Affiliation:
1. Department of Soil, Water, and Ecosystem Sciences University of Florida Gainesville Florida USA
2. State Key Laboratory of Subtropical Silviculture, College of Environment and Resources, College of Carbon Neutrality Zhejiang A&F University Hangzhou China
3. Alpine Ecosystem Observation and Experiment Station of Gongga Mountain, Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment, Chinese Academy of Sciences Chengdu China
4. Department of Renewable Resources University of Alberta Edmonton Alberta Canada
Abstract
AbstractConverting natural forests to agricultural lands has been widespread globally due to increasing population and the demand for food. Phosphorus (P) is often applied to agricultural lands in excessive amounts which can saturate the natural P sorption capacity of the soil, leading to P leaching and subsequent off‐site water eutrophication. We studied the effect of land‐use conversion from natural forests to tea plantations on total soil P, P fractions, and P sorption capacity in subtropical China. Compared to natural forests, total soil P concentrations increased significantly in both 0–20 and 20–40 cm depths in tea plantations, indicative of the accumulation of P fertilizer. The increases in total soil P were primarily found in NaOH‐extractable inorganic P and residual P fractions in both depths, suggesting that P fertilizer was sorbed and occluded into more stable forms due to the high abundance of sorbents (i.e., iron [Fe], aluminum [Al] minerals, and clay). Across all soil samples, oxalate‐extractable Fe was the best predictor of soil maximum P sorption capacity (r = 0.94, p < 0.001). Surprisingly, the conversion from natural forests to tea plantations decreased both oxalate‐extractable Fe concentration and soil maximum P sorption capacity, hereby increasing the degree of P saturation in soils. Depletion of P sorbents (i.e., soil amorphous Fe) is likely a consequence of Fe removal through tea production and soil erosion, indicating soil degradation. Plantation soils have also shown other signs of degradation including the loss of nutrients (e.g., total soil nitrogen and oxalate‐extractable calcium) and soil organic matter. Our results demonstrate that the conversion of natural forests to tea plantations reduced the ability of the soil to sorb P by both saturating the natural P sorption capacity and depleting P sorbents. Soil degradation resulting from land‐use conversion has increased the environmental risk of P leaching loss, emphasizing the need for improved P fertilization management.
Funder
National Natural Science Foundation of China
Subject
Soil Science,General Environmental Science,Development,Environmental Chemistry