Understanding the role of spring grazing of lucerne in the Central Otago environment

Abstract

The Lucerne for Lambs Sustainable Farming Fund project used on-farm data and whole-farm modelling to help farmers understand the impact of increasing the amount of grazing dryland lucerne on Central Otago farms. On-farm results from 2 years showed that spring stocking rate on lucerne-based pasture averaged 10 ewes and their lambs per hectare compared with 3 ewes and their lambs on dryland grass-based pasture. Lamb growth rate was approximately 50 g/day higher on lucerne-based pastures, resulting in a total lamb production of 358 kg liveweight/ha at weaning compared with 108 kg liveweight/ha on grass-based pastures. Whole-farm modelling showed that increased profitability could be achieved by the addition of significant areas of grazing lucerne. Profitability increased by $119/ha on a 5000 ha traditional merino property. Profitability of a 522 ha partially irrigated valley floor property running crossbred ewes was increased by $249/ha. Using lucerne for spring grazing also reduced the impacts of both winter and summer droughts in the variable conditions of Central Otago. Keywords: dryland, lamb growth, lucerne, modelling, profitability, stocking rate, whole farm systems.

Relationships between sheep liveweight production and dry matter yield for lucerne-based pastures in spring

“…One issue consistently raised at lucerne field days has been a potential feed deficit between animal demand and lucerne growth in early spring (late pregnancy and early lactation). This has been addressed previously through the use of more winter cropping but can be seen as an impediment to using more lucerne (Stevens et al 2012). One suggestion is to use lucerne/grass mixes, which have been researched since the 1960s (Cullen 1960;O'Connor 1967;Vartha 1967;Fraser 1982).…”

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

“…More stock then increased winter feed requirements in line with attempts to capture extra spring and summer growth generated from development of the feed resource using legumes. Studies using lucerne to increase whole-farm productivity and profitability have often captured the value in increased spring productivity (Stevens et al 2012;Fraser et al 2016), or changes in overall feed quality (Rendel et al 2017), thus supporting current Table 6 Production parameters for 5 scenarios with and without Lotus over-sowing farm enterprise configuration. However, Lotus at high elevations provides feed during late spring and summer, leading to the need for potential changes in enterprise configuration.…”

“…How is the resilience of the business affected? Walker et al (2010) defined resilience as the capacity of a social ecological system to deal with shocks, the specific nature of that shock to be defined at the time of occurrence. We propose that the key driver of biophysical shock in grazing systems is climatic variation, and that the key indicator of resilience is the ability to limit financial impacts of that variation.…”

Over the fence: understanding what people do and how they might change

“…Any progress may be hidden and some knowledge may be unknown. A recent lucerne programme in Central Otago (Stevens et al 2012;Casey et al 2015a) provided the example of implementing grazing of lucerne in spring, which caused farmers to question where their conserved winter feed was going to come from. Thus, the project had to address the whole management system to provide the answers to alternate winter feed supply and how much lucerne to plant before farmers would readily adopt grazing systems.…”