In 2009, controlled field trials were conducted on three certified organic farms with field pea (leaf type), spring barley and spring wheat in monocultures and mixtures (pea:cereal ratio 60:40) to study the possibility of producing fodder for monogastric animals under Czech conditions. By grain harvest time, seed samples were collected and analysed for dry matter, ash, crude protein, fat and crude fiber, and content of organic matter and nitrogen-free extracts (NFE) were determined. Weed harrowing at various pea heights were included at one farm. Samples for analysis of tannins and trypsin-inhibitor activity (TIA) were taken from treatments with no weed harrowing (H0) and harrowings at 5 and 10 cm pea height (H2). Analyses of amino acids were conducted from H0-samples. To complement the data from the farm trials, samples of grains from treatments with the same pea and cereal varieties in plot trials conducted in 2008 and 2009 studying the effect of pea:cereal seed ratio and weed harrowing at various pea heights, were analysed. In cereals, the crude protein content increased by intercropping with pea. This increase was compensated for by a decrease in NFE. Wheat and barley grown in mixtures with peas seemed to contain more methionine than cereals in monoculture, and there tends to be higher threonine content in intercropped barley compared with barley monoculture. This is positive for the nutrition of monogastric animals. There were no pronounced effects of intercropping on tannins or TIA or on the content of other analysed nutrients in the cereals. The chemical composition of peas was not significantly impacted by intercropping.
