The interactive effectof silicon (Si) application on soil fertility is poorly understood when inoculation with Azospirillum brasilense is performed. This research determined if Si application and A. brasilense inoculation to corn (Zea mays L.) and wheat (Triticum aestivum L.) has agronomic benefits on soil nutrient concentration and grain yield. Treatments were tested under a no-till system in a Rhodic Haplustox in a full factorial design with four replicates and comprised (a) two soil amendment sources—calcium (Ca) and magnesium (Mg) silicate and dolomitic limestone; (b) with and without seed inoculation with A. brasilense; and (c) five sampling dates collected during two corn–wheat crop rotations (2015–2017). Calcium and Mg silicate application was effective at decreasing soil hydrogen + aluminum (H+Al) and Al content and increasing soil pH, sum of bases, and base saturation. However, silicate changed soil nutrient availability, reduced cation exchange capacity, phosphorus (P) and Mg content and did not significantly affect (p > .05) corn and wheat grain yield. Inoculation reduced Al toxicity, with lower H+Al and Al contents, and increased K content, leading to a greater pH and base saturation after four cropping seasons. Inoculation increased corn and wheat grain yield by 8.2 and 8.3%, respectively. Application of Ca and Mg silicate was more effective than limestone as a liming agent but could result in decreased availability of certain nutrients in soil. Inoculation with A. brasilense could be an important management practice to maintain adequate Si content in soil when limestone is applied. However, with silicate application, A. brasilense could increase Si depletion in soil.

中文翻译：

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玉米-小麦轮作中硅酸盐和固氮螺应用对养分有效性的影响

当接种巴西固螺菌时，人们对硅 (Si) 施用对土壤肥力的交互作用知之甚少。本研究确定了在玉米 ( Zea mays L.) 和小麦 ( Triticum aestivum L. ) 上施用硅和巴西木霉是否对土壤养分浓度和谷物产量具有农艺学效益。在 Rhodic Haplustox 的免耕系统下以四次重复的全因子设计对处理进行了测试，包括 (a) 两种土壤改良源——硅酸钙 (Ca) 和镁 (Mg) 以及白云质石灰石；(b) 有和没有用巴西曲霉进行种子接种; (c) 在两次玉米-小麦轮作（2015-2017）期间收集的五个采样日期。施用硅酸钙和镁可有效降低土壤氢 + 铝 (H+Al) 和铝含量，并提高土壤 pH 值、碱总和和碱饱和度。然而，硅酸盐改变了土壤养分有效性，降低了阳离子交换能力、磷（P）和镁含量，并没有显着影响（p > .05) 玉米和小麦的粮食产量。接种降低了铝的毒性，降低了 H+Al 和 Al 含量，增加了 K 含量，导致四个作物季节后的 pH 值和碱饱和度更高。接种使玉米和小麦的产量分别增加了 8.2% 和 8.3%。施用钙和镁硅酸盐作为石灰剂比石灰石更有效，但可能导致土壤中某些养分的有效性降低。接种A. brasilense可能是在施用石灰石时保持土壤中足够硅含量的重要管理措施。然而，随着硅酸盐的应用，A. brasilense会增加土壤中硅的消耗。