水稻SPRI農法與不同比例肥料施用對土壤化學性質和根際微生物的影響

水稻(Oryza sativa L.)為禾本科的單子葉植物，是全球最重要的糧食作物之一，產量僅次於小麥和玉米，其栽培需要大量的肥料，特別是緩效基底肥料。肥料若施用過量，會導致土壤中的氮含量過高，經常會造成水稻結穗期出現倒伏的狀況，並伴隨著蟲害與疾病，嚴重的影響產量及品質，並且引發許多環境問題，導致當地生態系統退化。為改善慣行農法所帶來的問題，本研究利用益生菌與水稻強化栽培系統 ( System of Probiotic and Rice Intensification，簡稱SPRI )中所強調的灌溉系統與合理化施肥的重要性，於2018年至2020年連續五個水稻栽培期，並搭配離子層析儀測定土壤中營養離子與次世代定序(Next Generation Sequencing，簡稱NGS)了解土壤微生物組成，探討整個栽培季中水稻生長四個時段，即分糵期、抽穗期、開花期以及黃熟期中的土壤成分的變化，以了解在灌溉系統、合理化施肥以及益生菌添加的搭配下，對水稻產量與土壤化學、生物性質的影響。2018第一期作研究結果顯示SPRI農法系統的葉綠素和穀粒蛋白質含量較慣行農法明顯提高，此結果為SPRI農法系統可以增加生物量訂定良好的方向。2018第二期作至2019第二期作等三期稻作中，以SPRI+50%化肥(chemical fertilizer，簡稱CF)為最高產量，其中甚至於2018第二期作增加了約66%的產量，在2019兩個期作中也分別增加25%和13%。而穀物蛋白質以最大施肥量的慣行農法為最高含量，而穀物中過多的蛋白質會降低水稻的外觀和品質。 2019第一期作的土壤微生物群落分析以SPRI+50％CF為三者中最高物種豐度，而生物多樣性則以SPRI+25%CF為最高值，確定生物肥料應用的潛力。SPRI栽培法讓益生菌通過間歇性供水有效地將肥料輸送到田間不同位置，有效改善土壤的化學和生物性質，同時更容易分解土壤中的養分，有利於水稻有效的吸收，使肥料更有效地利用。因此，本研究中的 SPRI+50%CF處理組是最好的結果，為可持續農業提供了創新建議。除了減少 50% 以上的化肥用量和節約農業用水外，它還可以提高產量、改善稻米質量和增加土壤可持續性。

關鍵字

稻作強化栽培系統；合理化施肥和灌溉；土壤化學性質；根際微生物；離子層析

並列摘要

Rice (Oryza sativa L.) is a monocotyledonous flowering plant of the Poaceae family. It is one of the most important food crops in the world. Its production is second only to wheat and corn. Its cultivation requires a lot of fertilizers, especially slow-acting basal fertilizers. Excessive application will lead to high nitrogen content in the soil, often leading to lodging of rice during the fruiting period, accompanied by pests and diseases, seriously affecting the yield and quality, causing many environmental problems and leading to the degradation of the local ecosystem. To improve the problems caused by traditional farming methods, this study assessed soil nutrients for five consecutive rice planting seasons from 2018 to 2020 using the importance of irrigation systems and rational fertilization in the systems of probiotic and rice intensive farming (SPRI). Using next-generation sequencing (NGS) technology and ion chromatography, the soil composition of four rice growth stages (seedling stage, booting stage, flowering stage and yellow maturity stage) during the rice planting season was explored. To understand the effects of irrigation system, rational fertilization and addition of probiotics on rice growth and soil chemical and biological properties. Results for the first quarter of 2018 showed that SPRI farming had significantly higher chlorophyll and grain protein content than customary farming. This result points the way for SPRI agricultural methods to increase biomass. From the second quarter of 2018 to the second quarter of 2019, the production of SPRI+50% chemical fertilizer (CF) was the highest, and even the production in the second quarter of 2018 increased by about 66%. The two planting periods in 2019 also increased by 25% and 13%, respectively. For grain protein, customary farming practices with the highest fertilization rates are the highest concentration, and too much protein in grains reduced the appearance and quality of rice. In the first quarter of 2019, the soil microbial community analysis took SPRI+50% CF as the highest species abundance among the three, and the biodiversity took SPRI+25% CF as the highest value, which determined the potential of biological fertilizer application. The SPRI cultivation method allows probiotics to effectively transport fertilizers to different positions in the field through intermittent water supply, effectively improving the chemical and biological properties of the soil, and at the same time, it is easier to decompose the nutrients in the soil, which is conducive to the effective absorption of rice and makes fertilizers more efficient. Therefore, the SPRI+50% CF treatment group in this study was the best result, providing innovative recommendations for sustainable agriculture. In addition to reducing fertilizer use by more than 50% and saving agricultural water, it can also increase yields, improve rice quality and soil sustainability.