Improving the fit of new annual pasture legumes in Western Australian farming systems: experience from Cadiz and Casbah

Abstract

Annual pasture legumes (APLs) are important in Western Australian farming systems, with subterranean clovers and annual medics being dominant. However, due to potential environmental, economic and biological constraints of these species, alternatives have been sought, with a second generation of new species being introduced since 1991. Despite the views of researchers about the advantages in WA conditions of the newly released annual pasture legumes over traditional pastures, there is a perception by some industry decision makers that their level of adoption has been lower than expected. However, there was not a good method for evaluating the level of adoption. The aim of this study was therefore to enhance understanding of how to improve the fit of new annual pasture legumes in Western Australian farming systems, taking two pastures, French serradella (Ornithopus sativus) cv. Cadiz and Biserrula (Biserrula Pelecinus) cv. Casbah (Hereafter, will be referred to as Cadiz and Casbah.), as examples.The objectives of the study were implemented in four steps. In step one, a framework, built on a three-tier hierarchy (broad adoption potential or BAP, broad attainable adoption potential or BAAP, and maximum attainable adoption potential or MAAP) was developed based on the agro-ecological suitability of the annual pasture legumes. BAP was calculated from the amount of suitable land in terms of soil and rainfall requirements for an APL. The BAAP was calculated by multiplying BAP with two coefficients related to the proportion of cropping area within a geographic region, and the crop-pasture ratio within the cropping area. The MAAP was calculated by multiplying BAAP with a coefficient related to the certainty of a successful pasture-growing season. This coefficient was derived from a Microsoft-Excell®-based Climate Reliability Calculator particularly developed for this study. The broad attainable adoption potentials (BAAP) for Cadiz and Casbah were calculated as 1.67 M ha and 1.18 M ha, respectively. These figures were about 81% less than the calculated broad adoption potential (BAP). The maximum attainable adoption potentials (MAAP) for Cadiz and Casbah in Western Australian cropping-belt were calculated as 0.99 and 0.89 M ha, respectively.In step two, a survey was conducted to understand the salient issues that farmers consider in relation to adopting a new annual pasture legume for their farming systems. An open-ended question was used for them for the attributes they desired for their ‘dream’ pasture. Questions were also asked about their experiences of strengths and weaknesses for Cadiz and Casbah. Responses were analysed using the principles of ‘grounded theory’. Furthermore, based on farmers’ perceptions, an APL-characteristics framework was developed for Western Australia. The framework consisted of six attributes of a pasture. They are, in order of importance calculated from the percent of farmers responses: superiority in establishment and growth (79%), ability in supplying quality feed (49%), improved potential in controlling weeds (38%), adaptability in broader agro-ecological horizon (36%), tolerant to major insect-pests (20%), and inexpensive (15%). Many farmers desired a combination of these components rather than just a single component. The two test APLs, Cadiz and Casbah, were compared under this framework based on the responses of the farmers.In the third step, using farmers’ perceptions of the salient attributes and other variables, an empirical model was developed to predict the likely adoption of any annual pasture legume in Western Australian farming systems. The model consisted of the product of two components, AAAR and TRMAP. The AAAR was the averaged annual adoption rate (as the percentage of all pastures grown in Western Australia) of the APL. TRMAP is the time, in years, required to reach the maximum adoption potential of the APL. The AAAR was related to the agronomic characteristics of the APL (the three most wanted characteristics by farmers, i.e. establishment and growth, feed supply and quality and weed control) and an ‘inter-competition’ factor, whereas the TRMAP was attributed to its scope of adaptation. Both AAAR and TRAMP were essentially regression models. The model performed well when tested independently for Cadiz and Casbah using inputs from two different sources, i.e. breeders and farmers. In the final step, the model was applied to predict the adoption of Cadiz and Casbah using inputs from breeders and farmers in order to understand what level of adoption breeders would have expected and to what extent farmers would support the breeders’ view. Results showed that breeders were expecting Cadiz and Casbah would be adopted in about 32% and 22% of their potential areas (MAAP) compared to the achieved adoption of 23% for Cadiz and 20% for Casbah, respectively.On the other hand, model output using farmers’ evaluation scores indicated that the adoption would be 20% for Cadiz and 19% for Casbah, which is much closer to the achieved adoption level. The difference between breeders’ expectation and farmers’ evaluation on adoption potential of Cadiz and Casbah was due to differences in evaluation scores provided by the two groups on different pasture characteristics in relation to establishment and growth, weed control and feed supply and quality. Some of the pasture characteristics desired by the farmers, such as reliable regeneration, seed settings, easy establishment, general vigor, good chemical tolerance, good feed supply and quality, suitable for wide range of soils, good insect tolerance are not commonly present when Cadiz and Casbah are grown in the farming environments.Two issues for further consideration if the adoption levels of Cadiz and Casbah were to be increased in WA farming systems are: decreasing the knowledge gap among farmers on tactical management of APLs though extension, and improved pasture characteristics through the breeding/selection process. Furthermore, this study designed a system consisting of three major components: the maximum attainable adoption potential (MAAP), the annual pasture legume characteristics framework (APL-characteristics for Western Australia) and achievable adoption potential (AAP). This system acts as a common platform - where breeders, farmers, extension specialists and policy makers could work as a team towards improving the fit of annual pasture legumes, and potentially other crops if the required supporting information was collected, in Western Australian farming systems.