Agriculture and Environment: Sorghum
Environmental Impacts of Production: Use of Agrochemical Inputs
One of the main environmental impacts from commercial sorghum production is the use of agrochemical inputs.
Sorghum is one of the most chemically dependent of all agricultural crops (Thurman 1996).
Many types of fertilisers and pesticides are used in sorghum cultivation and storage, but since most storage occurs off-farm, only the impacts related to cultivation are discussed below.
A number of toxic pesticides applied
On the cultivation side, a number of pesticides are commonly used on sorghum, including organophosphates such as chlorpyrifos, dimethoate, and malathion. Carbamates like carbaryl and carbofuran are increasingly used as well, and are highly toxic.
Pyrethroids are also used and this is important because these substances are extremely toxic to fish and other aquatic life. Lindane is the only organochlorine that is used; it is registered for use as a seed treatment in sorghum.
Direct/Indirecr exposure to wildlife
Fungicides are also used in sorghum fields as foliar sprays and for seed treatment. Mancozeb, a fungicide that is commonly used, is toxic to fish. Birds, insects, mammals, and reptiles are exposed to these agrochemicals.
Small grains such as wheat and sorghum provide food and cover for many wildlife species. Wildlife are directly exposed to pesticides when they eat plants or seeds with chemical residues or when they swallow the pesticide granules or water that is contaminated by them.
They are exposed indirectly when they eat insects or other animals exposed to or killed by pesticides. Pesticides washed by rain into streams, ponds, or other wetlands can harm aquatic animals (Rollins et al. 1997).
Herbicides are used to control weeds both in and adjacent to sorghum fields. Globally, atrazine is the most commonly used herbicide in sorghum cultivation, alone or in combination with other preplant herbicides like alachlor, metolachlor, 2, 4-D, dimethenamid, paraquat, etc.
And the habitat is degraded too
The greatest risk to wildlife from herbicides is the effects they can have on wildlife habitat, as wildlife rely on the trees, brush, grass, and weeds in and near fields for food and cover (Rollins et al. 1997).
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