Abstract
This study was to investigate the effects of rice straw incorporation by cutting height on paddy soil fertility. The average residual amount of rice straw by cutting height were showed 1,420 kg $ha^{-1}$, 1,850 kg $ha^{-1}$, and 2,400 kg $ha^{-1}$ for depths of 10 cm, 15 cm, and 20 cm, respectively. For soil physical properties, soil hardness and bulk density were decreased while porosity was increased by rice straw incorporation. But soil organic matter (SOM), available silicate content, and cation exchange capacity (CEC) were significantly decreased when rice straw was removed from the field. These results indicated that the SOM as residual amount of rice straw was influenced by level of cutting height. Milled rice yield was increased by 28% and 32% for cutting heights of 15 cm and 20 cm, compared with that of control, respectively. The number of spikelets per square meter and the percentage of ripeness were increased with increasing incorporation by lower level of cutting height of rice straw. Therefore, incorporation of rice straw practices under cutting method influenced soil improvement and rice yield in paddy field.
본 연구는 논토양 비옥도에 대한 예취높이별 볏짚 혼입효과를 구명하고자 수행하였다. 예취높이별 잔존량은 1,420 kg $ha^{-1}$ (10 cm), 1,850 kg $ha^{-1}$ (15 cm), 2,400 kg $ha^{-1}$ (20 cm)를 나타냈다. 볏짚 혼입으로 토양경도, 용적밀도는 낮아졌고 공극률이 증가하여 토양물리성이 개선되었다. 볏짚 수거로 토양유기물, 유효인산 및 유효규산 함량이 적어지고 양이온치환용량이 낮아졌다. 토양에 볏짚 혼입시 비옥도 감소 폭이 적었고 예취높이별 잔존량이 많을수록 혼입효과가 크게 나타났다. 볏짚혼입에 따라 수수, 영화수 확보가 많고 등숙비율이 높아졌으며 쌀수량은 관행 (3.67 Mg $ha^{-1}$)대비 28~32% 증수되었다. 연구결과 예취방법에 의하여 볏짚을 혼입한 재배기술이 수거에 비하여 쌀수량을 증가시켰고 논토양을 개선하였다.