1. Distributions of soil phosphorus in China’s densely populated village landscapes.
- Author
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Jiao, Jiaguo, Ellis, Erle C., Yesilonis, Ian, Junxi Wu, Hongqing Wang, Huixin Li, and Linzhang Yang
- Subjects
AGRICULTURAL landscape management ,PHOSPHORUS in agriculture ,LAND use ,EUTROPHICATION control ,SOIL pollution prevention ,SOIL remediation ,SOIL density - Abstract
Village landscapes, which integrate small-scale agriculture with housing, forestry and a host of other land use practices, cover more than 2 × 10
6 km2 across China. Village lands tend to be managed at very fine spatial scales (≤30 m), with managers altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Under these conditions, accumulation of excess phosphorous in soils has become important contributor to eutrophication of surface waters across China’s densely populated village landscapes. The aim of this study was to investigate relationships between fine-scale patterns of agricultural management and soil total phosphorus (STP) within China’s village landscapes. First, China’s village landscapes were divided into five environmentally distinct regions across China. Within each region, a single 100 km2 research site was then selected, and 12 500 × 500 m square landscape sample cells were selected for fine-scale mapping. Soils were sampled within fine-scale landscape features using a regionally weighted landscape sampling design. STP stock across the 0.9 × 106 km2 area of our five village regions was approximately 0.14 Pg (1 Pg = 1015 g), with STP densities ranging from 0.08 kg m−2 in Tropical Hilly Region to 0.22 kg m−2 in North China Plain and Yangtze Plain, with village landscape STP density varying significantly with precipitation and temperature. Outside the Tropical Hilly Region, STP densities also varied significantly with land form, use, and cover. As expected, the highest STP densities were found in agricultural lands and in areas near buildings, while the lowest were in nonproductive lands and forestry lands. As a combined result of these high STP densities and the predominance of agricultural land use, most village STP stock was found in agricultural lands. A surprisingly large portion of village STP stock was associated with built structures and disturbed lands surrounding them (15.0% in North China Plain, 19.3% in Yangtze Plain, 5.9% in Sichuan Hilly Region, 7.8% in Subtropical Hilly Region, 2.7% in Tropical Hilly Region), which had a significant relationship with population density. Our results demonstrated that local patterns of land management and human residence were associated with substantial differences in STP both within and across China’s village landscapes which have increased their potential contribution to P pollution. With the rapid change in land use/land cover in China’s densely populated landscapes, such information is essential for rational planning of future management to reach agricultural sustainability. [ABSTRACT FROM AUTHOR]- Published
- 2010
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