BULLETIN 3.05 Crop Production & Biosecurity 2015 RESEARCH FINDINGS in the School of VETERINARY & LIFE SCIENCES SOFIE DE MEYER, TOM EDWARDS, SAMANTHA LUBCKE, NEIL BALLARD & JOHN HOWIESON Lebeckia ambigua, a perennial for deep sandy soils L ebeckia ambigua is a perennial forage legume that Murdoch University is domesticating. It has demonstrated great production potential on the acid infertile sandy soils frequently encountered across the wheatbelt of Western Australia (Figure 1). Currently there are very limited grazing options for farmers with these soils, and this land is mostly left barren and unfarmed. This legume is a summer active perennial (Figure 2) and will not drop its leaves. It therefore provides high quality forage for sheep over the summer–autumn feed gap on soils that currently only support tagasaste. Unlike tagasaste, Lebeckia does not require expensive and time-intensive management, and will always remain within the reach of grazing sheep. Our latest Lebeckia research has focused on leaf and stem nutritive value, soil improvement capacity of the plant and the identification of the associated root nodule symbionts. FIGURE 1 Lebeckia ambigua field site in spring in Tincurrin, second year after establishment Methods and results Plant nutrition analyses shows that, over summer, Lebeckia leaves provide 23.1% crude protein and have 81% digestible dry matter (Table 1). This contrasts with tagasaste, which has 13.9% crude protein content and 75 to 85% digestible dry matter and a high phenolic content. These results indicate that Lebeckia is a promising pasture plant, with high nutritive value for grazing. FIGURE 2 Lebeckia ambigua active growth over summer. Left 8 weeks after sowing (Nov. 2014), right 8 months after sowing (May 2015) A series of bulletins outlining key research in the School of Veterinary & Life Sciences | 2015 TABLE 1 Nutritive value of Lebeckia ambigua leaf and stem material Nutritive value Leaf Stem Dry Matter (%) 92.9 93.7 Crude Protein (%) 23.1 13.1 Neutral Detergent Fibre (%) 34.0 57.0 Acid Detergent Fibre (%) 21.9 44.1 Acid Detergent Lignin (%) 8.5 10.2 ASH (%) 8.7 5.7 Organic Matter (%) 91.3 94.3 Digestible Dry Matter (%) 81.0 54.7 Digestible Organic Matter in DM (%) 75.5 53.2 Metabolisable Energy (MJ/Kg DM) 12.3 7.8 Water Soluble Carbohydrates (%) 9.47 6.4 In order to obtain its nitrogen, Lebeckia forms a symbiosis with a special group of rhizobia that have only been discovered in the last 20 years (Figure 3). Several of the bacteria have been described as new species and shown to have high nitrogen fixation efficiency with Lebeckia, which enables the plant to grow without nitrogen fertiliser1,2. Further research has focused on monitoring soil health changes 4 years after introduction of Lebeckia. The initial data indicate that Lebeckia is capable of improving the soil fertility and increasing soil stability by encouraging improved growth of other plant species (Figure 4). Conclusions and recommendations The development of Lebeckia is a breakthrough for woolgrowers and mixed farm enterprises. Farmers will be able to graze their sheep on high quality feed during the summer-autumn period. The plant produces good forage and nutrition for animals, fixes nitrogen and is very efficient with P and K fertiliser. Moreover, it is a legume that can produce a lot of seed and can be established by seed through a normal seeding program, which makes it easy for farmers that are already familiar with handling small seeds and establishing pastures. ■ More information Contact John Howieson E: J.Howieson@murdoch.edu.au References FIGURE 3 Lebeckia ambigua nodulating bacteria using scanning (left) and transmission (middle) electron microscopy and the appearance of colony morphology on solid media (right) 0.50 Error bars: +/- 1SE 2.00 Mean organic (C) Mean nitrate (N) 2.50 1.50 1.00 0.50 0.00 1m away from Lebeckia Under Lebeckia stand Depth 0–10cm 11–30cm 31–50cm 0.40 1 Howieson, J.G., De Meyer, S.E., Vivas-Marfisi, A., Ratnayake, S., Ardley, J.K., and Yates, R.J. Novel Burkholderia bacteria isolated from Lebeckia ambigua — A perennial suffrutescent legume of the fynbos. Soil Biol Biochem 2013, 60:55–64. 2 De Meyer, S.E., Cnockaert, M., Ardley, J.K., Van Wyk, B.E., Vandamme, P.A., Howieson, J.G. Burkholderia dilworthii sp. nov., isolated from Lebeckia ambigua root nodules. Int J Syst Evol Microbiol 2014, 64(4):1090–1095. 0.30 0.20 0.10 0.00 1m away from Lebeckia Under Lebeckia stand Location If you are interested in our research and would like to know more, then please contact us on vlsresearch@murdoch.edu.au Our research bulletins can be downloaded from www.murdoch.edu.au/School-of-Veterinary-and-Life-Sciences/Our-research/Our-Bulletins/ Undergraduate or postgraduate degrees, please see www.murdoch.edu.au/School-of-Veterinary-and-Life-Sciences/Our-courses/ A series of bulletins outlining key research in the School of Veterinary & Life Sciences | 2015 CRICOS Code: 00125J FIGURE 4 (Left) Mean nitrate level and (right) mean organic carbon shown at three soil depths with and without Lebeckia plants