Testing of site-specific yield in different harvest passes

Abstract

Original scientific paper 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. Keywords: Mann-Whitney U test; median; pass; rapeseed Testiranje lokacijske specifičnosti prinosa u različitim žetvenim prohodimaIzvorni znanstveni članak U ovom radu analizirana je razlika u masenom prinosu vlažnog zrna uljane repice za 6 različitih prohoda žitnog kombajna duž parcele. Za potrebe analize korišten je Mann-Whitney U test i Z statistike. Za prvi i četvrti prohod je Z vrijednost svega 0,211, a razina statističke značajnost kojim se ovo tvrdi 0,8333, te nema statistički značajne razlike između vrijednosti prinosa u ovim prohodima. Utvrđeno je da postoji još tri para sličnih prohoda, od kojih su dva susjedna, dok su svi ostali prohodi statistički različiti u odnosu na prinos. Približna vrijednost statističkog pokazatelja effect size r primijenjena je za sve prohode kod kojih se ispostavilo da se statistički značajno razlikuju. Najveća razlika uočena je između drugog i trećeg prohoda za koje vrijednost effect size r iznosi 0,464 što bi se po Cohenov kriteriju smatralo srednjim utjecajem. Ovaj rad sugerira proširenje trenutne rutine analize prinosa ka automatiziranoj naknadnoj analizi.

Analyzing Site-Specific Tractor Draft Force in Different Passes during Plowing

“…Investigation of differences between draft force values from one pass to another was conducted using the Mann-Whitney U test. Statistical significance was proved for differences in yield values between individual passes during harvest [16,17]. Plowing is a more challenging operation in terms of measuring and analysis, primarily due to smaller working width and greater data variability but, at the same time, the draft force and soil force resistance mapping, respectively, generate multiple times better resolutions regarding data variability than during harvesting.…”