Semester

Spring

Date of Graduation

2008

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Horticulture

Committee Chair

Louis McDonald

Abstract

The study was conducted to improve lime recommendations as well as to design better management practices for acidic grasslands of Appalachian region. These goals were achieved by two experiments. In the first experiment, the accuracy of lime predictions by quick tests were improved by accounting soil order and develop equation based lime correlations for acidic pasture soils of West Virginia. In order to achieve this objective, 26 surface soil samples (0--7.5 cm) from three most important soil orders for the state (Alfisols, Inceptisols, Ultisols) from each of the Major Land Resource Areas (MLRAs) in West Virginia with large proportions of pasture land were collected in cooperation with state soil scientists. Standard procedures for the determination of lime requirements by the Mehlich Buffer (MB), Adams-Evans Buffer (AEB) and Shoemaker-McLean-Pratt Single Buffer (SMPB) methods were used. Statistically significant improvements in lime recommendations for target pH 6.5 and 5.5 were achieved by accounting for soil order. Mehlich single buffer recommendations were better for Alfisols and Ultisols than for Entisols to achieve pH 6.5. Lime correlations were developed for all three chemical buffers by multiple regression where the independent variables were target pH and soil-buffer pH. The Adam-Evans buffer predicted lime rates better for target pH 5.5. Equation-based lime correlations were also developed for all three chemical buffers by multiple regressions where the independent variables are target pH and soil-buffer pH. The second experiment was conducted to quantify the critical growth factors such as water potential, pH, nitrogen, and phosphorus and their interactions to deduce a comprehensive prescription of site-specific management techniques to forage production in acidified hill land pastures of West Virginia. In order to achieve this objective, a pot experiment was set up with two water potentials, five pH levels, five N and P fertilizer rates were imposed on bluegrass (sole) and bluegrass + white clover mixture. The estimation of overall effects of these four factors showed that levels of water potential, pH, N fertilizer doses as well as their interactions significantly affected the bluegrass (sole) production (p<0.05). In case of bluegrass and white clover mixture cropping system, all four factors (water potential, pH, N and P levels) and their interactions exhibited significant influence on dry matter yield as well as nutrient concentration in shoot tissue. Nutrient concentrations also showed a synergistic relationship among each other as well as with dry matter yield in both bluegrass and bluegrass + white clover mixture. Response yield function was determined using significant factors and their interactions for blue grass (sole) and blue grass and white clover mixture.

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