Effects of terracing on soil properties in three key mountainous regions of China

Abstract

Abstract Terracing is a great human footprint which highly affects soil properties, ecosystem services, human welfare and geographical sustainability. The main purpose of this article, therefore, is to determine the influence of terracing on soil properties across diverse geographical regions in China. Three representative terrace types, including dryland loess terraces, dry-stone terraces, and paddy terraces, were selected for further analysis. Soils were sampled stratified according to the thickness of soil layers in each terraced area. Based on field investigation and soil samplings, combined with the means of variance, correlation, redundancy and regression analysis, we analyzed the characteristics of soil properties in the related terraces across three typical areas. Results showed that (1) the alterations of soil physicochemical properties mainly depend on the differences between soil parent materials in such regions. However, different environmental conditions in the same area had minimal impacts on soil properties; (2) Paddy terraces in southern China had the greatest impact on soil properties. Due to the existence of “four-element isomorphism” in the ecosystem and reasonable human activities, terracing can effectively improve soil quality, which is mainly reflected in decreasing soil pH and increasing SOC, TN, and TK; (3) The contents of SOC and TN in different areas were higher in terraced fields than in the sloped land and decreased with soil deepening; (4) To maintain the sufficient supply of soil nutrients and support the sustainability of agricultural terraces, it is necessary to apply manure to improve soil fertility and accelerate its aggregation in the terraces. For example, an increase in the application of nitrogen fertilizer in terraced fields in Hebei and Gansu provinces, which have a serious deficiency in soil AP, is necessary to get greater amounts of P fertilization. The present study offers a theoretical foundation for the sustainability of terraced ecosystems through efficient crop production, which is the basis for strengthening the ecological security of terraced areas and promoting regional sustainability in those fragile mountains.