Kenneth W Farrish

Nutrient dynamics and tree growth of silvopastoral systems: impact of poultry litter.

Fertilizing pastures with poultry litter has led to an increased incidence of nutrient-saturated soils, particularly on highly fertilized, well drained soils. Applying litter to silvopastures, in which loblolly pine (Pinus taeda L.) and bahiagrass (Paspalum notatum) production are integrated, may be an ecologically desirable alternative for upland soils of the southeastern USA. Integrating subterranean clover (Trifolium subterraneum) into silvopastures may enhance nutrient retention potential. This study evaluated soil nutrient dynamics, loblolly pine nutrient composition, and loblolly pine growth of an annually fertilized silvopasture on a well drained soil in response to fertilizer type, litter application rate, and subterranean clover. Three fertilizer treatments were applied annually for 4 yr: (i) 5 Mg litter ha(-1) (5LIT), (ii) 10 Mg litter ha(-1) (10LIT), and (iii) an inorganic N, P, K pasture blend (INO). Litter stimulated loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff potential threshold ranges. However, both litter treatments led to accumulation of several nutrients (notably P) in upper soil horizons relative to INO and unfertilized control treatments. The 10LIT treatment may have increased N and P leaching potential. Subterranean clover kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly pine. Thus, although these silvopasture systems had a relatively high capacity for nutrient use and retention at this site, litter should be applied less frequently than in this study to reduce environmental risks.

Fuel loading prediction models developed from aerial photographs of the Sangre de Cristo and Jemez mountains of New Mexico, USA

Fuel load prediction equations that made use of aerial photographs were developed for Mixed Conifer, Ponderosa Pine (Pinus ponderosa Dougl. ex Laws.) and Pinyon–Juniper (Pinus edulis Engelm.)–(Juniperus monosperma Engelm.) cover types from one-time measurements made in the Santa Fe watershed (SFWS) located in the Sangre de Cristo Mountains of northern New Mexico, and at Los Alamos National Laboratory (LANL) located in the Jemez Mountains of northern New Mexico. The results of the watershed data set were favorable and exhibited a high degree of relative accuracy. The results from the LANL data set did not share the same degree of accuracy, but rather exhibited a high degree of error. Use of these or similar prediction equations may be limited to certain regions and community types that exhibit similar regional characteristics such as terrain, soil, and weather conditions. Applied use of the prediction equations required less time than traditional fuel sampling performed onsite, but suffered from a loss of accuracy. It is strongly suggested that additional study of this method be undertaken to generate more accurate and reliable equations. Hopefully, more accurate equations may augment existing fuel sampling techniques and be put to practical use for fire planning purposes.

Denitrification and soil characteristics of wetlands created on two mine soils in east Texas, USA

Recovery of wetland function is the primary goal of wetland creation. This study was undertaken to quantify denitrification and soil characteristics of wetlands created after lignite mine reclamation in east Texas, USA. Surface-soil denitrification rate and capacity were quantified using an acetylene (C2H2) inhibition/gas chromatography method in created wetlands of two age classes (4–8 years, and 10 years) on two mine soil types. Soil texture, pH, total-N, ammonium (NH4+), nitrate (NO3−), cation exchange capacity (CEC), total-P, and organic matter (OM) content were determined. Soil characteristics varied by soil type and by age. Denitrification rate ranged from less than 1 to 105 kg N ha−1yr−1, was highly variable, but did not differ among created wetlands. Denitrification rate was similar between natural and created wetlands. Denitrification capacity, denitrification rate when nitrate is in excess, ranged from 23 to 302 kg N ha−1yr−1 and varied by soil type. Denitrification appears to function as well in wetlands created on mine soil as in natural wetlands, but may be limited by soil characteristics.

Quantifying Land Cover Change Due to Petroleum Exploration and Production in the Haynesville Shale Region Using Remote Sensing

The Haynesville Shale lies under areas of Louisiana and Texas and is one of the largest gas plays in the U.S. Encompassing approximately 2.9 million ha, this area has been subject to intensive exploration for oil and gas, while over 90% of it has traditionally been used for forestry and agriculture. In order to detect the landscape change in the past few decades, Landsat Thematic Mapper (TM) imagery for six years (1984, 1989, 1994, 2000, 2006, and 2011) was acquired. Unsupervised classifications were performed to classify each image into four cover types: agriculture, forest, well pad, and other. Change detection was then conducted between two classified maps of different years for a time series analysis. Finally, landscape metrics were calculated to assess landscape fragmentation. The overall classification accuracy ranged from 84.7% to 88.3%. The total amount of land cover change from 1984 to 2011 was 24%, with 0.9% of agricultural land and 0.4% of forest land changed to well pads. The results of Patch-Per-Unit area (PPU) index indicated that the well pad class was highly fragmented, while agriculture (4.4-8.6 per sq km) consistently showed a higher magnitude of fragmentation than forest (0.8-1.4 per sq km).

Short communication: A GIS tool for plant spatial pattern analysis

A GIS program, ArcPlantPattern, was developed with Visual Basic .NET and ArcObjects as an ArcGIS extension to assist the investigation of plant distribution patterns (species composition as occurrence probability and spacing as distances among species) and to design planting plan maps for patch planting. ArcPlantPattern is the first software of its kind. It can be used for arid and semiarid lands reclamation, burned area rehabilitation, or designing landscapes with a required plant community distribution. ArcPlantPattern may also be applicable to other spatial point pattern analysis, such as geology, geography and wildlife habitat.

Understory Vegetative Diversity of Post-Thinned Pine Plantations Treated with Fertilizer, Fire and Herbicide in East Texas

This study assessed biodiversity in the understory of two pine plantations where different management tools (fertilizer, prescribed burning, and herbicide application) were utilized. During three growing seasons, species, percent cover, and number of individuals, and physical characteristics were recorded. Responses to treatment were examined based on comparison of species richness, evenness, diversity, and importance. Two years after treatment, fertilized plots showed a decline in species richness, evenness, and diversity. Prescribed burning and herbicide treatments increased species richness but decreased species evenness, resulting in no change in diversity index. Herbicide treatment reduced the importance of dominant shrubs and increased the importance of disturbance-adapted species.

Plant Communities Associated with Pinus Ponderosa Forests in the Sky Islands of the Davis Mountains, Texas1

Abstract Species composition of Pinus ponderosa P.&C. Lawson var. scopulorum Engelm. forests in the sky islands of the Davis Mountains was evaluated and classified using ordination and classification techniques. Twelve study sites were established within Pinus ponderosa forests in the summers of 2002 and 2003. Overstory (tree) and understory (shrub and herbaceous) vegetation strata were sampled. Thirteen associations were recognized by combining four overstory groups and eight understory groups. The associations reflected a wide range of ecological conditions with Juniperus deppeana associations occupying dry sites and Pinus ponderosa associations occupying wetter sites. The major environmental factors responsible for the differences in vegetation of these forests were altitude, slope position, slope inclination, and soil moisture.

Fertilization response in a natural bottomland hardwood stand in north-central Louisiana

The effect of nitrogen and phosphorus fertilization on growth of a natural bottomland hardwood stand in north-central Louisiana was evaluated. A typical mixed stand of pole-sized and small saw-timber bottomland hardwoods with about 23.7 m 2 ha -1 of basal area was used in the study. Soils were Guyton silt loam (Fine-silty, siliceous, thermic Typic Glossaqualf). Three fertilizer treatments plus a control were replicated three times on 0.1 ha plots. The treatments consisted of nitrogen (168 kg ha -1 ) as ammonium nitrate, phosphorus (56 kg ha -1 ) as triple super phosphate, and N+P. Trees greater than 10 cm at dbh were measured for diameter before fertilization and remeasured after one and two growing seasons. Diameter increment served as the response variable. Results showed a statistically significant (p<0.05) increase (70 pct greater than the control) in diameter growth for the 2 year total increment on the N+P treatment with all species combined. While the small sample size and relatively high amount of variability resulted in no further statistical significance among the treatments, the data did reveal trends that need further investigation. Sweetgum (Liquidambar styraciflua L.) responded to N alone, while the oaks (Quercus), especially the white oaks, responded to P alone. The oaks also responded to N+P, while no similar response was seen from sweetgum for that treatment.

Mapping oilfield brine-contaminated sites with mid-spatial resolution remotely sensed data

An environmental problem associated with petroleum production is the disposal of brine, which is produced during petroleum exploration and production. Oilfield brine, if improperly handled, transported, and disposed of, can pose a serious threat to surrounding water resources, arable lands, and plant communities. Although field checking of known oilfield brine-contaminated sites is relatively straightforward, the ability to detect and inventory brine-contaminated sites over remote and expansive areas can be time consuming and expensive. A more efficient and cost-effective method is needed to delineate brine-contaminated sites accurately. The chief aim of this project was to test a remote sensing method to map accurately and quantify contaminated oilfield brine sites in west Texas. Landsat ETM+ data of west Texas were obtained, de-correlated with a three-band dataset using principal component analysis (PCA), and classified into brine and non-brine locations using supervised classification with a maximum likelihood classification algorithm. Results show the Landsat ETM+ data is effective in quantifying previously unknown oilfield brine-contaminated areas larger than 2 acres in west Texas. Overall map accuracy was 91.67%, user’s accuracy was 87.50% for brine-contaminated sites, and the kappa statistic was 82.35%. Once contaminated brine sites have been mapped via remote sensing, the spatial location and quantity of the sites can make land reclamation and restoration decisions more timely and cost-effectively compared to traditional ground surveys.

Vegetative Community Development Over 30 Years within Pine Plantations on Reclaimed Mine Land in East

Reclamation of surface mines to plantation forests is a management option that reestablishes both economic and ecological functions after mining. This study investigated vegetative community characteristics (composition, richness, importance) over time in loblolly pine (Pinus taeda L.) plantations established over a thirty-year period on reclaimed lignite coal surface mine land in East Texas, United States. The open landscape of newly planted loblolly pine plantations on reclaimed mine land was amenable to shade-intolerant herbaceous and grass species but, when the canopy closed, favored woody species (trees, shrubs, vines) within two decades after stand establishment. Given that these plantations were established on sites generally described as dry to mesic uplands, species composition was generally congruent with East Texas ecology. Community composition, species richness and species importance were discussed, and loblolly pine growth data and vegetative community characteristics of unmined loblolly pine plantation sites in East Texas were compared to reclaimed sites. Surface mined lands reclaimed to plantation forests are ideal locations to conduct further research on how biodiversity and other ecosystems services can be improved while maintaining intended economic and ecological purposes.