Testing of site-specific yield in different harvest passes

Abstract

This paper analyzes the differences in mass yield of moist rapeseed grain for six different passes of combine harvester along the plot. The Mann-Whitney U test and Z-statistic are used for analysis needs. For harvest pass 1 and pass 4 the Z-value is only 0,211, whereas the statistical significance level to confirm this finding is 0,8333, therefore there is not statistically significant difference between yield levels in mentioned passes. It is established that there are another three pairs of similar harvest passes, of which two are adjacent, while all other passes exhibit statistical difference with respect to the yield. The approximate value of the effect size r indicator is applied for all passes, where a statistically significant difference turned out to exist between them. The highest difference is noted between pass 2 and pass 3, the effect size r value amounting to 0,464, which can be considered a large effect size according to Cohen's criterion. This paper suggests extending the current routine implementation of yield analysis to an automated post-processing system.