Effect of Green Manure Crops Incorporation with Rice Cultivation on Soil Fertility Improvement in Paddy Field

This study was carried out to investigate the improvement effect of soil fertility by incorporation of GMC(green manure crops) at rice cropping after cultivation GMC such as the barley for alternative rye in paddy field over the past two years(2006~2007). Plots, which consisted of incorporation time of GMC as rye; heading stage, barley; heading stage, heading stage of rye and 10days after heading stage were divided by amount of applied rates; standard fertilizer fertilization, diagnosis fertilization and non-fertilization. we investigated change of soil physico-chemical properties, degree of decomposition on GMC in soil, growth and yield potential. The obtained results were summarized as follows. The fresh weight of GMC at incorporation time on heading stage of rye, heading stage and 10days after heading stage of barley were $2,715,\;2,352,\;2,867kg\;10a^{-1}$ respectively. Content of total nitrogen at three incorporation times was 1.31, 1.46, 1.38% and the C/N ratio were 33.4, 28.7, and 34.6, respectively. Some soil physical properties, such as soil hardness and bulk density tended to decrease with incorporation of GMC, while surface soil depth and porosity were increased. Some soil chemical properties, such as content of exchangeable cations and cation exchangeable capasity(CEC) were increased with incorporation of GMC compared with before experiment. Rice yields was increased 3~9% in diagnosis application plots on application of barley compared with control($559kg\;10a^{-1}$) and incorporation of barley caused to improve perfect kernel ratio 73.6~78.7% in appearance characteristics of brown rice compared with cotrol(73.0%). It was found that incorporation with 10days after heading stage of barley was more effective to reduce chemical nitrogen fertilizer and to improve soil fertility.

벼 재배시 녹비작물 혼입에 따른 지력개선 효과

본 시험은 벼 재배시 녹비작물로 녹비용 보리의 투입효과를 구명하여 호밀 대체 가능성을 검토코자 수행하였다. 호밀은 출수기, 녹비용 보리는 출수기, 출수 후 3일 및 출수 후 10일에 경운로타리 작업을 하고 담수시켜 부숙을 촉진한 다음 녹비작물 무시용구는 표준시비, 녹비작물 시용구는 토양검정시비 및 무시비 하여 동진 1호를 재배 후 토양물리화학성, 녹비작물 부숙정도, 생육 및 수량성을 검토한 결과는 다음과 같다. 녹비작물 투입시기별 생체중은 각각 10a당 2,715, 2,352, 2,867 kg이였고 건물중에 있어서 총질소 함량은 1.31, 1.46, 1.38%이었으며 탄질률은 33.4, 28.7, 34.6이였다. 녹비작물 투입으로 작토심이 깊어졌고 토양경도와 용적밀도가 낮아졌으며 공극률이 증가하여 물리성이 개선되었다. 또한 시험 전에 비하여 녹비용 보리 환원으로 양이온치환용량이 높아졌으며 치환성 양이온 함량이 증가되는 경향을 나타냈다. 쌀 수량은 관행($559kg\;10a^{-1}$)에 비하여 녹비용 보리+토양검정진단시비구에서 3~9% 증수되었으며, 현미 외관품위 중 완전립비율은 관행(73.0%)에 비하여 녹비용 보리 투입시 73.6~78.7%로 높은 경향을 나타냈다. 결론적으로 녹비용 보리를 출수 후 10일경 투입하여 벼 재배시 질소비료 절감과 지력개선에 효과적인 것으로 판단되었다.