Effects of Different Tillage Practices on Changes of Soil Physical Properties and Growth of Direct Seeding Rice

경운방법의(耕耘方法) 차이(差異)가 토양물리성(土壤物理性)과 직파(直播)벼생육(生育)에 미치는 영향(影響)

This study was conducted to find out the changes of soil physical properties and rice growth by the different soil prepartion, such as direct seeding in dry or submerged condition, tillage or no-tillage, and transplanting the infant seedlings. Soil bulk density and hardness were higher in no-tillage plots than tillage plots, and in dry-seeding plots than submerged seeding plots. Permeability of no-tillage plot was increased 56% and water requirement was also increased 27% compare to the conventional transplanting condition. In no-tillage plot, the soil water contents were so rapidly decreased that easily changed to optimum condition for machinery working. The root growth of rice was inhibited as increasing the soil bulk density at early stage, bottom of culm in no-tillage submerged plot was located 0.9cm above the soil surface and the rice plant slightly lodged. The root distribution of surface layer was higher in no-tillage plot and the heading date was 2 days earlier in no-tillage plots than tillage plots, and 3 days earlier in dry seeding plot than submerged seeding plot. Rice yields of no-tillage plots were 5.55 M/T/ha and 5.16 M/T/ha for dry and submerged seeding respectively. These yields were lower about 12.1 % in dry seeding and 18.3% in submerged seeding compare with 6.31M/T/ha of transplanting plot. Rice yields were higher at dry seeding than submerged seeding in no-tillage condition, but in tillage condition, the rice yields were better at submerged seeding plot than dry one.

논토양(土壤) 경운(耕耘) 및 관기방법(灌漑方法)에 따른 토양(土壤)의 물리적특성(物理的特性)과 수도생육(水稻生育)의 차이(差異)를 구명(究明)하고자 석천통(石泉統)에서 무경운(無耕耘) 건답(乾畓), 무경운(無耕耘) 담수(湛水), 경운(耕耘) 건답(乾畓), 경운(耕耘) 담수구(湛水區)와, 관행(慣行)(기계이앙경운(機械移秧耕耘)-로타리) 등(等)의 5개(個) 처리구(處理區)를 두고 수도(水稻)를 3년간(年間) 재배(栽培)하면서 토양(土壤)의 물리적특성(物理的特性)과 수도생육(水稻生育)을 조사(調査)한 시험결과(試驗結果)는 다음과 같다. 토양(土壤)의 가비중(假比重)과 경도(硬度)는 경운구(耕耘區)보다는 무경운구(無耕耘區), 담수구(湛水區)보다는 건답구(乾畓區)에서 높았다. 무경운(無耕耘), 건답구(乾畓區)의 투수원도(透水速度)는 경운비토구(耕耘碑土區)보다 56% 빨라 전관개기간중용수량(全灌漑期間中用水量)이 27% 증가(增加)되었으나, 무경운구(無耕耘區)에서는 관행구(慣行區)보다 낙수기이후(落水期以後) 수분감소(水分減少)가 빨라 농기계(農機械) 작업(作業)이 유리(有利)한 조건(條件)이었다. 층위별(層位別) 뿌리분포(分布)를 보면 무경운구(無耕耘區)는 주로 표토(表土)에 분포(分布)하였다. 출수기(出穗期)는 무경운구(無耕耘區)가 경운구(耕耘區)보다 2일(日)정도 빠르고 건답구(乾畓區)가 담수구(湛水區)보다는 3일(日) 빨랐다. 처리별(處理別) 수도생육(水稻生育)은 건답구(乾畓區)보다는 담수구(湛水區)에서 양호(良好)하였고 줄기매몰(埋沒) 깊이는 무경운담수구(無耕耘湛水區)에서 지상부(地上部)로 0.9cm 올라와서 도복(倒伏)의 위험(危險)이 있었다. 무경운시(無耕耘時) 3년(年) 평균(平均) 정조수량(正租收量)은 건답구(乾畓區) 및 담수구(湛水區)가 각각(各各) 5.55M/T/ha, 5.16M/T/ha로써 관행구(慣行區) 6.31M/T/ha 보다 각각(各各) 12.0%, 18.2% 감수(減收)되었으며 대체로 무경운시(無耕耘時)는 건답구(乾畓區), 경운시(耕耘時)에는 담수구(湛水區)에서 수량(收量)이 많은 경향(傾向)이었다.