Effects of Planting Density and Fertilizer Level on Corn Growth and Yield for Bio-energy Production in No-till Cultivation with Hairy Vetch Cut Mulching
겨울철 유휴 논토양에 헤어리베치를 재배 이용하여 바이오에너지 원료작물인 옥수수를 재배할 경우 화학비료와 제초제를 절감하고, 옥수수의 무경운 재배법을 개발하고자 수행하였다. 헤어리베치 피복 이용 옥수수 무경운 직파재배 시 재식밀도에 따른 옥수수의 간장, 경태 및 엽색도 등은 관행재배에비하여 감소하였으며, 착수고는 밀식할 경우 증가하는 경향이었다. 그 밖의 옥수수의 출사기는 헤어리베치를 피복한 처리구에서 관행재배구에 비하여 평균 3일 지연되었으며, 재식밀도가 높을수록 또는 시비량이 감소될수록 지연되었다. 한편 경작지에서 우점하는 잡초는 여뀌, 바랭이 및 피였으며, 헤어리베치 피복량 증가는 잡초 건물중을 감소시켰다. 바이오에탄올생산량은 헤어리베치를 피복한 처리구에서 관행과 비교하여58.9~89.8%까지 확보할 수 있었으며, 재식밀도가 낮거나 시비량이 적을수록 감소 정도가 크게 나타났다. 바이오에너지 작물인 옥수수를 친환경적으로 생산하는 방법 중의 하나로 헤어리베치를 피복하고 무경운 직파하여 시비량을 50% 감량하고, 재식밀도를 125,000 주 ha-1로 높이면 총 건물수량과 바이오에탄올량을 관행과 유사한 수준을 얻을 수 있을 것으로 판단되었다.
This study was conducted to develop no-till cultivation system and to reduce agro-chemicals input by cut mulching of hairy vetch on corn cultivation for bio-energy production. Corn was sown with 2 planting density (71,430 and 125,000 plants ha-1) on 20 May in 2009 under no-till cultivation with cut mulching of hairy vetch. In no-till corn cultivation with cut mulching of hairy vetch, the plant height, diameter of main stem and SPAD value decreased with increasing the planting density. Ear position of corn was high and silking date of corn cultivated in cut mulching of hairy vetch was also delayed average 3 days as compared with the conventional practice, and it was associated with increasing the plant density and reducing the fertilizer application level. Moreover, dominant weeds in corn cultivation field were Persicaria blumei, Digitaria ciliaris (Retz.) Koel. and Echinochloa crusgalli, and the dry weight of weed decreased with increasing the soil cover rate of hairy vetch. Amount of the bio-ethanol production in cut mulching of hairy vetch decreased by 10.2 to 41.1% and it seemed to be associated with increasing the plant density and reducing the fertilizer application level. At no-till corn cultivation with cut mulching of hairy vetch for bio-energy production, the biomass production of combined system of reducing fertilizer application level of 50% and the planting density of 125,000 plants ha-1 would be similar to the conventional one and it could be suitable for eco-friendly bio-energy corn production.