Microbial community structure is affected by cropping sequences and poultry litter under long-term no-tillage

Soil microorganisms play essential roles in soil organic matter dynamics and nutrient cycling in agroecosystems and have been used as soil quality indicators. The response of soil microbial communities to land management is complex and the long-term impacts of cropping systems on soil microbes is largely unknown. Therefore, changes in soil bacterial community composition were assessed in response to cropping sequences and bio-covers at long-term no-tillage sites. Main effects of four different cropping sequences of corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean (Glycine max L.) were rotated in four year phases for 12-yrs at two Tennessee Research and Education Centers in a randomized complete block design with split-block treatments of four winter bio-covers: hairy vetch (Vicia villosa L.), wheat (Triticum aestivum L.), poultry litter, and a fallow control. Using Illumina high-throughput sequencing of 16S rRNA genes, bacterial community composition was determined. Composition, diversity, and relative abundance of specific taxa were correlated per cropping system, bio-cover, and their interaction. We found that i) richness and diversity varied temporally and spatially, coinciding with soil carbon, pH, nutrient levels, and climatic variability; ii) community composition varied by cropping system, with continuous corn, soybean, and the corn-soybean rotation presenting a hybrid of the continuous corn and soybean communities; however, continuous cotton resulted in the most varied assemblage; iii) bio-covers asserted the greatest influence on microbial communities; specifically poultry litter treatments differed from cover crops (all of which received inorganic-N). Consequently, microbial diversity was greatest under nutrient rich bio-covers (poultry litter) and high residue producing, less pesticide-intensive cropping sequences (soybean and corn compared to cotton), suggesting a more dynamic soil ecology under these no-till cropping systems. This suggests that nutrient management (inorganic fertilizers vs. animal manure) and greater crop rotations (within 4-yr phases) may directly drive phylogenetic community structure and subsequent ecosystem services across agricultural landscapes. Resources in this dataset:Resource Title: Microbial diversity based on crop rotation, cover crop, and poultry litter after 14-years of managment . File Name: Ashworth microbial data by PLOT.xlsxResource Title: Microbial diversity based on crop rotation, cover crop, and poultry litter after 14-years of managment. File Name: Ashworth microbial data by PLOT.csvResource Description: CSV version of the dataResource Title: Data Dictionary. File Name: Ashworth-PLOT-Jul2019-data-dictionary.csvResource Description: Defines variables, data type, accepted values, size, if required, etc. for the tabular data.

土壤微生物在土壤有机质动态变化及农业生态系统中的养分循环中扮演着至关重要的角色，并已被用作土壤质量的指示指标。土壤微生物群落对土地利用方式的响应复杂多变，而作物系统对土壤微生物的长期影响尚大多未知。因此，在长期免耕的试验点上，对土壤细菌群落组成随作物轮作和生物覆盖的变化进行了评估。本研究在田纳西州两个研究教育中心，以随机完全区组设计并采用分块处理的四因素（玉米（Zea mays L.）、棉花（Gossypium hirsutum L.）和豆类（Glycine max L.）四种不同的作物轮作序列、四个年度阶段，共计12年的基础上进行。四种冬季生物覆盖（毛苕子（Vicia villosa L.）、小麦（Triticum aestivum L.）、家禽粪便和休闲处理）的交互作用被纳入研究。通过Illumina高通量测序16S rRNA基因，确定了细菌群落组成。具体到作物系统、生物覆盖及其相互作用，对特定类群的组成、多样性和相对丰度进行了相关性分析。研究发现，i)物种丰富度和多样性随时间和空间变化，与土壤碳、pH值、养分水平和气候变率相一致；ii)群落组成随作物系统而异，连续玉米、豆类和玉米-豆类轮作呈现了连续玉米和豆类群落之间的混合特征；然而，连续棉花导致了最为多样化的群落；iii)生物覆盖对微生物群落的影响最为显著；具体而言，家禽粪便处理与覆盖作物（所有处理均接受无机氮）存在差异。因此，在富含养分的生物覆盖（家禽粪便）和高残留产量、农药使用量较低的作物轮作序列（豆类和玉米相对于棉花）下，微生物多样性最高，这表明在这些免耕作物系统中，土壤生态系统具有更加动态的特征。这一发现表明，养分管理（无机肥料与动物粪便）和更广泛的作物轮作（在四年周期内）可能直接驱动农业景观中的系统发育群落结构和随后的生态系统服务。本数据集包含的资源：资源标题：基于作物轮作、覆盖作物和家禽粪便的14年管理后的微生物多样性。文件名：Ashworth微生物数据按地块.xlsx资源标题：基于作物轮作、覆盖作物和家禽粪便的14年管理后的微生物多样性。文件名：Ashworth微生物数据按地块.csv资源描述：数据的CSV版本资源标题：数据字典。文件名：Ashworth-PLOT-Jul2019数据字典.csv资源描述：定义了表格数据的变量、数据类型、可接受值、大小、是否必需等信息。