Abstract
To investigate the effects of paper sludge on seasonal variations of volatile lower fatty acids in paddy soil, paper sludge was applied to pots at the rate of either 300, 600, 900 or 1,200 kg/l0a which was either preadjusted at a C/N ratio of 30 : 1 or not adjusted. The decomposition rate of paper sludge, the evolution of $CO_2$, and the fractions of volatile lower fatty acids in the soil were determined. The results are summarized as follows: 1. Paper sludge was decomposed to $35{\sim}44%$, and its C/N ratio was $55{\sim}82$, respectively, at 120 days after treatment. 2. The evolution of $CO_2$, in the soil was proportional to the amount of paper sludge added. Significant positive correlations were observed the $CO_2$ evolution was compared with the decomposition rate of paper sludge, and volatile fatty acid contents in soil. 3. Acetic, propionic, butyric, i-butyric, valeric and i-valeric acids were identified in all the soils investigated. The content of the total volatile fatty acids in the soil increased with as the application of paper sludge increased. The formation of the acids was the highest at 25 days after treatment, and thereafter the contents of the acids decreased as time elapsed. 4. The volatile fatty acids in the soil inhibited the growth of paddy rice in early stages. The contents of acetic, propionic and i-valeric acids in the soil negatively, correlated with the uptake of N, $P_2O_5$, $K_2O$, CaO, MgO and $SiO_2$ in the paddy rice at 25 days after transplantation. In addition, the uptake of $P_2O_5$ and CaO in the paddy rice negatively correlated with the content of butyric acid in the soil. 5. The content of total volatile fatty acids positively correlated with the content of $Fe^{++}$ and $Mn^{++}$ in the soil at 25 days after transplantation. A significantly positive correlation was observed between $Fe^{++}$ and acetic acid contents in the soil.
제지(製紙)슬러지의 시용량(施用量)을 300, 600, 900 및 1,200kg/10a으로 달리하고 각(各) 시용수준별(施用水準別) C/N율(率)을 30 : 1로 조절(調節)하여 Pot시험(試驗)을 실시(實施)함으로써 토양중(土壤中) 휘발성저급지방산조성(揮發性低級脂肪酸組成)을 시기별(時期別)로 조사(調査)하였다. 그리고 제지(製紙)슬러지의 분해양상(分解樣相) 및 토양중(土壤中) $CO_2$발생량(發生量)을 경시적(經時的)으로 조사(調査)하였으며, 토양중(土壤中) 휘발성지방산함량(揮發性脂肪酸含量)과 수도(水稻)의 무기성분흡수(無機成分吸收)와의 관계(關係)등을 검토(檢討)한 결과(結果)는 다음과 같다. 1. 제지(製紙)슬러지 시용후(施用後) 120일간(日間)의 분해율(分解率)은 $35{\sim}44%$, C/N율(率)은 $55{\sim}82$였다. 2. 토양중(土壤中) $CO_2$발생량(發生量)은 슬러지의 시용량(施用量)이 많을수록 증가(增加)하였으며 $CO_2$발생량(發生量)과 슬러지의 분해율(分解率) 및 토양중(土壤中) 휘발성방린산함량(揮發性肪燐酸含量)과 고도(高度)의 유의적(有意的)인 정(正)의 상관(相關)이 있었다. 3. 토양중(土壤中) 휘발성지방산(揮發性脂肪酸) acetic, propionic, i-butyric, butyric, i-valeric 및 valeric acid의 6종(種)이 동정(同定)되었으며, 그 함량(含量)은 슬러지의 시용량(施用量)이 많을수록 증가(增加)하였고, 슬러지시용후(施用後) 25일경(日頃)이 가장 높았으며 그후 시일(時日)이 경과할수록 감소(減少)하는 경향(傾向)이었다. 4. 토양중(土壤中) 휘발성지방산(揮發性脂肪酸)은 수도(水稻)의 초기생육(初期生育)을 억제(抑制)하였으며 벼이앙후(移秧後) 25일(日)의 토양중(土壤中) acetic, propionic, i-valeric acid 함량(含量)과 수도(水稻)의 질소(窒素), 린산(燐酸), 칼리, 석탄고토(石炭苦土) 및 규산흡수량간(珪酸吸收量間)에는 유의적(有意的)인 역상관(逆相關)이 있었고, butyric acid 함량(含量)과 린산(燐酸) 및 석탄흡수량간(石炭吸收量間)에도 같은 경향(傾向)이었다. 5. 이앙후(移秧後) 25일(日)의 토양중(土壤中) 총휘발성지방산함량(總揮發性脂肪酸含量)은 토양중(土壤中) $Fe^{++}$ 및 $Mn^{++}$ 함량(含量)과 유의적(有意的)인 정의(正) 상관(相關)이 있었으며 $Fe^{++}$ 함량(含量)은 특히 acetic acid 함량(含量)과 고도(高度)의 유의적(有意的)인 정(正)의 상관(相關)이 있었다.
(College of Agriculture, Gyeongsang National University)
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