施用稻穀炭對臺灣農田土壤中氮礦化的影響

Effects of Applying Rice Hull Biochar on Nitrogen Mineralization in Rural Soils, Taiwan

丹亞拉(Taniela Kepa Siose)

指導教授 ： 簡士濠 ； 許正一 ； 陳光堯

國立屏東科技大學/國際學院/熱帶農業暨國際合作系/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00023

摘要

生物炭為一高比表面積及多孔性之資材，當施入土壤後可改善物化性質，進而間接提升肥力及作物產量。生物炭利用於農業土壤的改良上已逐年增加；然而，相關於施用生物炭對土壤中氮礦化影響的研究尚不足。因此，本研究目的於評估施用不同溫度製備之稻殼炭對農業土壤中氮礦化作用及作物產量之影響。本研究以台灣南部兩種代表性農業土壤(周厝寮(Ct)土系和老埤(Lp)土系)為供試土壤。在20 ton ha-1的蔗渣堆肥添加基準下，分別再添加1%、2%和4% (w/w)比例之400℃及700℃厭氧製成的生物炭(B-400和B-700)，以進行孵育試驗。孵育期間分別於0、3、7、14、21、28及42天採集孵育土壤，測定土壤pH值及無機態氮(NH4+-N及NO3--N)含量之變化。此外，本研究另在相同之處理下進行盆栽試驗，評估小白菜(Brassica chinensis L.)的產量變化。結果顯示，砂質土壤(Ct)的pH值，於孵育結束後(42天)皆明顯下降，而粘質土壤(Lp)中

，除對照組外，孵育期間所有處理下之土壤pH值皆無明顯變化。在無機態氮動態變化上，相較於對照組，砂質土(Ct)之NH4+-N和NO3--N的含量隨生物炭施用量提高而增加，其中以B-700之生物炭在4%施用量下為最高。此結果顯示施用高溫製備之生物炭且高施用量下，將使土壤中無機態氮礦化量增加。粘質土(Lp)於孵育期間，無機態氮含量在不同生物炭添加量下，與對照組並無明顯差異。在小白菜地上部產量方面，Ct土壤在所有處理下小白菜乾重產量皆較低，各處理間無明顯差異(p < 0.05)；而Lp土壤於施用生物炭後，小白菜乾重產量皆較顯著高於對照組。

關鍵字

生物炭 ； 坋質粘壤土 ； 氮 ； 礦化作用 ； 砂質壤土

並列摘要

Biochar application in soils has become increasingly practiced since its resurgence following the discovering of the remarkably fertile dark earth of the Amazon called the Terra Preta. It has been proven that biochar addition to soil increases soil fertility and thus crop yields. However, there are limited studies on the nutrient mineralization when biochar is incorporated. Therefore, the objectives of this study were to evaluate the dynamics of nitrogen mineralization in rural soils influenced by the addition of biochar and determine the above ground biomass yield of Chinese cabbage (Brassica chinensis L.) under similar application of biochar. Biochar derived from rice hull pyrolysed at 400 °C (B-400) and 700 °C (B-700) was incorporated into sandy and silty clay loam soils at application rates of 1%, 2 % and 4%. Bagasse compost was also added to the soils at an application rate of 20t/ha at

the initial of incubation. During incubation, soil samples were collected at days of 0, 3, 7, 14, 21, 28 and 42, and soil pH and concentrations of NH4+-N and NO3--N were estimated. In a greenhouse experiment, B. chinensis L. were sown in pots with treatments similar to the incubation study, and the above ground biomass yield was determined at 6 weeks after transplanting. The results showed that soil pH decreased significantly at the end of the incubation in the sandy soil, while the pH kept constant, even increased in the B-700-amended soils in silty clay loam soil. The results also found that higher application rates of biochar resulted in higher retention of NH4+-N and NO3--N in the amended sandy soil than the control at the end of the incubation, especially for the B-700 at 4% application rate. On the contrary, with the silty clay loam soil, the application of rice hull biochar caused insignificant changes as compared to the control. Based on our results, rice hull biochar could be a good amendment for reducing sandy soil’s pH and increasing pH in the silty clay loam soil. Nitrogen transformation is greatly influenced by incorporating rice hull biochar particularly with sandy soil, however, further research is recommended to find the optimum application rates of rice hull biochar on both soils. The cabbage above ground biomass yield is suppressed when rice hull biochar was incorporated to sandy soil although an increasing production was seen with increasing application rates of B-700. On the other hand, the addition of rice hull biochar to silty clay loam soil significantly improved the biomass yield with increasing yield corresponding to increasing application rates of B-700. Higher application rates for rice hull biochar need to further test to find out the best application rates for production of cabbage, therefore, merit further investigation.

並列關鍵字

biochar ； silty clay loam soil ； nitrogen ； mineralization ； sandy soil

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