벼 2모작 논에서 보릿짚 시용이 토양이화학성 및 양분흡수에 미치는 영향

Effects of Barley Straw Application on Soil Physico-Chemical Properties and Nutrient Uptake in Rice Paddy Field of Double Cropping

벼 2모작 재배시 보릿짚시용후 질소시용량별 토양의 이화학적 변화와 수도체의 양분흡수량, 질소이용효율을 조사하기 위하여 2년간('97~'98) 전북통에서 시험한 결과는 다음과 같다. 보릿짚시용으로 경도, 용적밀도, 고상율이 낮아졌고 공극율과 기상율이 증가하여 토양의 물리성이 개선되었다. 보릿짚시용으로 벼 재배후 토양의 pH, OM, T-C, $SiO_2$, K, CEC가 증가한 반면 $P_2O_5$이 감소되었다. 보릿짚시용후 벼 재배시 토양중 $Fe^{+{+}}$함량은 분얼기~유수형성기까지 높은 함량을 보였으나 출수기에는 낮아졌고 $Mn^{+{+}}$함량은 증가되었다. 보릿짚시용시 수도체로의 시비질소 흡수량은 질소시용량 $126kg\;ha^{-1}$ 시용구까지는 증가하였으나 질소 $144kg\;ha^{-1}$ 시용구에서는 감소되었다. 또 질소시용량이 적을수록 보릿짚시용구에서 무시용구보다 시비질소 흡수기간이 길었다. 수도체로의 질소이용율은 분얼기에는 1% 전후였지만 최고분얼기부터 크게 증가하였고 보릿짚시용구에서 낮았다. 수도체로의 인산흡수량은 보릿짚시용구에서 질소시용량에 관계없이 모두 높았으나 칼리함량은 낮았다.

This experiment was carried out to investigate the effects of amount of nitrogen application with the barley straw application on the changes in soil physical and chemical properties. nutrient uptake and percentage recovery of chemical fertilizer N in the rice plant from 1997 to 1998. The soil physical properties, such as bulk density, hardness, porosity and gaseous phase were improved by barley straw application. There was also improvement or increment in the soil chemical properties, such as pH, organic matter, T-C. T-N, available $SiO_2$, exchangeable K and cation exchange capacity, but decrease in available $P_2O_5$. The $Fe^{+{+}}$ content in soil after barley straw application was high from tillering stage to panicle forming stage, but becoming lowered toward the heading stage, while $Mn^{+{+}}$ content was increased. N uptake with barley straw application was increased in the N $126kg\;ha^{-1}$ plot, but decreased in the N $141kg\;ha^{-1}$ plot. The uptake of fertilized N was continued longer in barley straw application than none-application plot. Percentage recovery of chemical fertilizer N in rice straw was around 1% at tillering stage, but was highly increasing till maximum tillering stage, while the recovery was generally low in barley straw application. Meanwhile, fertilizer P uptake in barley straw application was high, but potassium uptake was low at all different levels of N application.