Analysis of plant nutrient management strategies: Conventional and alternative approaches

During times of economic uncertainty, such as the current period, all costs of agricultural production become important and worthy of close scrutiny if the threat of farm foreclosures is to be minimized. This concern particularly applies to the cost of plant nutrients, which, under conventional approaches, typically represents 24%–30% (or more) of the total variable costs of production [Lu et al. (2000) Food Reviews International 16(2): 121–157; Bullen and Brown (2001) Economic Evaluation of UNR Cotton, NC State University, Raleigh, North Carolina]. The purpose of this paper is to examine, via a review of the literature, the economics and profitability of various plant nutrient management strategies–both conventional and alternative ones–in an attempt to identify those strategies that can lead to financial resource optimization and, ultimately, maximum profits for farm enterprises. The results of this analysis are as follows: In a meta-analysis of 120 studies, conventional nutrient management systems, using commercial fertilizers, showed higher profit for most grain crops (with the exception of corn and sorghum), than organic nutrient management systems. Both cover crop and animal manure-based systems show considerable promise as alternative nutrient management strategies for increasing farm profitability. A cover crop system produced the highest average corn yield and gross margin per hectare with the smallest coefficient of variation compared to no-tillage conventional, manure-based, or crownvetch systems. Manure-based systems that do not require purchase or transport of the manure (as in combined animal and crop production systems) can be considerably more profitable than conventional systems. Both manure-based and cover crop systems that do not include the use of commercial fertilizers (i.e., organic systems), hold particular promise due to the output price premiums typically garnered by the organic crops grown under such conditions.