Field Performance of Winter Lupins.

Abstract

The yield potential of winter lupins is of the order of 3.5–4.5 t/ha. However, this potential is very dependent on sowing during the optimum sowing window of approximately fifteen days. Crops sown between the 11 and 26 September gave the highest yields. However, there can be significant variation around this date which cannot be predicted in advance. This became very evident in crops sown in autumn 2000, where the Rothamsted model identified the 4-19 September as the optimum sowing date. This fact creates a serious risk for the commercial exploitation of winter lupins. Maximum yields are achieved at a plant density of between 20 and 29 plants/m2 in spring. Higher plant densities can result in lodging and a loss in yield. Using the recommended seed rate of 40 seeds/m2, equivalent to 98 kg/ha, will ensure the correct plant density over a wide range of conditions. Pest and diseases are not a serious problem in winter lupin production. The only serious pest, Bean Seed Fly, is easily controlled by routine use of an insecticide before sowing. Yellow Rust, which attacks the crop occasionally, can be adequately controlled by two fungicides, Alto and Folicur. Winter lupins should be grown on light to medium well-drained soils only. Sowing on heavy or poorly drained soils can result in very high seedling losses over the winter period, and can also seriously delay the natural maturation process in lupins, resulting in a late September harvest. The variety Ludet proved to be the best all round variety in these trials. It combines good yield potential with a relatively early harvest. New varieties are required which are less sensitive to sowing date before winter lupins can be regarded as a safe reliable crop for commercial production.