Estimation of Weeds Leaf Cover Using Image Analysis and Its Relationship with Fresh Biomass Yield of Maize Under Field Conditions

In order to reduce herbicide application an intelligent sprayer boom is being developed. It only sprays with herbicides if the weed infestation exceeds a certain weed control threshold. The estimation of leaf cover of weeds through image analysis is a prerequisite for the weed management model of the intelligent sprayer boom. Destructive and human perception methods of leaf cover estimation are laborious and practically not feasible to implement in a real time system. An alternative method is developed in the image analysis program “ImageJ”. The relationship between fresh biomass yield of maize and the leaf cover of weeds at the fourth and sixth leaf stages was analysed. Weeds were grown in maize under field conditions in Denmark. Chenopodium album was the most dominant species. Our data showed that yield loss was linearly related to leaf cover of weeds and may be used in the decision algorithm for the intelligent sprayer boom.