Phillip N. Johnson

Variability of Cotton Yield and Quality

Precision agriculture technologies offer an opportunity to vary production inputs within a field. Variable rate application offers the potential to increase production efficiency and minimize potential adverse environmental effects of agricultural chemicals. As an initial step in the development of precision agriculture technologies for cotton, studies are needed to document variability of cotton. The primary objective of this study was to document variability of yield and quality of irrigated cotton within and across three growing seasons. This study was conducted on a 5.3 ha irrigated field located at the Erskine Research Farm at Texas Tech University, Lubbock, TX. The crop was grown under a conventional tillage system with a 1.0 m row spacing. With the exception of sample collection, the field was managed traditionally with respect to production inputs. A grid system (57 points) was established on 30.5 m (approximately 0.1 ha) intervals. Production of fruiting sites, fruit retention, lint yield, fiber length, strength, micronaire, and gross revenue were estimated for each grid point. Soil chemical and physical properties were also determined for each grid point. Highest variability was observed for lint yield and production of fruiting sites, and lowest variability was observed for lint quality parameters. Yield was correlated to production of fruiting sites each season. Nitrate concentrations were highly variable, and yield was negatively correlated to nitrogen (N) in 1997. This suggests that variable application of N may be a viable management option in the future. Yield was positively correlated to calcium (Ca), pH, and CEC in 1997. Yield variability was correlated across growing seasons. Gross revenues were quite variable, due primarily to yield variability.

Ogallala aquifer depletion: economic impact on the Texas high plains

The impacts of the depletion of the Ogallala aquifer on the economy of the Southern High Plains of Texas were estimated by predicting future cropping patterns over a 30-year time horizon as the saturated thickness of the aquifer declines. Increased adoption of sprinkler irrigation methods, increased cotton acreage, and a shift to dryland production were the main responses found to declining water availability in the region. As the Ogallala aquifer is depleted, the region could experience a downturn in agricultural production with possible negative impacts on the regional economy assuming no other offsetting exogenous shocks to the economy.

Economics of redberry juniper control in the Texas Rolling Plains

Redberry juniper (Juniperus pinchotii Sudw.) is a common invasive brush species that reduces rangeland productivity over vast acreages in the Rolling Plains and Edwards Plateau regions of Texas. The objectives of this study were to evaluate the economic feasibility of redberry juniper control and determine the optimum treatment cycle for maintenance burning. A response equation was used to estimate the relationship between herbage production and redberry juniper canopy. Data to estimate the relationship was obtained for a site in the Texas Rolling Plains. The analysis used chaining as the initial treatment and periodic prescribed burns as maintenance treatments. Additional livestock production resulting from brush treatments and the costs of treatments were estimated and used to calculate net present values of the investment in brush control over a 30-year time horizon. Net present values indicated that juniper control was economically feasible across a wide range of economic and environmental conditions. Prescribed burn intervals were found to be optimal at 7-year intervals under most conditions.

Cotton Farmers' Technical Efficiency: Stochastic and Nonstochastic Production Function Approaches

Technical efficiency for cotton growers is examined using both stochastic (SFA) and nonstochastic (DEA) production function approaches. The empirical application uses farm-level data from four counties in west Texas. While efficiency scores for the individual farms differed between SFA and DEA, the mean efficiency scores are invariant of the method of estimation under the assumption of constant returns to scale. On average, irrigated farms are 80% and nonirrigated farms are 70% efficient. Findings show that in Texas, the irrigated farms, on average, could reduce their expenditures on other inputs by 10%, and the nonirrigated farms could reduce their expenditures on machinery and labor by 12% and 13%, respectively, while producing the same level of output.

Energy and Carbon Costs of Selected Cow-Calf Systems

Abstract Fossil fuel-derived inputs can increase cow-calf production per unit of land or labor but can raise financial and environmental concerns. Eleven US cow-calf systems from nine ecological regions in Iowa, South Dakota, Tennessee, and Texas were analyzed to determine quantities of energy used and carbon (C) emitted due to fossil fuel use (excluding emissions from soils and biota) and to determine how management and environment influenced those quantities. Total energy and C cost, calculated cow−1 or ha−1, were highly correlated (0.99). Energy use cow−1 and ha−1 varied greatly across systems, ranging from 3 000 to 12 600 megajoules (MJ) · cow−1 · yr−1 and from 260 to 20 800 MJ · ha−1 · yr−1. As stocking rate increased, MJ · cow−1 increased at an increasing rate. Differences in quantity of fertilizer accounted for most variation in energy use. Fertilizer allowed higher stocking rates but reduced energy efficiency of liveweight marketed. Compared to intensive, higher stocking rate systems, rangeland systems based on native or naturalized forages used little or no fertilizer, but used more energy cow−1 for crude protein (CP) supplementation, fencing, and pickup trucks. Across all systems, energy used to produce winter feed ranged from 0% to 46% of total energy. Northern systems used higher percentages of total energy for winter feed and fed for more days year−1, but southern systems that included large amounts of bermudagrass (Cynodon dactylon L.) hay used the most MJ · cow−1 for winter feed. Systems with high MJ · cow−1 were vulnerable to shocks in energy prices. Reducing energy use and C emissions from cow-calf operations is possible, especially by reducing fertilizer and hay use, but would likely reduce productivity ha−1. Forages with high nitrogen use efficiency, locally adapted plants and animals, and replacement of hay with unfertilized dormant forage and CP supplementation could reduce energy use.

Econometric Models for Quarterly Shell Egg Prices

Relationships determining shell egg prices were analyzed by developing models involving a simultaneous equation system estimated by using the three-stage least squares method. The findings substantiated the postulated relations including the interdependency of the shell egg and breaking egg sectors. Price estimates generated from the models appeared acceptable.

Groundwater Policy Research: Collaboration with Groundwater Conservation Districts in Texas

The unique nature of the Ogallala Aquifer presents interesting and confounding problems for water policymakers who are coping with changing groundwater rules in Texas. The purpose of this article is to link previous efforts in water policy research for the Ogallala Aquifer in Texas with current collaborations that are ongoing with regional water planners. A chronological progression of economic water modeling efforts for the region is reviewed. The results of two recent collaborative studies are presented that provide estimates of impacts of alternative policies on groundwater saturated thickness, water use, net farm income, and regional economic activities.

An Evaluation Of Post Conservation Reserve Program Alternatives In The Texas High Plains

Four policy alternatives for CRP lands upon expiration of the current contracts in Hale county, Texas are evaluated using chance-constrained programming. It was found that if CRP contracts are extended at the current average rental rate, 40 percent of the current enrollment would be expected to return to crop production, while 66 percent would return to crop production if the program were eliminated. The results also indicate that the marginal value of CRP payments to producers is lower than the marginal value of deficiency payments.

Standardized Performance Analysis: An Application to the Texas High Plains

The Standardized Performance Analysis method was used to complete a whole-farm financial analysis and crop enterprise financial and production analysis of a farming operation in the Texas High Plains for three years of crop production. The Standardized Performance Analysis procedure is described and illustrated for an individual farming operation in addition to a regional level analysis.

A Monte Carlo analysis on the impact of climate change on future crop choice and water use in Uzbekistan

Central Asia is considered a hot spot for severe water stress. According to the Intergovernmental Panel on Climate Change (IPCC), over the next century this region is expected to see a rise in temperatures and experience lower amounts of rainfall, creating a more arid climate. Regional agricultural policies have dominated water resource use. The impact of climate change coupled with market distorting economic policies, inefficient irrigation systems, and lack of water rights, could lead to social instability in the region. This analysis employs two downscaled climate projections and two Relative Concentration Pathway (RCP) scenarios (4.5 and 8.5) to simulate the impact of climate change on crop production, water use, and future crop allocations in the Khorezm region of Uzbekistan. Drought scenarios show drastic changes in crop productivity and producer profitability. If production quotas are removed, this region has the ability to become self-sufficient in wheat production, increasing its capacity to achieve food security.