Reduced early growth of direct drilled wheat in southern New South Wales: causes and consequences

1987 ◽  
Vol 27 (6) ◽  
pp. 869 ◽  
Author(s):  
PS Cornish ◽  
JR Lymbery

In five experiments with wheat over 4 years on a red earth soil in southern New South Wales, direct drilling reduced plant population by an average of 15% and individual plant dry weight at 10- 11 weeks by an average maximum of 33% compared with sowing into a cultivated seed bed. The maximum reduction in dry weight per unit area averaged 44% (at tillering), but compensatory growth reduced this to 17% by anthesis. Time to emergence was not reduced and differences in plant weight soon after emergence were very small, which suggests that the effect on plant growth occurred only after emergence. Effects of direct drilling on soil surface (0- 10 cm) temperature and water content were not important factors reducing plant population or early growth but high soil strength seemed the most likely cause of reduced root extension in the direct drilled seedbed (0-1 5 cm). Reduced root extension had no direct effect on plant water relations or nitrogen concentration in leaves, but there was a small effect on phosphorus concentration. Reduced root growth appears to reduce shoot growth but the mechanisms require further study. The reduced shoot growth led to reduced preanthesis water-use. After anthesis direct drilled crops generally used more water and had higher leaf water potentials than crops in cultivated soil, leading to yield increases in 2 of the years with dry spring conditions. Only in a drought year (1982) was there evidence of direct drilling reducing the maximum depth of rooting and therefore reducing total water-use resulting in lower grain yield (8%). Overall, direct drilling increased grain yields by 2.4% (2.514 v. 2.576 t/ha) compared with conventional tillage, despite the large reduction in early growth.

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.


1981 ◽  
Vol 32 (6) ◽  
pp. 967 ◽  
Author(s):  
RWJ Pidgeon

The diets and growth rates of rainbow trout in the Wollomombi and Guy Fawkes Rivers in northern New South Wales were examined. The growth rate of trout in the Wollomombi River was much higher than that of fish in the Guy Fawkes River. Spearman rank correlation coefficients indicated that stream type was more important than fish size in determining the composition of the diet of the trout. Benthic invertebrates formed the largest component of the diet in both streams: 66.0 and 63.0% of ash-free dry weight (AFDW) in the Wollomombi River and the Guy Fawkes River, respectively. Trout in the Wollomombi River consumed more nektonic prey (33.3% of AFDW) than fish in the Guy Fawkes River (3.7% of AFDW). In contrast, surface food (aquatic imagines and terrestrial insects) made up a much higher proportion of the diet of trout in the Guy Fawkes River (33.9% of AFDW) than in the Wollomombi River (0.6% of AFDW). Crayfish were a major component of the diet (in terms of AFDW) in both streams, their proportions increasing with fish size. The significance of crayfish in relation to fish growth is discussed.


1993 ◽  
Vol 33 (2) ◽  
pp. 245 ◽  
Author(s):  
PG Tow

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.


1994 ◽  
Vol 34 (7) ◽  
pp. 1069 ◽  
Author(s):  
E Humphreys ◽  
WS Meyer ◽  
SA Prathapar ◽  
DJ Smith

This paper reviews field measurements of evapotranspiration from rice (ET rice) in the Murrumbidgee Valley of southern New South Wales. The results are compared with US Class A open pan evaporation (E pan) at CSIRO Griffith, and with reference evapotranspiration (ETo) calculated using a locally calibrated Penman equation. Both methods (+ETrice = +Epan or +ETrice = +ETo) give good estimates of total evapotranspiration from flooded rice over the ponded season of about 5 months, from October to February. Variation between seasons in total ETo, rainfall, and ETo minus rainfall is large. Over 32 years, total seasonal ETo varied by a factor of 1.5, while rainfall varied >10-fold. The irrigation water requirement for rice +(ETo - rainfall) varied from 685 mm in 1992-93 to 1350 mm in 1990-91. This large variation highlights the need to adjust the rice water use limit (16 ML/ha or 1600 mm) on a seasonal basis, to detect and eliminate high water use paddocks where percolation to the groundwater or surface runoff is excessive (>2 ML/ha). On average, an irrigation requirement of 10.5 ML/ha is needed to replace net evaporative loss +(ETo - rainfall) for rice flooded for 5 months, October-February. Monthly totals of ETo are compared for several locations within the rice-growing areas of southern New South Wales, and differences between locations are found to be small and not significant. This reflects the strong dependence of evaporation on radiant energy, which is unlikely to vary spatially to a significant extent across the region. ETo calculated from meteorological data collected at CSIRO Griffith therefore provides a definitive basis for estimating evapotranspiration from rice in southern New South Wales. Furthermore, CSIRO Griffith has a computerised meteorological data base going back to the 1930s. Current meteorological data and historical records are readily available by contacting the Metdata Manager. Therefore, the case is made for using CSIRO Griffith ETo as the reference for estimating evapotranspiration from rice in southern New South Wales. This study provides farmers, Land and Water Management Plan groups, and policy makers with a tool that can be used, on a yearly basis, to evaluate rice paddock water use efficiency. It should be adopted to confine rice growing to the least permeable soils.


1980 ◽  
Vol 2 (2) ◽  
pp. 208 ◽  
Author(s):  
RD Graetz

Plant population data for the pass white-top (Danthonia caespitosa) and for bladder saltbush (Atriplex vesicaria) were collected for four years from a pasture continuously grazed by either cattle or sheep (at equivalent stocking rates) at a site near Booligal, New South Wales. During the four years of the experiment the cattle and sheep had different Impacts on the grass and scrub components of the pasture Sheep tended to deplete the numbers of pass plants far more than did cattle, whereas saltbush shrub numbers here little affected by either type of stock. The rainfall pattern experienced throughout the experiment had a far greater influence on the survival of both grass and shrub than did grazing.


1979 ◽  
Vol 19 (100) ◽  
pp. 570 ◽  
Author(s):  
JA Thompson ◽  
IG Fenton

Three experiments conducted in the Murrumbidgee Irrigation Area of southern New South Wales examined the influence of plant population on the yield and yield components of irrigated sunflowers. Populations ranged from 25,000 plants ha-1 to 140,000 plants ha-1. Furrow irrigation was employed with rows spaced 76 cm apart. In two of the experiments the wide range of plant populations examined had little effect on seed yield. Individual seed weight (g 1000-1) and seed number per head interacted with plant population so that seed yield was only marginally affected. In the remaining experiment, insufficient total dry matter production without improved harvest index prevented the attainment of an acceptable seed yield. There was a consistent trend for harvest index to fall with increasing plant population. Values recorded ranged from 0.36 to 0.23. Plant population had little effect on oil percentage. A plant population of 50,000 plants ha-1 is suggested as a minimum recommendation for irrigated sunflowers in southern New South Wales.


2004 ◽  
Vol 44 (1) ◽  
pp. 53 ◽  
Author(s):  
S. Simpfendorfer ◽  
D. P. Heenan ◽  
J. A. Kirkegaard ◽  
K. D. Lindbeck ◽  
G. M. Murray

Narrow-leafed lupins (Lupinus angustifolius) were grown in cultivated and direct-drilled plots at 4 field sites in southern New South Wales in 1998 to determine the effect of tillage on seedling vigour, disease and yield. The early growth of lupins in direct-drilled plots was reduced compared with seedlings in cultivated plots at 3 of the sites. However, the biomass of lupin plants in the direct-drilled treatments was 20% greater than in adjacent cultivated plots at harvest. The lower biomass in cultivated plots appeared to be primarily related to an increased incidence and severity of stem rot caused by Sclerotinia sclerotiorum. The increased stem rot in cultivated plots was also associated with a decline in yield of between 16 and 35% across the sites compared with direct-drilled plots. The direct-drilled treatment reduced the severity of brown spot, caused by Pleiochaeta setosa, at the 2 sites where stubble was retained from the previous wheat crop. These results suggest that direct drilling into cereal residue provides benefits over cultivation for the growth of lupins in southern New South Wales where crop infection by Sclerotinia and/or brown spot may be significant.


1985 ◽  
Vol 36 (4) ◽  
pp. 615 ◽  
Author(s):  
DK Muldoon

White Spanish, Red Spanish and Virginia Bunch cultivars of Arachis hypogaea L. were sown at two row spacings (30 and 60 cm) and two times (29 October and 3 December) on an alkaline clay soil in western New South Wales. The crops were furrow irrigated between raised beds 1 m wide. Maximum oven dry pod yields were 3.0, 2.3 and 3.3 t ha-1 for white Spanish, Red Spanish and Virginia Bunch respectively. Corresponding shelling percentages were 65, 68 and 57%. White Spanish and Virginia Bunch matured 180-190 days after early sowing and Red Spanish after 210 days when frost stopped growth. The late sown crop failed to mature before the frosts, and yielded 15-25% less than the early sowing. The late crop had a shorter period for the production of pods and also a slightly lower rate of pod production because of reduced shoot growth; kernel weight per pod was similar at both sowings. Differences between cultivars were accounted for by differences in the rate of pod filling and hence ultimate kernel weight per pod, and furthermore, the harvest index differed among cultivars. White Spanish or Virginia Bunch sown in 30 cm rows before December can be recommended for irrigated groundnut production in western New South Wales.


1991 ◽  
Vol 31 (1) ◽  
pp. 85 ◽  
Author(s):  
AD Doyle ◽  
RA Shapland

Experiments were conducted with dryland wheat on a nitrogen (N) deficient site near Gunnedah, northern New South Wales, in 1987 and 1988 to compare post-sowing foliar applications of N with urea drilled between the rows at sowing. Post-sowing N was applied at tillering, booting or at both stages at rates of 20 or 40 kg N/ha while presowing applications ranged from 0-106 kg N/ha. Above ground dry weight and N uptake increased with increasing N application at sowing. Post-sowing N application increased dry weight and N uptake, with generally greater increases in N uptake than in dry weight. Dry weight and N uptake for post-sowing N application were invariably less than when an equivalent amount of N had been applied at sowing. Grain yield was increased by the application of up to 106 kg N/ha at sowing in 1987 and up to 80 kg N/ha in 1988 when a greater degree of moisture stress during grain filling restricted yield responses. Post-sowing N increased grain yield, but the yield response was lower than for the application of an equivalent amount of N at sowing. Grain yield responses were lower when N was applied at booting rather than tillering. Yield responses over the 2 years were 0.35-0.39 t/ha and 0.44-0.68 t/ha for 20 and 40 kg N/ha, respectively, applied at tillering and 0.26-0.4 t/ha and 0.26-0.48 t/ha for N application at booting. Post-sowing N application increased grain protein, with greater increases for booting than for tillering applications. There was an apparent recovery in the grain of 48-56% of N applied at sowing, but only 25-48% of N applied post-sowing.


1971 ◽  
Vol 19 (2) ◽  
pp. 191 ◽  
Author(s):  
RA Malik ◽  
DJ Anderson

Pattern analyses of density and performance data collected from separate populations of Atriplex inflata in the western Riverine Plain of New South Wales consistentiy indicated two linear scales of contagion at 2-4 and 16 m. The largerscale plant pattern corresponds to a similar pattern of microtopographical variation but regressions of density alone on microtopography are significant, indicating possible alternative mechanisms for establishment (as indicated by density data) and subsequent performance (as indicated by cover data). The performance of A. inflata plants has been assessed experimentally on a range of natural soils and in controlled nutrient solution culture. The results suggest that performance (as estimated by dry weight yield) is significantly affected by soil type, water stress, and a soil type ° water stress interaction. The prime effect of soil variation on yield appears to be mediated by variation in soil cation balance.


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