黄河三角洲贝壳堤土壤微生物生物量对不同生境因子的响应

从土壤微生物生物量角度分析黄河三角洲贝壳堤不同生境的土壤肥力状况,基于黄河三角洲贝壳堤植被类型,以4种不同生境的土壤为研究对象,测定了微生物生物量碳、氮、磷和相关的土壤理化性质。结果表明,不同生境中土壤微生物生物量碳(MBC)、土壤微生物生物量(MBN)、土壤微生物生物量(MBP)均值均为滩脊背海侧高潮线向海侧,且表现出明显的垂直分布特征:0—5 cm5—10 cm10—20 cm20—40 cm40—60 cm。土壤MBC、MBN、MBP占土壤有机碳(SOC)、全氮(TN)、全磷(TP)百分比变化范围分别为1.09%—3.48%、2.62%—7.27%、0.78%—2.86%,滩脊、背海侧和高潮线处MBC/SOC无显著差异(P0.05),但显著高于向海侧MBC/SOC(P0.05)。土壤MBN/TN、MBP/TP的变化趋势为滩脊和背海侧向海侧和高潮线。滩脊和背海侧土壤微生物碳、氮、磷的非生物限制性因子为土壤含水量、p H值、含盐量;向海侧和高潮线区域土壤微生物碳、氮、磷的非生物限制性因子为含水量和pH值。滩脊、背海侧和高潮线土壤微生物生物量碳、氮、磷及土壤养分间的相关关系显著或极显著,且协同性和稳定性高,表明土壤微生物生物量碳、氮、磷可以作为判断黄河三角洲贝壳堤土壤肥力状况的生物学指标,这为黄河三角洲贝壳堤的土壤肥力管理和植被恢复提供一定的理论依据。

Responses of soil microbial biomass to different habitat factors in the chenier of the Yellow River Delta

Soil microbes are the most vital decomposers in terrestrial ecosystems, and play a crucial role in wetland carbon (C), nitrogen (N), and phosphorus (P) cycles. Several studies have been conducted on the microbial biomass in the forests, plateaus, grasslands, and farmland; however, few studies on soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and microbial biomass phosphorus (MBP) have been conducted in the chenier of the Yellow River Delta, especially studies of the spatial distribution of soil microbial biomass C, N, and P in different habitats. To investigate the soil fertility of different habitats, the soil microbial biomass C, N, P and physicochemical properties were observed in five soil layers (0-5, 5-10, 10-20, 20-40, 40-60 cm) of the high tide line, seaward side, dune crest, and landside of the chenier of the Yellow River Delta. The results showed that the microbial biomass C, N, and P of different habitats were ranked as follows:dune crest > landside > high tide line > seaward side. The microbial biomass C, N, and P displayed an obvious vertical distribution in decreasing order of 0-5 cm > 5-10 cm > 10-20 cm > 20-40 cm > 40-60 cm. Soil microbial biomass C, N, and P accounted for 1.09%-3.48%, 2.62%-7.27%, and 0.78%-2.86% of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP), respectively. There were no significant differences between the ratio of microbial biomass carbon to soil organic carbon (MBC/SOC) in the dune crest, landside, and high tide line (P > 0.05), but they were significantly higher than those on the seaward side (P < 0.05). The changing trend of the ratio of microbial biomass nitrogen to total nitrogen (MBN/TN) and the ratio of microbial biomass phosphorus to total phosphorus (MBP/TP) were the dune crest and landside > seaward side and high tide line. The abiotic limiting factors of soil microbial biomass C, N, and P were soil water content, pH value, and salt content in the dune crest and landside. The abiotic limiting factors of soil microbial biomass C, N, and P were water content and pH value in the seaward side and high tide line areas. The positive correlations between soil microbial biomass C, N, and P and soil nutrients were significant or extremely significant in the dune crest, landside, and high tide line. The coordination and stability were higher, indicating that soil microbial biomass C, N, and P could be used as biological indices to evaluate soil fertility in the chenier of the Yellow River Delta, which provides a theoretical basis for soil fertility management and vegetation restoration of cheniers in the Yellow River delta.