Tian Hui, Wang Hui, Hui Xiaoli, Wang Zhaohui, Drijber Rhae A, Liu Jinshan
Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture/College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, China.
Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
PLoS One. 2017 Sep 7;12(9):e0184223. doi: 10.1371/journal.pone.0184223. eCollection 2017.
Agricultural management methods, such as cultivation or fallowing, have led to significant changes in soil fertility and hence, crop yield. Such changes may have stemmed from changes in soil microbial communities and associated biogeochemical processes. This phenomenon is particularly true in organic-poor soil in the Loess Plateau of China. In this study, we examined three existing soil management regimes as part of a 10-year field experiment and evaluated their effects on fungal and bacterial community structures by performing high-throughput 454 pyrosequencing. These management regimes were (i) fertilized winter wheat (Triticum aestivum L.) (FW), (ii) continuous natural fallow with weeds but without crop grown (NF), and (iii) continuous bare fallow without weeds or crop grown (BF). After 10 years, soil organic carbon (SOC), microbial biomass carbon (MBC), and available potassium (K) concentrations were highest in NF. Soil N behaved differently, with BF obtaining the highest nitrate nitrogen (N). Meanwhile, slight differences in total N (TN) were observed among FW, NF, and BF. Available phosphorus (P) was highest and available K was lowest in FW. Microbial communities were dominated by Ascomycota (59.1% of fungal sequences), and Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria (75.7% of bacterial sequences) in FW, NF and BF at the phylum level. Soil management regimes did not affect the fungal and bacterial richness and diversity but significantly modified their community compositions. Compared with FW, the abundances of Ascomycota (fungi phylum) and Alternaria, Gibberella, and Emericella (fungi genus) were increased by NF, whereas the values of Chaetomium, Humicola, and Cryptococcus (fungi genus) were decreased by BF. The abundances of Verrucomicrobia (bacteria phylum), and Steroidobacter (bacteria genus) were increased by NF, and Bacteroides (bacteria genus) was increased by BF. Canonical correspondence analysis showed that SOC, available P, and TN might be the key factors in community formation. Therefore, the decadal absence of plants (BF) affected soil fertility by increased available K and nitrate N, whileas natural fallow (NF) affected soil fertility by increased SOC, available K, and MBC, and they all changed fungal and bacterial community compositions.
农业管理方法，如耕种或休耕，已导致土壤肥力发生显著变化，进而影响作物产量。这种变化可能源于土壤微生物群落的改变以及相关的生物地球化学过程。在中国黄土高原的贫瘠土壤中，这种现象尤为明显。在本研究中，作为一项为期10年的田间试验的一部分，我们考察了三种现有的土壤管理方式，并通过高通量454焦磷酸测序评估了它们对真菌和细菌群落结构的影响。这些管理方式分别为：（i）施肥冬小麦（Triticum aestivum L.）（FW）；（ii）连续自然休耕且有杂草但无作物种植（NF）；（iii）连续裸地休耕且无杂草和作物种植（BF）。10年后，土壤有机碳（SOC）、微生物生物量碳（MBC）和有效钾（K）浓度在NF中最高。土壤氮的表现有所不同，BF中的硝态氮（N）含量最高。同时，FW、NF和BF之间的全氮（TN）略有差异。有效磷（P）在FW中最高，有效钾在FW中最低。在门水平上，FW、NF和BF中的微生物群落主要由子囊菌门（占真菌序列的59.1%）以及酸杆菌门、放线菌门、拟杆菌门、厚壁菌门和变形菌门（占细菌序列的75.7%）组成。土壤管理方式并未影响真菌和细菌的丰富度与多样性，但显著改变了它们的群落组成。与FW相比，NF增加了子囊菌门（真菌门）以及链格孢属、赤霉属和艾氏霉属（真菌属）的丰度，而BF降低了毛壳菌属、腐质霉属和隐球菌属（真菌属）的值。NF增加了疣微菌门（细菌门）以及甾体杆菌属（细菌属）的丰度，BF增加了拟杆菌属（细菌属）的丰度。典范对应分析表明，SOC、有效P和TN可能是群落形成的关键因素。因此，连续十年无植物（BF）通过增加有效钾和硝态氮影响土壤肥力，而自然休耕（NF）通过增加SOC、有效钾和MBC影响土壤肥力，并且它们都改变了真菌和细菌的群落组成。
