The Effects of Hairy-Vetch and Rye, as Green Manure Crops, on Biomass Production and Nitrogen Utilization of Red Pepper.
Jwa-Kyung Sung, Organic Farming Division, National Institute of Agricultural Science and Technology, 250. Seodundong, Kwonsungoo, Suwon, South Korea
Integration and incorporation of green manure crops have been practiced in agricultural production systems to reduce runoff and soil erosion, improve soil structure through the addition of organic matter, improve soil microbial activity and nutrient availability. The main purpose of this experiment is to find out differences on uptake and accumulation of nitrogen by different nitrogen sources. We sown seeds of two green manure crops early in Oct. 2004, those residues after cutting reused as an organic fertilizer, and red pepper plants were transplanted on May 10, 2005. Red pepper plants under hairy vetch and rye showed different growth responses. Rye-input soil with high C/N ratio resulted in temporal nitrogen starvation, thus, growth of red pepper plants was retarded. However, their growth was slowly recovered, when measured on 30th day after transplanting, dry matter and leaf area of red pepper plants grown chemical, hairy vetch and rye increased 2.0, 1.7, 1.5-fold higher compared with control. As a result of analyzing foliar nitrogen contents, limitation factors on growth reduction proved excessive accumulation of nitrate and nitrite in leaves as well as nitrogen starvation. It was reaffirmed that negative feed-back regulation caused by nitrate accumulation block nitrate uptake into roots from rhizosphere. However, there was a question in that plant leaves grown under low nitrogen concentration accumulated excessive nitrate and nitrite. Key-words: nitrate, nitrite, growth rate, green manure crops, red pepper.