Wu Chun-Xiao, Gao Xiao-Feng, Yan Ben-Shuai, Liang Cai-Qun, Chen Jia-Rui, Wang Guo-Liang, Liu Guo-Bin
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2022 Jan 8;43(1):521-529. doi: 10.13227/j.hjkx.202104277.
Long-term fertilization has an important effect on soil fertility and soil microbial activity. In order to explore the effects of long-term fertilization on soil extracellular enzyme activities and nutrient characteristics in a terrace on the Loess Plateau, we based our investigation on the long-term nutrient localization plot of Ansai Soil and Water Conservation Experimental Station, Chinese Academy of Sciences. We measured the soil physicochemical properties, microbial biomass, and extracellular enzyme activities of six fertilization treatments, which included no fertilization (CK); manure and nitrogen fertilization (MN); manure and phosphate fertilization (MP); manure, nitrogen, and phosphate fertilization (MNP); manure (M); and nitrogen and phosphate fertilization (NP). The results showed that all fertilization treatments significantly increased soil nutrient content and soil extracellular enzyme activities compared with that in CK. Correlation analysis showed that extracellular enzyme activity and soil physicochemical properties had an extremely significant correlation. The redundancy analysis indicated that soil nutrient and soil microbial biomass could explain 79.66% and 74.87% of the variation in soil extracellular enzyme activity and its stoichiometric ratio, respectively. Thus, the effects of fertilization on soil fertility were primarily through influencing soil extracellular enzyme activities indirectly. M, MN, MP, and MNP significantly improved soil organic carbon (SOC); soil total nitrogen (STN); and carbon (C), nitrogen (N), and phosphorus (P) source enzyme content; however, MNP changed the soil pH, which had an inhibitory effect on microbial activities. Vector analysis showed that the microbial communities of all treatments were in the condition of P limitation. Although MNP could alleviate the extent of P limitation, there was no significant difference between M and MP. Our study indicated that long-term application of manure[7500 kg·(hm·a)]could meet the nutrient requirements of dryland crop growth, and long-term application of manure combined with phosphorus fertilization could alleviate the resource constraints faced by microorganisms. Consequently, our results provide a new insight into improving regional nitrogen excess.
长期施肥对土壤肥力和土壤微生物活性具有重要影响。为了探究长期施肥对黄土高原梯田土壤胞外酶活性和养分特征的影响，我们以中国科学院安塞水土保持试验站长 期养分定位试验田为研究对象。测定了6种施肥处理的土壤理化性质、微生物生物量和胞外酶活性，这6种施肥处理包括：不施肥（CK）；有机肥与氮肥配施（MN）；有机肥与磷肥配施（MP）；有机肥、氮肥与磷肥配施（MNP）；单施有机肥（M）；氮肥与磷肥配施（NP）。结果表明，与CK相比，所有施肥处理均显著提高了土壤养分含量和土壤胞外酶活性。相关性分析表明，胞外酶活性与土壤理化性质具有极显著相关性。冗余分析表明，土壤养分和土壤微生物生物量分别可以解释土壤胞外酶活性及其化学计量比变化的79.66%和74.87%。因此，施肥对土壤肥力的影响主要是通过间接影响土壤胞外酶活性实现的。M、MN、MP和MNP显著提高了土壤有机碳（SOC）、土壤全氮（STN）以及碳（C）、氮（N）和磷（P）源酶含量；然而，MNP改变了土壤pH值，对微生物活性产生了抑制作用。向量分析表明，所有处理的微生物群落均处于P限制状态。虽然MNP可以缓解P限制程度，但M和MP之间没有显著差异。我们的研究表明，长期施用有机肥[7500 kg·(hm·a)]能够满足旱地作物生长的养分需求，长期施用有机肥并配施磷肥可以缓解微生物面临的资源限制。因此，我们的研究结果为改善区域氮素过剩问题提供了新的见解。
