Journal of Agricultural Sciences (Nov 2005)
Determination of Spatial Weed Variability for Precision Spraying
Abstract
Weeds are patchy because weed spread, survival and reproduction are variable within a field and over time. Weed patches stay in about the same place from year to year, even though weed density within a patch may vary. Weeds, and methods used to control weeds, can have negative economic and environmental impacts. With precision agriculture, growers can take advantage of the patchy nature of weeds by targeting management efforts only where they are needed instead of wasting expensive and potentially hazardous inputs where weeds are not present. The availability of geographic information systems GIS and global positioning systems GPS allows to generate site-specific application maps in order to apply herbicides only in those portions of a field in which weeds are present. In this study, weeds in winter wheat were sampled in 2001 and 2002 in two fields of 6.7 ha inSarayköy research station and 6.4 ha in Atatürk Orman Çiftliği AOÇ respectively. The most frequent weed species were taken into account in weed sampling. Weed infestation was determined by a combination of visual assessment within a 5 metre radius and actual weed counts within a 1 m2 quadrant of the grid sample point. Additional sampling was undertaken if the 1 m2 quadrant appeared unrepresentative. Weed density and spraying maps were generated using Arcgis 3.2a GIS software package. The results demonstrate that mapping weeds for precision spraying to control weeds can theoretically reduce herbicide applications. Compared to traditional application, the amount of herbicides in a small grain cereal would be reduced by % 25 in Sarayköy and 55 % in AOÇ field respectively
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