MOVING FROM UNIFORM TO VARIABLE FERTILIZER RATES ON IOWA CORN: EFFECTS ON RATES AND RETURNS

This study develops a model based on the yield potential of various soil types in 12 Iowa counties to estimate the potential value of switching from uniform to variable fertilizer rates. Results indicate modest increases in the gross returns over fertilizer costs, ranging from $7.43 to$1.52 per acre. The net profitability of variable-rate technology (VRT) is sensitive to the per acre costs of moving to a VRT program. Under the assumptions of the model, applying variable rates would increase yield by 0.05 to 0.5 bushels per acre, and would reduce fertilizer costs by $1.19 to$6.83 per acre.Crop Production/Industries,

Moving from Uniform to Variable Fertilizer Rates on Iowa Corn: Effects on Rates and Returns

There is a growing need for research that estimates the potential value to farmers of acquiring and using improved information about spatial variability within their fields. This paper considers the potential value of switching from single rate technologies (SRT) to variable rate technologies (VRT) for applying nitrogen fertilizer in 12 Iowa counties. Changes in yields, nitrogen use, and profits are estimated for individual field and entire counties. The economic and environmental impacts of moving from SRT to VRT depend heavily on the amount of inherent yield variability in field

Optimal Information Acquisition Under a Geostatistical Model

Studies examining the value of switching to a variable rate technology (VRT) fertilizer program assume producers possess perfect soil nitrate information. In reality, producers estimate soil nitrate levels with soil sampling. The value of switching to a VRT program depends on the quality of the estimates and on how the estimates are used. Larger sample sizes, increased spatial correlation, and decreased variability improve the estimates and increase returns. Fertilizing strictly to the estimated field map fails to account for estimation risk. Returns increase if the soil sample information is used in a Bayesian fashion to update the soil nitrate beliefs in nonsampled sites

RELATIVE EFFICIENCY OF SEQUESTERING CARBON IN AGRICULTURAL SOILS THROUGH SECOND BEST MARKET-BASED INSTRUMENTS

The total expected cost of sequestering carbon in agricultural soils is estimated under a possible EQIP program offering a per-acre subsidy to adopt conservation tillage and a carbon credit program where producers can sell their carbon credit in an external market. Both programs are compared to the minimum cost solution.Land Economics/Use, Resource /Energy Economics and Policy,

Efficiency of Sequestering Carbon in Agricultural Soils (The)

Agricultural tillage practices are important human-induced activities that can alter carbon emissions from agricultural soils and have the potential to contribute significantly to reductions in greenhouse gas emission (Lal et al., 1998). This research investigates the expected costs of sequestering carbon in agricultural soils under different subsidy and market-based policies. Using detailed National Resources Inventory data, we estimate the probability that farmers adopt conservation tillage practices based on a variety of exogenous characteristics and profit from conventional practices. These estimates are used with physical models of carbon sequestration to estimate the subsidy costs of achieving increased carbon sequestration with alternative subsidy schemes.

Economic reform and aggregate cropping patterns for Egypt

Beginning in the early 1980s, the government of Egypt embarked on an aggressive initiative to progressively change its centrally planned economy to a system more dependent on domestic and international markets. The agriculture and food sectors have taken the lead in the economic reforms. This paper investigates changes in Egyptian cropping patterns as an indicator of the 'success' of the transition toward a more market-oriented economy. First, trends in cultivated area and gross margins during the economic reforms are described. Responses of cropping patterns to changes in gross margins are then evaluated. A random effect distributed lag model with pooled cross-sectional time-series methods is used to examine the relationship for individual crops. Canonical correlation analysis provides a more general assessment of responsiveness of the overall cropping pattern

A vehicle replacement policy for motor carriers in an unsteady economy

Recently, the motor carrier industry has experienced: (1) the sharp decline of vehicle (tractor) re-sale values, and (2) the substantial increase of vehicle insurance premiums. This study examines how motor carriers should adjust their vehicle replacement policies when dramatic changes of vehicle re-sale values and insurance premiums are observed. The study first develops a model of vehicle replacement optimization, and then solves the model by using the actual data obtained from a motor carrier. Intensive sensitivity analyses are performed to examine how the optimal solution is affected by the changes of vehicle re-sale values and insurance premiums, so that carriers can obtain normative policy implications. The results imply that: (1) carriers should use longer replacement cycles (extend the duration of vehicle use) when re-sale values decline, and (2) carriers' vehicle replacement policies should not be affected by the fluctuations of insurance premiums unless the fluctuations are substantial.