Biases in Nutrient Management Planning â€“ Land Economics

The PI’s are Drs. Chad Lawley, E. Lichtenberg and D. Parker. WQIA requires all agricultural operations with sufficiently large annual incomes or livestock numbers to have and implement a nutrient management plans by prescribed dates. The intent of this requirement is to reduce nutrient runoff and leaching by improving the efficiency of fertilizer use. That goal may not be realized if plans systematically overstate fertilizer requirements. Nutrient management planning is typically introduced and conducted by extension in its early years. But extension usually relies on training and certifying private sector agents—consultants employed by fertilizer dealers, independent crop consultants, and farmers—to make nutrient management planning services more widely available.

Questions have arisen as to whether there are systematic biases in the recommendations made by some private sector agents, notably fertilizer dealers. We use data from a survey of Maryland farmers from a time just prior to mandatory nutrient management planning to explore whether there are systematic differences in plans prepared. We do find systematic differences in fertilizer application rate recommendations. Fertilizer dealers and, especially, independent crop consultants recommended increases in commercial fertilizer application rates more frequently and decreases less frequently than all other plan preparers. Extension and other certified personnel (typically farmers preparing plans for other farmers) recommended no change in fertilizer application rates most of the time and otherwise recommend decreases more often than increases. Farmers preparing plans for their own operations almost always recommended decreases and virtually never recommended increases.

These findings suggest that plans prepared by professional consultants are unlikely to improve the productive and environmental efficiency of commercial fertilizer use significantly. They suggest further that extension could be more aggressive in recommending cuts in fertilizer application rates.

For more information, contact Dr. Erik Lichtenberg

Last updated: 02/7/2008