Recent research suggests that the perennial legume Leucaena leucocephala (leucaena) mitigates ruminant enteric methane emissions. However its high crude protein content may offset methane mitigation by increasing nitrous oxide emissions from livestock systems. Researchers examined the effects of leucaena on emissions, production and profitability at the whole farm level using a Queensland cattle breeding and finishing property as a model.
Leucaena increased farm production by increasing animals carried and liveweight gain, improving gross margins by up to 37%. It increased nitrous oxide emissions by more than 38% but this had minimal effect on whole farm emissions because enteric methane emissions were an order of magnitude greater. Overall, leucaena reduced emissions intensity by more than 17% relative to the baseline, via a combination of enhanced liveweight gain and reduced methane.
Importantly, the returns from increased production in a leucaena system are greater than those from emissions abatement via the CFI / ERF.
Harrison M, McSweeney C, Tomkins N, Eckard R (2015). Improving greenhouse gas emissions intensities of subtropical and tropical beef farming systems using Leucaena leucocephala. Agricultural Systems 136, 138-146. http://dx.doi.org/10.1016/j.agsy.2015.03.003.
Taylor CA, Harrison MT, Telfer M, Eckard R (2016). Modelled greenhouse gas emissions from beef cattle grazing irrigated leucaena in northern Australia. Animal Production Science, 56, 594–604, http://dx.doi.org/10.1071/AN15575.