Weed density was sampled in a number of quadrats in five crops and at eight locations in Italy. For every location and species of crop and weed, a mean/variance pair was calculated. The relationship between these two parameters was significantly influenced by crop and, to a lesser extent, by site, but not by species of weed. The goodness of fit of the negative binomial distribution to the samples was assessed. Its k exponent was estimated on the basis of the observed variance/mean regression. A good fit was found for weed populations with fewer than 10 plants m−2. The applicability of a sequential sampling procedure based on the negative binomial distribution to a weed control strategy that uses a threshold density is discussed.
FREQUENCY-DISTRIBUTION OF WEED COUNTS AND APPLICABILITY OF A SEQUENTIAL SAMPLING METHOD TO INTEGRATED WEED MANAGEMENT
BERTI, ANTONIO;ZANIN, GIUSEPPE;
1992
Abstract
Weed density was sampled in a number of quadrats in five crops and at eight locations in Italy. For every location and species of crop and weed, a mean/variance pair was calculated. The relationship between these two parameters was significantly influenced by crop and, to a lesser extent, by site, but not by species of weed. The goodness of fit of the negative binomial distribution to the samples was assessed. Its k exponent was estimated on the basis of the observed variance/mean regression. A good fit was found for weed populations with fewer than 10 plants m−2. The applicability of a sequential sampling procedure based on the negative binomial distribution to a weed control strategy that uses a threshold density is discussed.
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