Evolution of nutrient availability in maturation phase of composting using proportions of different residues inoculated with Beijerinckia indica

ABSTRACT. Organic matter has low N content; however, organic matter may be enriched by inoculation with selected diazotrophic bacteria. The aim of the paper was to evaluate the effects of biofertilizer produced by mixing different types and proportions of organic matter inoculated with the diazotrophic bacteria Beijerinckia indica. The experiment consisted of plastic trays (6 L) containing 5 kg of three different types of organic matter (filter mud cake, earthworm compost, and crop residue) applied in the following proportions (v:v:v): 1-(5:0:0), 2-(4:1:0), 3-(4:0:1), 4-(3:2:0), 5-(3:1:1), 6-(3:0:2), 7-(2:3:0), 8-(2:2:1), 9-(2:1:2), 10-(2:0:3), 11-(1:4:0), 12-(1:3:1), 13-(1:2:2), 14-(1:1:3), 15-(1:0:4), 16-(0:5:0), 17-(0:4:1), 18-(0:1:4), 19-(0:3:2), 20-(0:2:3), and 21-(0:0:5). Samples were collected following inoculation with B. indica at 0, 10, 20, 30, and 40 days of the maturation phase. The chemical analyses were: pH (H2O), total C and N, available P and K, and exchangeable Na+, Ca+2, Mg+2. The treatments with the best results showed significant effects following the maturation phase. The exceptions were C and N, which presented only individual effects. In general, the organic matter proportions (5:0:0), (3:2:0), and (2:3:0) resulted in a significant increase in the availability of nutrients. Biofertilizers with optimal organic matter proportions may be used to produce organic substrates that are more effective and have the potential to be applied as alternatives to soluble NPK fertilizers.摘要 有机质本身氮含量较低，但通过接种筛选得到的固氮细菌（diazotrophic bacteria）可实现有机质的氮素富集。本研究旨在评估接种拜氏固氮菌（Beijerinckia indica）的不同类型、不同配比有机质制备的生物肥料的施用效果。试验采用6 L塑料托盘，装载5 kg共3种不同类型的有机质：滤泥饼、蚯蚓堆肥及作物残体，并设置21组体积比（v:v:v）配比处理，分别为：1-(5:0:0)、2-(4:1:0)、3-(4:0:1)、4-(3:2:0)、5-(3:1:1)、6-(3:0:2)、7-(2:3:0)、8-(2:2:1)、9-(2:1:2)、10-(2:0:3)、11-(1:4:0)、12-(1:3:1)、13-(1:2:2)、14-(1:1:3)、15-(1:0:4)、16-(0:5:0)、17-(0:4:1)、18-(0:1:4)、19-(0:3:2)、20-(0:2:3)、21-(0:0:5)。于接种拜氏固氮菌后，在腐熟阶段的第0、10、20、30及40天采集样品。本试验测定的化学指标包括：pH（水提液法）、总碳、总氮、速效磷、速效钾，以及交换性钠离子（Na+）、钙离子（Ca²+）、镁离子（Mg²+）。经腐熟阶段后，多数处理组表现出显著的促效作用，仅总碳与总氮仅呈现个体效应，未表现出组间显著差异。总体而言，配比为(5:0:0)、(3:2:0)及(2:3:0)的有机质可显著提升养分有效性。具备最优有机质配比的生物肥料，可用于制备更高效的有机基质，有望作为可溶性氮磷钾（NPK）肥料的替代方案进行推广应用。