He Chen, Li Kaikai, Li Jinku, Fan Pingshan, Ruan Yunze, Jia Zhongjun
Sanya Nanfan Research Institute of Hainan University, Hainan University, Sanya, China.
School of Tropical Agriculture and Forestry, Hainan University, Haikou, China.
Front Microbiol. 2024 Feb 28;14:1283675. doi: 10.3389/fmicb.2023.1283675. eCollection 2023.
Soil microorganisms play an important role in soil ecosystems as the main decomposers of carbon and nitrogen. They have an indispensable impact on soil health, and any alterations in the levels of organic carbon and inorganic nitrogen can significantly affect soil chemical properties and microbial community composition. Previous studies have focused on the effects of carbon and nitrogen addition on a single type of soil, but the response of soil microorganisms to varying carbon and nitrogen inputs under different land soil use types have been relatively understudied, leaving a gap in our understanding of the key influencing factors. To address this gap, we conducted a study in the tropical regions of Hainan province, focusing on four distinct land use types: natural forest soil (NS), healthy banana soil (HS), diseased banana garden soil (DS), and paddy soil (PS). Within each of these environments, we implemented five treatments: CK, RS (rice straw), RSN (rice straw and NHNO), RR (rice root), and RRN (rice root and NHNO). Our aim was to investigate how soil bacteria response to changes in carbon and nitrogen inputs, and to assess their potential for biological nitrogen fixation. The results showed that the addition of rice straw increased the absorption and utilization of nitrate nitrogen by microorganisms. The addition of rice roots (RR) did not increase the absorption capacity of inorganic nitrogen by microorganisms, but increased the content of poorly soluble organic carbon. Most importantly, the addition of rice straw increased microbial respiration and the utilization efficiency of N by microorganisms, and the further addition of ammonium nitrate increased microbial respiration intensity. With the change of soil type, the rice straw increases microbial nitrogen fixation, bacterial and genes abundance. Meanwhile, microbial respiration intensity is an important factor influencing the differences in the structure of bacterial communities. The addition of inorganic nitrogen resulted in ammonium nitrogen accumulation, reduced microbial richness and diversity, consequently diminishing the soil microorganisms to resist the environment. Therefore, we believe that with the change of soil types, corresponding soil nutrient retention strategies should be devised and incorporated while reducing the application of ammonium nitrogen, thus ensuring healthy soil development.
土壤微生物作为碳和氮的主要分解者，在土壤生态系统中发挥着重要作用。它们对土壤健康有着不可或缺的影响，有机碳和无机氮水平的任何变化都会显著影响土壤化学性质和微生物群落组成。以往的研究主要集中在碳氮添加对单一类型土壤的影响上，但不同土地利用类型下土壤微生物对不同碳氮输入的响应相对研究较少，这使得我们对关键影响因素的理解存在空白。为了填补这一空白，我们在海南省热带地区进行了一项研究，重点关注四种不同的土地利用类型：天然林土壤（NS）、健康香蕉园土壤（HS）、患病香蕉园土壤（DS）和稻田土壤（PS）。在这些环境中的每一个环境中，我们实施了五种处理：CK、RS（稻草）、RSN（稻草和NHNO）、RR（稻根）和RRN（稻根和NHNO）。我们的目的是研究土壤细菌如何响应碳氮输入的变化，并评估它们的生物固氮潜力。结果表明，添加稻草增加了微生物对硝态氮的吸收和利用。添加稻根（RR）并没有增加微生物对无机氮的吸收能力，但增加了难溶性有机碳的含量。最重要的是，添加稻草增加了微生物呼吸和微生物对氮的利用效率，进一步添加硝酸铵增加了微生物呼吸强度。随着土壤类型的变化，稻草增加了微生物固氮、细菌和基因丰度。同时，微生物呼吸强度是影响细菌群落结构差异的重要因素。添加无机氮导致铵态氮积累，降低了微生物的丰富度和多样性，从而削弱了土壤微生物抵抗环境的能力。因此，我们认为随着土壤类型的变化，应制定并纳入相应的土壤养分保持策略，同时减少铵态氮的施用，从而确保土壤健康发展。
