토양 pH 조절과 윤작에 의한 감자 더뎅이병 방제

Abstract

감자 더뎅이병 방제에 대한 토양 pH 조절의 효과를 더뎅이병에 감염된 포장에서 2006년 평가하였다. 원래 pH가 5.7이었던 토양을 pH 5.0, 6.0, 6.5로 조절하고자 유황(42 kg/10a)과 소석회(81.6 kg/10a, 184.5 kg/10a)를 처리하였고 석고(522 kg/10a)도 토양 pH와 더뎅이병 발생에 미치는 영향을 구명하고자 처리하였다. 유황처리구의 토양 pH는 괴경형성기에 5.13, 수확기에는 5.01로 지속적으로 감소하였다. 또한 괴경의 발병도는 22.8%로 상대적으로 낮았으며 90.5%의 높은 상품수량을 나타내었다. 반면 소석회를 81.6 kg/10a과 184.5 kg/10a 처리한 구의 토양 pH는 수확기에 6.06과 6.49로 증가하였고, 각각 51.0%와 61.1%의 높은 발병도와 55.7%와 37.0%의 낮은 상품수량을 보였다. 한편 석고처리구는 수확기까지 토양 pH의 변화가 거의 없었으며 발병도와 상품수량도 무처리구와 유의적인 차이가 없었다. 감자 더뎅이병의 방제를 위하여 윤작작물을 2005년부터 2007년까지 재배하고 2008년에 감자를 재배하였다. 3년 윤작 후의 발병도는 파, 콩, 옥수수, 배추 시험구에서 각각 13.1%, 16.7%, 28.9%, 30.2%로 감자 연작구의 73.1%에 비해 상당히 낮았으며 상품수량도 이와 유사한 경향을 보였다. 본 연구 결과에서 살펴본 바와 같이 토양 pH의 조절과 윤작은 감자 더뎅이병 방제를 위해 단장기적으로 활용될 수 있을 것으로 판단된다. In 2006, the effect of soil pH adjustment on control of common scab of potato caused by Streptomyces spp. was evaluated in the field. Soil with an original pH 5.7 was treated with sulfur of 42 kg/10a and calcium hydroxide of 81.6 kg/10a and 184.5 kg/10a to adjust pH 5.0, 6.0 and 6.5, respectively. Additionally, the effect of gypsum (522 kg/10a) on soil pH and disease severity was examined. The soil pH of sulfur treatment plot was continuously declined from 5.13 at tuber initiation time to 5.01 at harvest. The disease severity of sulfur treatment plot was relatively low (22.8%) and the marketable yield of that was high (90.5%). By contrast, the soil pHs treated with calcium hydroxide (81.6 kg/10a and 184.5 kg/10a) were increased (pH 6.06 and 6.49, respectively) at harvest. In addition, calcium hydroxide treatment plots showed higher disease severities (51.0% and 61.1%), and lower marketable yields (55.7% and 37.0%). Meanwhile, the soil pH of gypsum treatment plot was not changed until harvest, and the disease severity and the marketable yield were not significantly different from those of control. The effect of crop rotation was also evaluated with four crops such as welsh onion, soybean, corn and Chinese cabbage. These crops were planted in the infested field from 2005 to 2007, and potatoes were planted in the same field in 2008. The disease severities of potatoes produced after rotations with welsh onion, soybean, corn and Chinese cabbage for 3 years were 13.1%, 16.7%, 28.9% and 30.2%, respectively. However, the disease severity of 73.1% was shown in continuous cropping of potato for 3 years. In addition, similar effects were exhibited in the marketable yield. These results demonstrate that the adjustment of soil pH and crop rotation might be very useful tools to control common scab of potato.