Dry Matter and Minerals in Loblolly Pine Plantation on Four Arkansas Soils

Average contents of N, P, K, Ca, and Na and total above ground dry matter were determined in 19-year-old unthinned loblolly pine (Pinus taeda L.) plantations in southeastern Arkansas. Three stands were sampled on each of four sites: well and poorly drained coastal plain soils and well and poorly drained loessial soils. Total dry weights, determined from 15 felled trees on each of the 12 plots, ranged from 127,000 kg/ha on poorly drained loessial soil to 173,300 kg/ha on poorly drained coastal plain soil. Ranking of sites, in descending order of production of dry matter, P, K, and Na was: coastal plain poorly drained, coastal plain well drained, loess well drained, and loess poorly drained. Quantity of Ca in stemwood and stembark was 36% higher on well than poorly drained soils; P was 30% higher on coastal plain than loess soils. Results permit calculation of nutrient drain in timber harvests. Bark in 19-year-old plantations contained 44, 44, 25, and 50% of total N, P, K, and Ca in the stems

Growth Ring Characteristics, Specific Gravity, and Fiber Length of Rapidly Grown Loblolly Pine

Intensive thinning, understory control, and green pruning of loblolly pine trees growing on a test area near Crossett, Arkansas, have produced trees with a diameter of 18.9 inches at breast heights in 35 years. Large increment borings extracted from experimental trees and control trees were examined for growth patterns and wood properties alternations related to growth rate differences.During some growth periods, radial growth of test trees was almost three times as great as radial growth of control trees. In the outer juvenile wood formed after the first thinning, growth rate differences were greatest between experimental trees. During the last 10 years of the study (mature wood zone), growth rate differences between treated and control trees were not as great, and there were no significant differences in latewood percentage or tracheid length. Specific gravity was not significantly influenced by growth rate differences in any growth zone. This result leads to the conclusion that trees can be rapidly grown without affecting specific gravity

Estimating the Impacts of Storage Dry Matter Losses on Switchgrass Production

This poster estimates dry matter losses as a function of harvest method, storage treatment, and time in storage. We then calculate the cost to store switchgrass bales under alternate harvest method and storage treatment scenarios; and determine the breakeven harvest method and storage treatment as a function of biomass price and time in storage.Biomass, bioenergy crops, function form, sustainable systems, Farm Management, Production Economics, Q10, Q42,

Analysis of Factors Affecting Farmers’ Willingness to Adopt Switchgrass Production

In the United States, biomass is the largest source of renewable energy accounting for over 3 percent of the energy consumed domestically and is currently the only source for liquid, renewable, transportation fuels. Continued development of biomass as a renewable energy source is being driven in large part by the Energy Independence and Security Act of 2007, which mandates that by 2022 at least 36 billion gallons of fuel ethanol be produced, with at least 16 billion gallons being derived from cellulose, hemi-cellulose, or lignin. However, the market for cellulosic biofuels is still under development. As such, little is known about producer response to feedstock prices paid for dedicated energy crops. While there have been some studies done on factors that determine farmers’ willingness to produce switchgrass, these have been very regional in nature. This study will provide information regarding potential switchgrass adoption by agricultural producers in twelve southeastern states. The objectives of this research are 1) to determine the likelihood of farmers growing switchgrass as a biomass feedstock and the acres they would be willing to devote to switchgrass production and 2) to evaluate some of the factors that are likely to influence these decisions, including the price of switchgrass.Switchgrass, Farmer Adoption, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy, Q12, Q16,

VARIABLE RATE NITROGEN APPLICATION ON CORN FIELDS: THE ROLE OF SPATIAL VARIABILITY AND WEATHER

Meta-response functions for corn yields and nitrogen losses were estimated from EPIC-generated data for three soil types and three weather scenarios. These metamodels were used to evaluate variable rate (VRT) versus uniform rate (URT) nitrogen application technologies for alternative weather scenarios and policy option. Except under very dry conditions, returns per acre for VRT were higher than for URT and the economic advantage of VRT increased as realized rainfall decreased from expected average rainfall. Nitrogen losses to the environment from VRT were lower for all situation examined, except on fields with little spatial variability.Corn, environment, meta-response functions, nitrogen restriction, precision farming, site-specific management, spatial variability, weather variability, Crop Production/Industries,

Is Switchgrass Yield Response to Nitrogen Fertilizer Dynamic? Implications for Profitability and Sustainability at the Farm Level

Revised version of the paper submitted 2/11/2010Biomass, Energy Crops, Sequential Inputs, West Tennessee, Crop Production/Industries, Farm Management, Production Economics, Resource /Energy Economics and Policy,

EFFECTS OF RISK ON OPTIMAL NITROGEN FERTILIZATION DATES IN WINTER WHEAT PRODUCTION AS AFFECTED BY DISEASE AND NITROGEN SOURCE

Optimal fertilization dates were found for two nitrogen sources in the presence of two diseases for wheat farmers with different risk preferences. Risk was independent of fertilization date. Ammonium Nitrate and Urea-Ammonium Nitrate did not affect risk differently. Ammonium Nitrate applied on March 9 was optimal regardless of risk preferences.Crop Production/Industries,

Switchgrass Production in Marginal Environments: A Comparative Economic Analysis across Four West Tennessee Landscapes

Switchgrass (Panicum virgatum L.) has been identified as a model feedstock for the emerging biofuels industry. Its selection was based, in part, upon the observation that switchgrass can produce high yields in marginal production environments. This trait may become particularly valuable in coming years, as renewable fuel mandates begin to take effect and concerns over the food-versus-fuel debate increase. Relatively little research information exists about how management practices and production costs vary across different production environments. The objectives of this research were (a) to compare switchgrass yields as influenced by seeding rate and nitrogen fertilization rates in low-, intermediate-, and high-yielding switchgrass production environments, (b) to determine the economically optimal seeding rate and nitrogen fertilization rate for each environment, and (c) to calculate per-ton production costs. Experimental yield data from four locations were utilized for this study. Plots were seeded in 2004 with treatments of 2.5, 5.0, 7.5, 10.0, and 12.5 lbs/acre. Nitrogen was applied in subsequent intervals at 0, 60, 120 and 180 lbs/acre. For an expected stand lifespan of 10 years, production costs ranged from $45 per ton in a well drained level upland environment ideal for the production of row crops to$70 per ton in a marginal, poorly drained flood plain in which the switchgrass stand was slow to establish and which demonstrated lower overall yields.Crop Production/Industries, International Relations/Trade,

EFFECTS OF RISK, DISEASE, AND NITROGEN SOURCE ON OPTIMAL NITROGEN FERTILIZATION RATES IN WINTER WHEAT PRODUCTION

Interactions among nitrogen (N) fertilization rate, N source, and disease severity can affect mean yield and yield variance in conservation tillage wheat production. A Just-Pope model was used to evaluate the effects of N rate, N source, and disease on the spring N-fertilization decision. Ammonium nitrate (AN) was the utility-maximizing N source regardless of risk preferences. The net-return-maximizing AN rate was 92 lb N/acre, providing $0.52/acre higher net returns than the best alternative N source (urea). If a farmer could anticipate a higher than average Take-All infection, the difference in optimal net-returns between AN and urea would increase to$35.11/acre.Crop Production/Industries,