Semester

Spring

Date of Graduation

2021

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Division of Plant and Soil Sciences

Committee Chair

Jeff Skousen

Committee Member

Louis McDonald

Committee Member

Jamie Schuler

Abstract

Soils in the Monongahela National Forest (MNF) are acidic due to sandstone parent material, acid deposition, uptake of base cations by vegetation, and release of organic acids by organic matter (OM) decomposition. Increases in soil acidity have caused declines in forest health and changed species composition and nutrient status. Liming can neutralize soil acidity, but no large-scale liming projects have been done on acid forest soils in the USA. In anticipation of acquiring funding for a proposed liming project in the MNF, in 2007 and 2009 10 sites were selected to sample and analyze soils before lime was applied. In 2018, funds were approved and a total of 284 ha (700 ac) were limed by helicopter in the MNF near Richwood, WV. Liming material particle size varied from small sand to small gravel chips and the liming rate was targeted for 6.7 to 11.2 Mg/ha (3 to 5 tons/ac). These same 10 sampling sites representing Limed and Unlimed areas were then resampled in 2019 (previous sampling dates were simplified to 2009) using the same procedures and analyses.

On Unlimed soils in 2019, pH in the O, A, and B horizons was 4.6, 4.3, and 4.8, respectively. Acidity values averaged 11, 11, and 7 cmol+/kg and aluminum (Al) concentrations were high in these acid soils at 261, 627, and 464 mg/kg in O, A, and B horizons. Average Ca concentrations varied from 7.9, 0.5, and 0.1 cmol+/kg, while average % organic matter (OM) ranged from 58, 14, and 7% in O, A, and B horizons. When comparing Unlimed sites sampled in 2009 and 2019, differences in measured parameters were small. In Limed soils in 2019, pH in the O, A, and B horizons was 5.9, 4.6, and 4.7, a significant rise in the O horizon. Average acidity values were reduced by 73% in O horizons, and less so in A and B horizons. Average Al concentrations were drastically reduced in O and A horizons (261 mg/kg in 2009 to 58 mg/kg in 2019; 627 mg/kg in 2009 vs 325 mg/kg in 2019), with similar values in the B horizon (~475 mg/kg). Average Ca concentrations in 2019 Limed sites were at least three times higher at 27.2, 3.2, and 0.4 cmol+/kg in O, A, and B horizons compared to Unlimed sites. Average concentrations for K, Mg, and P were very similar to Unlimed soils in O, A, and B horizons. Average ECEC values increased slightly in O horizons (33 compared to 22 cmol+/kg) due to liming but were similar in A and B horizons. Average OM values decreased from 58% to 35% in O Horizons, but again, little change in A and B horizons. Based on these first-year results, liming had a significant effect on several properties in O and A horizons. However, lime particles in the O horizon (which were observed during sampling of O horizons) caused these increases in soil pH, Ca, ECEC concentrations, along with decreases in acidity and aluminum. These changes are an artificial effect due to collecting undissolved lime particles during our sampling. As lime dissolves and is integrated into the soil, these parameters will change and more accurately reflect the effect of the liming on the O and A horizons.

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