An Australian contribution to farming systems research in international partnerships

This review of an Australian contribution to farming systems research (FSR) honours Dr R L (Bob) McCown (1937-2017) and his innovations in and advocacy of FSR practice in Australia, Africa and globally. Australian contributions to international FSR development and practice are widely recognized, notably in the CGIAR Centers, World Bank and ACIAR-supported international research partnerships. There has been a resurgence of interest in farming system approaches with the growing challenges of complex, uncertain, 'wicked' problems. McCown's leadership and insights helped shape a particular "Australian-style" of FSR and influenced international FSR practice over four decades, particularly the incorporation of simulation modelling in framing researcher connections with farmers' decision-making. The paper concludes with some priorities for refinement of FSR methods for international agricultural research in the years ahead

Modelling genotypic and environmental control of leaf area dynamics in grain sorghum. II. Individual leaf level

Development of leaf area on tiller axes of grain sorghum (Sorghum bicolor (L.) Moench) has previously either been ignored or treated with over-simplifications in crop simulation models. This paper describes a framework to simulate total leaf area of tillering sorghums based on the prediction of the appearance and expansion of individual leaves. Data were collated from experiments on grain sorghum hybrids grown at locations ranging in latitude from 39-degrees-11'N to 27-degrees-33'S. A leaf area model was developed which simulated axes within plants independently, such that the production and expansion of individual leaves were simulated on the main culm and each developing tiller. The model simulates total leaf area per plant (TPLA) (without losses due to senescence) using functions to predict: (i) the appearance of successive axes on plants as a function of thermal time from emergence; (ii) a constant rate of mature leaf production per axis per unit of thermal time; (iii) the profile of mature leaf areas for leaves on each axis as a function of total number of leaves produced per axis; and (iv) the leaf area contribution of immature leaves at any time as equivalent to that for a constant number of mature leaves. For seven sorghum hybrids grown at three locations, a general model simulated TPLA over time, accounting for 90% of observed variation with a root mean square deviation of 905 cm2 for observed values of TPLA ranging from 161 cm2 to 10584 cm2

Modelling genotypic and environmental control of leaf area dynamics in grain sorghum. I. Whole plant level

Leaf area dynamics are controlled by genotypic and environmental influences. In this series of papers, general models of leaf area dynamics of uniculm and tillering sorghum (Sorghum bicolor (L.) Moench) at the whole plant and individual leaf levels were developed to examine and quantify both genotypic and environmental controls. Green leaf area was modelled by examining leaf area production and senescence separately. Data from field experiments involving broad ranges of hybrids and environments were collated and analysed. Crops were grown with adequate water and nutrient supply

Row configuration as a tool for managing rain-fed cotton systems: Review and simulation analysis

Rain-fed cotton production can be a significant proportion (average 17%) of the Australian Cotton Industry. One of the management techniques that rain-fed cotton growers have is to modify row configuration. Configurations that have entire rows missing from the sowing configuration are often referred to as ‘skip row’. Skip configurations are used to: increase the amount of soil water available for the crop, which can influence the potential lint yield; reduce the level of variability or risk associated with production; enhance fibre quality; and reduce input costs. Choosing the correct row configuration for a particular environment involves many, often complex, considerations. This paper presents an examination of how rain-fed cotton production in Australia is influenced by row configuration with different management and environmental factors. Data collated from field experiments and the cotton crop simulation model OZCOT, were used to explore the impact of agronomic decisions on potential lint yield and fibre quality and consequent economic benefit. Some key findings were: (i) soil water available at sowing did not increase the advantage of skip row relative to solid configurations; (ii) reduced row spacing (75 cm) did not alter lint yield significantly in skip row crops; (iii) skip row, rain-fed crops show reasonable plasticity in terms of optimum plant spacing within the row (simular to irrigated cotton); (iv) sowing time of rain-fed crops would appear to differ between solid and skip row arrangements; (v) skip row configurations markedly reduce the risk of price discounts due to short fibre or low micronaire and this should be carefully considered in the choice of row configuration; and (vi) skip configurations can also provide some savings in variable costs. In situations where rain-fed cotton sown in solid row configurations is subject to water stress that may affect lint yield or fibre quality, skip row configurations would be a preferential alternative to reduce risk of financial loss

Vegetative nitrogen stress decreases lodging risk and increases yield of irrigated spring wheat in the subtropics

In-crop nitrogen (N) application is used widely in rainfed winter wheat production to reduce lodging risk; however, uncertainty exists as to its ability to reduce lodging risk in subtropical irrigated wheat production without simultaneously reducing yield potential. The objective of this study was therefore to determine whether in-crop N application reduces lodging risk without reducing yield of irrigated spring wheat in a subtropical environment. Irrigated small-plot experiments were conducted to compare the effect of alternative N timing on lodging and yield in two cultivars. Variable N regimes were imposed during the vegetative growth phase, after which additional N was applied to ensure that total season N application was uniform across N-timing treatments. Treatments with low N at sowing had significantly less lodging and were the highest yielding, exhibiting yield increases of up to 0.8 t ha–1 compared to treatments with high N at sowing. Increased leaf area index, biomass and tiller count at the end of the vegetative growth phase were correlated with increased lodging in both cultivars, although the strength of the correlation varied with cultivar and season. We conclude that canopy-management techniques can be used to simultaneously increase yield and decrease lodging in irrigated spring wheat in the subtropics, but require different implementation from techniques used in temperate regions of Australia

Accelerating genetic gains in legumes for the development of prosperous smallholder agriculture: integrating genomics, phenotyping, systems modelling and agronomy

Grain legumes form an important component of the human diet, provide feed for livestock, and replenish soil fertility through biological nitrogen fixation. Globally, the demand for food legumes is increasing as they complement cereals in protein requirements and possess a high percentage of digestible protein. Climate change has enhanced the frequency and intensity of drought stress, posing serious production constraints, especially in rainfed regions where most legumes are produced. Genetic improvement of legumes, like other crops, is mostly based on pedigree and performance-based selection over the past half century. To achieve faster genetic gains in legumes in rainfed conditions, this review proposes the integration of modern genomics approaches, high throughput phenomics, and simulation modelling in support of crop improvement that leads to improved varieties that perform with appropriate agronomy. Selection intensity, generation interval, and improved operational efficiencies in breeding are expected to further enhance the genetic gain in experimental plots. Improved seed access to farmers, combined with appropriate agronomic packages in farmers’ fields, will deliver higher genetic gains. Enhanced genetic gains, including not only productivity but also nutritional and market traits, will increase the profitability of farming and the availability of affordable nutritious food especially in developing countries

Program projects and learning inquiries: institutional mediation of innovation in research for development

This paper explores innovation processes and institutional change within research for development (R4D). It draws on learning by Australian participants associated with the implementation of a three-year Australian-funded food security R4D programme in Africa, and in particular a sub- component designed to support and elicit this learning. The authors critically examine this attempt at institutional innovation via the creation of a ‘learning project’ (LP) in a larger programme. For systemic innovation to be achieved, it is concluded that the system of concern must envisage institutional innovation and change within the donor and external research organizations as well as with project recipients and collaborative partners. Institutional constraints and opportunities are explored, including how the overall approach to learning in this programme could have been reframed as an organizational innovation platform (IP), designing, managing and evaluating IPs at different systemic levels of governance – including within the collaborative programme with African partners, in the constituent in-country projects, in the collaborating Australian organizations and at the level of personal practice