Seasonal variation in the nutrient composition of the foliage of pecan (Carya illinoensis)

1986 ◽  
Vol 26 (3) ◽  
pp. 393 ◽  
Author(s):  
GC Cresswell ◽  
RJ Wickson

Leaves were sampled every 2 weeks throughout the 1980-81 and 1981-82 growing seasons from a commercial pecan orchard in New South Wales. Leaf concentrations of nitrogen, phosphorus and potassium were highest at leaf emergence and decreased with time. Concentrations of calcium, magnesium and boron were lowest early in the season and increased with time. There was no true seasonal pattern in leaf zinc which varied in apparent response to foliar zinc spray use. These trends were similar for the cultivars Witchita and Western Schley. Minimum seasonal variation in nitrogen, phosphorus, and potassium, the main fertiliser nutrients, occurred between 1 February and 21 March. This period is therefore the most suitable for general diagnostic purposes such as the evaluation of fertiliser programs and surveys of crop nutrient status.


1985 ◽  
Vol 25 (1) ◽  
pp. 109 ◽  
Author(s):  
CJ Pearson ◽  
H Kemp ◽  
AC Kirby ◽  
TE Launders ◽  
C Mikled

Three experiments were carried out to test the hypotheses that (a) there are quantitative differences in growth rate and quality between newly registered cultivars and older cultivars in response to changes in temperature and fertility, and (b) responsiveness to temperature varies between sites because cultivars acclimatize to their current environment. Performance in simulated swards indicated that potential productivity was highest from bermuda grass (Cynodon x Burton Pearson). This was, however, a poor indicator of performance in the field, where yield of bermuda grass was depressed by weeds whereas that of kikuyu (Pennisetum clandestinum) was unaffected. In the field, a newly registered kikuyu, cv. Crofts, outyielded bermuda grass and paspalum (Paspalum dilatatum) either alone or when combined with lucerne. A further experiment compared cvv. Crofts, Whittet and common kikuyu at three levels of nitrogen at three sites. Peak growth rates were the same at all locations but Crofts outyielded the other genotypes by 60, 13 and 18% at Bega (37�S.), Camden (34�S.) and Taree (32�S.) respectively. Average growth rates varied seasonally and were correlated with temperature (r > 0.9). Analysis of temperature responsiveness (kg/ha.�C) indicated that responsiveness varied consistently between genotypes at any location. Furthermore, the base temperature (the temperature below which there was negligible growth) was the same for all genotypes at any location but it increased with increasing latitude. That is, there was a tendency to greater dormancy with increasing coldness of location. Nitrogen responsiveness was the same for all genotypes and sites. Seasonal variations in digestibility and mineral concentrations in kikuyu, bermuda grass and paspalum were similar in the field and in simulated swards; quality was the same in all kikuyu genotypes. Calcium, magnesium and nitrogen concentrations of plant tops (but not phosphorus and potassium concentrations) increased with increasing rates of application of nitrogen fertilizer.



1995 ◽  
Vol 58 (3) ◽  
pp. 135-141 ◽  
Author(s):  
R. C. Woollons ◽  
W. J.B. Crane ◽  
P. Snowden


1998 ◽  
Vol 20 (2) ◽  
pp. 215
Author(s):  
N.P. New ◽  
J.M. Jakubowski ◽  
G.M. Stone ◽  
R.C. Jones

The seasonal pattern of androgen secretion in free-ranging male platypuses was determined in samples of peripheral blood plasma and rectal contents collected between February and November 1996, from animals captured in the Upper Barnard River, New South Wales. Cortisol concentrations in peripheral blood were also measured and seasonal changes in body condition were assessed. Androgen concentrations in samples from the different sources all followed a distinctly seasonal pattern, being low from February to June, rising in July to reach the highest values in August before reducing to lower values by September. The high concentrations occurred within a relatively narrow time frame and appeared to be well synchronised among individuals. Within animal comparisons showed that androgen concentrations in excreta were highly correlated with values for blood. Cortisol concentrations were higher in July and August than other months. Males lost body condition during this period (as indicated by changes in the Tail Volume Index) and it is suggested that they were under increased stress at this time due to rivalry between males around the mating season.



1954 ◽  
Vol 5 (3) ◽  
pp. 422 ◽  
Author(s):  
EG Hallsworth ◽  
FR Gibbons ◽  
TH Lemerle

A study has been made of the nitrogen, organic carbon, phosphate, and pH levels of the wheat soils of north-western New South Wales, and the cultivation practices adopted. They are found generally to be high in both total and available phosphate, and particularly high figures for available phosphate, over 1000 p.p.m., were found in limited areas. The nitrogen levels of the virgin chernozemic soils are distinctly higher than those of the red-brown earths and red solodic soils, but soils of all groups show a decline with cultivation, which is most rapid in the first 10 years. The introduction of periods under lucerne raises the nitrogen level, but the wheat/grazed fallow or wheat/grazing oats appear to cause the same nitrogen losses as are encountered under continuous wheat, in spite of the prevalence of stubble burning which inevitably accompanies this practice. The average yields of wheat on the chernozemic soils are distinctly higher than those obtained on the red-brown earths and red solodic soils, on some of which nitrogen appears to be limiting.



Soil Research ◽  
2002 ◽  
Vol 40 (5) ◽  
pp. 761 ◽  
Author(s):  
R. A. Sarooshi ◽  
G. C. Cresswell ◽  
L. Tesoriero ◽  
P. J. Milham ◽  
I. Barchia ◽  
...  

The study compares the effects of biosolids compost (BC) and inorganic fertiliser (IF) on the nutrient status of a clay loam at Rydalmere in Western Sydney, and an earthy sand at Somersby, 85 km north of Sydney. The soils represent the textural range used for vegetable production in the Sydney Basin of New South Wales. The soils had been under permanent sod (Rydalmere) or native vegetation (Somersby) for at 40 years prior to the experiment. There were 3 treatments during February 1994: IF, fallow (F), and BC. The same plots were treated again during September 1994 to give the combinations: IF followed by IF (IF + IF); F by BC (F + BC); BC by BC (BC + BC). The 4 replicates of each treatment were randomised in blocks. Treatments were incorporated into raised beds to a depth of 15 cm and vegetables were planted in March and again in October 1994. The total amounts of C and N initially present in the soil in the beds (0-15 cm) at Rydalmere were at least 3 times greater than at Somersby and the ratio was greater for S, P, Ca, Mg, K, and Na. By April 1995, the quantities of the 8 monitored nutrients had decreased at both sites for the IF + IF treatment; increased at Somersby, but not at Rydalmere for F + BC; and increased at both sites for the BC + BC treatment. The changes caused by the BC + BC treatment were greater in relative terms at Somersby, because of the initial difference in fertility between the 2 soils. For example, the C and N content increased by an approximate factor of 2 at Somersby, and by greater factors for the other elements. BC + BC was also the only treatment to increase other indices of fertility, such as effective cation exchange capacity (ECEC) and Bray-P, in the surface 15 cm. The treatments did not affect pH in the soil profile (0-50 cm) and increases in EC were ephemeral. The nutrient composition of the 20-30 cm zone was affected at both sites. By the end of the experiment the concentration of C, N, P, Ca, and Bray-P increased and Mg decreased. For C and N between-treatment differences were small, indicating that the observed effects were mostly caused by leaching of the products of mineralisation of soil organic matter. Treatment effects were larger for P, Ca, Mg, and Bray-P, and the final concentrations for the F + BC and BC + BC treatments exceeded those for the IF + IF treatment. At Somersby, both BC treatments increased ECEC, consistent with the importance of leaching as a process of nutrient loss at this site. Consequently, intensive vegetable cropping may pose serious environmental risks particularly on sandy sites.



1993 ◽  
Vol 20 (5) ◽  
pp. 559 ◽  
Author(s):  
G Saunders

The demography of a sub-alpine population of feral pigs was examined at Kosciusko National Park in south-eastern New South Wales. Reproductive data and age structures indicated a seasonal pattern of breeding, most births occurring in summer and autumn. It is proposed that a decreasing availability of high protein food in the autumn and winter months caused reduced rates of conception. Sows produced 0.84 litters per year with postnatal mortality as high as 85%. The population appeared relatively stable at a density of 1.6 pigs kg-2. Hunting, although illegal in a national park, removed 4.4-15.4% of pigs each year. The overall health and body condition of pigs was good, with no evidence of heavy parasitic burdens or disease. Age-specific body weight and body length in this study were greater than those reported for pigs in semi-arid wester New South Wales.



Nematology ◽  
2002 ◽  
Vol 4 (4) ◽  
pp. 527-539 ◽  
Author(s):  
Sven Jonasson ◽  
Inger Schmidt ◽  
Anders Michelsen ◽  
Liliane Ruess

AbstractNutrient availability is a major constraint on plant production and carbon storage in arctic ecosystems but knowledge on the decomposer food web interactions and their effect on nutrient cycling is scarce. We manipulated the soil food web at two contrasting subarctic sites, a low altitude heath and a high altitude fell-field. The influx of nutrients and energy in the soil was increased by addition of fertiliser nitrogen, phosphorus and potassium and of labile carbon (sugar). In addition, two bactericides (penicillin and streptomycin) and a fungicide (benomyl) were applied to manipulate the bacterial and fungal component of the soil. Experiments were carried out in a factorial design with repeated additions over four growing seasons. The present study investigated the nematode fauna and the effects of the manipulations on the abundance of nematode species. Fertilisation resulted in an increase of general opportunists, especially Aphelenchoides. Application of carbon or bactericides had only minor impact on the nematode community. In contrast, the fungicide was very toxic to non-target organisms and greatly reduced the abundance of most nematode species, although Acrobeloides buetschlii showed tolerance and greatly increased in number. At both sites, Eudorylaimus was most affected by the treatments. Generally the manipulations performed resulted in a significant increase in stress tolerant or competitive dominant nematode species.



2013 ◽  
Vol 29 (5) ◽  
pp. 449-454 ◽  
Author(s):  
Andrea G. Vincent ◽  
Edmund V.J. Tanner

Abstract:Leaf litter is an important source of nutrients to tropical forest trees, but its importance for understorey seedling growth is not well understood. Seedlings of Licania platypus (n = 190) and Coussarea curvigemmia (n = 304) were transplanted into deeply shaded forest plots in Panama having received 2 y of litter addition or removal and 7 y of fertilization with nitrogen, phosphorus and potassium combined, and their growth and foliar nutrients measured after 13 and 6 mo respectively. Licania platypus growing in litter addition and removal plots had faster height growth and slower leaf growth respectively than in control plots; C. curvigemmia showed no significant effects apart from lower survival in litter addition plots. These effects may be driven by soil nutrients, as suggested by differences in foliar nitrogen and potassium (but not phosphorus) concentrations, and by a pot experiment in a shadehouse using Ochroma pyramidale seedlings, which showed higher leaf area in soils from litter-addition plots, although seedling dry weight was higher only in fertilized soils. Overall, these results show that for one of two species, understorey seedling growth was increased by 2 y of doubled litterfall, and thus that they were probably nutrient limited even in the relatively fertile soils of this semi-deciduous tropical forest.



1978 ◽  
Vol 12 (1) ◽  
pp. 69-71 ◽  
Author(s):  
Gordon Parker

An association between spring birth and anxiety neurosis in New South Wales is confirmed. Two possible explanations, that the association might reflect a seasonal variation in conceiving or in giving birth among mothers of those with significant anxiety, or that spring birth selectively disposes to anxiety, were examined. Findings suggest that both effects may be operating.



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