Manirakiza Noel, Melkani Suraj, Rabbany Abul, Medina-Irizarry Natalia, Smidt Samuel, Braswell Anna, Martens-Habbena Willm, Bhadha Jehangir H
Department of Soil, Water, and Ecosystem Sciences, University of Florida, Everglades Research and Education Center, Belle Glade, Florida, United States of America.
School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, Florida, United States of America.
PLoS One. 2025 Mar 25;20(3):e0318092. doi: 10.1371/journal.pone.0318092. eCollection 2025.
In subtropical preserve ecosystems, natural factors combined with anthropogenic activities have led to significant seasonal changes, including distinct dry and rainy seasons. These changes can potentially impact soil health indicators, which are keystone properties that control ecosystem services across terrestrial landscapes. Few studies have evaluated the impact of seasonal changes on soil health within non-agronomic landscapes, such as preserves. As part of this study, we collected topsoil samples (0-15 cm) from twenty-three land cover types within a 109 km² preserve in central Florida during two different seasons (dry and wet) to advance the understanding of how soil health responds to seasonal changes and to explore the environmental factors controlling soil health within non-agronomic landscapes. Ten soil indicators were analyzed and incorporated into the total dataset (TDS). From the TDS, a minimum dataset was derived using Principal Component Analysis, which was then used to calculate the Soil Health Index (SHI) for soil health assessment. Our findings showed that changes in soil indicators, their relationships, and the SHI across seasons depend on land cover type. Based on soil health classification grades, soil health status either improved, declined, or remained constant between seasons, depending on land cover type. The regression analysis of eight selected environmental factors, such as soil profile moisture (SPM), surface soil wetness (SSW), precipitation (P), soil temperature (T), elevation (El), slope gradient (S), global horizontal irradiance (GHI) and surface albedo (ALB), showed that only slope gradient significantly explains variations in SHI during wet season, whereas other environmental factors do not show significant explanatory power for SHI variations in either dry or wet season. These findings highlight the dominant influence of slope gradient on soil health within non-agronomic landscapes, while indicating that other evaluated environmental factors may have limited relevance in this context. Furthermore, the non-significant findings among soil indicators across seasons may be attributed to the study's small sample size (i.e., three replications), a limitation stemming from constrained funding. This highlights the importance of future research incorporating larger sample size to validate the findings of this study.
在亚热带保护区生态系统中，自然因素与人为活动相结合导致了显著的季节性变化，包括明显的旱季和雨季。这些变化可能会影响土壤健康指标，而土壤健康指标是控制陆地景观生态系统服务的关键属性。很少有研究评估季节性变化对非农业景观（如保护区）土壤健康的影响。作为本研究的一部分，我们在佛罗里达州中部一个109平方公里的保护区内的23种植被类型中，在两个不同季节（旱季和雨季）采集了表层土壤样本（0 - 15厘米），以增进对土壤健康如何响应季节性变化的理解，并探索控制非农业景观土壤健康的环境因素。分析了10个土壤指标并将其纳入总数据集（TDS）。从TDS中，使用主成分分析得出了一个最小数据集，然后用它来计算土壤健康指数（SHI）以进行土壤健康评估。我们的研究结果表明，土壤指标、它们之间的关系以及不同季节的SHI变化取决于植被类型。根据土壤健康分类等级，不同季节之间土壤健康状况要么改善、要么下降、要么保持不变，这取决于植被类型。对八个选定环境因素的回归分析，如土壤剖面湿度（SPM）、表层土壤湿度（SSW）、降水量（P）、土壤温度（T）、海拔（El）、坡度（S）、全球水平辐照度（GHI）和地表反照率（ALB），结果表明，只有坡度在雨季能显著解释SHI的变化，而其他环境因素在旱季或雨季对SHI的变化均无显著解释力。这些发现突出了坡度对非农业景观土壤健康的主导影响，同时表明其他评估的环境因素在这种情况下可能相关性有限。此外，不同季节土壤指标之间不显著的结果可能归因于本研究样本量较小（即三次重复），这是由于资金受限导致的一个局限性。这突出了未来研究纳入更大样本量以验证本研究结果的重要性。
