Soil Quality Indicators for the North Appalachian Experimentalwatersheds in Coshocton Ohio

Identification of soil quality indicators (SQI) is important to sustainable management of natural resources. The objective of this project was to develop a technique for identifying SQIs for agricultural land use. Soil structure, water retention and transmission properties, and pH and electrical conductivity (EC) were measured and related to agronomic productivity for five land use and soil management treatments at the experimental farm of the North Appalachian Experimental Watersheds, Coshocton, Ohio. The five treatments were no-till corn without manure (NTWM), no-till corn with manure (NTM), no-till corn (Zea mays)-soybean (Glycine max) rotation (NTCSR), conventional tillage corn (CT), and meadow (M). Soil properties measured were bulk density (ρb), drainable porosity (fa), available water capacity (AWC), steady state infiltration rate (ic), saturated hydraulic conductivity (Ks), soil organic carbon (SOC) concentration, water stable aggregation (WSA), mean weight diameter of aggregates (MWD), and texture. The correlation analysis on the measured soil attributes reduced the number of key variables from 17 to 11. A rating index on a 1 to 5 scale was obtained for each of the key soil properties. The linear regression analysis was first performed with key soil attributes as independent variables and biomass or grain yields as dependent variables, with the rating factor later assigned to each measured key soil attribute. The multiple regression analysis showed that SOC and WSA explained more than 35% of variability in biomass and 33% in grain yields, respectively, and were identified as the major SQIs. Other important SQIs were ρb, AWC, MWD, pH, and EC. The cumulative sustainability ratings (CR) for each land use showed that NTM was the most sustainable soil management treatment (CR = 20) and CT the least sustainable (CR = 30). The CR was also correlated significantly with grain yield (R2 = 0.31, P < 0.002). The CR for different land uses suggests that soil management with NTM is the most sustainable and CT the least.