Effects of Amount of Nitrogen Application on Decomposition of Barley Straw and Growth & Yield of Rice in Paddy Field of Double Cropping

이모작(二毛作) 답(畓)에서 질소시용량(窒素施用量)이 보릿짚 분해(分解)와 수도생육(水稻生育) 및 수량(收量)에 미치는 영향(影響)

To investigate the effect of amount of nitrogen application on decomposition of barley straw, growth and yield of rice in paddy field of double cropping, this study was conducted to Jeonbuk series at the Honam area from 1997 to 1998. Carbon persistence of barley straw was lowered while nitrogen persistence rate was increased as increasing amount of nitrogen application and carbon -nitrogen ratio was not decreased as increasing amount of nitrogen application. Soil microflora under barley straw application was high in order of actinomycetes>cellulosedecomposer>bacteria>fungi. Nitrogen starvation under barley straw application showed at tillering stage of rice, but this was not appeared in plot of N $144kg\;ha^{-1}$ application. Plant height, culm length and ear length of rice plant by barley straw application were short, but those of N $108kg\;ha^{-1}$ application was not different from compared with none-application barley straw. Rice yield of N $108kg\;ha^{-1}$ applied barley straw was smiliar to none-application barley straw, but that of N 90. $144kg\;ha^{-1}$ was highly decreased.

본 연구는 2년간('97~'98) 벼 2모작 재배시 질소시용량별 보릿짚의 분해정도(分解程度)와 벼 생육(生育) 및 수량성(收量性) 변이(變異)를 조사하기 위하여 전북통(全北統)에서 시험한 결과는 다음과 같다. 보릿짚의 탄소잔존률(炭素殘存率)은 질소시 용량이 많을수록 적어졌으나 질소잔존률(窒素殘存率)은 증가하였고 C/N율(率)은 낮아졌다. 보릿짚시용시 토양미생물(土壤微生物)은 방사선(放線菌)>셀룰로오스분해균(分解菌)>세균(細菌)>사상균(絲狀菌) 순으로 많았다. 보릿짚시용에 의한 질소기아현상(窒素飢餓現象)은 분얼기(分蘖期)에 나타났으나 질소 $144kg\;ha^{-1}$시용구에서는 나타나지 않았다. 보릿짚시용으로 초장(草長), 간장(稈長), 수장(穗長)이 짧아졌으나 질소 $103kg\;ha^{-1}$ 시용구에서는 보릿짚무시용과 큰차이가 없었다. 보릿짚시용시 쌀수량(收量)은 질소 $108kg\;ha^{-1}$ 시용구에서 보릿짚무시용구와 같았으며 질소 90, $144kg\;ha^{-1}$ 시용구에서는 보릿짚무시용구(無施用區) 대비(對比) 감소폭(減少幅)이 컸다.