Responsiveness to seasonal temperature and nitrogen among genotypes of kikuyu, paspalum and bermuda grass pastures of coastal New South Wales

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.

1980 ◽  
Vol 20 (102) ◽  
pp. 9
Author(s):  
ID Sanderson ◽  
JD McFarlane ◽  
WR McManus

An experiment was conducted on the Central Western Slopes of New South Wales with Dorset Horn x Merino lambs to assess their liveweight gains during summer when weaned on to a lucernebased pasture under dryland conditions, and when weaned on to irrigated lucerne and red clover pastures. Lambs grazing irrigated lucerne, irrigated red clover and dryland lucerne had average growth rates of 155, 178 and 124 g day-1/head, respectively, throughout the 106 day experimental period. The poor growth rates of lambs on the dryland lucerne were apparently due mainly to the low digestibility of the dry feed on offer as a result of low rainfall, which also caused feed supply to be limiting during part of the experimental period. Lamb growth and intake data suggest that the diets selected from the red clover were of higher digestibility than those selected from the irrigated lucerne. It was concluded that irrigated red clover and irrigated lucerne provided useful diets for young lambs in this environment, although the growth rates achieved were less than reported elsewhere for these species in cooler climates. Growth rates achieved by lambs grazing dryland lucerne were less satisfactory for prime lamb production.


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.


2020 ◽  
pp. 1-21
Author(s):  
Smilja Lambert ◽  
Hussin bin Purung ◽  
Syawaluddin ◽  
Peter McMahon

Summary Cocoa (Theobroma cacao) farmers in Sulawesi, Indonesia typically use subsidised, ammonium-based rice fertilisers that in combination with poor agricultural practices have resulted in soil acidification, loss of organic matter, aluminium toxicity and lower soil fertility. As a result, these soils are only marginally appropriate for replanting cocoa to boost production. A field experiment was performed to test alternative soil amendments for successful replanting of cocoa on these deficient soils. In a trial with a randomised block design, 6-month old seedlings, top-grafted with the local MCC02 clone, were planted under light Gliricidia sepium shade and after 3 months treated quarterly with two options of mineral fertilisers: either a customised fertiliser, consisting of Nitrabor (a combination of calcium nitrate and boron), dolomite, rock phosphate and KCl or a NPK/urea mix used by farmers, each supplied with or without ‘micronutrient’ rock salt, organic fertiliser and beneficial microorganisms or their culture medium, a mixture of chitin and amino acids (a total of 20 treatments). Over a 4-year period, the marginal mean rates of stem diameter increment and flowering score were higher in customised fertiliser than NPK/urea treatments. The average growth rate was highest in the first year and was increased by supplying organic fertiliser. A significant correlation (r = 0.22, p < 0.05) occurred between growth and available P, but concentrations of available P were higher in the NPK/urea plots, which also had lower mean growth rates. Combined supply of organic fertiliser and microbes increased available P, as well as growth rates, in both the customised and NPK/urea treatments. In contrast, NPK/urea-treated plots without these amendments demonstrated very low growth rates. The customised formulation was more effective with or without added organic fertiliser or inoculated microbes. Micronutrient supply stimulated flowering. Growth rates in trees supplied with NPK/urea were also promoted by micronutrients. Leaf flush production occurred in regular cycles and was unaffected by the nutrient amendments. After 3 years, the customised and organic fertiliser application increased soil pH and exchangeable Ca and Mg concentrations, although they remained below recommended levels for cocoa production. These treatments had little impact on soil C content (about 1.3%) which was also deficient. Exchangeable Al and total Zn concentrations were higher in soils amended with NPK/urea. The results of the trial provide evidence that utilisation of organic fertiliser in combination with customised nitrate-based formulations improves cocoa establishment, growth and soil properties and should be recommended as a replacement for the NPK/urea fertilisers traditionally used by farmers.


1981 ◽  
Vol 11 (3) ◽  
pp. 689-695 ◽  
Author(s):  
Craig G. Lorimer

Mortality and growth rates of trees in various crown classes and size classes were analyzed from 40-year permanent plot records of slope and ravine forest dominated by chestnut oak (Quercusprinus L.) and northern red oak (Quercusrubra L.). Average 5-year mortality rates for suppressed trees ≥2.5 cm dbh of chestnut oak and red oak in the slope forest were 26 and 45%, respectively. None of the suppressed red oaks survived the 40-year period, compared with 14% of the chestnut oaks and 33% of the red maples (Acerrubrum L.). Mortality of oak trees in the intermediate crown class was less than half that of suppressed trees, but still much higher than that of maples and birches on the tracts. Survival was reasonably high for oaks as long as the top of the crown was receiving direct sunlight, but the expected 40-year survival rate of red oaks in such a position is only 20%, with an average growth rate of 1.0 mm in diameter per year. Curves and equations expressing average mortality and growth rates at various levels of competition are presented for each species.


1969 ◽  
Vol 43 (4) ◽  
pp. 215-227
Author(s):  
José Vicente-Chandler ◽  
Servando Silva ◽  
Jacinto Figarella

The effects of nitrogen rates ranging from 0 to 2,000 pounds of N per acre yearly and of 40-, 60-, and 90-day harvest intervals on the yield and composition of Napier grass and on soil acidity, were determined for three consecutive years. Yields increased with nitrogen fertilization to at least the 800-pound level during all seasons. Crude-protein contents and protein yields increased with nitrogen fertilization up to the 2,000-pound level. More than 60 percent of the fertilizer nitrogen was recovered in the forage at all rates up to 1,200 pounds per acre yearly, but efficiency of utilization in terms of dry matter produced per pound of nitrogen decreased beyond the 400- pound level. The phosphorus and potassium contents of the forage decreased, but the lignin content increased with increasing nitrogen rates. The calcium and magnesium contents were not markedly affected by nitrogen fertilization. Dry-matter and protein yields and lignin content of the forage increased, while the protein, phosphorus, calcium, magnesium, and potassium contents decreased with length of harvest interval. With a 60-day harvest interval and 800 pounds of nitrogen per acre yearly, which seemed to be the optimum combination, Napier grass yielded 44,561 pounds of dry matter, or about 130 tons of green forage, per acre yearly, containing 9.7 percent of protein. With this treatment, Napier grass removed 674 pounds of nitrogen, 554 of potassium, and 120 each of calcium, magnesium, and phosphorus per acre yearly from the soil. Over-all yields did not decrease during the 3 years of experimentation but seasonal yields varied by as much as 70 percent of the average. The treatments affected residual yields obtained more than 6 months after the experiment was terminated. The application of 800 pounds of N as ammonium sulfate per acre annually over a 3-year period caused a drop of 3 pH units and a loss of 10.4 m.e. of exchangeable bases per 100 gm. of soil in the upper 6 inches of soil.


1979 ◽  
Vol 11 (4) ◽  
pp. 411-424
Author(s):  
H. Mary Fellowes ◽  
Catherine A. Hytten ◽  
W.Z. Billewicz ◽  
A.M. Thomson

SummaryOne hunderd and forty 'normal' children aged 0—5 years, selected from three large general medical practices to represent a wide socioeconomic range, were seen monthly for periods of at least one year. Average growth patterns, previously shown to be related to the energy value of diets, conformed to British standards. Height and weight were not significantly related to socioeconomic status, maternal 'efficiency', number of sibs nor place in family. About half the children aged 0.5 years or less changed growht 'channels', falling to 0.4% in children aged 2 years or more. Respiratory illnesses showed seasonal changes, but growth rates did not, and there was no evidence that illness of any kind or severity had more than a transient effect on growth rates. Developmental test scores were not found to be related to growth rates. Girls tended to have higher scores than boys. Children from non-manual families and those with sїbs at least 5 years older scored more highly in tests of language than those in other types of family.


1979 ◽  
Vol 92 (3) ◽  
pp. 591-603 ◽  
Author(s):  
I. McDonald ◽  
J. J. Robinson ◽  
C. Fraser ◽  
R. I. Smart

SUMMARYThe concentrations of dry matter, crude protein, fat and ash and of Ca, P, Mg, Na and K were determined for 22 sets of twin foetuses, 33 of triplets and 11 of quadruplets of known gestational ages within the range 55–145 days. In addition, determinations were made of the concentrations of dry matter, crude protein, fat and ash in their associated placentae and empty uteri, and of dry matter, nitrogen, energy and ash in the foetal fluids. The dry matter, crude protein and fat concentrations in the placentae increased with foetal age and decreased with increasing litter size. Ash concentrations were unaltered. There was no effect of litter size or foetal age on the concentration of nutrients in the empty uteri. Dry matter and nitrogen concentrations in the fluids increased with foetal age but were independent of litter size, whereas ash concentrations increased with litter size but not with age.The form of the mathematical model for foetal growth is considered in relation to the estimation of rates of accretion and the estimation of the differences in composition to be expected between foetuses that are heavy and others that are light relative to their age. When the weights of the foetal constituents were fitted by Gompertz equations extended to include foetal weight as an allometric term, the effects of litter size on foetal composition could be estimated from the foetal weights for each size of litter. Concentrations of dry matter and of most constituents in the foetuses became less as numbers of foetuses increased, irrespective of stage of gestation.A description of the changing composition of the growing foetuses was provided by specific growth rates calculated from the fitted equations. With minor exceptions, derived estimates of foetal concentrations of each constituent were found to agree quite well with most previously published estimates for ovine foetuses, but similar agreement on daily accretion rates was not to be expected in view of the sensitivity of such estimates to the choice of model for foetal growth. Rates of accretion in the gravid uterus increased up to about 5 weeks before parturition and tended to level off thereafter, but most of them still increased slightly over the last 2 weeks, even in ewes bearing triplets or quadruplets. Taking account of the changes in the maternal body of the ewes, it was concluded that although the prolific ewes incurred a substantial energy deficit, and could not have consumed sufficient of the diet to avoid this, their intakes in late pregnancy were nevertheless adequate to support the high rates of accretion of protein and of minerals in the gravid uterus.


2008 ◽  
Vol 48 (7) ◽  
pp. 966 ◽  
Author(s):  
S. Hatcher ◽  
J. Eppleston ◽  
R. P. Graham ◽  
J. McDonald ◽  
S. Schlunke ◽  
...  

Two monitoring projects were conducted to investigate weaner mortality in commercial Merino flocks in the Yass and the Central Tablelands Rural Lands Protection Boards located in the Southern Tablelands agricultural region of New South Wales. The projects were conducted in Yass in 2005 and in the Central Tablelands in 2006. A random sample of weaners from four flocks in the Yass board and 11 flocks in the Central Tablelands board were regularly weighed, growth rates were calculated after weaning and survival was determined by the continuing presence of an individual weaner at subsequent weighing activities. Weaning weight was the most important factor in determining postweaning liveweight, growth rates and survival with the significant impact of weaning weight on liveweight persisting for up to 6 months after weaning. Despite the lightest weaners being capable of considerable compensatory growth given sufficient postweaning nutrition, the lightest 25% of weaners were more than twice as likely to die as heavier weaners. A focus on ewe nutrition and parasite control during late pregnancy and lactation will allow Merino producers to achieve higher weaning weights that will set their weaners up for strong postweaning growth with a decreased likelihood of mortality.


2008 ◽  
Vol 48 (7) ◽  
pp. 974 ◽  
Author(s):  
J. E. Hocking Edwards ◽  
R. M. Gould ◽  
K. J. Copping

Merino weaner survival is poor under normal traditional management practices. Data from four trials conducted between 2001 and 2005 were used to assess the effectiveness of current industry recommendations to achieve 95% survival rates of Merino weaners. There was very little difference between 2001 and 2003 in survival of Merino weaners despite average weaning weight ranging from 20 to 24 kg between years. The recommended target weaning weight of 23 kg does not always appear to be a good predictor of survival. However, a target of 45% mature liveweight at pasture senescence achieved the industry recommendation of 95% weaner survival. Merino weaners were fed over the summer–autumn period to reach 40 kg liveweight by the time green feed became available. Weaner survival reached 93% compared with 89% survival to hogget shearing in weaners managed under normal growth paths. Furthermore, twice as many ewe weaners died in the traditional feeding program compared with the well fed ewe weaners. Differences in mortality between feeding levels in the wether weaners was less than that observed in the ewe weaners. Flock average growth rates were not useful indicators of weaner survival and there was no relationship between Merino ram estimated breeding values for weaning weight and the survival of the progeny.


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