Soil health assessment in the Yangtze River Delta of China: Method development and application in orchards

Abstract

Soil health is universally acknowledged to be an integrative tool in revealing soil degradation and agro-ecosystem health, and it has been the focus of many national investigations to find a compromise between the increase of human demands in urbanization and the conservation of agricultural soils. Based on the soil survey database of the Yangtze River Delta Region in China, including 66 soil samples collected from 22 representative orchards and 20 soil indicators analyzed for each sample, this study made a preliminary attempt to determine a minimum data set (MDS) of 10 sensitive indicators by factor analysis, to calculate weights and establish scoring function curves respectively, and a localized comprehensive assessment methodology of soil health was successfully developed and applied in orchards with organic, green and conventional management practices in Shanghai, China. The results indicated that, the rankings of soil health index (SHI) were generally organic>green>conventional, and 95% of the orchards were rated as the grades of moderate (40−60) to better (60−80). The SHI in green orchards with different cultivation durations followed the pattern of gradual increase over 5 years. The improvement of soil fertility, soil aggregation structure and soil bio-community were crucial to improve soil health, prevent soil degradation and promote soil sustainability in this region, particularly under the circumstance of encouraging green agriculture development.