Agriculture and Environment: Corn (Maize)

Better Management Practices: Reduce Use of Fertilizers and Pesticides

In the cases of both pesticides and fertilizers, application timing and methods can greatly influence total use levels.

More precise application of pesticides, and their increased efficiency, has resulted in continual increases in yields in the 1990s even as total pounds applied of active ingredients per area of land cultivated has fallen.

Lin et al. (1995) report that switching from preplanting to after-planting applications and from broadcast to band applications can reduce nitrogen use by 4.5 to 64.8 kilograms per hectare.

The recommended use of nitrogen, for corn and for other crops, is often base on monocrop trials rather than on crop rotation systems of production. Researchers have found that with typical crop rotations, nitrogen applications can be reduced as much as 34 kilograms per hectare (30 pounds per acre) below the manufacturer's recommended rate (Vanotti and Bundy 1994, as cited in Runge and Stuart 1998). Not only is this a savings to farmers, it means that less fertilizer will be put into the ecosystem to pollute it.

In a study of continuous corn cultivation in lowa, it was found that the herbicide atrazine was less concentrated in drain tiles under fields if it was applied in narrower bands than if it was spread over the entire crop. Banding allowed producers to apply one-third less (Kanwar and Baker 1994).

Biological substitutes for chemical pesticides (e.g., sex-linked insect attractors) can also be effective. There should be added to the options of producers around the world as well as encouraged by the various groups that work with them. As such measures become more common, their costs are far cheaper too. Microorganisms, for example, have proven to be a valuable disease control solution that is becoming cheaper as well.

PlantShield (Trichoderma harzianum) and Mycostop (Streptomyces griseovirdis), manufactured by BioWorks, Inc. and Kemira Agro, respectively, are labelled for control of a number of vegetable crop diseases (Reid 2002). All these approaches can be developed further and applied more broadly. The application of some of these approaches can even reduce the use of some chemical inputs by making them more effective by reducing pest resistance to them.