Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2002
Publication Date: 1/1/2002
Citation: Huang, X., Skidmore, E.L., Tibke, G.L. 2002. Soil quality of two Kansas soils as influenced by Conservation Reserve Program (CRP). Journal of Soil and Water Conservation. 57:344-350. Interpretive Summary: Maintaining soil quality is essential for sustained agricultural production and environmental quality. Comparing soil chemical and physical properties between 10 years grass-planting Conservation Reserve Program land and continuously cropped land provided an opportunity to evaluate soil quality during land-management transition. The benefits resulting from CRP included reducing soil acidification, alleviating compaction, and reducing topsoil susceptibility to erosion. Total C mass significantly increased at the surface layer (0 to 5 cm) in CRP compared with continuous cropping. Increasing and maintaining higher soil carbon levels might require more than 10 years in grass status, which is the current standard in CRP contracts. When CRP was taken out to production under a conventional tillage system, total C and aggregate stability gradually decreased. This suggested that appropriate land-management practices are needed to extend residual benefit from CRP on soil quality.
Technical Abstract: Achieving and maintaining a good soil quality is essential for sustaining agricultural production in an economically viable and environmentally safe manner. The transition of land management provides an opportunity to measure soil-quality indicators to quantify the effects of those management practices. This study compared soil chemical and physical properties after 10 years of grass on Conservation Reserve Program (CRP) land with those in continuously cropped land (CCL). The sample sites, located in central Kansas, have two mapping units, Harney silt loam (fine, montmorillonitic, mesic Typic Arigiustolls) and Naron fine sandy loam (fine-loamy, mixed, thermic Udic Argiustolls). Soil samples were collected at two depth increments, 0 to 5 cm and 5 to 10 cm. Soil-quality indicators measured were soil acidity (pH), exchangeable cations, nutrients, total carbon, structure, and aggregation. Soil pH was significantly lower in CCL than in CRP. Soil total C and N in the surface layer (0 to 5 cm) was much greater than in the deeper layer (5 to 10 cm) in the CRP site. The mass of total carbon on Naron soil was significantly higher for 0 to 5 cm and lower for 5 to 10 cm depth in CRP land than in CCL. However, the mass of total carbon of Harney soil was significantly higher in no-tilled CCL than in CRP. Bulk density significantly increased in CCL. Based on dry and wet aggregate stability analysis, the results indicated that CRP land had a greater resistance to erosion by both water and wind than CCL. The improvements in soil quality resulting from CRP included reducing soil acidification, alleviating compaction, and reducing topsoil susceptibility to erosion. However, when CRP was taken out for crop production with conventional tillage, total carbon in the surface layer (0 to 5 cm) and aggregate stability gradually decreased. This suggested that appropriate land management practices are needed to extend residual benefit from CRP on soil quality.