Douglas G. Boyer

Chicken manure biochar as liming and nutrient source for acid Appalachian soil.

Acid weathered soils often require lime and fertilizer application to overcome nutrient deficiencies and metal toxicity to increase soil productivity. Slow-pyrolysis chicken manure biochars, produced at 350 and 700°C with and without subsequent steam activation, were evaluated in an incubation study as soil amendments for a representative acid and highly weathered soil from Appalachia. Biochars were mixed at 5, 10, 20, and 40 g kg into a Gilpin soil (fine-loamy, mixed, active, mesic Typic Hapludult) and incubated in a climate-controlled chamber for 8 wk, along with a nonamended control and soil amended with agronomic dolomitic lime (AgLime). At the end of the incubation, soil pH, nutrient availability (by Mehlich-3 and ammonium bicarbonate diethylene triamine pentaacetic acid [AB-DTPA] extractions), and soil leachate composition were evaluated. Biochar effect on soil pH was process- and rate-dependent. Biochar increased soil pH from 4.8 to 6.6 at the high application rate (40 g kg), but was less effective than AgLime. Biochar produced at 350°C without activation had the least effect on soil pH. Biochar increased soil Mehlich-3 extractable micro- and macronutrients. On the basis of unit element applied, increase in pyrolysis temperature and biochar activation decreased availability of K, P, and S compared to nonactivated biochar produced at 350°C. Activated biochars reduced AB-DTPA extractable Al and Cd more than AgLime. Biochar did not increase NO in leachate, but increased dissolved organic carbon, total N and P, PO, SO, and K at high application rate (40 g kg). Risks of elevated levels of dissolved P may limit chicken manure biochar application rate. Applied at low rates, these biochars provide added nutritional value with low adverse impact on leachate composition.

Soil spatial variability relationships in a steeply sloping acid soil environment

Management of pastures in steep terrain can be expensive in terms of time, chemical inputs, and equipment requirements. Management of those portions of pasture that will yield the most for minimum inputs requires a knowledge of the spatial patterns of the soil and atmospheric environments. A steep 2.4-ha unimproved pasture in southern West Virginia was studied to determine the spatial dependency of aboveground biomass production on soil characteristics. The predominant soil of the study site was Gilpin silt loam (fine-loamy, mixed, mesic, Typic Hapludults) with an average A-horizon pH (1:1 H 2 O) of 4.5 (range 3.8 to 6.1). The study site was broadcast seeded with red fescue (Festuca rubra L.) in 1982, making it the major plant species. However, several other plant species, including orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), white clover (Trifolium repens L.), broomsedge (Adropogon virginicus L.), velvet grass (Holcus lanatus L.), yarrow (Achillea millefolium L.), and wild strawberry (Fragaria virginiana L.), and others were common. Transects were laid out up and down the north-facing, south-facing, and west-facing slopes and one transect was established on the contour for measurement of soil characteristics at a 1-m spacing. Plant aboveground biomass was measured at a 2-m spacing on three of the slope transects and on the contour transect. Although correlation analysis failed to find many statistically significant relationships between biomass production and soil characteristics, cross-semivariogram analyses of biomass production and surface soil pH and extractable Al, Mn, and P indicated that a strong spatial dependency exists. Those relationships were used for identifying homogeneous areas of biomass production and associated soil characteristics by ordinary kriging.

Effect of soil temperature on evapotranspiration by C3 and C4 grasses

Abstract The relationship between evapotranspiration (ET) and soil temperature was studied for two C3 and two C4 grasses grown in 20-cm diameter plastic containers and managed to provide 10-cm high dense leaf canopies. Soil temperature treatments were 13, 21, and 29°C while leaf canopies were exposed to ambient climate conditions. Except for one C3 grass at the highest soil temperature, all grasses had higher ET as soil temperature increased. The C4 grasses averaged 30% lower ET than the C3 grasses at 13°C soil temperature, but the relative difference decreased to only 10% lower than the nonstressed C3 grass at 29°C soil temperature. Canopy temperature showed no statistical relation to soil temperature. Soil heat flux differences appeared to have a greater influence on ET than plant resistance changes due to the influence of soil temperature on roots.

Surface Limestone Application Increases Ammonia Volatilization from Goat Urine in Abandoned Pastures

ABSTRACT Concentrated application of nitrogen (N) resulting from urine deposition by livestock can cause nitrate pollution of ground water. Use of goats (Capra hircus) at high stocking densities to clear unwanted shrubs from abandoned pasture during renovation increases the probability of multiple depositions of urine. We hypothesized that applying limestone early in the pasture restoration process would favor ammonia (NH3) volatilization. This would increase the area over which N was distributed and reduce the potential for localized nitrate pollution, although atmospheric NH3 loading would be increased. To study the effect of surface limestone application on NH3 generation, we collected 32 soil profile columns with intact vegetation from an abandoned pasture in southern WV. Urine was applied 18 weeks after surface application of 6720 kg/ha (6000 lb/ac) limestone. Columns received one, two, or three applications of 100 mL goat urine, adding a total of 9.8, 31.7, and 66.4 g/m2 N, respectively. The amount of NH3 increased markedly with increased urine application. Ammonia production decreased exponentially with time after each addition. Overall, limed columns generated 132% more NH3 than unlimed columns. Dry matter production was highest in the treatment receiving two urine applications and lowest in the control receiving no urine. Three urine applications damaged plants; this scorching was correlated with amount of NH3 generated. With time, plant cover in damaged treatments recuperated, with broadleaf plants tending to replace grass. Surface limestone application increased the amount of urine N transformed to NH3 gas, especially where there were multiple urine deposits.

Resistance to water loss from warm and cool-season forage canopies in a growth chamber

Abstract Data are presented from a growth chamber study which indicate that there is a difference in the internal plant resistance of warm and cool-season forages to water loss. The resistance of warm-season species was higher and resulted in lower evapotranspiration and warmer canopy temperatures at any given vapor pressure deficit. While species within each photosynthetic group shared a similar non-water-stressed baseline, between groups there was a substantial difference.

Bellani evaporation variation in Hill-land pasture

Abstract In the Appalachian region, pasture production is frequently limited by water availability, a parameter strongly influenced by microclimate variability. This study was conducted to determine the magnitude of potential evaporation variability across a hilly pasture on a seasonal basis. A steep pasture watershed was instrumented at 32 sites with black and white Bellani plate evaporimeters. Evaporation was measured during the summers of 1985, 1986 and 1987. Average potential evaporation, assessed by readings from black plate evaporimeters, ranged from 4.5 to 6.1 mm day −1 averaged over the frost-free period, June–September. Over the same period and across the same area, solar radiation was estimated to vary from 11.9 to 16.9 MJ m −2 , and wind from 50 to 131 km day −1 . These substantial microclimate differences suggest the importance of developing management practices suited to specific sites within hilly pastures.

Use of Bellani plate evaporimeters for estimation of pet

Abstract There is a need to understand better water budgets in hilly terrain and the potential evapotranspiration (PET) component as related to topography. Black and white Bellani plate evaporimeters were evaluated for suitability as a tool for obtaining weekly estimates of PET in remote areas with steep slopes. Polypropylene check valves were substituted for the Livingstone-Thone check valves and were superior for restricting water uptake during periods of extended rainfall. Assemblies were mounted in 500-ml Erlenmeyer flasks with screw-top closures which provided an adequate reservoir for weekly measurement and could be capped for transport to the laboratory for weighing. Black plate evaporation was more highly correlated with climate parameters than white plate evaporation, or USWB class A pan evaporation. Bellani plate evaporation was most highly correlated with an advective term calculated by multiplying the average vapor pressure deficit at 15.00 h by daily wind. Solar radiation was slightly less correlated to evaporation than the advection term. The two terms together gave a very good prediction of weekly evaporation. Black plate evaporimeters appear to be useful tools for estimating PET as a function of topography where rough terrain prohibits the use of USWB class A pans or lysimeters.

Soil spatial variability and steep pasture management considerations in an acid soil environment

Management of pastures in steep terrain can be expensive in both time and equipment requirements. Management of those portions of pasture that will yield the most for minimum inputs requires a knowledge of the spatial patterns of the soil and atmospheric environments. A steep 2.4 ha unimproved pasture in southern West Virginia was studied to determine the spatial dependency of aboveground biomass production on soil characteristics. The predominant soil on the study site was Gilpin silt loam (fine-loamy, mixed mesic, Typic Hapludults) with an average A-horizon pH (1:1H2O) of 4.6 (range 3.8 to 6.1). Three transects were laid out up and down the slope and one transect on the contour for measurement of soil characteristics at a one meter spacing. Plant aboveground biomass was measured at a two meter spacing on three of the slope transects and the contour transect. Although correlation analysis failed to find any strong relationships between biomass production and soil characteristics, cross-semivariogram analyses of biomass production and surface soil pH and extractable Al, Mn, and P indicated that a strong spatial dependency existed. Those relationships were used for identifying homogeneous areas of biomass production and associated soil characteristics by ordinary kriging.

Sustainable Turkey Litter Amendments for Mixed Swards Grazed by Sheep in Appalachia: Nitrate Leaching

ABSTRACT Increased poultry production in the Appalachian Region provides a readily available nutrient source and a means to improve soil quality. As with any applied source of nutrients, surface and ground water quality can be compromised if nutrient inputs exceed plant nutrient requirements. Understanding nutrient dynamics in hill-land pasture enables us to develop management practices that minimize detrimental effects on water quality, and stabilize and improve the productive capacity of highly eroded soil. The objective of this research was to assess nitrate leaching under mixed swards of orchardgrass (Dactylis glomerata), white clover (Trifolium repens), and chicory (Cichorum intybus) receiving various loadings of composted turkey litter and grazed by sheep (Ovis aries). Treatments were applied in the early spring of 1997, 1999, and 2001 and consisted of P and K only; N, P and K; 3 Mg ha−1 composted turkey litter; and 6 Mg ha−1 composted turkey litter. Indications were that any of the treatments supplied adequate herbage to sustain rotational stocking of growing lambs at 50 lambs per hectare, but NO3-N leaching occurred at the litter application rate of 6 Mg ha−1. Nitrate leaching also occurred when no additional N was applied as a result of an increased ratio of white clover in the sward. When chicory is included in the sward composition, rates of composted turkey litter application greater than 3 Mg ha−1 cannot be recommended from a NO3-N leaching perspective.