줄(Zizania latifolia)의 생장에 의한 저토에서 질소와 인의 형태 변화

Changes in Forms of Nitrogen and Phosphorus in Sediment by Growth of Zizania latifolia

정수식물인 줄(Zizania latifolia)의 생장에 따른 저토로부터의 무기영양소 흡수와 저토의 산화환원전위(Eh) 및 pH와 같은 물리, 화학적 특성과 $NH_4^+$와 $NO_3^-$의 질소형 그리고 유동성 인$(PO_4^{3-})$, 착화합물 인, 인회석 인 및 유기 인의 변화를 화분 재배실험을 통하여 조사하였다. 화분재배 실험에서 저토의 Eh는 식재 후에 식물구의 환원층이 무식물구의 것보다 높았다. 환원층의 $NH_4^+-N$ 함량은 식물구가 무식물구보다 적었고, $NO_3^--N$ 함량은 그것과 반대의 양상으로 나타났다. 형태별 인의 비율은 식재 전에 유기 인이 높았고, 식재 후에 착화합물 인이 높음으로써, 전자가 분해되어 후자로 변형됨이 확인되었다. 상층수와 침출수의 $NH_4^+-N$ 및 $PO_4^{3-}-P$ 농도는 무식물구보다 식물구에서 낮았다. 침출수의 $NO_3^--N$ 농도는 무식물구보다 식물구에서 높았고, 이는 뿌리로부터의 산소공급이 저토를 산화시켰기 때문인 것으로 판단되었다.

The effects of the presence of a submerged plant, Zizania latifolia, on physico-chemical characteristics, including Eh, pH, and concentrations of nitrogen and phosphorus in the sediments were studied under pot culture condition. It was shown that Eh value at reduced layer of the sediments was higher in the planted pots than in the non-planted. It was also revealed that $NH_4^+-N$ concentration of the sediments in the planted pots was lower than that of the non-planted, which might be due to the uptake by the plants. In contrast, $NO_3^--N$ concentration in the sediment increased in the presence of the plants compared to the non-planted, which might be attributed to oxygen released from the roots to the reduced layer. The concentration of organic phosphorus in the sediments was much higher than that of NAIP at the beginning of the planting experiment. However, at the end of the experiment, it was reversed; NAIP concentration was much higher than that of organic phosphorus, possibly indicating the transformation of organic phosphorus to NAIP during the experimental period. Both concentrations of $NH_4^+-N$ and $PO_4^{3-}-P$ in the overlying and percolated water were lower in the planted pots than in the non-planted. The concentration of $NO_3^--N$ in the percolated water, however, was higher in the planted pots than in the non-planted. The data was discussed with regard to the potential effects of a submerged plant on dynamics of phosphorus and nitrogen in the rhizosphere of the sediment.