The relationship of soil properties to the growth of barrel medic at Condobolin, New South-Wales

Soil Research ◽  
1992 ◽  
Vol 30 (3) ◽  
pp. 371 ◽  
Author(s):  
IP Little ◽  
CJ Chartres ◽  
RR Young

Poor growth of barrel medic (Medicago truncatula) has been observed in established pasture on the red duplex and gradational soils of the semi-arid sheep and wheat growing areas of western New South Wales. Red-brown earth soils were examined from three paddocks on Condobolin Research and Advisory Station in conjunction with a visual assessment of the growth of medic. The soils were sampled at 20 m intervals along three line transects in each of three paddocks with different cropping histories. Bray-P; pH, Mn and Al extracted by 0.01 M CaCl2; exchangeable plus soluble Na, K, Ca and Mg; and pH in a 1:5 soil/water suspension were measured at four depth increments at each sampling point. Although the pH in CaCl2 was often less than 5.0, in general no Al was extracted from the 0-5 cm soil layer. Classification of the soils on medic growth alone showed medics were absent from the most acid soils. However, there was considerable within class variability. A better approach was provided by classifying the soils by means of a Euclidean distance/flexible sort of scores from the first principal component. This classification showed that the poorest medic growth was associated with the most acid group with considerable amounts of Al soluble in 0.01 M CaCl2 in the 10-20 cm horizon. Medics grew best in soils with moderate pH values between 5 and 6 in CaCl2 where there was no soluble A1 and moderate levels of exchangeable Ca and Na and soluble Mn. Medics appeared also to grow less well in more alkaline soils where there was very little soluble Mn. There were no differences between classes in available P. There were differences between paddocks; the uncultivated paddock being the most acid and the paddock with the longest cropping history having more Bray-P, more exchangeable Na and more exchangeable Ca at 10-20 cm. The uncropped paddock became more acid and the base status was lowered by natural soil processes and its condition probably indicates the status of many such soils in the district.

Soil Research ◽  
1969 ◽  
Vol 7 (2) ◽  
pp. 143 ◽  
Author(s):  
Dijk DC Van

The genesis is discussed of a range of pedological differentiations which occur unusually deep in the soil and characterize low, but not the lowest, catenary segments of the Gundaroo pedomorpholith. This soil layer forms a large part of the soil mantle on the Southern Tablelands and is of considerable age. The deep-seated differentiations have developed as separate 'accessory' features below red-yellow and meadow podzolic, prairie soil, and red-earth sola of normal depth (2-4 ft). The zone in which they occur is termed the 'subsolum'. The features are dominated by vertical patterns related to planar and tubular voids. They include, besides a range of sesquioxidic forms, conspicuous clay differentiations comprising pronounced cutans and up to 1-1 1/2 in. wide vertical clay veins and well-developed pedality with thick colloid coatings. These features are believed to represent 'descendant' pseudogley and to be related to an unusually dynamic palaeoclimatic regime.


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.


1974 ◽  
Vol 14 (71) ◽  
pp. 785 ◽  
Author(s):  
BJ Scott ◽  
H Brownlee

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


Soil Research ◽  
1997 ◽  
Vol 35 (4) ◽  
pp. 863 ◽  
Author(s):  
I. P. Little

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.


1991 ◽  
Vol 31 (2) ◽  
pp. 211 ◽  
Author(s):  
J Brockwell ◽  
A Pilka ◽  
RA Holliday

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.


1983 ◽  
Vol 23 (122) ◽  
pp. 259
Author(s):  
GD Denney

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.


Soil Research ◽  
1985 ◽  
Vol 23 (4) ◽  
pp. 647 ◽  
Author(s):  
ICR Holford ◽  
BR Cullis

In a study using earlier data from 44 wheat field experiments on acidic (pH < 5.6) soils in southern New South Wales, eight soil phosphate extractants (Bray,, Bray,, neutral fluoride, Mehlich, Truog, lactate, Olsen and Colwell) were evaluated and calibrated in terms of responsiveness (�) and response curvature (C) parameters derived from the Mitscherlich equation. All extraction procedures, except Colwell, had a standard shaking time of 30 min and so1ution:soil ratio of 50. The order of efficacy of the tests was different from that obtained on moderately acid to alkaline soils of central and northern New South Wales. Neutral fluoride and acidic sulfate (Truog) replaced lactate as the best extractant, followed by the double acid Mehlich extractant. The Colwell test was more effective on these very acid soils than on the more alkaline soils, being equal to Bray1 and greatly superior to Bray2 and Olsen. The critical values of the fluoride, Mehlich, Truog, lactate and Colwell tests were significantly lower than they were for more alkaline soils in central New South Wales. The changes in extraction procedures could explain the lower critical values of the lactate and Truog tests, but differences in the critical values of the other three tests were inconsistent with changes in extraction procedures. The results support the hypothesis that a different phosphate extractant is required on very acid soils from that required on moderately acid to alkaline soils.


1973 ◽  
Vol 13 (65) ◽  
pp. 705 ◽  
Author(s):  
BJ Scott

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.


2006 ◽  
Vol 46 (10) ◽  
pp. 1291 ◽  
Author(s):  
C. L. Mullen ◽  
B. J. Scott ◽  
C. M. Evans ◽  
M. K. Conyers

On some of the lighter textured soils in the wheatbelt of central-western New South Wales near Dubbo, soil acidity is a major problem, and lucerne (Medicago sativa) often establishes and grows poorly. We selected a site with a surface soil pHCa of 4.4 and an exchangeable aluminium of 0.4 cmol(+)/kg, which was also acidic down the soil profile. Experimental plots of 4 application rates of lime (nil, 1, 2 and 3 t/ha) in 4 replications were established. The site was limed in 1990 and lucerne sown in May 1991. Over the next 6 years the trial was periodically grazed with sheep, and lucerne regrowth and stand density were monitored. In October 1997, the lucerne was removed and 3 crops of varying acid tolerance (wheat, barley and canola) were sown as split plots in both 1998 and 1999. Lucerne density was higher in the limed plots compared with the unlimed treatment, and this difference persisted for 6 years. Dry matter production of lucerne was increased by lime applied at rates up to 2 t/ha. All 3 crops sown after the lucerne phase responded to lime applied 8 and/or 9 years earlier. The responses were attributed to the strong residual effect of the lime in the 0–10 cm soil layer, to smaller improvements in the 10–20 cm zone (possibly due to the movement of lime down the soil profile over the 7 years before the date of measurement) and to carry over effects of nitrogen fixation by the lucerne into the cropping phase. The protein content of the wheat grain was increased concurrently with grain yield due to the previous liming and resultant legume nitrogen effects. The results support the application of lime to improve the productivity of lucerne and subsequent crops, even when the soil is acidic to depths below the cultivation layer.


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