Soil quality indices based on long-term conservation cropping systems management

Authors: AMORIM, HELEN - University Of Arkansas; Ashworth, Amanda; Wienhold, Brian; SAVIN, MARY - University Of Arkansas; ALLEN, FRED - University Of Tennessee; SAXTON, ARNOLD - University Of Tennessee; Owens, Phillip; CURI, NILTON - Universidade Federal De Lavras

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2020
Publication Date: 4/11/2020
Citation: Amorim, H.C., Ashworth, A.J., Wienhold, B.J., Savin, M.C., Allen, F.L., Saxton, A.M., Owens, P.R., Curi, N. 2020. Soil quality indices based on long-term conservation cropping systems management. Agrosystems, Geosciences & Environment. 3(1). Article e20036. https://doi.org/10.1002/agg2.20036.
DOI: https://doi.org/10.1002/agg2.20036

Interpretive Summary: Improved soil quality is essential to the sustainability of long-term agricultural activities. Best management practices, e.g., crop rotations, cover crops, and applications of animal manures are deemed to be beneficial to the overall soil quality; however, landowners still need an evaluation tool to assess the extent of these effects long-term. Researchers evaluated soil quality in a 15-year no-tillage cropping system, including rotations of cotton, corn, and soybean, with cover crops and poultry litter. For that, they integrated multiple soil properties into soil quality indices through a soil quality framework (SMAF). They also investigated the relationship between soil quality and crop yields. Rotations including corn had the greatest soil quality. Poultry litter applications led to phosphorus excess on soil surface, reducing soil quality in this soil layer. In sub-surface soil layers, poultry litter applications contributed to increased soil fertility and, therefore, improved soil quality. Sub-surface soil quality and cotton yields presented a positive relationship, indicating that improved soil quality contributed to increased cotton yields. Therefore, the applied framework was useful to quantify soil quality in long-term conservation systems and may be helpful for decision-making processes regarding the adoption of best management practices and nutrient management strategies.

Technical Abstract: The Soil Management Assessment Framework (SMAF) may provide insight into how conservation practices affect soil quality (SQ) regionally. Therefore, we aimed to quantify SQ in a long-term (15-years) cover crop, crop rotation, and poultry litter experiment under no-tillage by using SMAF. Main effects were cropping rotations of soybean (Glycine max L.), corn (Zea mays L.), and cotton [Glycine max (L.) Merr.]. Split-block bio-cover treatments consisted of winter wheat (Triticum aestivum L.), Austrian winter pea (Pisum sativum L. sativum var. arvense), hairy vetch (Vicia villosa Roth), poultry litter, and a fallow control. Seven SQ indicators including soil pH, total organic C (TOC), bulk density (BD), soil extractable P and K, electrical conductivity (EC), and sodium adsorption ration (SAR) were scored using SMAF algorithms and investigated individually and as an overall soil quality index (SQI). Simple linear regressions were performed between SQI and crop yields. Differences (p<0.05) in SQI were found among rotations and between soil depth × bio-cover. Corn based rotations had the greatest SQI. Poultry litter had the overall greatest TOC, pH, K and BD scores, with the lowest SQI at the 0-15 cm depth and the highest SQI at the 15-30 cm depth. Reductions in SQI were linked to greater P scores. A positive regression was found between 15-30 cm soil depth SQI and cotton yield (R2= 0.48; p<0.05; n=10). Overall, SMAF can address the effects of long-term conservation practices on soil quality and can be used to develop best management practices and nutrient management strategies.