Influence of moist - dry cycles on pH changes in surface soils

Soil Research ◽  
1999 ◽  
Vol 37 (6) ◽  
pp. 1057 ◽  
Author(s):  
K. I. Paul ◽  
M. K. Conyers ◽  
A. S. Black
Keyword(s):  
Soil Moisture ◽  
New South ◽  
N Mineralisation ◽  
Moist Soil ◽  
Water Acidification ◽  
Acidic Soils ◽  
Surface Soils ◽  
Soil Layers ◽  
South Wales ◽  
Dry Soil

It is well established that in the moderately acidic soils of southern Australia, the 0–2 cm layer commonly has a higher pH than soil layers between 2 and 10 cm depth. The surface 2 cm of soil is also exposed to much greater fluctuations of moisture content than deeper soil layers. There are contradictory or speculative reports in the literature on how soil moisture fluctuation affects pH and processes which influence pH. Therefore, the aim of this study was to determine the effect of moist–dry cycles on pH, and on processes involving H+ transformations, in 3 surface soils (0–2 cm) sampled from southern New South Wales. Following a pre-incubation, the 3 surface soils were incubated for 28 days at 30°C and were: (i) maintained continuously dry, (ii) subjected to short (2 days dry, 5 days moist) or long (7 days dry, 7 days moist) moist–dry cycles, or (iii) maintained continuously moist. During the incubation, the pH of continuously dry soil slightly increased by 0.03–0.10 units, while the pH of continuously moist soil decreased by 0.16–0.39 units. In soils subject to both short and long moist–dry cycles, the pH decreased by 0.06–0.34 units. However, relative to soils maintained moist, exposure to moist–dry cycles suppressed acidification by 0.05–0.26 pH units. In dry soils the pH increased, since some of the NH4+-N produced by net N mineralisation was not subsequently nitrified, and there was a net reduction of Mn. In soils which received water, acidification was predominately attributed to nitrification. Relative to soils maintained moist, acidification was suppressed by 1.6–6.5 mmol H+/kg due to the 11–35% decrease of nitrification on exposure to moist–dry cycles. In acidic surface soils (pH <5.5), acidification rates were further suppressed by 0.1–1.0 mmol H+/kg due to the 1.06–2.06 times greater net Mn reduction in moist–dry soils than in continuously moist soils.

Surface soil acidity and fertility in the eastern Riverina and Western Slopes of southern New South Wales

2007 ◽  
Vol 47 (8) ◽  
pp. 949 ◽  
Author(s):  
B. J. Scott ◽  
I. G. Fenton ◽  
A. G. Fanning ◽  
W. G. Schumann ◽  
L. J. C. Castleman
Keyword(s):  
Surface Soil ◽  
New South ◽  
Annual Rainfall ◽  
Acidic Soils ◽  
The West ◽  
Surface Soils ◽  
South Wales ◽  
Subsurface Soil ◽  
Average Annual Rainfall

This study, in southern New South Wales (NSW), examined the chemical properties of ~4700 surface soils in agricultural paddocks and recorded lime and gypsum inputs. The area was bounded approximately by Cootamundra in the north, the NSW/Victorian border in the south, extending to Tumbarumba in the east and to near Berrigan in the west. The long-term average annual rainfall ranged from ~420 mm in the west to a maximum of 1175 mm in the east. The data, collected between 1997 and 2003, were for the surface 20 cm of soil, in two 10-cm layers. The data were generated from a soil testing program conducted with farmers in the region. We grouped the soils into three zones based on a GPS location taken at the time of sampling. These zones were 1 (lower rainfall mixed farming), 2 (higher rainfall mixed farming) and 3 (long-term pasture). Acidic soils occurred across all three zones; however, the soils in zone 1 appeared to be less acidic than soils in the other two zones. We found that surface soils (0–10 cm) with soil pH in 1 : 5 soil : 0.01 mol/L calcium chloride (pHCa) ≤4.5 represented 27%, 57% and 54% for zones 1, 2 and 3, respectively. In addition, zone 1 had 74% of surface soils with a pHCa ≤ 5.0, and this was more acidic than previously reported. However, the surface soils in zone 1 had relatively low exchangeable aluminium (Alex) and had less acidic subsurface soils (10–20 cm), so that responses to lime application by pastures and crops may be less frequent or smaller than the surface soil pHCa alone may indicate. There was a higher frequency of acidic soils (pHCa ≤ 4.5) in the subsurface soils than in the surface soils in zones 2 (62 cf. 57%) and 3 (64 cf. 54%), suggesting that the acidity problem at this depth was a major problem. Low pHCa in the subsurface soil is known to be a constraint on crop yield. We found no evidence of the amendment of this soil depth when lime was applied and incorporated into the 0–10 cm depth, and economic amendment of acidity in the 10–20 cm depth remains unresolved. Increased adoption of liming occurred in the late 1990s, and by 1997 the percentage of paddocks limed was 14.3%, 21.3% and 13.6% in zones 1 to 3, respectively. Soil pH buffering and long-term pHCa decline after liming were similar to rates reported in field experiments. The total quantities of lime applied were insufficient for soil amendment and maintenance of soil pHCa, particularly in the long-term pasture areas. The rate of soil acidification in the 0–20 cm depth in the average annual rainfall range of 525–625 mm was estimated to be 1.52 kmol H+/ha.year. This would require 76 kg lime/ha.year to neutralise. Sodic and saline soils occurred mainly in the lower rainfall cropping areas, and were more frequent in an area around the township of Lockhart. Half the gypsum applications were at low rates (≤0.5 t/ha), and were probably for sulfur application to canola. Some of the sodic soils were acidic (34% ≤ pHCa 4.5) so that the application of lime/gypsum mixes could be appropriate in the amendment of these soils. Soils in the pasture system had mean organic carbon content (OC%) of 2.42, compared to the cropping zones at 1.65 and 1.75%. OC% was related to annual average rainfall; the increase in OC% was 0.19% and 0.08% for each 100 mm of average annual rainfall for the surface and subsurface soil, respectively. A group of soils in the cropping areas had surface OC% ≤ 1.25% OC (zone 1, 12%; zone 2, 20%) and this could be the result of intensive cropping. Most soils (55–63%) were of moderate P status (P(Colwell), 21–60 µg/g). However, there was still a substantial group of soils (31–43%) of low P status (P ≤ 20 µg/g). Most surface soils in all zones (72–80%) were low to marginal in sulfur status (KCl 40, ≤10 mg S/kg). Sulfur deficiency has been identified in canola, and current practice in the cropping areas is for inputs of gypsum at low rates.

The Influence of Soil Moisture and Soil Type on the Oviposition Behaviour of the Migratory Grasshopper, Melanoplus sanguinipes (Fabricius)

1965 ◽  
Vol 97 (4) ◽  
pp. 401-409 ◽  
Author(s):  
Roy L. Edwards ◽  
Henry T. Epp
Keyword(s):  
Soil Moisture ◽  
Free Choice ◽  
Melanoplus Sanguinipes ◽  
Moist Soil ◽  
Moist Sand ◽  
Subsurface Soil ◽  
Water Ph ◽  
Dry Soil ◽  
Oviposition Sites ◽  
Different Soils

Abstract Three different soils – sand, loam and clay – at each of three moisture levels – saturated, intermediate, and dry – were offered to female Melanoplus sanguinipes as oviposition sites. When given a free choice the females preferred moist sand to all other oviposition sites and avoided soil that was completely dry. When no moist soil was available, coarse dry soil was preferred to fine dry soil, but the oviposition rate was reduced. The females would probe and dig at random into any of the soil offered but would withhold their eggs temporarily if the subsurface soil was not moist. Soil water pH appeared to have very little influence on the females' acceptance of an oviposition site as egg pods were deposited in soils with a range of pH from 3.0 to 11.6. It is suggested that although the absence of moisture in the soil may affect the distribution of egg-pods in the microhabitat and may reduce the rate of egg-pod production slightly, the temperature prevailing during the oviposition period is perhaps a more important factor in determining the number of egg-pods deposited.

Effect of parent material, natural available soil boron, and applied boron and lime on the growth and chemical composition of lucerne on some acidic soils of the Central Tablelands of New South Wales

1982 ◽  
Vol 22 (117) ◽  
pp. 317 ◽  
Author(s):  
KS Haddad ◽  
CJ Kaldor
Keyword(s):  
Boron Content ◽  
Boron Concentration ◽  
New South ◽  
New South Wales ◽  
Water Soluble ◽  
Hot Water ◽  
Boron Deficiency ◽  
Alluvial Soils ◽  
Acidic Soils ◽  
South Wales

Fifteen acidic soils (0-1 5 cm), three from each of the five main parent materials in the Central Tablelands of New South Wales, were collected for a glasshouse experiment. The hot water soluble boron content of these soils and some other related soil properties were measured. Boron at nil and 1.5 �g/g air-dried soil and lime at nil and 670 �g/g air-dried soil in a factorial combination were applied to the soils. The effects of the treatments on the performance of lucerne (Medicago sativa cv. Hunter River) grown on these soils were studied. Boron application tended to increase the production of lucerne dry matter on sandstone, shale and slate, and granitic soils, but not on basaltic or alluvial soils. Also, it increased the boron concentration in the leaves of lucerne grown in all soils and consequently, reduced the calcium to boron ratio. The boron levels that produced 90% of the maximum yield and below which boron deficiency symptoms were manifested by the plants, were 0.34 �g/g in air-dried soil and 25 �g/g in oven-dried leaves. There was a linear correlation (r = 0.98) between the hot water soluble boron content of the untreated soils and the boron concentration in the leaves. The hot water soluble boron content of the soils derived from sandstone, shale and slate, and granite was much lower than the basaltic or alluvial soils and were nearly equal to or below the determined critical level. Although liming had the tendency to induce the symptoms of boron deficiency, the effect of lime was greater than boron in increasing the yield. The role of lime in eliminating the problems of these acidic soils and hence promoting the yield of lucerne is discussed.

The distribution of net nitrogen mineralisation within surface soil. 1. Field studies under a wheat crop

Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 129 ◽  
Author(s):  
Erry Purnomo ◽  
A. S. Black ◽  
C. J. Smith ◽  
M. K. Conyers
Keyword(s):  
Soil Depth ◽  
New South ◽  
Field Studies ◽  
Soil Disturbance ◽  
Wheat Crop ◽  
N Mineralisation ◽  
Total N ◽  
South Wales ◽  
Highly Correlated ◽  
Soil Temperature And Moisture

To test the hypothesis that net nitrogen (N) mineralisation is concentrated in the surface few centimetres following minimal soil disturbance for crop establishment, mineralisation was measured during the growth of wheat. The soil was a Red Kandosol located in southern New South Wales. Mineralisation was estimated usingin situ incubations inside capped PVC tubes, which were sampled every 3 weeks. Soil from the tubes was sampled at depth intervals of 2 cm to a depth of 10 cm and at 5-cm intervals from 10 to 20 cm. The results showed that net N mineralisation decreased with depth to 20 cm. Over the season, an average of 32% of the N mineralised in the top 20 cm of soil originated from the 0–2 cm layer, 72% was from the 0–6 cm layer, and only 13% was from soil below 10 cm. The decrease in N mineralisation with soil depth was highly correlated with decreases in the organic carbon (r2 = 0.84, P < 0.05) and total N (r2 = 0.83, P < 0.05) concentration. The soil's N-supplying ability is concentrated near the surface where it is susceptible to erosional loss. The N supply may also be inhibited by temperature and moisture extremes, which are common in the surface few centimetres of soil where mineralisation was concentrated. The PVC enclosures created artefacts in soil temperature and moisture, although it is argued that the effects on net N mineralisation were small in most sampling periods.

Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 199 ◽  
Author(s):  
Brian R. Wilson ◽  
Ivor Growns ◽  
John Lemon
Keyword(s):  
New South ◽  
New South Wales ◽  
Tree Canopy ◽  
Deep Drainage ◽  
Grazing Land ◽  
Near Surface ◽  
Soil Layers ◽  
South Wales ◽  
Eastern Australia ◽  
Canopy Effect

Over large areas of south-eastern Australia, the original cover of native woodland has been extensively cleared or modified, and what remains is often characterised by scattered trees beneath which the ground-storey vegetation is largely grazed or otherwise managed. This study investigated the influence of scattered Blakely’s red gum (Eucalyptus blakelyi) trees on both near-surface and deeper soil layers in temperate grazed pastures on the Northern Tablelands of New South Wales, Australia. A significant canopy effect was observed with elevated soil pH, carbon, and nutrient status inside the tree canopy indicating soil enrichment in a zone around the tree. This effect, however, was largely restricted to the surface (0–0.20 m) soil layers. Chloride concentrations were elevated near to trees but only in the deeper soil layers, suggesting that a modified water use and deep drainage mechanism occurred near the trees. Close to the tree, however, a significant acidification was observed between 0.40–0.60 m depth in the soil, without any obvious depletion in other soil element concentrations. It is concluded that this acidification provides strong evidence in support of a ‘biological pumping’ mechanism that has been proposed elsewhere. Key questions remain as to the management implications of these results, whether the subsurface acidification that was observed is common among native Australian trees, if it might be persistent through time, and if this might be a soil issue that requires management.

The role of stolons and seedlings in the persistence and production of white clover (Trifolium repens L. cv. Huia) in temperate pastures on the Northern Tablelands, New South Wales

1989 ◽  
Vol 40 (3) ◽  
pp. 605 ◽  
Author(s):  
KA Archer ◽  
GG Robinson
Keyword(s):  
Soil Moisture ◽  
White Clover ◽  
Seedling Establishment ◽  
New South ◽  
New South Wales ◽  
Late Summer ◽  
South Wales ◽  
Cool Temperate ◽  
Plant Frequency ◽  
Temperate Pastures

This paper reports the findings of a five-year study on the growth patterns, production and means of persistence of white clover in a cool temperate environment with summer dominant rainfall, on the Northern Tablelands of New South Wales. White clover essentially persisted as a perennial, but large and rapid declines in plant frequency occurred during late summer if soil moisture levels became depleted. The critical combination of conditions at which plant frequency was adversely affected occurred when available soil moisture levels declined below 35 mm and mean weekly maximum temperatures exceeded 20�C; conditions which often occur in late summer in this environment. During one prolonged period of moisture stress in the second spring and summer period of the study, all plants died. Regeneration was due to germination of seeds and seedling establishment, but plants subsequently persisted as perennials. Relationships were developed to predict the probability of survival of white clover over the range of temperatures and soil moistures recorded in these experiments. Germination occurred to a variable extent each year, but was observed only during winter and spring. Seedling establishment was effective in only one year, which followed the death of white clover in summer, 1980-81. The sward was slow to recover after seedling regeneration owing to low winter temperatures and competition from established temperate perennial grasses in spring. Seedlings contributed little to dry matter production in spring. These results indicate that white clover is unlikely to be of value as an annual in temperate pastures. Strategies aimed at improving white clover in cool temperate environments, either by management or selection/breeding programs, should therefore focus upon improving the ability of white clover to persist as a perennial.

Differential habitat use by a local population of subadult common dunnarts, Sminthopsis murina, following wildfire in coastal wet heath, New South Wales, Australia

2005 ◽  
Vol 32 (7) ◽  
pp. 617 ◽  
Author(s):  
Vaughan Monamy ◽  
Barry J. Fox
Keyword(s):  
Soil Moisture ◽  
Habitat Use ◽  
New South ◽  
Habitat Preferences ◽  
Local Population ◽  
New South Wales ◽  
High Soil Moisture ◽  
South Wales ◽  
Unusual Occurrence ◽  
Habitat Fidelity

Little has been published about Sminthopsis murina, a small insectivorous marsupial encountered infrequently during trapping studies. Individuals favour vegetation associations found in recently burnt heathlands and forests; however, individuals rarely remain in such areas long enough for repeated capture. We report an unusual occurrence of habitat fidelity by a dense population of subadult S. murina in coastal wet heath, New South Wales, Australia. Individuals were captured repeatedly in the first 16 months following wildfire (30 subadults trapped 154 times: recapture rate = 80%). Densities peaked 10 months after fire at 3.75 individuals ha–1. More males than females were captured (23 males, 7 females). Habitat analyses revealed differential use of regenerating coastal wet heathland by S. murina. Significantly more captures were made in areas of high soil moisture in the first six months following fire. Captures then decreased in these areas but increased where soil moisture had been lower and where vegetation had been growing more slowly. Beyond the 1995/96 breeding season, regenerating vegetation became increasingly dense and less patchy and captures of S. murina ultimately declined to zero. This paper records a rare opportunity to examine habitat preferences of a single cohort of subadult S. murina. Habitat use may have been determined by the presence of a narrow range of vegetation structure.

Correction - Use of a soil moisture model and risk analysis to predict the optimum time for the aerial sowing of pastures on the Northern Tablelands of New South Wales

1976 ◽  
Vol 16 (83) ◽  
pp. 871
Author(s):  
PM Dowling ◽  
RCG Smith
Keyword(s):  
Soil Moisture ◽  
New South ◽  
New South Wales ◽  
Practical Importance ◽  
Balance Model ◽  
Optimal Time ◽  
Plant Survival ◽  
South Wales ◽  
Close Relationship ◽  
June July

The objective of this study was to determine the time of year that maximized establishment and . minimized the risk of failure in aerial sowing of pasture seed on the Northern Tablelands of New South Wales. This was achieved by relating a set of monthly measurements of establishment spanning two years to mean soil moisture, predicted by a water balance model for the six-week period following sowing. From this relationship, establishment was simulated for 61 years using historical rainfall data to estimate probability density functions of establishment for each week of the year. From these functions it was concluded that maximum establishment with minimum risk can be expected from sowing in the June-July period. For perennial species plant survival over the first summer is of more practical importance than per cent establishment. Our data on plant survival, although not presented, indicated a close relationship existed between establishment and survival and supported the conclusion that the optimal time for oversowing is June-July.

Climatic conditions for seedling recruitment within perennial grass swards in south-eastern Australia

2012 ◽  
Vol 63 (4) ◽  
pp. 389 ◽  
Author(s):  
R. Thapa ◽  
D. R. Kemp ◽  
M. L. Mitchell
Keyword(s):  
Soil Moisture ◽  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Climatic Conditions ◽  
South Eastern ◽  
South Wales ◽  
Eastern Australia ◽  
Moisture Conditions ◽  
South Eastern Australia

Recruitment of new perennial grass plants within existing grassland ecosystems is determined by seed availability, suitable microsites, nutrients and climatic conditions, water and temperatures. This paper reports on the development of criteria to predict recruitment events using modelled soil moisture conditions associated with recruitment of species in five field experiments at Orange (Phalaris aquatica), Trunkey Creek (Austrodanthonia spp.), and Wellington (Bothriochloa macra) in central New South Wales, Australia, and the frequency of those conditions during the past 30 years. Recruitment events were recorded when a rainfall event (median 68 mm across the three sites) kept the surface volumetric soil moisture (0–50 mm) above the permanent wilting point for at least 15 continuous days, allowing for, at most, two ‘dry days’ in between. A key finding from our study is that rainfall events creating favourable soil moisture conditions for seedling emergence typically occurred in the second half of February, sometimes extending to early March. Previously it was thought that recruitment would more likely occur through autumn, winter, and spring when rainfall in southern Australia is more reliable. The 30 years’ data (1975–2004) showed that the P. aquatica site had a median of 20 continuous moist days each year in February–March, whereas, there were 16 and 10 days for the Austrodanthonia and B. macra sites, respectively. The probabilities of exceeding seven or 15 continuous days of moist surface soil were 98% and 78% at the P. aquatica site, 91% and 49% at the Austrodanthonia site, and 73% and 30% at the B. macra site, and indicated that some recruitment is possible in most years. These analyses were extended to several sites across New South Wales, Victoria, and Tasmania to estimate the frequency with which recruitment could occur within natural swards. Across these sites, the probabilities of exceeding seven continuous days of soil moisture were >55% and of exceeding 15 continuous days were lower, which showed that suitable climatic conditions exist during late summer–early autumn across south-eastern Australia for a recruitment event to occur. Future research may show that the criteria developed in this paper could have wider regional application.

Efficacy of various soil phosphate tests for predicting phosphate responsiveness and requirements of clover pastures on acidic tableland soils

Soil Research ◽  
1988 ◽  
Vol 26 (3) ◽  
pp. 479 ◽  
Author(s):  
ICR Holford ◽  
GJ Crocker
Keyword(s):  
White Clover ◽  
Significant Positive Correlation ◽  
New South ◽  
Acid Soils ◽  
Critical Values ◽  
Yield Response ◽  
Acidic Soils ◽  
Soil Phosphate ◽  
South Wales ◽  
Fertilizer Requirement

The efficacies of six different soil phosphate tests (Bray1, Bray2, alkaline fluoride, lactate, Olsen and Colwell) for predicting yield responsiveness and phosphate requirements of white clover pastures were investigated in 41 experiments over five years on acidic soils of the Northern Tablelands of New South Wales. The results contrasted with those obtained on slightly acid-to-alkaline wheat-growing soils and supported the dual hypothesis that a different type of phosphate extractant is required on acidic pasture soils from that required on more alkaline wheat-growing soils, and that phosphate sorptivity is of little importance on more acid soils. The Bray1 test was the most effective, and the lactate test least effective, in predicting responsiveness and fertilizer requirement. All soil tests, except Bray2 and lactate, were more effective on these acidic soils than on more alkaline wheat-growing soils. This was partly caused by a significant positive correlation between values of the more effective tests and yield response curvatures. However, there was no correlation between phosphate sorption and response curvature. The critical values for Bray1, fluoride and bicarbonate tests were similar to those on wheat-growing soils, but those for Bray2 and lactate were somewhat higher. Critical values for the Colwell test tended to increase with increasing phosphate sorptivity.

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