Effect of applied nitrogen, increased inoculation, broadcast lime, and seed pelleting on establishment of Lotus pedunculatus cv. ‘Grasslands Maku’ in tussock grasslands

Abstract

Two series of trials examined methods of improving the poor establishment of ‘Grasslands Maku’ lotus in acid tussock grassland. At four sites (pH 4.4–5.1), increasing rates of fertiliser nitrogen (0–30 kg N/ha) at sowing, and increasing inoculation rate were investigated. At a further two sites (pH 4.6, 5.1), the effects of 5× and 10× the recommended inoculation rate, broadcast lime (at 500 kg/ha), and pelleting seed with rock phosphate/dolomite were evaluated. Nitrogen reduced plant weight and nodule number at three sites in the first year, and reduced second year plant production where vegetation cover was dense. The reduction in establishment was probably caused by nitrogen inhibiting nodulation, together with competition from resident vegetation. Addition of nitrogen at sowing to Maku lotus in the field should be avoided. Increasing the recommended inoculation rate increased establishment, by improving nodulation, winter survival, individual plant growth, and overall production. Broadcast lime improved nodulation at pH 4.6, but not at pH 5.1. However, total production was increased at both sites. The nodulation response to pelleting was similar to that for broadcast lime at low pH (4.6), but the lime effect was less than that obtained with increased inoculation and was lost by the second year.

Keywords:

• Lotus pedunculatus
• ‘Grasslands Maku’ lotus
• legume establishment
• inoculation
• lime
• nitrogen fertiliser
• nodulation
• pelleting
• acid soil