施用稻殼生物炭及有益微生物對有機栽培紅豆及水稻生長及土壤性質之影響

紅豆(Vigna angularis)及水稻(Oryza sativa)是台灣高屏地區普遍的輪作栽培之作物。台灣目前有機栽培紅豆及水稻面積與慣行栽培面積相比甚少，因此如何推廣並精進有機栽培技術，仍是重要的課題。生物炭是有機物質在低氧高溫條件下，熱裂解及炭化後的固態物質。生物炭透過熱裂解及炭化後的諸多特性，能改善土壤理化性質，並為土壤微生物提供碳源及棲息地，進而影響作物生長。本試驗目的為藉由稻殼生物炭對土壤性質之改良，搭配有益微生物(根瘤菌、叢枝菌根真菌、木黴菌、枯草桿菌)之複合接種，探討在有機栽培下對紅豆及水稻土壤理化性質、植株生育、產量及營養元素濃度之影響。此外，亦探討共同處理稻殼生物炭及有益微生物後，兩者是否具有相輔相成的協同作用。本試驗於西元2020年1月，於國立屏東科技大學永續農業研究農場中，相鄰的兩塊試驗田區分別種植紅豆及水稻。試驗處理為有無施用稻殼生物炭(0 %、2 % (w/w))、兩種有益微生物之複合接種(根瘤菌及叢枝菌根真菌、木黴菌及枯草桿菌)及無接種之對照組。試驗結果指出，對紅豆而言，施用2 % 稻殼生物炭顯著提高土壤入滲速率，並提高土壤pH值、有機質、Bray-1-P、交換性鉀、鈣和鎂含量，其中以土壤交換性鉀含量提高效果最明顯。共同處理稻殼生物炭和有益微生物，對提高土壤有效磷含量效果，較單獨處理有益微生物明顯。然而，無論單獨或共同處理2 % 稻殼生物炭和接種根瘤菌及叢枝菌根菌，均對紅豆菌根定殖率無顯著影響。施用2 % 稻殼生物炭能顯著提高紅豆株高、地上部及根部乾物質。然而共同處理稻殼生物炭和有益微生物，對紅豆株高、葉片長寬、葉片數、地上部及總乾物質之促進效果，與單獨處理稻殼生物炭相比，並無顯著差異。施用2 % 稻殼生物炭顯著降低紅豆缺株率，亦顯著增加紅豆籽粒產量。施用2 % 稻殼生物炭對提高紅豆植株磷和鉀濃度的效果，較共同處理稻殼生物炭和有益微生物明顯。對水稻而言，施用2 % 稻殼生物炭提高土壤pH值，並顯著提高土壤交換性鉀含量，然而對土壤總體密度及土壤入滲速率均無顯著影響。此外，共同處理稻殼生物炭和有益微生物與單獨處理稻殼生物炭相比，對水稻株高、分蘗數、有效分蘗數、地上部及根部乾物質、穀粒產量及產量構成因子及植株氮、磷、鉀和鎂濃度亦無顯著影響。綜合上述，有益微生物之兩種複合接種(根瘤菌及叢枝菌根真菌、木黴菌及枯草桿菌)，無論有無與2 % 稻殼生物炭共同處理，均對改善紅豆及水稻土壤理化性質，及促進植株生長、產量和營養元素濃度之影響較不明顯，因此有待未來進一步研究及探討。故本試驗建議以單獨施用2 % 稻殼生物炭處理即可。

關鍵字

土壤肥力；土壤改良劑；有益微生物；協同作用

並列摘要

Adzuki bean (Vigna angularis) and rice (Oryza sativa) are commonly cultivated crops in Kaohsiung and Pingtung city in Taiwan. For now, the area of organically cultivated adzuki bean and rice in Taiwan is relatively very small compared with the conventionally cultivated area. Therefore, how to promote and improve organic cultivation technology is still an important issue. Biochar is a solid substance obtained by thermally cracking and carbonizing organic substances under low oxygen and high-temperature conditions. Biochar can improve soil physicochemical properties and provide a carbon source and habitat for soil microorganisms, through its many characteristics after thermal cracking and carbonization, thereby affecting the growth of crops. The purpose of this experiment was to investigate the effects of organic cultivation on the soil physicochemical properties, plant growth, yield and nutrient element concentration of adzuki bean and rice through the improvement of soil properties with rice husk biochar and compound inoculation of beneficial microorganisms including Rhizobium, Arbuscular mycorrhizal fungi, Trichoderma and Bacillus subtilis. In addition, it also was to investigate whether the two have complementary synergistic effects after co-treatment rice husk biochar and beneficial microorganisms. In this experiment, adzuki bean and rice were planted in two adjacent experimental fields in the permaculture research farm of National Pingtung University of Science and Technology in January 2020. The experimental treatments were controlled with or without the application of rice husk biochar (0 %, 2 % (w/w)), two compound inoculation of beneficial microorganisms (Rhizobium and Arbuscular mycorrhizal fungi, Trichoderma and Bacillus subtilis) and a control group of no inoculation. The test results indicated that, for adzuki bean, the application of 2 % rice husk biochar significantly increased soil infiltration rate, and increased soil pH, organic matter, Bray-1-P, exchangeable potassium, calcium and magnesium content, among them, the improvement of soil exchangeable potassium content was the most obvious. The effect of co-treatment rice husk biochar and beneficial microorganisms on improving soil available phosphorus content was more obvious than that of treating beneficial microorganisms alone. However, regardless of whether the treatment of 2 % rice husk biochar or the inoculation of Rhizobium and Arbuscular mycorrhizal fungi alone or together, there was no significant effect on the mycorrhizal colonization rate of adzuki bean. The application of 2 % rice husk biochar could significantly increase the plant height, shoot and root dry matter of adzuki bean. However, the promoting effect of co-treatment of rice husk biochar and beneficial microorganisms on plant height, leaf length and width, number of leaves, shoots and total dry matter of adzuki bean was not significantly different from that of single treatment of rice husk biochar. The application of 2 % rice husk biochar significantly reduced the plant deficiency rate of adzuki bean, and also significantly increased the grain yield of adzuki bean. The effect of applying 2 % rice husk biochar on increasing the concentration of phosphorus and potassium in plants was more obvious than the co-treatment of rice husk biochar and beneficial microorganisms. For rice, application of 2 % rice husk biochar increased soil pH and significantly increased soil exchangeable potassium content, but had no significant effect on overall soil bulk density and soil infiltration rate. In addition, compared with the single treatment of rice husk biochar, the co-treatment of rice husk biochar and beneficial microorganisms also had no significant effect on rice plant height, tiller number, effective tiller number, shoot and root dry matter, grain yield, yield components and plant nitrogen, phosphorus, potassium and magnesium concentrations. In summary, two compound inoculations of beneficial microorganisms (Rhizobium and Arbuscular mycorrhizal fungi, Trichoderma and Bacillus subtilis), with or without co-treatment with 2 % rice husk biochar, the effects on improving the soil physicochemical properties of adzuki bean and rice, and promoting plant growth, yield and nutrient element concentration were less obvious. Therefore, further research and discussion are needed in the future. So, in this experiment, it is recommended to apply 2 % rice husk biochar alone.