The Effect of Dicyandiamide (DCD) on the Mineralization of Nitrogen from Soild-Animalwaste

Dicyandiamide(DCD)가 고형(固形) 축산폐기물 중(中) 무기화(無機化)된 질소(窒素)의 경시적(經時的) 방출(放出) 및 억제(抑制)에 미치는 영향(影響)

A laboratory study was cunducted to obtain fundamental informations on environmental-conservative treatment technique of soiled animalwaste. The release rate of inorganic nitrogen which mineralized from solid pigwaste and the effect of nitrification inhibitor(Dicyandiamide, DCD) on nitrate concentration of fresh or fermented pigwaste were weekly checked for ten weeks under incubation condition. Average pH of soild pigwaste was maintained over 8 unit during all incubation periods with no difference by nitrification inhibitor addition and the pHs of fresh- or fermented pigwaste without DCD were elevated by passing time 0.04, 0.058 pH unit/week (P<0.05) during incubation. While $NH_4-N$ concentration of fermented pigwaste until two week was nearly the same as it before incubation, $NH_4-N$ concentration of fresh pigwaste was remarkably increased upto 3,732 ppm for 1 week after incubation and the portion of increased $NH_4-N$ concentration, 2,473 ppm was 20.1% of indigenous organic nitrogen of fresh pigwaste. By the passing incubation time, $NH_4-N$ concentration began to lower linearly at not only fresh- but fermented pigwaste after 1 or 2 week, respectively and the $NH_4-N$ concentration loss rate at fresh pigwaste was 61.8 ppm/week with DCD addition and 72.3ppm/week with no DCD. There was positive relationship between $NO_3-N$ concentrations of fresh pigwaste by the addition of DCD or not and $NO_3-N$ concentraion was significantly lowered with DCD treatment($r=0.79^{**}$).

질산화작용(窒酸化作用) 억제제(抑制劑) Dicyandiamide(DCD)가 축산폐기물 중 유기질소(有機窒素)의 무기화(無機化) 방출율(放出率)에 미치는 영향을 구명(究明)하고자 생돈분(生豚糞)과 발효돈분(醱酵豚糞)에 DCD를 처리하고 $30^+/-1^{\circ}C$에서 10주간(週間) 항온(恒溫)하면서 매 1주(週) 간격으로 돈분의 pH와 $NH_4-N$, $NO_3-N$을 분석하여 무기태질소(無機態窒素) 농도(濃度)의 경시적(經時的) 방출(放出) 양상(樣相)과 $NO_3-N$ 생성억제(生成抑制) 효과를 조사한 결과는 다음과 같다. 항온기간별(恒溫期間別) 돈분(豚糞)의 pH는 8이상으로 높았으며 DCD를 처리하지 않은 생(生)돈분과 발효돈분(醱酵豚糞)에서 pH는 각각 0.04, 0.06 unit/week로 증가되었다(P<0.05). 항온(恒溫) 1주(週) 만에 생돈분(生豚糞) 중 유기질소(有機窒素)의 20.1%인 2,473ppm이 $NH_4-N$으로 무기화되었으나 발효돈분(醱酵豚糞)에서는 항온 2주(週)까지 $NH_4-N$ 농도가 항온(恒溫) 전(前)과 차이가 없었으며 외형적(外形的)인 무기화작용(無機化作用)은 발견할 수 없었다. 생돈분(生豚糞)에서 항온기간(恒溫期間)이 경과(經過)함에 따른 $NH_4-N$ 농도(濃度) 손실율(損失率)은 DCD 처리시 61.8ppm $NH_4-N$/week, 그리고 DCD 무처리에서는 72.3ppm $NH_4-N$/week로 $NH_4-N$의 형태적 변화가 신속히 진행되었다. DCD 처리(處理)에 따른 $NO_3-N$ 생성억제(生成抑制) 효과는 생돈분에서 통계적(統計的)으로 유의성(有意性)있게 나타났으나($r=0.79^{**}$), 발효돈분(醱酵豚糞)에서는 효과가 인정(認定)되지 않았다. $NH_4-N$ 농도 손실율(損失率)은 생돈분(生豚糞)에서는 1차(次) 회귀(回歸)에 그리고 발효돈분(醱酵豚糞)에서는 2차(次) 회귀(回歸)에 유의성(有意性)있게 따르고 있음을 알 수 있었다.