Comparison of a herbal ley with a ryegrass-white clover pasture and pure ryegrass sward receiving fertiliser nitrogen

Abstract

This paper compares a herbal ley (of particular interest to farmers involved in the 'organic' branch of agriculture) with a conventional pasture (ryegrass-white clover) and a more intensive system (pure ryegrass receiving 400 kg fertiliser N/ha/yr) in a study lasting 2 years. The herbal ley seeds mixture was prepared following the pioneering ideas of Robert Elliot in his "Clifton ~~ ~~~~~Park"mixture,-whichbasically-included~a-group of 'non-aggressive' grasses, forage legumes and herbs. Pasture production (average of 2 years) from Herbal ley was 15 t DM/ha/yr, representing approximately 90% of the yield from the intensively managed pure ryegrass pasture receiving 400 kg N/ ha&r and some 2530% more than from ryegrassclover. A major feature of the herbal ley was substantialproductionduringlate.springandsummer, when chicory (the most dominant herb), and red clover and white clover made a major contribution to herbage yield. In winter the total yield was similar tothatI?omthegrass-cloverpasture.L.egumecontent was 23 and 3 1% (averaged over the year) for Grassclover and Herbal ley pastures respectively. In spite of this difference, symbiotic N fixation was similar. So fixation efficiency on a legume yield basis was 50.3 and 3 1.6 kg N fixed/t legume DM harvested, respectively. These results could reflect a different pattern of utilisation of soil N, as a consequence of the different botanical composition of the swards. In summary, the performance of the herbal ley offers the promise of an alternative, 'specialist' pasture and would be highly beneficial if quality feed is required in summer. Keywords herbal ley, biological fertility, nitrogen, symbiotic nitrogen fixation, pasture mixtures