Crop and Pasture Science Crop and Pasture Science Society
Plant sciences, sustainable farming systems and food quality
Table of Contents
Crop and Pasture Science

Crop and Pasture Science

Volume 63 Number 1 2012

CP11320 Break-crop benefits to wheat in Western Australia – insights from over three decades of research

Mark Seymour, John A. Kirkegaard, Mark B. Peoples, Peter F. White and Robert J. French
pp. 1-16

Wheat is the dominant winter crop in Australia, and growers are constantly considering – what is the best rotation to maximise the yield of wheat in a sustainable fashion? Over 160 experiments addressing this question have been conducted in Western Australia since 1974, finding that the highest wheat yields usually follow a break crop such as lupin, field pea or canola. The review provides a useful summary of a large number of experiments which can help growers and their advisers plan rotations to achieve yield, economic and sustainability goals.

The High Rainfall Zone of southern Australia is a relatively new area to cropping and has the potential to contribute significantly to national grain production. Current grain yields are approximately half the estimated potential but new high yielding canola varieties from Europe have performed above expectations. Either the direct importation of varieties, or the incorporation of important traits into new varieties combined with appropriate management will assist breeders, agronomists and growers maximise grain yields in this environment.

CP11321 Water and thermal regimes for field pea in Australia and their implications for breeding

V. O. Sadras, L. Lake, K. Chenu, L. S. McMurray and A. Leonforte
pp. 33-44

There is a gap between the refined genetic approaches and the coarse characterisation of environments in breeding, which is akin to fitting the latest Ferrari with 1950s tyres. We combined data from 185 variety trials and long-term modelling to produce a nation-wide quantitative characterisation of the thermal and water regimes for field pea. Shifting from a nominal (i.e. location and season) to a quantitative (i.e. stress type) characterisation of environments could help improving breeding efficiency of field pea in Australia.

CP11181 Growth dynamics and agronomic-economic benefits of pea–oat and pea–barley intercrops

Christos A. Dordas, Dimitrios N. Vlachostergios and Anastasios S. Lithourgidis
pp. 45-52

Intercropping is a practice that is used in low-input cropping systems and has several advantages. The intercropping of pea with oat and barley were not studied extensively and the present study showed that pea–oat intercrops were more productive than the pea–barley intercrops with higher crude protein yield. Therefore, pea–oat intercrops can be used by the farmers in Mediterranean climates as they are the most profitable systems with the greatest economic return.

It is unclear how phosphorus (P) affects symbiotic nitrogen (N) fixation of crop and pasture legumes under future, higher CO2 levels. We found that improved P status enhanced the [CO2] fertilisation effect on the growth, grain yield and amount of N fixed of several legumes. The results suggest that the predictions of future climates on the potential contribution of legumes to maintaining soil N fertility will depend on the particular response of a species to soil P status.

As pressure on water resources increases, pasture species that use water efficiently are needed. This study, using a simulation model for ryegrass across a range of soils and climates, showed that the traits of deep rooting and high partitioning of carbon to shoots led to the highest yields and greatest water-use efficiency. These traits should be investigated under more realistic conditions while also considering other desirable traits such as nutrient capture and agronomic suitability.

Projections for warmer and possibly drier future climates in south eastern Australia will impact on both annual pasture production and the seasonal pattern of pasture growth. A sensitivity analysis was conducted to address the question: what amount of temperature and/or rainfall change is required before changes in production are observed? Different responses were simulated across a range of climates and pasture types. The approach can be used to identify strategies that may increase resilience of agricultural systems to climate change.

Seed yield and seed quality, are two foundational factors for new grassland establishment and degraded grassland renewal. In this paper, we evaluated the effect of increasing ambient temperature on seed production, seed mass, germinability, and subsequent seedling growth in a dominant perennial grass; and found the germinating seeds per unit area were reduced by increased temperature. The result implies that climate warming will constrain new grassland establishment depending on the viability implications for seeds under further global climate warming.

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