Soil macrofauna, mesofauna and microfauna and their relationship with soil quality in agricultural areas in northern Colombia: ecological implications

ABSTRACT Soil fauna is an essential component of the soil ecosystem for maintaining nutrient cycling and biological soil fertility. This study assessed the soil biodiversity (macrofauna, mesofauna, and microfauna) to define strategies for the sustainable management of tropical agricultural soils. The study was carried out in 200 agricultural production units in the Department of Sucre, in northern Colombia. Physicochemical properties (organic matter, nitrogen, phosphorus, and pH) were determined for each soil sample. The Berlesse-Tullgren method was used to determine the composition of macrofauna and mesofauna, while the sown surface plate counting method was applied for microfauna. Community biodiversity was quantified with diversity indices, and Pearson correlation was carried out to determine the relationships between soil fauna and soil quality indicators. For the macrofauna, 1330 individuals were found, distributed in 22 orders and 65 families; the families Tenebrionidae, Formicidae, Staphylinidae, Scarabaeidae and Julide presented the highest abundance and distribution. Mesofauna presented 1,171 individuals, distributed in the classes Arachnida with seven families and Collembola with four families; the Scheloribatidae, Isotomidae and Galumnidae families presented the highest abundance and distribution. The indices of richness, Shannon-Wiener diversity and Simpson dominance indicated that biodiversity was higher for macrofauna. Pearson’s correlation indicated significant correlations between soil mesofauna and soil organic matter (R2 = 0.87; p≤0.05) and phosphorous (R2 = 0.70; p≤0.05). The relationships between fauna and soil chemical properties indicate that soil biological diversity is sensitive to changes in the soil environment. This study revealed the importance of investigating the three components of soil fauna (macrofauna, mesofauna, and microfauna), since all three contribute to soil enrichment to grow nourished crops that allow plants to survive under climate change. Finally, this study may serve as a baseline to define strategies for sustainable management of tropical agricultural soils.

摘要 土壤动物是维持土壤生态系统养分循环与土壤生物肥力的核心组成部分。本研究针对土壤生物多样性（大型土壤动物（macrofauna）、中型土壤动物（mesofauna）与小型土壤动物（microfauna））展开评估，旨在明确热带农田土壤的可持续管理策略。本研究于哥伦比亚北部苏克雷省的200个农业生产单元中开展。针对每份土壤样品，测定了其理化性质：有机质、氮、磷与pH值。采用贝尔莱斯-杜格林（Berlesse-Tullgren）分离法测定大型与中型土壤动物群落组成，小型土壤动物则采用平板涂布计数法进行分析。通过多样性指数对群落生物多样性进行定量表征，并采用皮尔逊相关分析探究土壤动物与土壤质量指标间的关联。大型土壤动物共采集到1330个个体，隶属于22个目、65个科；其中拟步甲科（Tenebrionidae）、蚁科（Formicidae）、隐翅虫科（Staphylinidae）、金龟科（Scarabaeidae）与马陆科（Julidae）的个体丰度与分布范围最高。中型土壤动物共采集到1171个个体，分别隶属于蛛形纲（Arachnida）的7个科与弹尾纲（Collembola）的4个科；其中谢甲螨科（Scheloribatidae）、等节跳科（Isotomidae）与甲螨科（Galumnidae）的个体丰度与分布范围最高。物种丰富度指数、香农-威纳（Shannon-Wiener）多样性指数与辛普森（Simpson）优势度指数均显示，大型土壤动物的生物多样性水平更高。皮尔逊相关分析结果显示，中型土壤动物与土壤有机质（决定系数R²=0.87；p≤0.05）、磷（决定系数R²=0.70；p≤0.05）均存在显著相关性。土壤动物与土壤化学性质间的关联表明，土壤生物多样性对土壤环境变化具有较高敏感性。本研究证实了同时探究三类土壤动物的重要性：三类土壤动物均可促进土壤养分富集，助力培育健壮作物，使植物能够在气候变化背景下存活。最后，本研究可为热带农田土壤可持续管理策略的制定提供基准参考。