Nie Mengen, Yue Guangqian, Wang Lei, Zhang Yizhong
Center for Agricultural Gene Resources Research, Shanxi Agricultural University, Taiyuan, China.
College of Agronomy, Shanxi Agricultural University, Taiyuan, China.
Front Plant Sci. 2024 Nov 8;15:1492797. doi: 10.3389/fpls.2024.1492797. eCollection 2024.
Chemical fertilizer reduction combined with organic fertilizer (organic fertilizer substitution) has a positive impact on crop productivity and sustainable development. However, the effects of short-term organic fertilizer substitution on microbial community structure and functions of sorghum rhizosphere soil and on sorghum yield remain unclear. Herein, this study investigated the short-term effects of organic fertilizer substitution on sorghum soil physicochemical properties, microbial community structure and enzyme activities using Metagenomic sequencing technology.
The fertilization treatment included no fertilization (CK), pure chemical fertilizer N (CF), substitution of 25% chemical fertilizer N with organic N (NF25), substitution of 50% chemical fertilizer N with organic N (NF50), substitution of 75% chemical fertilizer N with organic N (NF75), and pure organic fertilizer N (NF100); soil samples were collected and analyzed in the flowering period of sorghum.
The results showed that the suitable organic fertilizer substitution rate of sorghum field was 50%, and its yield was the highest among all treatments (9789.9 kg/hm). Compared with the CF treatment, a medium ratio (50%) of organic fertilizer substitution significantly reduced soil alkalization (by 3.05%), improved soil nutrients, enhanced soil enzyme activities, and increased sorghum yield ( < 0.05). After organic fertilizer substitution treatment, higher protein, fat, and total starch levels accumulated in sorghum grains, and the tannin content of grains decreased. The effect of organic fertilizer substitution on bacterial diversity was greater than that on fungal diversity. Among the dominant bacterial phyla, the medium ratio of organic substitution treatment significantly increased the relative abundances of Proteobacteria (by 3.57%) and Actinomycetes (by 14.94%), and decreased the relative abundances of Acidobacteria (by 5.18%) and Planctomycetes (by 7.76%) compared with no fertilization, while the dominant fungal phyla did not respond significantly to the addition of organic fertilizer. Organic fertilizer substitution also improved soil microbial metabolic pathways, biosynthesis of secondary metabolites, and carbon metabolism. The biomarkers enriched in inorganic fertilizer treatment and organic fertilizer substitution treatments had similar relevant environmental elements but reversed correlation trends. Moreover, soil Alkali-hydrolyzable nitrogen and L-leucine aminopeptidase were important environmental factors influencing the structure of bacterial and fungal communities in sorghum soils, respectively. Soil nutrient levels and microbial communities together explained the variation in annual sorghum yield. The results of this study provide evidence that short-term organic fertilizer substitution increases sorghum yield by improving soil properties and regulating microbial community structure.
化肥减量与有机肥结合（有机肥替代）对作物生产力和可持续发展具有积极影响。然而，短期有机肥替代对高粱根际土壤微生物群落结构和功能以及高粱产量的影响尚不清楚。在此，本研究利用宏基因组测序技术研究了有机肥替代对高粱土壤理化性质、微生物群落结构和酶活性的短期影响。
施肥处理包括不施肥（CK）、纯化肥N（CF）、用有机N替代25%化肥N（NF25）、用有机N替代50%化肥N（NF50）、用有机N替代75%化肥N（NF75）和纯有机肥N（NF100）；在高粱开花期采集土壤样本并进行分析。
结果表明，高粱田适宜的有机肥替代率为50%，其产量在所有处理中最高（9789.9公斤/公顷）。与CF处理相比，中等比例（50%）的有机肥替代显著降低了土壤碱化（降低3.05%），改善了土壤养分，增强了土壤酶活性，并提高了高粱产量（<0.05）。有机肥替代处理后，高粱籽粒中积累了更高水平的蛋白质、脂肪和总淀粉，籽粒单宁含量降低。有机肥替代对细菌多样性的影响大于对真菌多样性的影响。在优势细菌门中，与不施肥相比，中等比例的有机替代处理显著增加了变形菌门的相对丰度（增加3.57%）和放线菌门的相对丰度（增加14.94%），并降低了酸杆菌门的相对丰度（降低5.18%）和浮霉菌门的相对丰度（降低7.76%），而优势真菌门对有机肥添加没有显著响应。有机肥替代还改善了土壤微生物代谢途径、次生代谢物生物合成和碳代谢。无机肥处理和有机肥替代处理中富集的生物标志物具有相似的相关环境元素，但相关趋势相反。此外，土壤碱解氮和L-亮氨酸氨基肽酶分别是影响高粱土壤细菌和真菌群落结构的重要环境因素。土壤养分水平和微生物群落共同解释了高粱年产量的变化。本研究结果提供了证据，表明短期有机肥替代通过改善土壤性质和调节微生物群落结构提高了高粱产量。
