The cultivation of legumes (like clover and alfalfa) in legume-grass mixtures and in permanent grassland and their ability to fix nitrogen build the basis for soil fertility in organic farming systems. The medium- to long-term fertility changes can be monitored via nitrogen balances. However, it is difficult to estimate the N-fixation of legume-grass mixtures under field conditions.



N-fixation is largely determined by two factors: total yield and the legume percentage in the total yield. While the total yield can be estimated quite easily (e. g. by the number of truckloads and the silo content), information on the legume percentage is usually not available and varies between < 5 % up to > 90 %. Permanent grassland differs a lot from arable forage systems as it contains a variety of grasses, herbs and clovers. With some practice, the legume percentage can be estimated visually. However, there is often neither enough time to determine the actual legume percentage (by cutting samples and sorting), nor an experienced estimator for instruction.



One solution could be this estimation trainer: the tool randomly displays pictures of legume-grass swards (plus related information on the average height of growth and total fresh and dry matter) while the user has to enter an estimate of legume percentages. A notification tells the user whether the estimate was correct or not. The success rate is shown in percentage which allows monitoring the success of the training.

It is advisable to read the background information and the manual before starting.