scholarly journals Frost Risk Management in Chickpea Using a Modelling Approach

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 460
Author(s):  
Yashvir S. Chauhan ◽  
Merrill Ryan

Post-flowering frosts cause appreciable losses to the Australian chickpea industry. The Northern Grains Region (NGR) of Australia, which accounts for nearly 95% of chickpea production in Australia, is frequently subjected to such events. The objective of this study was to map frost risk in chickpea in the NGR and develop strategies to minimise the impacts of such risk. The Agricultural Production System Simulator (APSIM) modelling framework was used to determine spatial and temporal trends in post-flowering frost risk. The NGR could be divided into six broad sub-regions, each delineating locations with similar frost risk. The risk was nearly two to three times greater in the Southern Downs and Darling Downs sub-regions as compared to the Central Queensland Highlands, Dawson Callide, New South Wales, and Northern New South Wales–Western Downs sub-regions. There was an increasing trend in the frequency of frost events in the Southern Downs and New South Wales sub-regions, and a decreasing trend in the Central Queensland Highlands and Dawson Callide sub-regions, consistent with the changing climate of the NGR. In each sub-region, frost risk declined with delayed sowings, but such sowings resulted in simulation of reduced water limited yield potential (unfrosted) as well. The model output was also used to compute 10, 30, 50, and 70% probabilities of the last day of experiencing −3 to 2 °C minimum temperatures and identify the earliest possible sowings that would avoid such temperatures after flowering. Choosing the earliest sowing times with a 30% frost risk could help increase overall yields in environments with high frost risk. Simulations involving genotype x environment x management interactions suggested additional opportunities to minimise frost losses through the adoption of particular cultivars of differing phenology and the use of different agronomy in various environments of the NGR. The study indicates that there is considerable variation in frost risk across the NGR and that manipulating flowering times either through time of sowing or cultivar choice could assist in minimising yield losses in chickpea due to frost.

1997 ◽  
Vol 48 (4) ◽  
pp. 433 ◽  
Author(s):  
L. D. J. Penrose

This study examined factors that determine ear emergence in winter wheats grown at Temora, New South Wales. Three development factors were considered: degree of winter habit, response to photoperiod, and intrinsic earliness. The effect of winter habit was first examined by using 3 pairs of related wheats that differed for spring–winter habit. Wheats were sown under irrigation from mid February to June, for up to 4 consecutive years. Ear emergence was recorded in days of the year for ease of field interpretation, and in photo-thermal time to measure delay in development. Winter habit was found to delay ear emergence throughout this sowing range. Ear emergence was then studied in 23 winter wheats that as a group encompassed a broad range for each of the 3 development factors, and these winter wheats were grouped on the basis of combinations of development factors. Differences in ear emergence between these groups guided the construction and testing of regression equations that described ear emergence as a function of sowing date and of the 3 development factors. Many combinations of factors were associated with the time of ear emergence (i.e. 1 October) at Temora that best optimises the balance between frost risk and yield potential. Combinations of development factors also influenced the flexibility of sowing time for winter wheats grown at Temora. These findings may assist the breeding of new winter wheats that can be sown over a longer period than current winter cultivars.


Lung Cancer ◽  
2017 ◽  
Vol 108 ◽  
pp. 55-61 ◽  
Author(s):  
Xue Qin Yu ◽  
Qingwei Luo ◽  
Clare Kahn ◽  
Paul Grogan ◽  
Dianne L. O’Connell ◽  
...  

2011 ◽  
Vol 62 (12) ◽  
pp. 1067 ◽  
Author(s):  
L. G. Gaynor ◽  
R. J. Lawn ◽  
A. T. James

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/m2 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.


2015 ◽  
Vol 66 (4) ◽  
pp. 349 ◽  
Author(s):  
Julianne M. Lilley ◽  
Lindsay W. Bell ◽  
John A. Kirkegaard

Recent expansion of cropping into Australia’s high-rainfall zone (HRZ) has involved dual-purpose crops suited to long growing seasons that produce both forage and grain. Early adoption of dual-purpose cropping involved cereals; however, dual-purpose canola (Brassica napus) can provide grazing and grain and a break crop for cereals and grass-based pastures. Grain yield and grazing potential of canola (up until bud-visible stage) were simulated, using APSIM, for four canola cultivars at 13 locations across Australia’s HRZ over 50 years. The influence of sowing date (2-weekly sowing dates from early March to late June), nitrogen (N) availability at sowing (50, 150 and 250 kg N/ha), and crop density (20, 40, 60, 80 plants/m2) on forage and grain production was explored in a factorial combination with the four canola cultivars. The cultivars represented winter, winter × spring intermediate, slow spring, and fast spring cultivars, which differed in response to vernalisation and photoperiod. Overall, there was significant potential for dual-purpose use of winter and winter × spring cultivars in all regions across Australia’s HRZ. Mean simulated potential yields exceeded 4.0 t/ha at most locations, with highest mean simulated grain yields (4.5–5.0 t/ha) in southern Victoria and lower yields (3.3–4.0 t/ha) in central and northern New South Wales. Winter cultivars sown early (March–mid-April) provided most forage (>2000 dry sheep equivalent (DSE) grazing days/ha) at most locations because of the extended vegetative stage linked to the high vernalisation requirement. At locations with Mediterranean climates, the low frequency (<30% of years) of early sowing opportunities before mid-April limited the utility of winter cultivars. Winter × spring cultivars (not yet commercially available), which have an intermediate phenology, had a longer, more reliable sowing window, high grazing potential (up to 1800 DSE-days/ha) and high grain-yield potential. Spring cultivars provided less, but had commercially useful grazing opportunities (300–700 DSE-days/ha) and similar yields to early-sown cultivars. Significant unrealised potential for dual-purpose canola crops of winter × spring and slow spring cultivars was suggested in the south-west of Western Australia, on the Northern Tablelands and Slopes of New South Wales and in southern Queensland. The simulations emphasised the importance of early sowing, adequate N supply and sowing density to maximise grazing potential from dual-purpose crops.


1974 ◽  
Vol 25 (2) ◽  
pp. 339 ◽  
Author(s):  
AD Wilson

The water consumption and water turnover of Merino sheep grazing on three natural pastures of south-western New South Wales were recorded throughout 1 year, and supplementary data on the water consumption of sheep on some pastures were collected for a further 2–4 years. On Danthonia caespitosa grassland, water was consumed for up to 7 months each year over the summer months. Maximum intakes were 3–3.5 litres per sheep per day, but this was reduced for 1–2 weeks after falls of rain of less than 25 mm and for longer periods after heavier falls. The provision of shade reduced water turnover by a maximum of 0.3–0.5 litre per day on some occasions only, which indicates that shade is of little importance to woolled sheep. On the saltbush (Atriplex vesicaria) and belah-rosewood (Casuarina cristata-Heterodendrum oleifolium) communities, water intakes were up to 6–7 litres per day in summer. In the particularly dry summer of 1972–73, water intakes of the sheep on saltbush rose to 12 litres per day for several months. The higher water intakes of these sheep were attributed mainly to the high mineral content of the Atriplex and Bassia spp. eaten by them, although the sheep on the belah-rosewood community were also in a hotter environment. In contrast to the sheep on Danthonia, those on the bush communities consumed significant amounts of water throughout the winter in years of low rainfall.


1994 ◽  
Vol 34 (7) ◽  
pp. 933 ◽  
Author(s):  
RF Reinke ◽  
LG Lewin ◽  
RL Williams

New South Wales rice crops commonly take >180 days from sowing to harvest, and a reduction in crop duration is sought to increase the efficiency of rice production. The response of rice cultivars of differing growth duration to sowing time and N application was examined across 2 growing seasons. The highest yields were obtained at early sowing dates in each season. In season 2, the maximum yield of the short-duration cultivar M101 was not significantly different to the long-duration cultivars Calrose, Pelde, and M7, with yields >12 t/ha. However, yield of cv. M101 was significantly less than the long-duration cultivars at an early sowing date in season 1. Analysis of yield components did not clearly indicate the reason for reduced yield of the short duration cultivar. Damage by birds and mice before harvest, exacerbated by early maturity, is a possible cause.Later sowing reduced yields of all cultivars, with the short-duration cultivar-least affected. Optimum N application decreased with delay in sowing. At early sowings there was a positive yield response to increasing N, whereas at the latest sowings in each season the N response was negative for all cultivars. Where the yield response to applied N was positive, the yield component most associated with yield was the number of florets per unit area (r = 0.55). Where the yield response was negative, yield reductions were primarily caused by a reduction in the proportion of filled grains (r = 0.83). Minimum temperatures during the reproductive stage of each cultivar explained only a small amount of the variation in percentage of filled grain. Low minimum temperatures during the reproductive stage were not the sole cause of the reduction in proportion of filled grains of late-sown, high-N plots. The high yield potential of short-duration cultivars in The high yield potential of short-duration cultivars in the New South Wales rice-growing area is clearly demonstrated, as is the value of such cultivars where late sowing is unavoidable.


2007 ◽  
Vol 58 (12) ◽  
pp. 1115 ◽  
Author(s):  
J. M. Lilley ◽  
J. A. Kirkegaard

Water stored deep in the soil profile is valuable to crop yield but its availability and conversion to grain vary with preceding management and seasonal rainfall distribution. We investigated the value of subsoil water to wheat on the Red Kandosol soils in southern New South Wales, Australia, using the APSIM Wheat model, carefully validated for the study area. Simulation treatments over 106 years of historic climate data involved a factorial combination of (1) a preceding crop of either lucerne (Dry treatment) or a low-yielding wheat crop (Wet treatment) and (2) restriction of wheat root depth to either 1.2 or 1.8 m. Root access to the subsoil (1.2–1.8 m) increased wheat yield by an average of 0.6 and 0.3 t/ha for the Wet and Dry treatments, respectively, at Cootamundra (mean annual rainfall 624 mm) and by 0.5 and 0.1 t/ha at Ardlethan (mean annual rainfall 484 mm). The differences were principally related to the frequency with which the subsoil failed to wet up, which occurred in 8% and 39% of years at Cootamundra in Wet and Dry treatments, respectively, but in 21% and 79% of years at Ardlethan. In seasons where water from the subsoil was used, the mean value of the water for grain yield, expressed as marginal water-use efficiency (MWUE), was 30–36 kg/ha.mm at both sites. High MWUE (>60 kg/ha.mm) generally occurred in seasons of above-average rainfall when subsoil water facilitated extra post-anthesis water extraction, including that from upper soil layers, to realise the high yield potential. Low MWUE (<10 kg/ha.mm) occurred when re-translocation of pre-anthesis assimilate to grain in the 1.2 m treatment compensated for reduced subsoil water extraction and no yield difference between 1.2 and 1.8 m treatments was observed. Counter-intuitively, the results suggest that subsoil water will be of more value in higher rainfall environments due to its more frequent occurrence, and in above-average seasons due to more efficient conversion to grain.


1987 ◽  
Vol 27 (1) ◽  
pp. 135 ◽  
Author(s):  
IA Rose

The development of new cultivars has provided impetus for soybean (Glycine max) production in northern New South Wales to expand into dryland cropping areas. These new cultivars differ from the traditional irrigated types by being indeterminate and maturing 3-4 weeks earlier. There is no information on the response of this type of cultivar to agronomic factors such as sowing date. However, knowledge of the response to sowing date is of particular importance as it allows producers to decide whether or not to take advantage of good seedbed moisture outside the most favoured range for sowing date. This study utilised irrigated conditions to examine the phenological and yield potential responses to sowing date of 6 early maturing genotypes, including the recently released cultivars. For sowing dates from early November to December the phenological responses were minor and unlikely to influence sowing date decisions, but yield responses varied among genotypes. The recently released cultivars Farrer and Valder showed similar yielding ability across sowing dates from early November to early December. However, the other 4 genotypes (Williams, Calland, Bill 55, Witch 101) showed a marked yield depression with early sowings. Thus choice of cultivar is important when deciding on sowing dates, and tests of sowing date response are necessary for cultivars released for dryland production in the future.


1989 ◽  
Vol 29 (3) ◽  
pp. 383 ◽  
Author(s):  
PL Milthorpe ◽  
RL Dunstone

Jojoba (Simmondsia chinensis [Link] Schneider) was tested at several sites and on various soil types to assess its production potential under rainfed conditions in semi-arid areas of New South Wales. Stands were established using either plants grown from seed or cuttings taken from selected plants. With good nutrition and weed control, plant height increased at a similar rate over the experiment at all but the most sandy site, where growth was consistently poorer despite similar climatic conditions and management. Stands established from seed had extremely variable yields. Some plants failed to produce seed after 8 years while other plants consistently produced fruit after year 4, with yields as high as 1 kg clean seed per bush by year 8. The average yield was well under 200 g plant-1 except at Trangie in 1986-87 (590 g plant-1). At year 3, 50-100% of female plants were unproductive and by year 8, between 8 and 26% of plants remained unproductive. The variation in yield of the sampled population was consistently high irrespective of seasonal conditions, and usually the upper quartile yield was only marginally higher than the mean. However, the maximum yielding plant produced up to 10 times the mean yield. By contrast, the variation in yield of individuals within a clone was low regardless of the yield potential of that clone and the maximum yielding plant rarely exceeded twice the mean yield. Some clones (A, B and F) show promise as agricultural lines as they are relatively consistent yielders and show early yield development. The highest yield obtained extrapolates to 1.1 t ha-1 at year 7 at a site which averages 417 mm rainfall per year. Further research is needed to identify the reasons for the high variability and fluctuations in yield.


2011 ◽  
Vol 62 (6) ◽  
pp. 676 ◽  
Author(s):  
D. D. Reid ◽  
W. D. Robbins ◽  
V. M. Peddemors

The New South Wales (NSW) government has operated a program of netting beaches for the protection of swimmers and surfers against shark attack since 1937 in Sydney, and since 1949 in Newcastle and Wollongong. The scope and directives of the Shark Meshing Program have remained constant since its inception, with operational modifications in net specifications in 1972, changes in spatial deployment in 1972, 1987 and 1992, and the elimination of winter netting since 1989. This markedly increased meshing effort in 1972, and again in 1987. In the present study, we examine the trends in catch and effort for the period from 1950–1951 to 2009–2010 over this 200-km section of the NSW coast. Significant temporal trends in species, size and sex composition are described herein. Catches were consistently dominated by three shark taxa, hammerhead sharks (Sphyrna spp.), whaler sharks (Carcharhinus spp.) and Australian angel sharks (Squatina australis), although their relative contributions to catches varied over time. Catch per unit effort has significantly declined for five of the most abundant shark taxa over the study period, increasing only for a single taxon, the sevengill shark (Notorynchus cepedianus). Catches of larger, potentially dangerous white sharks (Carcharodon carcharias) and tiger sharks (Galeocerdo cuvier) saw fewer large animals being caught over time. This pattern was not observed across other taxa. Four different monthly trends were observed in landings of the most abundant eight taxa, reflecting differences in the biology of the catch species. The current study also provides useful information on catches and sizes of grey nurse (Carcharias taurus) and white sharks before and after their protection in NSW waters in 1984 and 1998, respectively.


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