Can Lotus pedunculatus over-sowing in low-fertility tussock country increase farm resilience?

Abstract

The range of legumes to boost farm productivity in low-fertility hill country are limited. Lotus pedunculatus (Lotus) provides an option when soil pH is below 5 but is intolerant to severe and regular grazing. However, itcan be used at sites that are only grazed occasionally during spring summer and autumn. Oversowing of Lotus pedunculatus has been used to improve 17% of the total area of Avenel Station, Millers Flat. Measurements of pasture growth and animal production were collected over three years post-sowing, indicating a doubling of pasture production from the native form while providing liveweight gains of 0.135 and 0.75 kg/d in lambs and yearling cattle respectively. Systems modelling was used to re-examine the current farm-system configuration to test the possible outcomes from implementing further enterprises that may capture the increased late spring and summer production effectively. Reducing ewe numbers and concentrating on improving lamb survival were the most cost-effective and environmentally effective options. Buying in further finishing lambs to use the summer surplus also improved profitability. Increasing cow numbers was similarly profitable. Increasing ewe  numbers also required an increase in winter feed supply and was the least profitable way to capture the  benefits. Testing using climatic extreme scenarios demonstrated that the oversowing of Lotus on the higher, wetter tussock country increased the resilience of the farm by providing a buffer during dry summers.