Open access publications in the SLU publication database

Abstract

The Swedish oilseed rape association is running a project called 20/20. The goal is to reduce cost with 20 % and increase the oilseed production with 20 % until 2010. The big project is split into smaller projects and one of them is Establishment – degree-days. In this study, degree-days have been used as a tool in experiments concerning germination and establishment of oilseed rape. The main part of the study was carried out under laboratory conditions. The studies aimed at finding a base temperature for germination and plant emergence, and to study how different temperatures, seeding depths and seed weights affect germination and emergence. Six different varieties were sown at 5, 10, 15 and 20ºC at seeding depths of 1, 3 and 5 cm. The number of emerged plants was counted two or three times per day. The results from the laboratory study were then compared with results from field experiments. Plant emergence and soil temperature data from field experiments were collected from OS7-190 which included different varieties and seeding dates, R2-4135 which included different seeding dates and preceding crops and R2-5079 which was an establishment trial with spring oilseed rape. The location for the two OS7-190 trials used was in Östergötland, while R2-4135 and R2-5079 were located just outside of Uppsala. The base temperature for spring and winter oilseed rape was around 2,9°C. Oilseed rape needed 70 – 80 degree-days for emergence from 3 cm depth during controlled conditions (base temperature 2,9°C). Even at low temperatures and great seeding depths (5 cm) the number of emerged plants was more than 70 %. Number of emerged plants or emergence rate was not affected by seed weight. The results from the laboratory experiment correlated well with the results of the field experiments. The study shows that degree-days are useful for predicting plant emergence under field conditions. Increased number of degree-days for emergence indicates limiting factors in the germination and emergence process.