Differences in botanical and chemical composition of forage from organic and conventional leys: A survey at farm field level

Samples of grass and clover swards from leys were collected during one season on different Swedish farms converting to organic farming, in order to obtain a survey of general practical differences in the botanical and chemical composition of leys when converting to organic farming. The samples were analysed with traditional chemical methods as well as near‐infrared (NIR) spectroscopy and inductively coupled plasma analysis. Multivariate data analysis (principal component analysis and partial least squares regression) was used to evaluate the results. It was found that the main difference of practical importance was a significantly higher percentage of clover in organically grown leys. The NIR analysis detected differences in botanical composition and with harvest times. Differences other than botanical composition between organic and conventional samples could only be detected in samples within the same botanical fraction and harvest time. It was concluded that it is important for an organic farmer to monitor the botanical composition and integrate this information in the forage evaluation.