Response of soil OC, N and P to land-use change and erosion in the black soil region of the Northeast China

• Published in: Agriculture, ecosystems & environment Vol. 302; p. 107081
• Main Authors: Li, Haiqiang, Zhu, Hansong, Qiu, Liping, Wei, Xiaorong, Liu, Baoyuan, Shao, Mingan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2020
• Subjects: Conversion of forest to cropland; Organic carbon; Soil erosion intensity; Soil nutrients; Soil structure; Organic carbon; Soil nutrients; Soil structure; Conversion of forest to cropland; Soil erosion intensity
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2020.107081

•Soil erosion significantly decreased soil structural stability and OC, N and P.•Most of the effects of erosion were enhanced with the intensity of erosion.•Effects of the conversion of forest to cropland on OC and N were greater than effects of light erosion.•Effects of the conversion of forest to cropland were smaller than effects of moderate and heavy erosion.•Deposition increased soil OC, N and P due to burial. Converting forest to cropland generally results in the deterioration of soil structure and the loss of soil organic carbon (OC) and nutrients, while agricultural soil erosion accelerates such degradation. To understand how soil structure, OC and nutrients respond to the conversion of forest to cropland and agricultural erosion, we compared soils between forest and cropland that was established in forest 60 years ago, and among croplands suffering various intensities of erosion (from non-erosion to heavy erosion). Soil samples were collected from 0−70 cm depth for the measurement of bulk density, OC, nitrogen (N) and phosphorous (P). The soil structural stability index was calculated. We showed that the conversion of forest to cropland decreased the soil structural stability and the concentrations and stocks of OC and N in the top 30 cm soils but had no effects on P. Soil erosion significantly increased soil bulk density but decreased soil structural stability and the concentrations and stocks of OC, N and P along the 0−70 cm soil profile. Additionally, most of the effects of erosion were enhanced with the intensity of erosion. However, OC, N and P were significantly higher at the deposition sites than at the either non-erosion or eroding sites in 15−70 cm soils, probably due to the burial of OC, N and P in deep soils of deposition sites. Moreover, the effects of converting forest to cropland on OC and N were greater than the effects of light erosion but smaller than the effects of moderate and heavy erosion in the top 30 cm soils. Therefore, erosion intensity should be carefully considered when disentangling the effects of converting natural ecosystem to managed ecosystem and soil erosion.