School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
Tobacco Research Institute of Hunan Province, Changsha, 410004, China; College of Agronomy, Hunan Agricultural University, Changsha, 410128, China.
Environ Res. 2021 Sep;200:111319. doi: 10.1016/j.envres.2021.111319. Epub 2021 May 28.
Continuous cropping has become the most common system in intensive, modern agricultural production; however, obstacles often appear in continuous cropping patterns after a few years of use. There have been several studies about the impacts of continuous cropping on soil microbial, but few about differences between soil experiencing continuous cropping obstacles and those where such obstacles had been resisted. Here, after ten or twenty years of continuous tobacco cropping, we collected soil samples investigating discrepancies in soil property and bacterial community between soils experiencing continuous cropping obstacles and soils where the obstacles were resisted providing insight into preventing and controlling continuous cropping obstacles. Results showed that soil organic matter (SOM), available phosphorus (AP), total nitrogen (TN), nitrate-N (NO-N), and bacterial diversity of samples where continuous cropping obstacles had been resisted were significantly higher than those where continuous cropping obstacles were present. Besides, SOM, AP, TN, and Ammonium-N (NH-N) considerably affected the bacterial community. Among all variables, NH-N explained the largest proportion of bacterial community variation. Molecular ecological networks were used to putatively identify keystone taxa, including Acidobacteria Gp1, Acidobacteria Gp2, Acidobacteria Gp16, and WPS-1_genera_incertae_sedis. Their relative abundance significantly changed between the two conditions. Overall, our results indicate that decreases in soil nutrient content and bacterial diversity, and significant changes in some keystone taxa abundances may be important factors leading to increased soil-borne diseases and reduced tobacco production potential or quality. Thus, during agricultural production, we could regulate the stability of the soil-crop-microbial ecological system via crop rotation, intercropping, or the use of specialized bio-fertilizers and soil conditioners to mitigate continuous cropping obstacles.
连作已成为集约化、现代化农业生产中最常见的系统；然而，在连续几年使用后，连作模式常常会出现障碍。已有多项研究探讨了连作对土壤微生物的影响，但很少有研究关注经历连作障碍和抵抗连作障碍的土壤之间的差异。在这里，在连续种植烟草十年或二十年之后，我们收集了土壤样本，研究了经历连作障碍和抵抗连作障碍的土壤之间土壤性质和细菌群落的差异，为预防和控制连作障碍提供了深入的了解。结果表明，抵抗连作障碍的土壤样本中的土壤有机质（SOM）、有效磷（AP）、总氮（TN）、硝酸盐氮（NO-N）和细菌多样性明显高于存在连作障碍的土壤样本。此外，SOM、AP、TN 和氨态氮（NH-N）对细菌群落有显著影响。在所有变量中，NH-N 解释了细菌群落变化的最大比例。分子生态网络被用来推测关键类群，包括 Acidobacteria Gp1、Acidobacteria Gp2、Acidobacteria Gp16 和 WPS-1_genera_incertae_sedis。它们的相对丰度在两种条件下显著变化。总的来说，我们的结果表明，土壤养分含量和细菌多样性的降低，以及一些关键类群丰度的显著变化，可能是导致土壤传播疾病增加和烟草生产力或质量下降的重要因素。因此，在农业生产中，我们可以通过轮作、间作或使用专门的生物肥料和土壤改良剂来调节作物-土壤-微生物生态系统的稳定性，以减轻连作障碍。
