizer for rice was supplied 2 weeks before rice transplanting. The water level was maintained 10 cm water depth, and water samples were collected periodically. The pH, specific electrical conductance (EC), and inorganic nitrogen concentration in paddy water was monitored during the experimental period. The average pH value in paddy water was ranged from 7.1 to 7.7. The average EC value in paddy water were ranged from 0.25 to 0.97, and showed to appear higher tend rye > compost > hairy vetch > expeller cake > chemical fertilizers > control. The change of inorganic nitrogen concentration in paddy water is shown in figure 1. The inorganic nitrogen concentrations quickly reached their highest within 26 days after organic nutrient application and decreased afterwards. The inorganic nitrogen concentration for expeller cake and green manure treatments were higher as compared to that for compost and chemical fertilizers treatments. The increasing and decreasing of inorganic nitrogen concentration showed different trends according to the processing of organic nutrient sources.