Browsing by Subject "Juolavehnä"

Couch grass is one of the most common perennial weeds that cause significant yield losses in temperate regions. In conventional farming, glyphosate has been commonly used to control couch grass. As attitudes and regulations are tightening towards the use of herbicides, it is necessary to find effective alternatives to replace herbicides, especially glyphosate. This master’s thesis aimed to examine the efficacy of different mechanical methods to control couch grass. The second aim was to study how these methods affect the spring cereal yield and its quality. The hypothesis was that with mechanical control methods couch grass can be controlled as effectively as with glyphosate. Data was collected from two field trials located in Inkoo and Ruukki in 2020-2021. The study plan included seven treatments: direct drilling, ploughing (in two treatments), tine cultivation, a combination of tine cultivation and ploughing, Kvickfinn cultivator, and fallowing. The coverage of couch grass was visually estimated before tillage and before harvest. Field trials were photographed with drones before harvest. The density of couch grass was defined from direct drilling plots before sowing. Biomass samples of couch grass and barley were collected from every plot for one square meter in Ruukki at harvest timing. Spring barley was harvested, and grain yield and its quality were analyzed. The coverage of couch grass was lower with Kvickfinn and fallowing than with direct drilling in Inkoo. There was no difference in yield and quality between mechanical control methods and direct drilling. In Ruukki the infestation of couch grass was more abundant and more even than in Inkoo. The coverage and biomass of couch grass were highest in direct drilled plots in Ruukki. The yield and quality of spring barley were the lowest and poorest in direct drilled plots. Couch grass was almost totally controlled with fallowing. It has to be taken into account that the results base on the data of only one growing season. Therefore, the long-term effects or the effects of weather are still uncertain. Based on the data, it is possible to conclude that fallowing is the most effective method to control couch grass. It seems that with mechanical control methods, couch grass can be controlled as effectively as with glyphosate. With mechanical control methods the spring cereal yield and quality were better than with direct drilling. It is important to control couch grass because it limits crop growth and yield formation.