Effect of Ammonium Thiosulfate on Biological Activity in a Paddy Soil

Ammonium Thisoulfate 처리가 담수(湛水) 답토양(畓土壤)의 생물활성(生物活性)에 미치는 영향

The objective of this research was to examine the effect of ammonium thiosulfate(ATS) on urease activity and on biological and chemical properties of flooded paddy soil especially having high organic matter content by comparing with the effect of sodium thiosulfate(STS). The results obtained are summarized as follows. 1. The hydrolysis of urea was inhibited at 3 and 5 days after treatment of thiosulfate(ATS and STS) +glucose and thiosulfate only, respectively. The inhibitory effect of ATS on urea hydrolysis was slightly lower than that of STS in glusoce-added soils, but when the glucose was not added, the effects of ATS and STS were not different significantly. 2. The soil pH and Eh was lowered by 0.3~0.5 units and 30~120 mV, respectively, when incubated flooded soil with ATS and glucose at $25^{\circ}C$. 3. Soil respiration rate in/flooded soil was increased by 10~70% with the treatment of ATS during the 20 day experimental period. 4. The contents of acetic and butyric acid in thiosulfate treatment soil was below $10{\mu}g/g$, which was lower than that($220.3{\mu}g/g$) of critical growth inhibition of rice.

담수(湛水)된 고유기물(高有機物) 논토양에서의 ammonium thiosulfate(ATS)의 urease 활성(活性) 억제(抑制) 효과(效果)와 토양의 생물학적 활성 및 화학적 성질에 미치는 영향을 조사하고, ATS의 효과를 sodium thiosulfate(STS)와 비교하고 유기물 처리의 영향을 검토한 결과를 요약하면 다음과 같다. 1. Thiosulfate의 urease 활성 저해 효과는 3~5일후부터 나타났다. glucose 첨가구에서는 STS 처리가 ATS보다 효과가 다소 컸고, glucose를 첨가하지 않았을 때에는 처리 효과가 비슷하였다. 2. Thiosulfate 처리구의 pH는 초기에 높아지다가 glucose 무첨가시에는 10일 이후 낮아졌고, glucose 첨가시에는 15일 이후 낮아졌다. Eh는 thiosulfate 처리에 의하여 대체로 낮아졌다. 3. Thiosulfate 처리구에서 acet 산(酸)과 butyr 산(酸)은 소량($10{\mu}g/g$ 이하) 검출되었으므로, thiosulfate 처리에 의해 수도(水稻)의 생육이 저해되지는 않을 것이라 추정된다. 4. Glucose를 첨가하지 않았을 때에는 thiosulfate 처리에 의해 $CO_2$ 발생량이 증가하여 토양 생물의 활성을 높였다고 해석된다.