Soil-extractable sulfur and pasture response to applied sulfur

1998 ◽  
Vol 38 (6) ◽  
pp. 567 ◽  
Author(s):  
G. C. Anderson ◽  
R. D. B. Lefroy ◽  
G. J. Blair

Summary. A glasshouse experiment was conducted to study the correlation between various soil sulfur (S) extractants and pasture response to applied S grown under controlled environmental conditions (glasshouse) as influenced by variations in levels of extractable S. Intact paired soil cores were collected at 2-month intervals from an S x P factorial experiment at 4 field sites on the Northern Tablelands of New South Wales on 11 occasions. Soil samples were collected from each core and the cores placed in the glasshouse. Sulfur was applied to one core of each pair and basal nutrients applied to all cores which were then oversown with white clover (Trifolium repens L. cv. Haifa). The extractable S in the soil was analysed using the following techniques: 0.1 mol Ca(H2PO4)2/L (MCPt); 0.1 mol Ca(H2PO4)2/L, treated with activated charcoal (MCPi); water (H2O); 0.25 mol KCl/L, heated at 40°C for 3 h (KCl-40); 0.25 mol KCl/L, heated at 100°C for 4 h (KCl-100); 0.5 mol NaHCO3/L (NaHCO3); and an acid digestion of the soil (total). Dry matter yield and S content of the pasture shoots were measured for each 2-month growth period. The relationship between the various soil S extraction techniques and the response of pasture to applied S varied over time and was influenced by the level of inorganic S present in the soil and the amount of organic S extracted. When the level of MCPi-extractable S ranged between 2 and 22 µg S/g soil due to the application of fertiliser (summer 1987–88 and autumn 1988), or after a period of high mineralisation rates (spring 1988), the MCPi, MCPt, H2O and KCl-40 techniques had the highest correlation with the increase in S content of the pasture when S was applied. The higher correlation for the MCPt, H2O and KCl-40 techniques than the MCPi technique indicates that plants obtained some S from the organic S pool. In contrast, when the levels of MCPi-extractable S ranged between 2 and 10 µg S/g soil and the rate of mineralisation increased in response to an increase in soil temperature (June 1988 and June 1989) or moisture (September 1989) upon transfer of samples from the field to the glasshouse, the MCPt, H2O and KCl-40 techniques underestimated the available S pool and had lower r2 values than either the KCl-100 or NaHCO3 techniques.


Soil Research ◽  
1997 ◽  
Vol 35 (5) ◽  
pp. 1131 ◽  
Author(s):  
Nanthana Chinoim ◽  
Rod D. B. Lefroy ◽  
Graeme J. Blair

Soil testing for sulfur (S) is becoming increasingly important as soils become more S-deficient due to lower S inputs in fertiliser and higher offtake in product. Because of the differing rates of S supply required by a range of crops, the relative importance of the soil sulfate and organic S pools could be expected to vary between crops. A glasshouse experiment was conducted using an Aquic Haplustalf of granitic origin and an Ultic Haplustalf of basaltic origin collected from unfertilised pasture sites on the Northern Tablelands of New South Wales from Uralla and Walcha, respectively. The soil was labelled with 35S. The experiment consisted of 2 rates of S fertiliser (0 and 17·7 mg/kg soil, equivalent to 0 and 30 kg S/ha), 3 crop species (radish, corn, ryegrass), and 2 soils (granite and basalt). S was extracted using 2 extracts, mono-calcium phosphate (MCP) and 0·25 M KCl heated at 40°C (KCl-40), termed primary extracts, and the components of S in the extracts were determined. The relationship between the amount of S removed from the extract (S before planting – S after cropping) by the 2 test extractants in the – S treatment and plant S uptake was also determined. A higher S concentration was found in the KCl-40 extract than in the MCP extract in the granite soil. Conversely, the MCP extract had a higher S concentration in the basalt soil because of the relative size of the adsorbed S and ester-S pools in this soil. More than 33% of the 35S was recovered in the extracted S pool, and <11% from the organic S pool in both extractants and in both soils. Data showed a lower specific activity (SA) of the S in the MCP extract as measured by ICP than in KCl-40 in both soils and all crops. The specific activity ratio of the extractants, as measured by ICP, was closest to 1·00 for the KCl-40 extract in both soils for each crop. The removal of S from the MCP extractant during cropping was lower than plant uptake in all treatments except ryegrass in the basalt soil. The KCl-40 extract tended to underestimate S supply at low uptake and overestimate at higher uptake. The results reported in this experiment showed that the KCl-40 extract generally performed well for all 3 crops and on both soils. The data showed that the KCl-40 extract removed S from pools similar to those reached by the crops.



1998 ◽  
Vol 38 (6) ◽  
pp. 575 ◽  
Author(s):  
G. C. Anderson ◽  
G. J. Blair ◽  
R. D. B. Lefroy

Summary. Attempts to measure the sulfur (S) requirements of pastures using existing soil test procedures have largely been unsuccessful due to the extractants either under- or over-estimating the availability of S from soil organic matter. A range of extractants was used to assess the availability of S at 2 field sites on Kentucky yellow podzolic and Walcha krasnozem soils located on the Northern Tablelands of New South Wales. The experiments were conducted over a 2-year period on improved perennial pastures. The 7 extraction techniques used were: 0.1 mol Ca(H2PO4)2/L (MCPt); 0.1 mol Ca(H2PO4)2/L, treated with activated charcoal (MCPi); water (H2O); 0.25 mol KCl/L, heated at 40˚C for 3 h (KCl-40); 0.25 mol KCl/L, heated at 100˚C for 4 h (KCl-100); 0.5 mol NaHCO3/L, (NaHCO3); and an acid digestion of the soil (total). In both soils, the MCPi technique extracted the least amount of S. The amount of S extracted by the MCPt, H2O and KCl-40 techniques was intermediate. The KCl-100 technique extracted greater amounts of S than these techniques. For the Kentucky yellow podzolic soil, the KCl-100 technique extracted the same amount as the NaHCO3 technique but extracted less for the Walcha krasnozem soil. The extraction techniques which varied least throughout the year were total and NaHCO3 for both soils. The KCl-40 technique was as stable as these techniques for the Kentucky yellow podzolic soil but was less stable for the Walcha krasnozem soil. Nevertheless, the KCl-40 technique had a higher stability than the KCl-100, H2O and MCPt techniques, while the MCPi technique was the least stable. Pasture S content response to applied S fertilisers was related to dry matter production of each site, which was largely determined by the environmental factors (soil moisture, temperature and solar radiation). Seasonal changes in the level of soil S only modified this relationship for the Walcha krasnozem site when environmental conditions promoted mineralisation of soil organic S which was retained within the soil profile due to sulfate adsorption and resulted in an increase in inorganic soil sulfur. These findings suggest future research is required into field measurements of the ability of soil to supply S as determined by the rate of mineralisation and leaching in relation to the plant‘s demand for soil S.



1970 ◽  
Vol 10 (43) ◽  
pp. 196
Author(s):  
WM McArthur ◽  
K Spencer

A scheme is proposed as a basis for soil fertility studies in areas where little information is available. The first stage consists of sampling the area on a grid and determining the patterns of variation in the status of those nutrient elements likely to be deficient. These patterns are then compared with intensity patterns of environmental (including edaphic) variables. Where the two sets of variables can be quantified, regression analysis may be used to estimate the closeness of the relationship ; otherwise the relationship must be assessed visually from the degree of conformity between patterns. Those environmental variables that relate, causally or otherwise, to the distribution of components of chemical fertility are identified by strong correlations. Information so gained may be used in subsequent agronomic studies, both as a guide to number and location of field plots and as a framework for studies in soil chemistry and pedology. The scheme is illustrated using data derived from studies on the Dorrigo Plateau of New South Wales. Factors relating closely to phosphorus, sulphur, molybdenum, and nitrogen distribution were identified. In no case could one factor be used to predict the adequacy of all nutrients.



1975 ◽  
Vol 15 (77) ◽  
pp. 795 ◽  
Author(s):  
JA Thompson

A range of temperate annual and perennial legumes, naturalized or commonly sown in the area, was examined at three field sites in low fertility soils derived from granite on the south western slopes of the New England Region, New South Wales. They were compared over a four year period in terms of their persistence, dry matter and nitrogen production and their compatibility with associated temperate perennial grasses, The response of sown grass to nitrogen fertilizer application was also examined in the absence of legume. Ten legumes were examined at one site and six of these at the other two sites. In general, nitrogen yields were ranked similarly to total dry matter yields of all treatments, including grasses in the absence of legume. However, the legumes were ranked differently in terms of productivity of the legume component and productivity of associated grass. At all sites lucerne gave the highest yields of total dry matter and of legume and the lowest yield and persistence of associated grass-comparable to grass growing in the absence of legume or applied nitrogen. Subterranean clover was ranked second or third in total dry matter yield, depending on site, but provided the highest yield of associated grasscomparable to grass receiving high levels of applied nitrogen. Under this legume soil nitrogen levels tended to be highest. Rose clover, sown at one site only, yielded more legume dry matter than subterranean clover but grass yield was comparable to that with lucerne. The results suggest that subterranean clover is the superior legume for successful mixed sowings although inclusion of white clover could be justified. Lucerne appears to be best sown as a pure sward.



1971 ◽  
Vol 11 (50) ◽  
pp. 307 ◽  
Author(s):  
GJ Murtagh

The effectiveness of chemical seedbed preparation for sod-sown oats was studied using varying intervals between spraying and sowing. Four herbicides were compared in a second experiment. Both experiments were conducted on paspalum (Paspalum dilatatum) dominant pastures on red basaltic soil on the North Coast of New South Wales. Herbicides were most effective when applied at 6.7 kg acid equivalent a hectare. At this rate, the highest yields of dry matter and nitrogen were obtained when there was a three-week interval and considerably less when there was no interval. A mixture of 2,2-DPA (2,2-dichloropropionic acid) and amitrole (3-amino-1,2,4-triazole) was more effective than 2,2-DPA alone with a three-week spraying interval but there was no difference with a six-week interval. Both amitrole and a mixture of amitrole and ammonium thiocyanate were ineffective for chemical seedbed preparation on paspalum pastures;



2006 ◽  
Vol 46 (10) ◽  
pp. 1301 ◽  
Author(s):  
S. L. Davies ◽  
A. M. Storrie ◽  
A. S. Cook ◽  
R. A. Latta ◽  
A. D. Swan ◽  
...  

Farmers often experience inconsistent responses when using herbicides to terminate an established lucerne pasture prior to cropping. In an attempt to redress this problem, a series of field experiments were conducted between 1999 and 2002 at various locations in southern and northern New South Wales, the Australian Capital Territory, and south Western Australia that aimed to identify management guidelines that improved the efficacy of herbicide mixtures commonly used to remove lucerne. Collectively, these studies indicated that herbicides were generally less effective when applied either early (less than 2 weeks) or late (6 weeks or more) in the regrowth cycle of lucerne after defoliation. Herbicide efficacy tended to be greatest if applied to regrowth 3–5 weeks after defoliation, which corresponds to a time when the lucerne crown and root reserves are likely to be in the process of being replenished by photoassimilates transported from the shoot. The impact of timing of herbicide application in relation to season was compared at a number of locations. Across all the sites and years, spring herbicide applications were generally the most effective, removing on average 87% of the lucerne (range 53–100%) compared with 72% in summer (24–100%) and 60% in autumn (7–92%). Spring applications were also more consistent in their effect, removing >80% of the lucerne plants in 9 out of 12 experiments, whereas similar rates of removal occurred on 4 occasions in 9 summer applications and only twice in 8 autumn applications. Some of the seasonal variation could be explained by differences in the amount of rainfall prior to herbicide applications. It was assumed that the relationship between rainfall and herbicide efficacy reflected the stimulation of lucerne shoot and root growth by the additional soil moisture before herbicide treatment. Herbicide mixtures that contained ingredients such as picloram that retain residual activity in the soil tended to be more effective and were less influenced by lucerne growth and season than those herbicides with little or no residual activity. However, such chemicals could potentially restrict which crops can subsequently be grown after a lucerne pasture has been removed. It was concluded that >80% of lucerne plants were likely to be removed using herbicides provided that the herbicide treatment was applied to actively growing lucerne 3–5 weeks after defoliation, and when greater than 70–95 mm rain had fallen in the 6–8 weeks prior to application.



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.



2002 ◽  
Vol 14 (4) ◽  
pp. 431 ◽  
Author(s):  
J. C. Noble ◽  
G. H. Pfitzner

William Rodier (1859–1936) became well known throughout much of southeastern Australia during the late nineteenth and early twentieth centuries, mainly through the vigour with which he expressed his contentious views on how best to control certain vertebrate pests. Much of his 'plan', particularly in regard to rabbits, was based on his experience as a pastoralist in western New South Wales. In this article, we examine what is known about Rodier's family background, his occupations, preoccupations, and particularly, the effectiveness of his endeavours to convince a largely sceptical public as to the wisdom and practicality of his method for vertebrate pest control. Some of the circulars and flyers printed by Rodier are also reproduced for illustrative purposes. These were designed to demonstrate the effectiveness of the Rodier Method, especially for controlling the rabbit, perceived by him to be the most serious threat then facing landholders in Australia. Rodier's activities are appraised in light of the relationship then existing between community-based science and more orthodox, academically-based science in the late nineteenth and early twentieth century. Finally, this relationship is further explored in an historical context by examining the importance attached to local, informal knowledge in contemporary ecological research where landholder collaboration is now often regarded as an integral component.



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