Diagnostic leaf nutrient standards for low-chill peaches in subtropical Australia

1997 ◽  
Vol 37 (1) ◽  
pp. 119 ◽  
Author(s):  
D. O. Huett ◽  
A. P. George ◽  
J. M. Slack ◽  
S. C. Morris

Summary. A leaf nutrient survey was conducted of the low-chill peach cultivars, Flordaprince (October maturing) and Flordagold (mid November–early December maturing) at 3 commercial sites in both northern New South Wales and southern Queensland. Recently mature leaves from the middle third of a current season’s fruiting lateral (spring flush) were sampled at stone hardening and 2-weeks postharvest and of a non-fruiting lateral at maturity of the summer flush (after summer pruning) during the 1992–93 and 1993–94 seasons. At an additional site in New South Wales (Alstonville), leaf nutrient concentrations were also determined on cv. Flordagem (early November maturing) at 2-week intervals during both seasons. Soil (0–30 cm) chemical determinations were conducted at all sites at 2-weeks postharvest Seasonal trends in leaf nutrient composition were associated with a leaf age–maturity effect. As flush leaves matured during spring, and as mature leaves aged after hardening of the summer flush, nitrogen (N) concentration declined and calcium (Ca) concentration increased. Nitrogen and Ca concentrations increased when young leaves produced from the summer flush were sampled. Time of sampling produced the most consistently significant (P<0.05) main effects on leaf nutrient concentration. The 2-week postharvest period was selected as a convenient time to sample—when leaves were of a consistent age and maturity, and the effect of crop load on tree nutrient reserves was still present. Paclobutrazol, which reduces vegetative growth in stonefruit, was applied to all Queensland sites and, as a consequence, mid lateral leaves contained higher (P<0.05) Ca, magnesium (Mg) and chloride (Cl) and lower (P<0.05) N and phosphorus (P) concentrations than leaves from New South Wales sites. State effects can therefore be interpreted as paclobutrazol effects. Cultivar effects (P<0.05) occurred for many leaf nutrients, however, at the 2-week postharvest sampling, concentrations were sufficiently similar to combine as a narrow adequate concentration range for both cultivars. The diagnostic adequate leaf nutrient concentrations were within the range developed for high-chill peaches (Leece et al. 1971) with the exception of lower Ca, lower Mg for New South Wales (both cultivars), lower iron for Flordaprince (both states), higher P for Flordaprince in New South Wales and higher manganese values for Queensland (both cultivars). Regression analyses were conducted between leaf and fruit nutrient concentrations and soil chemical properties. The only consistent result demonstrated that as the soil Ca : Mg ratio increased, leaf Mg concentration decreased exponentially (P<0.001), indicating that the practice of heavy annual agricultural limestone or gypsum applications in the absence of Mg fertiliser, which had been adopted by several growers in the survey, is associated with lower leaf Mg concentrations.


Soil Research ◽  
2009 ◽  
Vol 47 (6) ◽  
pp. 555 ◽  
Author(s):  
Michael G. Jones ◽  
R. Willem Vervoort ◽  
Julie Cattle

Understanding the process by which nutrients and solids enter waterways from pastures in the Great Lakes district, New South Wales, Australia, may assist in maintaining water quality to ensure ongoing environmental and economic sustainability of the region. Rainfall simulations, using a 100-year return storm event, were conducted to determine nutrient and suspended solid concentrations in the runoff of 8 pasture sites in 3 of the catchments in the district. On 5 of the 8 sites, considerable concentrations of N or P were mobilised during the simulated rainfall event, but average nutrient concentrations and total loads across all sites were relatively low and similar to other studies of nutrient runoff from pastures. In addition, low runoff coefficients indicated that runoff is probably not the major pathway for nutrient losses from pasture in this area. Overall, rainfall runoff responses at the sites were similar in the 3 catchments. In contrast, the results suggest that, despite generating more runoff, the sites in the Wang Wauk catchment generated less nutrients in runoff than the sites in the Wallamba and Myall catchments. There was no difference in total suspended solids loads for the sites analysed by catchment. Relationships between soil physical and chemical characteristics and total nutrients loads or cumulative runoff were not strong.



1974 ◽  
Vol 14 (66) ◽  
pp. 112 ◽  
Author(s):  
DW Turner ◽  
B Barkus

At Alstonville, New South Wales, leaf position had a greater effect than season on the nutrient concentrations of N, P, K, Ca, Mn, Cu, and Zn in the laminae of Williams bananas growing on a krasnozem soil and sampled over a 4-year period. However, season was more important for Mg. The effect of stage of plant growth was significant but much smaller than the other influences. When sampling for leaf analysis, leaf position and plant age can be standardised, but a major problem in this investigation was unpredictable, significant changes in nutrient composition from one sampling date to another. If these results are true for other soils. the data do not allow critical levels to be applied.



Soil Research ◽  
1998 ◽  
Vol 36 (4) ◽  
pp. 669 ◽  
Author(s):  
A. M. Whitbread ◽  
Rod D. B. Lefroy ◽  
Graeme J. Blair

The soil survey was conducted on cropped and uncropped Red Earths (Alfisols), Grey Clays, and Black Earths (Vertisols) in northern New South Wales. The degradation of soil physical properties between the cropped and uncropped reference sites was reflected in declines of 29–86% in hydraulic conductivity (K) and 33–71% in aggregation. Generally there was a substantial loss of carbon with cropping, and the loss of labile carbon (CL) was usually greater than the loss of total carbon (CT). A Grey Clay which had been cropped for >40 years had lost 63% and 51% of its CL and CT, respectively. An adjacent Grey Clay which had been cleared and cropped for only 2 years had lost 43% and 26% of its CL and CT, respectively, resulting in a C management index (CMI) of 55, indicating that a large proportion of soil C was lost soon after the commencement of cropping. Where well-managed legume leys had recently been grown, the loss of C was reduced, resulting in a higher CMI. A loss of total and available nutrients after cropping was also found, with the magnitude of the losses modified by fertiliser history. A highly significant correlation was found between CT or CL and the proportion of water-stable aggregates >250 µm for the Red Earth and Grey Clay soils, but this correlation was poor for the Black Earth. The importance of organic matter in maintaining aggregation in low clay soils such as the Red Earth was highlighted.



Soil Research ◽  
1970 ◽  
Vol 8 (3) ◽  
pp. 221 ◽  
Author(s):  
JD Colwell

Statistical procedures are described for the characterization and comparison of profiles within soil classification units. Profile trends in a measured characteristic are represented by the coefficients of orthogonal polynomials in depth, and these coefficients are used as observations for standard statistical procedures. The mean of the respective coefficients provides estimates of the mean profiles for the classification units, and the variance-covariance matrix of the coefficients can be used to calculate the confidence intervals of these means. Differences between the mean profiles can be tested by analyses of variance. The variability of a range of chemical properties in the profiles of four Great Soil Groups, viz. yellow podzolic, red earth, red-brown earth, and grey clay, is described. The characterization is based on the analysis of profiles sampled from areas of about 0.4 ha chosen to represent cultivated examples of the groups in southern New South Wales. Variability of most soil properties is greater between these areas than within them, notable exceptions being exchangeable calcium and magnesium within the grey clay Group. This high localized variability is attributed to the gilgaied nature of this group in this region. Also variation between the soil groups is generally greater than within the groups. The differences seem, however, of limited importance from the point of view of soil fertility.





2007 ◽  
Vol 47 (7) ◽  
pp. 869 ◽  
Author(s):  
D. O. Huett ◽  
I. Vimpany

Leaf nutrient analyses are widely used to determine the nutritional status of macadamia orchards. A commercial database was developed from 2186 observations collected from 186 farms across 56 geographical areas spanning New South Wales and Queensland. The data were collected over 10 years, with 1 to 9 sequential annual observations on each farm. An experimental database was also developed where several of the most popular commercial cultivars growing in the Lismore area of New South Wales and the Bundaberg area of Queensland were sampled at monthly intervals over a 2–3 year period. Two canopy sampling heights were used to confirm the effect of shading (irradiance) on leaf nutrient composition. This latter study confirmed that spring was an appropriate time to sample and that irradiated leaves, usually located in an upper canopy position, should be sampled. The most important change to the recommended leaf nutrient standards was the increase in the leaf nitrogen range from 1.3–1.4% to 1.4–1.7% for all cultivars except 344, where we recommend 1.6–2.0%. The study also confirmed that the adequate concentration range for zinc should be much lower than originally recommended. We recommend concentrations of 6–15 mg/kg. Minor changes were made to most other macro- and micronutrients. We also advise caution when interpreting the analyses of some nutrients because concentrations can change over the spring period. The revised leaf nutrient standards were developed from two large and comprehensive databases and reliably represent adequate leaf nutrient concentrations in productive, well-managed macadamia orchards in Australia. A single leaf analysis will not reliably indicate the nutritional status of a macadamia orchard. Additional information is required on trends in leaf and soil analyses over time as well as fertiliser, yield and management history.



1971 ◽  
Vol 11 (52) ◽  
pp. 541
Author(s):  
JD Colwell

Estimates are made of the desirable number of soil core samples that should be taken from the sites of field experiments for the estimation of profile trends in chemical properties for between site comparisons. The estimates are made on the basis of the magnitude of within site variance relative to between site variance. Fewer samples are required when between site variance is high than when it is low. The data were obtained from the sites of experiments representing four great soil groups in southern New South Wales. The desirable number of samples varies amongst the soil groups, with the chemical properties and with depth down the soil profile. Estimates for mean profile trends and for the means of individual depth strata were similar, It is concluded that at least 9 to 12 core samples should be taken per site and preferably 29 to 40 to ensure reasonably safe estimates of profile trends in important chemical properties.



1994 ◽  
Vol 34 (8) ◽  
pp. 1197 ◽  
Author(s):  
GG Johns

Legume groundcovers have been promoted for controlling soil erosion in hillside banana plantations in northern New South Wales. An experiment was conducted at Alstonville to determine the effect of an Arachis pintoi (Pinto peanut) groundcover on banana productivity. The Arachis groundcover was slow to establish in the first year, but thereafter grew vigorously. While standing dry matter of groundcover was reduced at closer banana plant spacings, it was always more than adequate to control erosion. After 5.5 years many soil chemical parameters had been significantly affected by the presence of groundcover. Organic carbon concentrations to 30 cm depth were 5.6% greater on the groundcover plots (3.94 v. 3.71%), and total nitrogen was 8.5% greater (0.42 v. 0.39%). Other increases were exchangeable potassium 52%, calcium 26%, magnesium 43%, sodium 23%, electrical conductivity 24%, and pH 0.13 units. Banana leaf nutrient concentrations were not affected. Banana plants with groundcover produced 9% fewer bunches than their bare soil counterparts, with 4% fewer fingers per bunch. By the end of the experiment, fingers on the groundcover treatment were 9% lighter; consequently, the weight of marketable fruit (i.e. >120 g/finger) per bunch was reduced by 31% in the final year. The presence of groundcover reduced total fruit production over the whole trial by 16% and marketable fruit by 19%. In the last year of the experiment, total fruit production was reduced by 25%, and marketable fruit production by 40%. Over the whole trial, banana plants with groundcover produced 22% fewer suckers than the bare soil controls, with most of the effect occurring in the first 2 years. Soil temperatures at 20 cm under groundcover were as much as 0.7�C cooler than the controls in October-January, but similar for the rest of the year. This effect possibly contributed to decreased yields. Although the experiment was irrigated, the irrigation was possibly inadequate for the groundcover treatment, and competition for water between the Arachis and banana plants may also have been responsible for part of the yield depression. Rats fed on the buried Arachis seed each winter.



1994 ◽  
Vol 45 (5) ◽  
pp. 737 ◽  
Author(s):  
L Bowling

Although smaller cyanobacterial blooms had occurred in Lake Cargelligo in previous summers, a severe bloom of Anabaena circinalis occurred in the lake in November 1990. Cell numbers exceeded 100 000 cells m L -1 , and toxicity tests revealed the bloom to be highly hepatotoxic. This resulted in the first known closure of a town water supply due to cyanobacteria in New South Wales. Blooms of Microcystis aeruginosa, Aphanizomenon issatschenkoi, Oscillatoria rnougeotii and Cylindrospermopsis raciborskii also occurred in the lake at similar very high cell numbers during the summer and autumn of 1990-91. All five species persisted until May 1991, although there was no detectable toxicity from January onwards. Severe flooding in the Lachlan River valley upstream of Lake Cargelligo during the winter of 1990 led to nutrient enrlched inflows to the lake. These elevated nutrient concentrations would have been a major factor contributing to the bloom. However, other physico-chemical factors were also suitable for cyanobacterial growth.



2013 ◽  
Vol 35 (1) ◽  
pp. 71
Author(s):  
N. A. Streeton ◽  
R. S. B. Greene ◽  
K. Marchiori ◽  
D. J. Tongway ◽  
M. D. Carnegie

The degradation of semiarid agricultural rangelands in Australia can be traced back to the 19th century when Europeans expanded into these areas. That environmental degradation remains today and continues to harm agricultural productivity. The rehabilitation of a strongly incised ephemeral stream, ‘Spring Creek’, in central New South Wales, as an example of what can be achieved readily by landowners, is described. The causes of environmental degradation and the main environmental factors leading to the stream erosion were identified, rehabilitation began and the behaviour of the regime for 5 years within Spring Creek and the adjacent floodplain was monitored. It was found that intrinsically unstable sub-soils and sparse ground cover due to persistent grazing by domestic livestock were the major factors leading to incision. Several physical and chemical properties were found to be the primary causes of the soil’s instability. Rehabilitation focussed on stabilising the soils alongside the stream, promoting sedimentation and re-vegetation of the stream bed, with a longer-term objective of increasing the transfer of water, sediments and nutrients between the stream and its adjacent floodplain. The measures, implemented by local landowners, included the provision of in-stream porous rock weirs and the lowering of the grazing pressure on the stream bed and adjacent floodplain. Monitoring in 2007, 2009 and 2011 indicated that sedimentation was substantially faster above weirs than where there were no weirs. The rehabilitative measures resulted in the retention of fine sediment (<0.2 mm) along the stream bed behind weirs.



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