USE OF GIS TO ESTIMATE WASTE LOAD VERSUS AVAILABLE LAND FOR UTILIZATION

摘要

Large-scale poultry production, like other industrial activities, generates both useful products and byproducts which may or may not be useful. In the present context, the major byproduct of poultry production (animal waste) is considered a biological resource which, like other similar resources, may be used beneficially, if it is part of a properly designed and engineered bioproduction system, or wasted. Wasting the resource is however problematic from at least two perspectives: a) it may pose significant stress on the environment receiving the waste, and b) the potential monetary value of the resource is lost. Beneficial uses of poultry wastes, on the other hand, include plant nutrition, cattle nutrition and energy production (Collins et al, 1999). Their use in these systems must be carefully designed, in accordance with the receiving system's input requirements, to avoid producing secondary wastes. This paper is focused on the use of poultry manure for plant nutrition and on factors that affect the quantity of this biological resource that can be used beneficially for that purpose. The analysis is motivated in part by recent legislation mandating the adoption of (first) nitrogen-based and (later) phosphorus-based nutrient management plans by crop producers in Maryland and other states, before the end of the decade. This legislation is aimed partially at controlling the recurrence of fish kills believed to be caused by excessive nutrient concentrations in surface waters which trigger blooms of toxic microorganisms and cause low dissolved oxygen levels (Novotny and Olem, 1994). Wastes from animal agriculture are believed to be significant contributors to this nutrient load (Smith and Alexander, 2000). The lost resource (wasted) apparently becomes a stressor that adversely impacts other resources (here: aquatic). The loss of potential income from beneficial use of the resource might then be further compounded by income loss from exploitation of the now less productive aquatic resource.