ORGANIC SEED PRODUCTION OF TIMOTHY (PHLEUM PRATENSE) IN MIXED CROPS WITH CLOVERS (TRIFOLIUM SPP.)

T.S. Aamlid

The Norwegian Crop Research Institute, div.  Landvik, N-4890 Grimstad, Norway

Seed production of mixed crops of timothy (Phleum pratense L.) and alsike Trifolium hybridum L.), red (T. pratense L.) or white (T. repens L.) clover were compared in an organic cropping system with no supply of fertilizers except household compost.  The combination timothy plus alsike clover gave an average of 443 kg ha^-1  clover seed with 3.2 % timothy contamination in the first ley year and 849 kg ha-¹ timothy seed with 0.2% clover contamination in the second year.  Second year timothy yields of pure timothy crops, crops of timothy plus red clover and timothy plus white clover were, in turn, 55% lower, 44% lower and 7% higher than the corresponding yields from crops of timothy plus alsike clover.  Seed yields of timothy from first year crops of timothy plus white clover averaged only 297 kg ha-¹ and did not meet purity standards after ordinary cleaning. It is concluded that organic seed production of timothy should be based on second year crops of timothy plus alsike clover or timothy plus white clover.

Keywords: alsike clover; organic farming; purity; seed production; red clover; timothy; white clover.