[Soft-ridged bench terrace design in hilly loess region].
Reconfiguration of hillside field into terrace is regarded as one of the key techniques for water and soil conservation in mountainous regions. On slopes exceeding 30 degrees, the traditional techniques of terracing are difficult to apply as risers (i.e., backslopes), and if not reinforced, are so abrupt and easy to collapse under gravity alone, thus damaging the terrace. To improve the reconfiguration of hillside field into terrace, holistic techniques of soft-ridged bench terrace engineering, including revegetation, with trees and planting grasses on riser slopes, were tested between 1997 and 2001 in Xiabiangou watershed of Yan' an, Shaanxi Province. A "working with Nature" engineering approach, riser slopes of 45 degrees, similar to the pre-existing slope of 35 degrees, was employed to radically reduce gravity-erosion. Based on the concepts of biodiversity and the principles of landscape ecology, terrace benches, bunds, and risers were planted with trees, shrubs, forage grasses, and crops, serving to generate a diverse array of plants, a semi-forested area, and to stabilize terrace bunds. Soft-ridged bench terrace made it possible to significantly reduce hazards arising from gravity erosion, and reduce the costs of individual bench construction and maintenance by 24.9% and 55.5% of the costs under traditional techniques, respectively. Such a construction allowed an enrichment and concentration of nutrients in the soils of terrace bunds, providing an ideal environment for a range of plants to grow and develop. The terrace riser could be planted with drought-resistant plants ranging from forage grasses to trees, and this riser vegetation would turn the exposed bunds and risers existing under traditional techniques into plant-covered belts, great green ribbons decorating farmland and contributing to the enhancement of the landscape biology.
Cao
Shixiong
S
Regional Agriculture Research and Development Centre, College of Agronomy and Biotechnology, China Agriculture University, Beijing 100094, China. shixiongcao@126.com
Chen
Li
L
Gao
Wangsheng
W
D000383:Agriculture / Q000379:methods*; D044822:Biodiversity; D018556:Crops, Agricultural / Q000254:growth & development*; D004463:Ecology; D017753:Ecosystem; D006109:Poaceae / Q000254:growth & development*; D012987:Soil / Q000032:analysis; D014197:Trees / Q000254:growth & development*
D012987:Soil