• Authors:
    • Ward, G.
    • Jacobs, J.
  • Source: Animal Production Science
  • Volume: 51
  • Issue: 12
  • Year: 2011
  • Summary: Limitations to the current perennial ryegrass-based pasture system on dryland dairy farms in southern Australia has led to research into alternatives that can produce either additional DM, out of season feed or can improve nutritive characteristics. The use of winter annual crops followed by a summer crop have the potential to achieve these goals but often result in considerable periods where new crops are establishing and feed is not available for consumption. Companion cropping offers an option to overcome these limitations. The experiment reported in this paper examines the DM yields, nutritive characteristics and mineral content of companion cropping wheat or triticale at different sowing rates into an existing chicory monoculture over a 2-year period. We hypothesised that oversowing cereal crops in autumn into an existing stand of chicory would result in improvements in nutritive characteristics at ensiling, without adversely affecting DM yield or subsequent chicory DM yields following harvesting, thus negating the need to sow a new summer forage crop each year. Total DM yields for the chicory and cereal monocultures were similar over the experimental period, while DM yields for all triticale mixtures were higher than the chicory only treatment. Chicory produced lower DM yields for silage but higher DM yields at most grazing events. The crude protein and estimated metabolisable energy content of the chicory only treatment was higher than the cereal monocultures and all triticale/chicory mixtures at both silage harvests with wheat/chicory mixes being intermediate. The proportion of chicory in the mixed swards declined over the course of the experiment. The use of chicory with cereals resulted in no adverse effects on total DM yields, some improvements in nutritive characteristics and mineral content and a more continuous supply of DM compared with double cropping with annual species in winter and summer. This experiment has highlighted the potential of oversowing cereal forages into an existing chicory sward to contribute to DM production on dairy farms in southern Australia. Such forage mixes can provide flexibility into forage systems through the provision of forage for grazing in early winter, the production of high DM yield silage harvests and then subsequent feed supply over summer and early autumn.
  • Authors:
    • Lehane, K.
    • Orange, D.
    • Holmes, C.
    • King, A.
    • Weston, E.
    • Dalal, R.
    • Thomas, G.
  • Source: Journal of Sustainable Agriculture
  • Volume: 35
  • Issue: 1
  • Year: 2011
  • Summary: Rainfed grain production in semi-arid, subtropical south-west Queensland in north-east Australia is marginal, because of low and variable rainfall and low soil fertility. Current cropping systems are based around winter cereals, with a summer fallow period essential for storing soil water to reduce risk. Increasing the soil water storage and the efficiency of water and nitrogen use is essential for sustainable crop production in this region. The effects on crop production and economic returns of various crop rotations involving winter crops - wheat ( Triticum aestivum), chickpea ( Cicer arietinum), faba bean ( Vicia faba) and canola ( Brassica napus); summer crops - grain sorghum ( Sorghum bicolor) and mung bean ( Phaseolus mungo); and fertilizer N application to wheat, canola and grain sorghum were studied from 1996 to 2005 on a grey Vertisol. Annual rainfall was above the long-term average in 6 of these 10 years and below average in 4 years. Crops were either not sown or failed due to drought in 3 years during this period. Under the seasonal conditions and grain prices that occurred during this experiment, mean annual gross margin was $100/ha greater for a 2-year chickpea-wheat rotation, $20/ha greater for a faba bean-canola-wheat rotation and $45/ha greater for an alternate cereal-grain legume rotation involving grain sorghum, mung bean, wheat and chickpea than for continuous wheat ($40/ha), where no nitrogen fertilizer was applied to wheat, canola or grain sorghum. Where nitrogen fertilizer was applied to target prime hard grain protein in wheat and maximize yield in canola and grain sorghum, chickpea-wheat ($170/ha) was the only rotation to result in greater gross margin than continuous wheat ($110/ha). Chickpea generally yielded well and resulted in a mean yield increase of 22% in the following wheat crop compared with continuous wheat, where no nitrogen fertilizer was applied in wheat and of 11% where N fertilizer was applied in wheat to target prime hard grain protein. On average, the grain legumes, chickpea and faba bean, provided soil nitrogen benefits of 20 and 40 kg N/ha, respectively, thereby reducing nitrogen fertilizer requirements for following cereal crops and canola. Therefore, the profitability and sustainability of crop production in this semi-arid, subtropical environment can be improved, compared with continuous winter cereal cropping, by appropriate crop rotations and nutrient management.
  • Authors:
    • Lawn, R. J.
    • Gaynor, L. G.
    • James, A. T.
  • Source: Crop & Pasture Science
  • Volume: 62
  • Issue: 12
  • Year: 2011
  • Summary: The response of irrigated soybean to sowing date and to plant population was evaluated in field experiments over three years at Leeton, in the Murrumbidgee Irrigation Area (MIA) in southern New South Wales. The aim was to explore the options for later sowings to improve the flexibility for growing soybean in double-cropping rotations with a winter cereal. The experiments were grown on 1.83-m-wide raised soil beds, with 2, 4, or 6 rows per bed (years 1 and 2) or 2 rows per bed only (year 3). Plant population, which was manipulated by changing either the number of rows per bed (years 1 and 2) or the within-row plant spacing (year 3), ranged from 15 to 60 plants/m 2 depending on the experiment. Two sowings dates, late November and late December, were compared in years 1 and 3, while in year 2, sowings in early and late January were also included. Three genotypes (early, medium, and late maturity) were grown in years 1 and 2, and four medium-maturing genotypes were grown in year 3. In general, machine-harvested seed yields were highest in the November sowings, and declined as sowing was delayed. Physiological analyses suggested two underlying causes for the yield decline as sowing date was delayed. First and most importantly, the later sown crops flowered sooner after sowing, shortening crop duration and reducing total dry matter (TDM) production. Second, in the late January sowings of the medium- and late-maturing genotypes, harvest index (HI) declined as maturity was pushed later into autumn, exposing the crops to cooler temperatures during pod filling. Attempts to offset the decline in TDM production as sowing was delayed by using higher plant populations were unsuccessful, in part because HI decreased, apparently due to greater severity of lodging. The studies indicated that, in the near term, the yield potential of current indeterminate cultivars at the late December sowing date is adequate, given appropriate management, for commercially viable double-cropping of soybean in the MIA. In the longer term, it is suggested that development of earlier maturing, lodging-resistant genotypes that retain high HI at high sowing density may allow sowing to be delayed to early January.
  • Authors:
    • Smith, J. P.
    • Smith, M. K.
    • Stirling, G. R.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: Ginger (Zingiber officinale) production is facing increasing disease and pest pressure and declining yield with continuing intensive cultivation practices. A four year experiment was established in south-eastern Queensland on a red ferrosol that had a long (>60 years) history of ginger farming. Minimal tillage and organic amendments were compared with conventional practice that involved frequent tillage and soil fumigation using 1,3-dichloropropene (Telone (R)). Ginger crops were grown in the second and fourth year of the experiment, following an annual rotation with different cover crops including oats (Avena sativa), Brassica spp., soybean (Glycine max) and forage sorghum (Sorghum bicolour X S. sudanese). A pasture ley of Pangola grass (Digitaria eriantha subsp. pentzii) provided a treatment continuum from major to minor disruption in the soil's physical fertility and biological communities, and was therefore only planted to ginger in the fourth year of the experiment. Ginger seed-pieces (sections of the rhizome used for planting) were planted into both tilled and untilled beds using a double disc opener on a specially designed ginger planter. Rhizome yield in the final year was greatest (74.2 t/ha) and losses to pathogens (Pythium myriotylum and Fusarium oxysporum f. sp. zingiberi) minimal (7.0%) in the pasture ley that had been cultivated prior to planting ginger. Furthermore, the minimum-tilled cover cropped treatment, which likewise had been cultivated prior to planting ginger, yielded well (62.0 t/ha), with few losses (5.0%) from rhizome rots. Conversely the fumigated treatment had the highest losses (35.9%) due to Pythium Soft Rot and lowest yields (20.2 t/ha). Minimum-tilled plantings of ginger, however, resulted in poor yields (30.9-43.1 t/ha) but had acceptable levels of disease. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Lawn, . J.
    • Gaynor, L. G.
    • James, A. T.
  • Source: Crop and Pasture Science
  • Volume: 62
  • Issue: 12
  • Year: 2011
  • Summary: Serial sowing date studies were used to examine the response of a diverse range of soybean genotypes to sowing date in the Murrumbidgee Irrigation Area (MIA). The aim was to explore the scope to improve the flexibility for rotating irrigated summer soybean crops with winter cereals by broadening the range of potential sowing dates. Serial sowings of diverse genotypes were made in small plots at intervals of ~7 days (2006-07) or 10 days (2007-08) from late November to late January (2006-07) or mid-February (2007-08) and the dates of flowering and maturity recorded. Simple linear models relating rate of development towards flowering to photo-thermal variables indicated that large differences in time to flowering between genotypes, sowing dates, and years could be explained in terms of differences in genotype sensitivity to mean photoperiod and/or mean daily temperature between sowing and flowering. In general, warmer temperatures hastened and longer days delayed flowering, consistent with quantitative short-day photoperiodic response. The earliest flowering genotypes were insensitive to the prevailing photoperiods, and their smaller variations in time to flower over sowing dates and years were related to temperature. Conversely, later flowering genotypes were progressively more sensitive to photoperiod, with flowering occurring later and being more responsive to sowing date. In both seasons, late maturing genotype * sowing date combinations suffered cold temperature damage and frosting. For those genotype * sowing date combinations that were physiologically mature before the first frost, crop duration was a linear function ( r2=0.86**) of time to flowering. In 2007-08, measurements were also made at maturity of total standing dry matter (TDM), seed yield, and seed size. For those genotype * sowing date combinations that matured before the first frost, TDM was largely a linear function ( r2=0.83**) of crop duration, while seed yield was strongly related ( r2=0.86**) to TDM. Exposure to cold temperatures before physiological maturity reduced seed size and harvest index. Using the generalised relations developed in these studies, it was concluded that commercial yields may be possible for irrigated soybean crops in the MIA sown in December or possibly later. These options are evaluated in greater detail in the companion paper, using large-scale agronomic trials of a subset of adapted genotypes.
  • Authors:
    • McClymont, L.
    • McAllister, A.
    • O'Connell, M. G.
    • Whitfield, D. M.
    • Abuzar, M.
    • Sheffield, K.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: The METRIC algorithm (Allen et al., 2007) was applied to a Landsat 5 image to assess the range of vegetation cover (measured as Normalised Difference Vegetation Index; NDVI), and rates of evapotranspiration (ET), of major horticultural crops grown in the Sunraysia Irrigation Region of SE Australia. The image represented the period of maximum foliage cover of horticultural crops grown in the Region. The range in mid-season NDVI of almond, grape and citrus crops almost matched the whole-of-season range reported for broad-acre irrigated annual crops grown in Idaho, USA. Alfalfa reference ET (ETr) constituted the upper limit to ET rate seen in Sunraysia crops. The range of ET and NDVI observations in this study therefore complied with limits on ET and NDVI seen in irrigated crops in Idaho, USA. ET-NDVI relationships seen in USA crops appear to provide a useful reference framework for well-watered irrigated crops in cases where ETr is the upper limit on ET. ET rates in Sunraysia crops were strongly related to NDVI. The dependence of ET rates on NDVI, combined with the large range in NDVI, meant that irrigation water requirement varied widely within and between crop types in the Sunraysia region: results support the use of NDVI measures to account for site-specific differences in crop water requirement attributable to vegetation cover. Findings suggest that satellite-based METRIC methods of ET estimation may be used to formulate region- and crop-specific estimates of the crop coefficients (Kcb, Ke, and Kc) required for optimal irrigation water management of horticultural crops.
  • Authors:
    • Tann, C. R.
    • Baker, G. H.
    • Fitt, G. P.
  • Source: Bulletin of Entomological Research
  • Volume: 101
  • Issue: 1
  • Year: 2011
  • Summary: Pheromone and light traps have often been used in ecological studies of two major noctuid pests of agriculture in Australia, Helicoverpa armigera and H. punctigera. However, results from these two methods have rarely been compared directly. We set pheromone and light traps adjacent to or amongst cotton and various other crops for 10-11 years in the Namoi Valley, in northern New South Wales, Australia. Catches in pheromone traps suggested a major peak in (male) numbers of H. punctigera in early spring, with relatively few moths caught later in the summer cropping season. In contrast, (male) H. armigera were most abundant in late summer. Similar trends were apparent for catches of both male and female H. armigera in light traps, but both sexes of H. punctigera were mostly caught in mid-summer. For both species, males were more commonly caught than females. These catch patterns differed from some previous reports. At least three generations of both species were apparent in the catches. There was some evidence that the abundance of later generations could be predicted from the size of earlier generations; but, unlike previous authors, we found no positive relationships between local winter rainfall and subsequent catches of moths, nor did we find persuasive evidence of correlations between autumn and winter rainfall in central Australia and the abundance of subsequent 1st generation H. punctigera moths. Female H. punctigera were consistently more mature (gravid) and more frequently mated than those of H. armigera. Overall, our results highlight the variability in trap catches of these two species and question the use of trap catches and weather as predictors of future abundance in cropping regions.
  • Authors:
    • Hanan, J.
    • Qu, S.
    • Doherty, A.
    • Song, Y.
    • Birch, C.
  • Source: Plant Production Science
  • Volume: 13
  • Issue: 2
  • Year: 2010
  • Summary: It is essential to provide experimental evidence and reliable predictions of the effects of water stress on crop production in the drier, less predictable environments. A field experiment undertaken in southeast Queensland, Australia with three water regimes (fully irrigated, rainfed and irrigated until late canopy expansion followed by rainfed) was used to compare effects of water stress on crop production in two maize ( Zea mays L.) cultivars (Pioneer 34N43 and Pioneer 31H50). Water stress affected growth and yield more in Pioneer 34N43 than in Pioneer 31H50. A crop model APSIM-Maize, after having been calibrated for the two cultivars, was used to simulate maize growth and development under water stress. The predictions on leaf area index (LAI) dynamics, biomass growth and grain yield under rainfed and irrigated followed by rainfed treatments was reasonable, indicating that stress indices used by APSIM-Maize produced appropriate adjustments to crop growth and development in response to water stress. This study shows that Pioneer 31H50 is less sensitive to water stress and thus a preferred cultivar in dryland conditions, and that it is feasible to provide sound predictions and risk assessment for crop production in drier, more variable conditions using the APSIM-Maize model.
  • Authors:
    • Daniel, H.
    • King, K.
    • Williams, A.
    • Martin, B.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 3.1.2 Farm system and environment impacts
  • Year: 2010
  • Summary: No-till farming in Australia has revolutionised the way many farmers crop. Some of the moisture retention advantages of no-till farming have resulted in a reduced reliance of in-crop rain as well as increasing yields and profitability. Less clear is the effect on biological properties. Early results of a survey of the no-till cropping soils of the central west of NSW showed that most no-till cropping areas have lower soil carbon levels and lower microbial activity than nearby uncropped soils. This indicates that many no-till cropping soils may not be as sustainable as first thought. A long-fallow field trial was conducted on "Magomadine" near Coonamble NSW Australia using surface applied amendments (straw, compost, feedlot manure, biochar and zeolite) to investigate their effect on biological, chemical and physical soil properties. Early results are suggesting that the application of 10t/ha of straw can significantly ( P<0.05) increased soil moisture (24%), microbial respiration (50%), microbial biomass (21%), and mean weighted diameter of soil aggregates (75%). This research has highlighted the importance that high stubble residues have in improving these soil properties during a long-fallow.
  • Authors:
    • Hoffmann, A. A.
    • Penfold, C. M.
    • Sharley, D. J.
    • Thomson, L. J.
    • Danne, A.
  • Source: Environmental Entomology
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Indigenous cover crops have the potential to promote an increase in natural enemies providing fortuitous control of pest species and other ecosystem services. We test this idea in a vineyard in south eastern Australia, where reduced water availability because of drought coupled with increased temperatures has generated interest in sustainable alternatives to the exotic perennial cover crops commonly planted. Three endemic perennial cover crops, comprising the grasses Austrodanthonia richardsonii and Chloris truncata and a mix of two saltbushes ( Atriplex semibaccata and Atriplex suberecta) were established as cover crops and compared with introduced oats ( Avena sativa). Abundance of a range of predators and parasitoids was higher in vines with native cover crops compared with the oat control. In addition, predation levels of sentinel eggs of a common vineyard pest, light brown apple moth ( Epiphyas postvittana), were increased in the native cover crops. However, the native cover crops also increased the abundance of some potential pest species. Native plants therefore have potential to increase abundance of beneficial invertebrates that assist in pest control, but need to be used carefully to ensure that they do not increase local pest problems.