Soil Quality and Metabolic Activity Assessment after Fifty-Seven Years of Agricultural Management

• Published in: Soil Science Society of America journal Vol. 77; no. 3; pp. 903 - 913
• Main Authors: Stott, Diane E, Karlen, Douglas L, Cambardella, Cynthia A, Harmel, R. Daren
• Format: Journal Article
• Language: English
• Published: Madison The Soil Science Society of America, Inc 01-05-2013; American Society of Agronomy
• Subjects: Agricultural management; Assessments; continuous cropping; Crop management; Cynodon dactylon; Enzymatic activity; enzyme activity; Enzymes; Glass transition temperature; Herbivores; indigenous species; Litter; long term effects; long term experiments; Management; management systems; Meleagris gallopavo; Mineralization; Nutrient availability; Nutrients; Pasture; pastures; Population; poultry manure; Quality assessment; Ratings; River ecology; Soil (material); Soil conservation; Soil management; soil properties; Soil quality; Soils; Tillage; turkeys; Vertisols; Watershed management; Watersheds; Texas; United States > US
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj2012.0355

Soil quality assessment is a process for understanding long-term effects of soil and crop management. Our objective was to assess those effects on Vertisols in Texas after 57 yr. Five fields were sampled in 2006: a managed native pasture (NP), two pastures that were previously cropped and then seeded to Coastal bermudagrass [Cynodon dactylon (L.) Pers.] for the past 57 (CB) or 31 (CBTL) yr, and two fields that have been continuously cropped (RCTL and RC). The RCTL and CBTL fields have had turkey (Meleagris gallopavo) litter amendments. The soil quality assessment was conducted using the Soil Management Assessment Framework, using 10 measured soil attributes. There were significant differences in the overall soil quality ratings, which ranged from 75 to 94% of optimum in the following order: CBTL > NP = RCTL > CB ≈ RC. When separated into index values by sector, physical soil quality ranged from 66 to 84% of optimum, with NP ≈ CBTL > RCTL ≈ CB ≈ RC. All management systems had nearly the same chemical quality rating (94–95%). Focusing only on nutrient attributes, RC, RCTL, and CBTL had significantly higher ratings than the other treatments (99%), with NP being significantly lower (47%). Biological and biochemical soil quality ratings ranged from 44 to 81%, with the NP performing significantly better (81%) and RC significantly lower (44%) than the other treatments. The CBTL treatment exhibited the greatest levels of enzymatic activity and RC the lowest. There were several significant correlations between soil enzymatic activities and other soil parameters. Overall, turkey litter amendments improved soil quality, demonstrating that carefully managed bermudagrass pastures can be more productive than managed native grass pastures, primarily because of improved plant nutrient availability.