Abstract
This research was conducted to develop root media containing ground and aged pine bark (GAPB) and ground and raw pine bark (GRPB). After analysis of physico chemical properties, the pine barks were blended with peat moss (PM) or coir dust (CD) in various ratios to formulate 12 root media. Then, two out of 12 root media were chosen based on the physical properties for further experiments. The pre-planting nutrient charge fertilizers (PNCF) were incorporated into two root media and chemical properties were analysed again. The total porosity (TP), container capacity (CC), and air-filled porosity (AFP) of GAPB were 78.7%. 39.4%, and 38.3%, respectively, while those of GRPB were 74.7%, 41.2%, and 33.4%, respectively. The percentage of easily available water (EAW, from CC to 4.90 kPa tension) and buffering water (BW, 4.91-9.81 kPa tension) in GAPB were 12.7% and 8.5%, respectively, which were a little lower than the 13.5% and 8.8% in GRPB. The pH and EC were not different significantly, but cation exchange capacity was different between the two pine barks (GAPB: pH 5.26, EC $0.61dS{\cdot}m^{-1}$, CEC $15.7meq{\cdot}100g^{-1}$; GRPB: pH 5.19, EC $0.32dS{\cdot}m^{-1}$, CEC $9.32meq{\cdot}100g^{-1}$). The concentrations of exchangeable cations in GAPB were Ca 0.32, K 0.05, Mg 0.27 and $0.12cmol+{\cdot}kg^{-1}$, whereas those in GRPB were Ca 0.28, K 0.08, Mg 0.25 and $0.09cmol+{\cdot}kg^{-1}$. The concentrations of $PO_4$-P, $NH_4$-N and $NO_3$-N were 485.8, 0.62 and $0.91mg{\cdot}L^{-1}$ in GAPB and 578, 1.00 and $0.82mg{\cdot}L^{-1}$ in GRPB, respectively, when those were analyzed in the solution of the saturated paste. The TP, CC and AFP in the two selected media were 89.3 and 76.3, and 13.0% in PM+GAPB (8:2, v/v) and 88.2, 68.2 and 20.0% in CD+GRPB (8:2), respectively. The pHs and ECs were 3.8 and $0.24dS{\cdot}m^{-1}$ in PM+GAPB which were a little lower than 5.8 and $0.65dS{\cdot}m^{-1}$ in CD+GRPB. However, the pHs analysed before and after incorporation of PNCF in the two root media did not show large differences. This is because the solubility of dolomitic lime is very low, and the pH it is expected to rise gradually when crops are cultivated int he root media. The information obtained in this study should facilitate effective formulation of root media containing pine bark.
국내에서 유통되고 있는 각종 분쇄부숙수피(GAPB)와 분쇄수피(GRPB)를 포함한 혼합상토를 개발하기 위해 본 연구를 수행하였다. 연구목적을 달성하기 위해 두 종류 수피의 물리 화학성을 분석한 후 피트모쓰(PM) 또는 코이어 더스트(CD)와 다양한 비율로 혼합하였다. 혼합물 중 물리성이 적합하다고 판단한 두 종류 상토의 pH 및 EC를 측정한 후 기비를 혼합하고 다시 화학성을 분석하였다. GAPB는 공극률 78.7%, 용기용수량 39.4%, 기상률 38.3%, 가비중 $0.15g{\cdot}cm^{-3}$, GRPB는 공극률 74.7%, 용기용수량 41.2%, 기상률 33.4%, 가비중 $0.19g{\cdot}cm^{-3}$로 측정되었다. 쉽게 이용할 수 있는 수분(EAW)과 완충수(BW)의 비율은 GAPB는 12.7% 및 8.5%, GRPB는 13.5% 및 8.8%로 각각 분석되었다. 화학적 특성에서 GAPB는 pH 5.26, EC $0.61dS{\cdot}m^{-1}$, 양이온교환용량(CEC) $0.32cmol{\cdot}kg^{-1}$, GRPB는 pH 5.19, EC $0.32dS{\cdot}m^{-1}$, CEC $9.32cmol{\cdot}kg^{-1}$로 분석되었다. 치환성양이온 함량을 분석한 결과 GAPB는 Ca 0.32, K 0.05, Mg 0.27 및 Na $0.12cmol{\cdot}kg^{-1}$, GRPB는 Ca 0.28, K 0.08, Mg 0.25 및 Na $0.09cmol{\cdot}kg^{-1}$로 분석되었다. 질소 및 인산함량은 GAPB는 $PO4$-P 485.8, $NO_3$-N 0.91, $NH_4$-N $0.62mg{\cdot}L^{-1}$, GRPB는 $PO_4$-P 578, $NO_3$-N 0.82, $NH_4$-N $1.00mg{\cdot}L^{-1}$로 분석되었다. PM + GAPB(8:2, v/v) 혼합상토의 공극률, 용기용수량, 기상률은 각각 89.3, 76.3 및 13.0%였지만 CD + GRPB(8:2)는 각각 88.2, 68.2 및 20.0%로 측정되었다. 혼합 후 측정한 pH와 EC는 PM + GAPB는 3.8 및 $0.24dS{\cdot}m^{-1}$로 CD + GRPB 혼합상토의 5.8 및 $0.65dS{\cdot}m^{-1}$보다 낮았다. 그러나 두 종류 상토에 기비를 혼합한 후 측정한 pH는 기비 혼합 전과 큰 차이를 보이지 않았는데, 이는 pH를 상승시키기 위해 혼합된 고토석회의 용해도가 낮은 것이 주요 원인이라고 판단하였다. 이상의 연구를 통해 도출된 결과는 추후 각종 수피를 이용한 혼합상토 개발에 유효하게 활용될 것이라고 생각한다.
