Variation in the acidity of cropped and uncropped light-textured red soils of central western New South Wales

1999 ◽  
Vol 39 (8) ◽  
pp. 981 ◽  
Author(s):  
R. R. Young ◽  
C. L. Alston ◽  
C. J. Chartres
Keyword(s):  
Soil Acidity ◽  
Rhizobium Meliloti ◽  
New South ◽  
New South Wales ◽  
Soil Surface ◽  
Aluminium Toxicity ◽  
Total Carbon ◽  
Agricultural Activity ◽  
Barrel Medic ◽  
South Wales

Summary. The light-textured, red, gradational and duplex soils in semi-arid central western New South Wales were found to be on a pH threshold for suitability for the traditional cultivars of barrel medic (Medicago truncatula), an important pasture legume in the region, and other acid sensitive species. However, there was little evidence that cropping over a long time increased soil acidity. Over the 38 sampling sites, mean pHCa in the soil surface 0–20 cm was significantly higher in cropped compared to contiguous uncropped and usually timbered control areas. The return of cations and associated alkali in standing timber to the soil surface when trees were pushed and burnt is a plausible explanation. In the surface (0–20 cm) layers of 10 of 38 cropped paddocks, mean pH in 0.01 mol CaCl2/L was <5, sufficient to severely obstruct growth and the nitrogen fixing capacity of barrel medic. All but 4 sites had pHCa <6, where some reduction in nitrogen fixation would be expected to occur. Variation in pH within transects within paddocks was large, which is consistent with the common observation of poor and patchy growth of barrel medic. Exchangeable calcium, important for Medicago–Rhizobium meliloti symbiosis function, decreased with increasing acidity. The potential for manganese toxicity appeared low with aluminium toxicity likely only at some sites with pHCa ≤4.5. Total carbon decreased with increasing soil acidity and was less under cropping at any pHCa. Although acidification of these soils due to agricultural activity was not apparent from paired sampling of cropped and contiguous uncropped transects, they seem likely to be prone to acidification.

Rhizobium as a factor in the re-establishment of legume-based pastures on clay soils of the wheat belt of north-western New South Wales

1998 ◽  
Vol 38 (6) ◽  
pp. 555 ◽  
Author(s):  
A. M. Bowman ◽  
D. M. Hebb ◽  
D. J. Munnich ◽  
J. Brockwell
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Meliloti ◽  
New South ◽  
New South Wales ◽  
Clay Soils ◽  
Natural Fertility ◽  
Fixed Nitrogen ◽  
South Wales ◽  
Annual Medics ◽  
North Western

Summary. Populations of Rhizobium meliloti in self-mulching clay soils (Vertisols) at 48 sites on 27 properties in north-western New South Wales were classified according to number and ability to fix nitrogen with several species of Medicago. Rhizobia were counted using serial dilution, nodulation frequency, plant infection tests. Abilities of the soil populations to fix nitrogen were determined in the laboratory with whole-soil inoculation of Medicago seedlings in test tubes with shoots exposed to the atmosphere and roots within the tubes under bacteriological control, and in the field using a technique based on the natural abundance of 15N in the soil. The majority of soils contained >1000 cells of R. meliloti per gram. The major component of those populations fixed nitrogen with lucerne (Medicago sativa) and some components of some soils also fixed nitrogen with M. polymorpha, M. scutellata, M. littoralis, M. tornata, M. laciniata and Trigonella suavissima. However, a number of soils were located which contained few if any rhizobia effective in nitrogen fixation with M. polymorpha. Overall, the effectiveness of nitrogen fixation of the naturally occurring populations of R. meliloti in association with M. polymorpha, M. scutellata, M. littoralis and M. tornata was only 46% of the effectiveness of standard strains. At one particular site, where 10 lines of annual Medicago spp. were growing experimentally, fixed nitrogen as a proportion of shoot nitrogen averaged only 28%. At that site, there were no effective rhizobia for M. scutellata and it was wholly dependent on the soil as the source of its nitrogen. The results are discussed in relation to the need for a substantial input of legume nitrogen for restoring the natural fertility of self-mulching clay soils in degraded wheat lands of north-western New South Wales. It is suggested that lucerne, or perhaps other perennial Medicago spp., might fill this role better than annual medics such as M. polymorpha and M. scutellata that are more dependent than lucerne on specific strains of R. meliloti to meet their requirements for symbiotic nitrogen fixation.

Some investigations into soil and vegetation relationships associated with alkaline-saline soil surfaces in the Walcha area, Northern Tablelands, New South Wales

1995 ◽  
Vol 46 (1) ◽  
pp. 209 ◽  
Author(s):  
KH Kreeb ◽  
RDB Whalley ◽  
JL Charley
Keyword(s):  
Cynodon Dactylon ◽  
New South ◽  
New South Wales ◽  
Soil Surface ◽  
Tree Planting ◽  
Soil Parameters ◽  
Alkali Cations ◽  
Grazing Land ◽  
South Wales ◽  
Wide Range

The characteristics of the soil, vegetation and groundwater at a dryland salinity site on Miramoona, a property near Walcha on the Northern Tablelands of New South Wales, were investigated. Soil parameters measured at 23 points along a 200 m transect were highly correlated with the pattern of vegetation. Of overriding significance was soil pH, which varied from a high of over 10 on bare areas delineated by Critesion marinum and Cynodon dactylon to a low of less than 5 on grazing land supporting the growth of a wide range of pasture species. The bare areas were characterized by alkalinity. While they were sodic at all depths measured, they were only marginally saline and then only at the soil surface. The chemical composition of the groundwater collected from three piezometer tubes varied quite markedly over the site. It is hypothesized that the presence of alkaline bare areas on the Northern Tablelands is not a new problem, but rather the natural result of alternating wet and dry periods which have induced accumulation of carbonates and bicarbonates of the alkali cations, notably sodium. Drainage of the original perched swamps by the early landholders, tree clearing and the grazing of domestic livestock would have accelerated the process since European settlement. However, tree planting would appear unlikely to have any impact on the reclamation process in the short term. A more viable option would be the recreation of the original swamps in suitable situations, although this solution would create problems for grazing management.

Establishment of barrel medic under wheat, oats, barley and linseed in central western New South Wales

1974 ◽  
Vol 14 (71) ◽  
pp. 785 ◽  
Author(s):  
BJ Scott ◽  
H Brownlee
Keyword(s):  
Medicago Truncatula ◽  
Cover Crops ◽  
Dry Matter ◽  
New South ◽  
New South Wales ◽  
Barrel Medic ◽  
South Wales

Experiments in 1969 and 1970 at Condobolin, New South Wales, measured the effects of cover crops of wheat, oats, barley and linseed on the dry matter and pod production of undersown Jemalong barrel medic (Medicago truncatula). The cover crops differed in their capacities to produce dry matter. Medic regenerated densely each year after linseed, the lowest density being greater than after wheat, oats or barley sown at rates greater than 11 kg ha-1. When wheat or barley was sown at 6 kg ha-1, medic regeneration was comparable with that after linseed

The fate of nitrogen fertilisers added to red gradational soils at Batlow, New South Wales, and its implications with respect to soil acidity

Soil Research ◽  
1997 ◽  
Vol 35 (4) ◽  
pp. 863 ◽  
Author(s):  
I. P. Little
Keyword(s):  
Ammonium Sulfate ◽  
Soil Acidity ◽  
Surface Soil ◽  
Soil Analysis ◽  
New South ◽  
New South Wales ◽  
Soil Profiles ◽  
Eucalypt Forest ◽  
South Wales ◽  
Exchangeable Ca

Red gradational soils at Batlow, in New South Wales, which are used for apple growing, have acid subsoils with exchangeable aluminium (Al) frequently in excess of exchangeable calcium (Ca). There is often inadequate Ca in the fruit cortex of post-harvest apples to maintain good fruit quality and this can lead to losses in cool-store. It is possible that Al in these acid subsoils has interfered with Ca uptake by the trees. The excessive use of nitrogenous fertilisers leads to soil acidity, and it was thought likely that this was exacerbating the subsoil acidity common in the district. In October 1992, soil analysis detected considerable ammonium in the surface 0·3 m at orchard sites at Batlow monitored for mineral nitrogen (N). This probably came from heavy spring dressings of fertiliser. One site examined in detail showed that about half of the ammonium had disappeared by January 1993, but a large nitrate envelope appeared with a peak at 0·6 m which in turn disappeared by April that year. This establishes that heavy applications of ammonium are nitrified, leached into the subsoil, and lost. Under such a high N regime, orchard soil profiles should be more acid than adjacent forest soils. However, it was found that the acidity of the surface soil was less, and the exchangeable Ca greater in the orchard soils, compared with soil profiles in the adjacent eucalypt forest, although amelioration of the subsoils had not occurred. Samples taken from representative sites at Batlow, at the 0–0·1, 0·1–0·2, and 0·3–0·4 m depths, were dosed with ammonium sulfate and leached with water in the laboratory for 23 days in a free-draining environment. Nitrate and ammonium were determined in the leachates. At the end of the experiment, the pH and exchangeable Ca, Mg, and Mn were determined in the leached samples. Only the neutral surface soils were able to nitrify ammonium effectively and nitrification was positively correlated with pH, and with exchangeable Ca and Mg. From this it is argued that the acidity produced by the addition of ammonium sulfate or urea will be nitrified in the surface but the acidity produced will be neutralised, provided it is accompanied by an adequate dressing of lime. Ammonium tends to remain in the surface soil, but if leached, it will not be nitrified in the subsoil. Nitrate leached into the subsoil will not be acid-forming but, if denitrified, may help to reduce acidity. For this work, the soil pH was measured in 1 KCl. So that readers can refer this to the pH in 0·01 CaCl2, a relationship was established between the two measures.

Soil pH is a major determinant of the numbers of naturally occurring Rhizobium meliloti in non-cultivated soils in central New South Wales

1991 ◽  
Vol 31 (2) ◽  
pp. 211 ◽  
Author(s):  
J Brockwell ◽  
A Pilka ◽  
RA Holliday
Keyword(s):  
Soil Ph ◽  
Rhizobium Meliloti ◽  
New South ◽  
New South Wales ◽  
Acid Soils ◽  
Alkaline Soils ◽  
Naturally Occurring ◽  
South Wales ◽  
Dominant Soil ◽  
The Relationship

Measurements were made of soil pH, frequency of occurrence of annual species of Medicago (medics) and populations of Rhizobium meliloti at 84 sites on 7 dominant soil groups of the Macquarie region of central-western New South Wales. Over all sites, soil pH (0-10 cm; 1:5 soil: water) ranged from 5.26 to 8.07, medic frequency from 0 to 100% and most probable numbers of R. meliloti from undetectable to 675 000/g soil. There was a highly significant (P<0.001) relationship between soil pH and number of R. meliloti. Above pH 7.0, the mean soil population of R. meliloti was 89000/g; below pH 6.0, it was 37/g. Medics occurred most frequently on the more alkaline soils and with least frequency on the more acid soils, but the relationship between soil pH and medic frequency was weaker than between pH and R. meliloti number. Medics were more tolerant of low soil pH than their rhizobia were; at 2 sites, of pH 5.49 and 5.35, medics occurred at 100% frequency but R. meliloti was undetected. There was an indication of some acidification in these soils over a period of 35 years but this remains to be confirmed.

Supplementing Merino ewes at mating for reproductive gain in central western New South Wales

1983 ◽  
Vol 23 (122) ◽  
pp. 259
Author(s):  
GD Denney
Keyword(s):  
Reproductive Performance ◽  
New South ◽  
New South Wales ◽  
Ovulation Rate ◽  
Feeding Period ◽  
Barrel Medic ◽  
South Wales ◽  
Native Pasture ◽  
Ad Libitum

In four experiments at Condobolin on the Central Western slopes of New South Wales between 1976 and 1979, mature Merino ewes were given supplements for four to five weeks over mating and the effects on their reproductive performance were recorded. The ewes were run on barrel medic or native pasture with mating commencing in late February or early March each year. The supplements were: experiment 1 -1upins (0.25 kg/d), oats (0.25 kg/d); experiment 2-lupins (0.25 kg/d), oats (0.25 kg/d); experiment 3-lupins (0 25 kg/d), lupins (ad libitum), lupins (0.25 kg/d) with ad libitum oats and lucerne hay; experiment 4-lupins (0.25 kg/d). In experiment 4, ewe liveweight was manipulated in the pre-feeding period to obtain two liveweight classes at the start of supplementation. In the three to four weeks before mating, ewes either maintained or lost weight in experiments 1,2 and 4. However, in experiment 3, ewe liveweight increased after heavy summer rains caused an abundance of pasture. The only significant effect of any supplement on flock reproduction was to increase the ovulation rate. This resulted from lupin supplementation but only in two of four years (experiments 1 and 4). However, on these occasions, lambing rates did not significantly increase due to three factors: more barren ewes, higher ova loss or greater peri-natal lamb loss. Oats supplementation in experiments 1 and 2 did not significantly increase reproductive performance, nor was there an effect of any supplement in experiment 3. The results indicate that repeatable reproductive responses to lupin supplementation are unlikely to occur in the area of the study.

The relationship between average annual rainfall and exchangeable aluminium in soils of south-eastern New South Wales

1986 ◽  
Vol 26 (5) ◽  
pp. 587 ◽  
Author(s):  
M Conyers
Keyword(s):  
Surface Soil ◽  
New South ◽  
New South Wales ◽  
Aluminium Toxicity ◽  
Annual Rainfall ◽  
Neutral Salt ◽  
South Eastern ◽  
South Wales ◽  
Average Annual Rainfall ◽  
The Relationship

Surface soil samples (0-10 cm) from a range of soil types were collected in south-eastern New South Wales. Linear regression and analysis of variance were used to establish that, at a given pH (0.01M CaCl2), the amount of neutral salt exchangeable aluminium in surface soils tends to increase with increasing average annual rainfall. Where aluminium toxicity is a factor limiting plant growth, soils in higher rainfall areas will generally require higher pH for the removal of aluminium from the cation exchange complex.

Characters contributing to high yield in Currawong, an Australian winter wheat

1998 ◽  
Vol 49 (5) ◽  
pp. 853 ◽  
Author(s):  
L. D. J. Penrose ◽  
K. Walsh ◽  
K. Clark
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Soil Acidity ◽  
New South ◽  
New South Wales ◽  
Yield Component ◽  
Stem Rust Resistance ◽  
High Yield ◽  
South Central ◽  
South Wales

This study investigated characters that contribute to high grain yield in the recently released Australian winter wheat, cv. Currawong. Currawong was released as a feed grade wheat for south-central New South Wales, with a 10% yield advantage over the highest yielding milling wheat with winter habit, Rosella. When expressed as a percentage of the grain yield of Rosella, Currawong was found to perform best at sites with low soil pH and high grain yield. These sites corresponded to the wetter eastern margin of the wheatbelt in south-central New South Wales. While part of the yield advantage of Currawong is due to its tolerance of soil acidity, there remains an ability to yield particularly well in environments conducive to high yield. In yield component studies that were conducted over 2 seasons at Temora, the yield advantage of Currawong appeared to be associated with its grainfilling characters. Currawong had a more rapid rate of grainfill, and/or a longer duration of grainfilling than other high-yielding winter wheats, leading to significantly heavier grain. From a plant breeding perspective, the high yield of Currawong is significant for demonstrating rapid genetic gain for yield in Australian winter wheats. The yield of Currawong also demonstrates the possibility of combining high grain yield with the Sr26 stem rust resistance. Characters that confer high yield in Currawong may be of limited benefit in environments where drought stress limits the duration of grainfilling in wheat.

Regeneration of annual winter legumes at Tamworth, New South Wales

1974 ◽  
Vol 14 (66) ◽  
pp. 57 ◽  
Author(s):  
MW Hagon
Keyword(s):  
Seed Production ◽  
New South ◽  
New South Wales ◽  
Soil Surface ◽  
Moisture Stress ◽  
Late Spring ◽  
South Wales ◽  
Hard Seeds ◽  
Improved Cultivars

The seed production and regeneration of a range of naturalized and introduced cultivars of annual clovers and medics was studied at Tamworth, New South Wales, between 1971 and 1973. Seed production was correlated with maturity grading within species only when moisture stress occurred in late spring. The proportion of seed lost as summer seedlings and the proportion of unrecovered seed were greater the lower the level of hardseededness. A greater proportion of unrecovered seed was recorded for those cultivars which bore their burrs at the soil surface. As a group the medics had a higher proportion of residual hard seeds than did the clovers. The results are discussed in relation to the likely persistence of improved cultivars compared to the successful persistence of the naturalized medics and clovers in the Tamworth district.

The response of barrel medic pasture to topdressed and placed superphosphate in central western New South Wales

1973 ◽  
Vol 13 (65) ◽  
pp. 705 ◽  
Author(s):  
BJ Scott
Keyword(s):  
Dry Matter ◽  
New South ◽  
Soil Phosphorus ◽  
New South Wales ◽  
Phosphorus Uptake ◽  
Dry Matter Production ◽  
Barrel Medic ◽  
South Wales ◽  
Matter Production ◽  
Methods Of Application

The dry matter production of a pasture of barrel medic (Medicago truncatula cv. Jemalong) under different rates and methods of application of superphosphate was examined, during 1971 and 1972, on a phosphorus deficient soil at Condobolin, New South Wales. The treatments were factorial combinations of four rates of superphosphate (0, 126, 376, and 753 kg ha-1) and four methods of application of superphosphate (surface spread i.e. topdressed, surface applied in bands, placed at 5 cm depth, and placed at 1 0 cm depth). The dry matter production and phosphorus uptake results demonstrated the effectiveness of subsurface placement of superphosphate, but relative ineffectiveness of surface application during the dry winters experienced. The results also showed that root development in the dry 0-2 cm zone was restricted compared with that in the deeper moist soil layers. Soil phosphorus tests showed that one year after topdressing phosphorus had not moved below the 2-4 cm depth layer, even at 753 kg ha-1 of superphosphate.

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