不同溫度備製之生物炭對坡耕地土壤養分滯留能力之影響

本研究使用不同溫度之生物炭，以2%(w/w)施用率混入施用於砂土並添加化肥，其混入以稻殼在高溫厭氧環境下裂解而成 300°C與600°C之生物炭，肥料添加量則以 N:200kg ha-1 P:30kg ha-1 K:100kg ha-1為施用基準，孵育100天後以模擬降雨設備進行土壤沖蝕及養分淋洗試驗。研究結果顯示砂質土施用稻殼生物炭，孵育100天後，在降雨強度60mm/hr及降雨延時2小時的模擬降雨實驗中添加生物炭之樣本初始含水量及容水量高於對照組。添加生物炭之樣本入滲速率與對照組相比提高了22.3%，並有效減少逕流25% - 39%及土壤流失23% - 52%。而在養分分析部分，添加生物炭之樣本能提高土壤總氮含量38%-71%、交換性鉀140% - 320%，孵育100天後添加生物炭可顯著降少，並可減少地表逕流所產生的養分T.N.(Total netrogen)，NH4+，NO3–含量流失，TN、NH4+、NO3–、Avail. P及Exch. K之主要流失途徑皆為淋洗滲漏，其滲漏損失分別佔總損失的89%、97%、94%、61%及97%。結論是添加稻殼生物炭具有一定的減少土壤及部分養分流失的能力。

關鍵字

生物炭；模擬降雨；土壤沖蝕；逕流；養分淋洗

並列摘要

This study used rice husk biochars (RHB) pyrolized with different temperatures as soil amemdments to improve soil erosion potential and retention ability of nutrients. The biochars were applied by 2%(w/w) to the studied soil. Chemical fertilizers were simultaneously applied by a rate of N: 200kg ha-1 P: 30kg ha-1 K: 100kg ha-1. After 100 days incubation, erosion and leaching experiments were carried out using simulated rainfall equipment with a rainfall intensity of 60 mm hr-1. The results displayed that after incubation of RHB application, the initial water content (θi) and water retention capacity of the biochar-treated soils were higher than those of the control during 2 hours continuous similated rainfall event. Additionally, as comparsion with the control, the infiltration rate of biochar-treated soils increased by 22.3%. Biochar addition could effectively reduced runoff by 25% - 39% and soil loss by 23% - 52% compared with the control. Regarding retiontion of nutrients after biochar addition, the biochar-treated soil contained higher contents of nutrient, which the total nitrogen (TN) content increased by 38% - 71% and the exchangeable potassium was by 140% - 320% compared with the control. After 100 days of incubation, the biochar application can significantly reduce amounts of runoff water, and loss of nutrients of TN, NH4+, and NO3–. The main loss pathways of TN, NH4+, NO3–, Ava. P, and Ex. K are percolation, and this loss way accounts for the total loss passways (evaporation, ruoff, erosion, percolation) were 89%, 97%, 94%, 61% and 97%. As awhole, we could deduced that rice husk biochar application in the sandy soils in Tawan has been a suitable solution to reduce soil and partial nutrient loss.