Latkovic Dragana, Maksimovic Jelena, Dinic Zoran, Pivic Radmila, Stanojkovic Aleksandar, Stanojkovic-Sebic Aleksandra
Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovića 8, 21000 Novi Sad, Serbia.
Institute of Soil Science, Teodora Drajzera 7, 11000 Belgrade, Serbia.
Biology (Basel). 2020 Dec 8;9(12):452. doi: 10.3390/biology9120452.
This study evaluated the effects of the application of microbial inoculants (N-fixing and spp.), two rates of composite mineral fertilizers, and their combination on microbial biomass carbon (MBC), dehydrogenase (DHA), and proteinase activity (PTA) in Lessivated Cambisol and yield-related properties of maize and wheat grains in a two-year trial. Unfertilized soil was used as a control variant. MBC was measured using the chloroform fumigation-extraction method, DHA was determined spectrophotometrically by measuring the intensity of the formed red-colored triphenyl formazan, while PTA was determined using a titration method by measuring the degree of gelatine decomposition. In grain samples, P was determined spectrophotometrically, K-by flame emission photometry, N-on an elemental carbon/nitrogen/sulfur (CNS) analyzer, and crude proteins-by calculation of N content. Measuring both crops' yield was carried out at the end of the vegetation. The results indicated that mineral fertilizers are not, in general, negative for soil microbiota when used in the context of sustainable agriculture without monoculture. There is a significant increase in the values of soil MBC, DHA, and PTA in the variants with combined application of bacterial inoculants and lower rates of mineral fertilizers. The highest values of these parameters were determined in the period with a better distribution of precipitation during the vegetation period of the year. The mentioned combination also resulted in a higher grain yield of maize and wheat comparing to the application of lower rates of the NPK nutrients solely. The combined application of high rates of mineral fertilizers and bacterial inoculants resulted in significantly increased N, P, K, and protein content in the grains of crops, and the same applied to yield. Concluding, studied bacterial inoculants can be used to specify the replacement of nitrogen fertilizers, stimulating the microbial biomass and enzyme activity in the soil, helping to ensure that the supply of nutrients contributing to an optimized yield of crops is maintained.
本研究在一项为期两年的试验中，评估了微生物接种剂（固氮菌和其他菌种）、两种复合矿物肥料施用量及其组合对潜育始成土中微生物生物量碳（MBC）、脱氢酶（DHA）和蛋白酶活性（PTA）的影响，以及对玉米和小麦籽粒产量相关特性的影响。未施肥土壤用作对照变体。MBC采用氯仿熏蒸-提取法测定，DHA通过分光光度法测量形成的红色三苯基甲臜的强度来确定，而PTA采用滴定法通过测量明胶分解程度来确定。在谷物样品中，磷采用分光光度法测定，钾采用火焰发射光度法测定，氮采用元素碳/氮/硫（CNS）分析仪测定，粗蛋白通过计算氮含量来确定。在植被期结束时测量两种作物的产量。结果表明，在可持续农业且无单一栽培的背景下使用矿物肥料时，一般对土壤微生物群没有负面影响。在联合施用细菌接种剂和较低矿物肥料施用量的变体中，土壤MBC、DHA和PTA值显著增加。这些参数的最高值出现在一年植被期内降水分布较好的时期。与仅施用较低量氮磷钾养分相比，上述组合还使玉米和小麦的籽粒产量更高。高量矿物肥料和细菌接种剂的联合施用导致作物籽粒中的氮、磷、钾和蛋白质含量显著增加，产量也同样如此。总之，所研究的细菌接种剂可用于明确替代氮肥，刺激土壤中的微生物生物量和酶活性，有助于确保维持有助于作物优化产量的养分供应。
