Managing for rainfall variability: long-term profitability of different grazing strategies in a northern Australian tropical savanna

O’Reagain, Peter J.; Bushell, John; Holmes, Bill

doi:10.1071/an10106

Cited by 74 publications

(63 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ideally, given the marked influence climate has on pasture and livestock outcomes (Jones et al 1995;O'Reagain et al 2011), the length of the experimental period for farming systems research should be sufficient to allow adequate representation of the expected range of climatic conditions (Walker 1988). This would enable sufficient demonstration of treatment responses and would reduce the need for assumptions or modelling to extrapolate responses to climatic conditions for which there are no data to support calibration.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Comparing the climate experienced during the Cicerone farmlet experiment against the climatic record

et al. 2013

View full text Add to dashboard Cite

Abstract. Farming systems research conducted under dryland conditions is subject to the vagaries of the climate during the experimental period. Whether such an experiment experiences a representative series of climatic years must be examined in relation to the longer term climatic record. The Cicerone Project's farmlet experiment was conducted on the Northern Tablelands of New South Wales, Australia, to investigate the profitability and sustainability of three different management systems: one managed under typical, moderate-input conditions (farmlet B); a second which employed a higher level of pasture inputs and soil fertility (farmlet A); and a third which focussed on the use of moderate inputs and intensive rotational grazing (farmlet C).The climate experienced during the 6.5-year experimental period was compared with the 118-year climatic record, using a biophysical simulation model of grazed systems. The model utilised the long-term daily climate data as inputs and provided outputs that allowed comparison of parameters known to affect grazed pastures. Modelled soil-available water, the number of soil moisture stress days (SMSDs) limiting pasture growth, and growth indices over the experimental period (2000-06) were compared with data over the climatic record from 1890 to 2007. SMSDs were defined as when the modelled available soil moisture to a depth of 300 mm was <17% of water-holding capacity. In addition, minimum temperatures and, in particular, the frequency of frosts, were compared with medium-term (1981-2011) temperature records.Wavelet transforms of rainfall and modelled available soil water data were used to separate profile features of these parameters from the noise components of the data. Over the experimental period, both rainfall and available soil water were more commonly significantly below than above the 95% confidence intervals of both parameters. In addition, there was an increased frequency of severe frosting during the dry winters experienced over the 6.5-year period. These dry and cold conditions were likely to have limited the responses to the pasture and grazing management treatments imposed on the three farmlets. In particular, lower than average levels of available soil water were likely to have constrained pasture production, threatened pasture persistence, and reduced the response of the pasture to available soil nutrients and, as a consequence, livestock production and economic outcomes.Ideally, dryland field experimentation should be conducted over a representative range of climatic conditions, including soil moisture conditions both drier and wetter than average. The drier than average conditions, combined with a higher than normal frequency of severe frosts, mean that the results from the Cicerone Project's farmlet experiment need to be viewed in the context of the climate experienced over this 6.5-year period.

show abstract

Section: Discussionmentioning

confidence: 99%

“…climatic records over the long term (Laws et al 2000;O'Reagain et al 2011). Climate is especially important when the treatments being evaluated, such as changes in soil fertility and botanical composition, are known to take many years to reach equilibrium (Walker 1988;Jones et al 1995).…”

mentioning

confidence: 99%

Comparing the climate experienced during the Cicerone farmlet experiment against the climatic record

et al. 2013

View full text Add to dashboard Cite

show abstract

“…A local impact of intense low-pressure systems, including cyclones, is the combination of intense rainfall and high wind speeds, which causes lodging and reduction of sugar content in sugarcane (Singh et al 2002) and, potentially, damage to plantation forests. Northern inland pasture systems are generally favoured by La Niña events (Park et al 2003) and could respond positively to climate change in terms of productivity, albeit with a need to buffer production between years of high and low rainfall (O'Reagain et al 2011). Any increase in growing season temperature or in high-temperature events will affect the dynamics of production, but adaptation can be implemented through pasture and animal management .…”

Section: Systems Of Cultivated Plant Species and Relative Production mentioning

confidence: 99%

Plant adaptation to climate change—opportunities and priorities in breeding

et al. 2012

View full text Add to dashboard Cite

Abstract. Climate change in Australia is expected to influence crop growing conditions through direct increases in elevated carbon dioxide (CO 2 ) and average temperature, and through increases in the variability of climate, with potential to increase the occurrence of abiotic stresses such as heat, drought, waterlogging, and salinity. Associated effects of climate change and higher CO 2 concentrations include impacts on the water-use efficiency of dryland and irrigated crop production, and potential effects on biosecurity, production, and quality of product via impacts on endemic and introduced pests and diseases, and tolerance to these challenges. Direct adaptation to these changes can occur through changes in crop, farm, and value-chain management and via economically driven, geographic shifts where different production systems operate. Within specific crops, a longer term adaptation is the breeding of new varieties that have an improved performance in 'future' growing conditions compared with existing varieties.In crops, breeding is an appropriate adaptation response where it complements management changes, or when the required management changes are too expensive or impractical. Breeding requires the assessment of genetic diversity for adaptation, and the selection and recombining of genetic resources into new varieties for production systems for projected future climate and atmospheric conditions. As in the past, an essential priority entering into a 'climate-changed' era will be breeding for resistance or tolerance to the effects of existing and new pests and diseases. Hence, research on the potential incidence and intensity of biotic stresses, and the opportunities for breeding solutions, is essential to prioritise investment, as the consequences could be catastrophic. The values of breeding activities to adapt to the five major abiotic effects of climate change (heat, drought, waterlogging, salinity, and elevated CO 2 ) are more difficult to rank, and vary with species and production area, with impacts on both yield and quality of product. Although there is a high likelihood of future increases in atmospheric CO 2 concentrations and temperatures across Australia, there is uncertainty about the direction and magnitude of rainfall change, particularly in the northern farming regions. Consequently, the clearest opportunities for 'in-situ' genetic gains for abiotic stresses are in developing better adaptation to higher temperatures (e.g. control of phenological stage durations, and tolerance to stress) and, for C 3 species, in exploiting the (relatively small) fertilisation effects of elevated CO 2 . For most cultivated plant species, it remains to be demonstrated how much genetic variation exists for these traits and what value can be delivered via commercial varieties. Biotechnology-based breeding technologies (marker-assisted breeding and genetic modification) will be essential to accelerate genetic gain, but their application requires additional investment in the understanding, genetic characterisation,...

show abstract

“…In a study of different grazing strategies in northern Queensland, O'Reagain et al (2011) found that, under variable climatic conditions, the best financial and sustainable outcomes over the long term were achieved through a variable stocking strategy that allowed the adjustment of stocking rate early in each dry season. Such a system is similar to the flexible grazing management employed on farmlets A and B in the present experiment.…”

Section: Integrative Discussionmentioning

confidence: 99%

Integrated overview of results from a farmlet experiment which compared the effects of pasture inputs and grazing management on profitability and sustainability

Scott

Behrendt

Colvin³

et al. 2013

Anim. Prod. Sci.

View full text Add to dashboard Cite

Abstract. The Cicerone Project conducted a grazed farmlet experiment on the Northern Tablelands of New South Wales, Australia, from July 2000 to December 2006, to address questions raised by local graziers concerning how they might improve the profitability and sustainability of their grazing enterprises. This unreplicated experiment examined three management systems at a whole-farmlet scale. The control farmlet (farmlet B) represented typical management for the region, with flexible rotational grazing and moderate inputs. A second farmlet (farmlet A) also used flexible rotational grazing but had a higher level of pasture renovation and soil fertility, while the third farmlet (farmlet C) had the same moderate inputs as farmlet B but employed intensive rotational grazing. The present paper provides an integrated overview of the results collated from component papers and discusses the inferences that can be drawn from what was a complex, agroecosystem experiment. The measurements recorded both early and late in the experiment were tabulated for each of the farmlets and compared with each other as relative proportions, allowing visual presentation on a common, indexed scale. Because of equivalent starting conditions, there was little difference between farmlets early in the experimental period (2000-01) across a wide array of measured parameters, including herbage mass, potential pasture growth rate, liveweight, wool production per head, stocking rate, gross margin and equity. Although the experiment experienced drier-than-average conditions, marked differences emerged among farmlets over time, due to the effects of treatments. During the latter half of the experimental period (2003-06), farmlet A showed numerous positive and a few negative consequences of the higher rate of pasture renovation and increased soil fertility compared with the other two farmlets. While intensive rotational grazing resulted in superior control of gastrointestinal nematodes and slightly finer wool, this system had few effects on pastures and no positive effects on sheep liveweights, wool production or stocking rate. Whereas farmlet A showed higher gross margins, it had a negative and lower short-term cash position than did farmlets B and C, due largely to the artificially high rate of pasture renovation undertaken on this farmlet during the experiment. Although farmlet B had the highest cash position at the end of the experiment, this came at a cost of the declining quality of its pastures. Modelling of the farmlet systems allowed the results to be considered over the longer timeframes needed to assess sustainability. Thus, returns on investment were compared over realistic amortisation periods and produced outcomes based on long-term climatic expectations which were compared with those that arose under the drier-than-average conditions experienced during the experimental period. The main factors responsible for lifting the productivity of farmlet A were the sowing of temperate species and increased soil fertility, which enhanced the amo...

show abstract

Managing for rainfall variability: long-term profitability of different grazing strategies in a northern Australian tropical savanna

Cited by 74 publications

References 35 publications

Comparing the climate experienced during the Cicerone farmlet experiment against the climatic record

Comparing the climate experienced during the Cicerone farmlet experiment against the climatic record

Plant adaptation to climate change—opportunities and priorities in breeding

Integrated overview of results from a farmlet experiment which compared the effects of pasture inputs and grazing management on profitability and sustainability

Contact Info

Product

Resources

About