Interactions of surface drying and subsurface nutrients affecting plant growth on acidic soil profiles from an old pasture

1986 ◽  
Vol 26 (6) ◽  
pp. 681 ◽  
Author(s):  
A Pinkerton ◽  
JR Simpson

Previous studies on soils from old pastures in southern New South Wales have demonstrated that nutrients have accumulated at the soil surface, but that the 40-100-mm depth layer in many profiles has become strongly acidic (e.g. pH 4.7), and high in extractable aluminium. Poor growth of subterranean clover has occurred on such soils during dry periods and may be associated with poor root growth in the acidic, nutrient-poor subsurface layers. Possible nutritional causes of these observations were investigated using reconstituted soil profiles. The root and shoot growth of subterranean clover, wheat, oats and lucerne were compared in unamended profiles and in profiles amended by applying nutrients or calcium carbonate (lime) to correct the more obvious deficiencies of the subsurface layers. Subterranean clover grew well as long as the surface soil remained moist, so that plants could utilise the nutrients potentially available within it. When the surface (0-40 mm) was allowed to dry but the subsurface layers remained moist, growth was poor unless phosphate was applied to the moist layer. Subsurface application of lime alone was ineffective. Nitrogen application increased clover growth in the presence of added phosphate or surface moisture, but nitrogen alone did little to alleviate the effects of surface drought. Wheat, and to a lesser extent oats, responded to subsurface lime when the surface was moist, and both responded to subsurface phosphate when the surface was dry. Lucerne responded to subsurface phosphate similarly to subterranean clover but the response was more than doubled in the presence of additional borate and lime. Lime without borate was not effective. When the surface was maintained moist, liming both the surface (0-40 mm) and subsurface layers improved the response over liming the subsurface layer only. The results suggest that declining fertility and productivity in old pastures developed on acid soils may not be rectified by liming alone, but that cultivation, ripping or drilling of phosphate, and in some cases addition of borate, may be required to improve the penetration of nutrients, particularly phosphorus, to greater depth.


Soil Research ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 1
Author(s):  
Jason Condon ◽  
Helen Burns ◽  
Guangdi Li

Soil pH is seldom uniform with depth, rather it is stratified in layers. The soil surface (0–0.02 m) commonly exhibits relatively high pH and overlies a layer of acidic soil of 0.05–0.15 m deep, termed an acidic subsurface layer. Commercial and research sampling methods that rely on depth increments of 0.1 m either fail to detect or under report the presence or magnitude of pH stratification. The occurrence of pH stratification and the presence of acidic subsurface layers may cause the extent of acidity in NSW agricultural land to be underestimated. Though the cause of pH stratification in agricultural systems is well understood, the effect on agricultural production is poorly quantified due in part to inadequate sampling depth intervals resulting in poor identification of acidic subsurface layers. Although liming remains the best method to manage acidic soil, current practices of low pH targets (pHCa 5), inadequate application rates and no or ineffective incorporation have resulted in the continued formation of acidic subsurface layers. Regular monitoring in smaller depth increments (0.05 m), higher pH targets (pHCa > 5.5) and calculation of lime rate requirements that account for application method are required to slow or halt soil degradation by subsurface acidification. If higher pH is not maintained in the topsoil, the acidification of subsurface soils will extend further into the profile and require more expensive operations that mechanically place amendments deep in the soil. Although the use of organic amendments has shown promise to enhance soil acidity amelioration with depth, the longevity of their effect is questionable. Consequently, proactive, preventative management of topsoil pH with lime addition remains the most cost-effective solution for growers.



1983 ◽  
Vol 23 (121) ◽  
pp. 192 ◽  
Author(s):  
SM Bromfield ◽  
RW Cumming ◽  
DJ David ◽  
CH Williams

Three methods of estimating available manganese and aluminium status in acid soils were compared on three groups of soils from the Pejar district near Goulburn, New South Wales in which differences in pH had been brought about by different periods under subterranean clover pasture. Managanese extracted by 0.01 M calcium chloride gave the best correlation with the manganese concentration in rape and subterranean clover grown in pot culture, and provided the best index of available manganese. Soil solution manganese was inferior to CaCl2-extractable manganese and was more difficult to determine. Extraction with neutral ammonium acetate was unsatisfactory because this reagent overestimated available forms of manganese in soils containing high levels of reactive manganese. Aluminium extracted by 0.01 M CaCl2 was well correlated with exchangeable aluminium and with percentage aluminium saturation of the effective cation exchange capacity. None of the three measures of aluminium status alone was an effective index for predicting lime response by rape on these soils because both manganese and aluminium status were involved in this response. These three parameters were equally effective in multiple regressions for yield responses of rape to lime. Because of its relative ease of determination, CaCl2 extraction is preferred as a practical measure of aluminium status. Aluminium interacted with and increased the toxic effects of manganese in rape. Thus CaCl2-extractable manganese alone only provided a satisfactory index of a 'critical' value for manganese toxicity in rape for soils low in available aluminium. Subterranean clover was only slightly affected by aluminium and manganese levels in these soils, and manganese toxicity symptoms were only observed on soils containing 50 ppm or more CaCl2-extractable manganese. Nodulation failure in pots occurred in all soils with pH below 5.2 (water) or below 4.3 in CaCl2, whereas nodulation was normal when these soils were treated with CaCO3 to raise the pH to 5.8-6.0 (water). With one exception nodulation appeared adequate at field sites from which soils showing nodulation failure in the glasshouse had been collected.



Soil Research ◽  
2020 ◽  
Vol 58 (7) ◽  
pp. 662
Author(s):  
Jason R. Condon ◽  
A. Scott Black ◽  
Mark K. Conyers

This study aimed to ascertain whether application of sheep urine led to the development of acidic subsurface layers of a pasture soil. Deionised water or simulated urine solution delivering urea-nitrogen (N) at 44.8 g m–2 and potassium at 25 g m–2 was applied to soil in either winter or spring. Treatments were applied to the soil surface within 10.3 cm internal diameter PVC tubes inserted 20 cm into the soil either under ryegrass or kept bare. Main sampling times corresponded to the completion of various soil N transformations as determined by periodic sampling. Main samplings involved the collection of above ground plant material and soil sampling in 2 cm depth increments in 0–10 cm and 5 cm intervals in 10–20 cm depths. Following treatment application, urea and ammonium-N moved to a depth no greater than 20 cm but the extent of movement was greater in winter than spring due to the influence of initial soil moisture. Following urea hydrolysis, soil pH increased in the 0–15 cm depth. Subsequent nitrification significantly acidified soil under pasture by 0.8–1.0 pH units in the 2–8 and 2–6 cm depths in winter and spring respectively. This created a net acidic subsurface layer of 0.2–0.4 pH units compared with soil at the beginning of the experiment. Subsurface acidification was 0.5–0.7 pH units greater in bare soil compared with the presence of pasture. Transformations of N resulting from application of simulated urine solution formed acidic subsurface layers in the field regardless of the season of application.



1985 ◽  
Vol 25 (1) ◽  
pp. 157 ◽  
Author(s):  
LJ Horsnell

Subterranean clover responds poorly to superphosphate application on some acid soils of the Southern Tablelands of New South Wales. A field experiment was undertaken, for two years, to examine the effects of incorporating large additional amounts of superphosphate or rock phosphate in the soil, with and without lime, on the growth of subterranean clover, lucerne and phalaris sown with recommended rates of lime superphosphate. Dry matter responses of subterranean clover and lucerne to superphosphate topdressing in the second year were also recorded. In the first year, subterranean clover growth was increased by the additional lime and by lime plus superphosphate. Lucerne growth was increased by additional lime. In the second year, the growth of subterranean clover was increased by the lime treatments and the superphosphate treatments applied in the previous year and by the deep incorporation into the soil of lime and superphosphate together. Subterranean clover growth also responded to the application of rock phosphate without lime. Lucerne dry matter production in the second year was increased by the lime, superphosphate and rock phosphate treatments applied in the first year. Lime application increased the yield responses of subterranean clover and lucerne to superphosphate topdressed in the second year. Lime application had no effect on the nitrogen content of the clover but increased that of lucerne. Lime application reduced the aluminium levels in the tops of all three species. The data suggest that the responsiveness of pastures to superphosphate on these soils is increased by the application of lime and rock phosphate and is related to low nitrogen fixation and high aluminium levels in the plant.



1986 ◽  
Vol 26 (1) ◽  
pp. 107 ◽  
Author(s):  
A Pinkerton ◽  
JR Simpson

The effects of subsoil acidity and lime incorporation on plant growth were examined for several crop species (wheat, rape, lucerne and phalaris) growing in reconstituted soil profiles. The pH levels of the profiles had been differentially lowered because they had been under improved subterranean clover pastures for various periods up to 55 years. Acidities in the upper layers differed by at least one pH unit and the depth of the acidified horizons reached 60 cm in the most severely affected soil. All species showed good root growth in soil from 'unimproved' native pasture. Root growth was much poorer in the more acid profiles, particularly between 10- and 40-cm depths, where CaCl2-extractable aluminium was high (> 6 �g g-1). Liming throughout the profile reduced exchangeable aluminium (to about 1 �gg-1) and increased root lengths in the most acid profile by about 60% (0-40 cm depth), so that root lengths then approached those in the 'unimproved' soil. Liming increased shoot yields of all crops except phalaris. The increase was greatest for lucerne (400%), with smaller increases for wheat (39%) and rape (26%). Liming the surface horizon (0- 10 cm) had little effect on most species, but substantially improved root length and shoot yield of lucerne (75 and 300% respectively). The agronomic implications of these findings in crop establishment and drought resistance on acidified soils are discussed.



2018 ◽  
pp. 23-40 ◽  
Author(s):  
G. V. Vindeker ◽  
E. Yu. Prudnikova ◽  
I. Yu. Savin

During the model experiment we exposed samples from surface layer of leached chernozem, grey forest and soddy-podzolic soils to study the impact of raindrop action on their surface. According to our results, surface of leached chernozem and grey forest soil transformed similarly forming the crust separated by the cracks. The crust consisted of light (washed silt fraction) and dark (compacted fine material) areas. As for the soddy-podzilic soil, we observed surface accumulation of sand and washed mineral grains. Surface image classification showed that cracks generally tended to increase in area during the surface drying. However, leached chernozem cracked quicker and heavier compared to grey forest soil. In addition, the proportion between light and dark areas of the crust for these two types of soil changed differently as well. In conditions of different transformation cycles divided by heavy rainfalls, the changes of cracks position and the increase of light crust area was observed, while dark area moved to the cracks. Such spatial rearrangement resulted in the increase of average reflectance in RGB channels. The inequality between reflectance in different channels increased as well. During the experiment significant surface lightening occurred. It mainly affected the light area of crust and led to significant rise in reflectance in red channel.



2009 ◽  
Vol 57 (2) ◽  
pp. 132 ◽  
Author(s):  
Olusegun O. Osunkoya ◽  
Karina Pyle ◽  
Tanya Scharaschkin ◽  
Kunjithapatham Dhileepan

Cat’s claw creeper, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation in coastal Queensland and New South Wales, Australia. In densely infested areas, it smothers standing vegetation, including large trees, and causes canopy collapse. Quantitative data on the ecology of this invasive vine are generally lacking. The present study examines the underground tuber traits of M. unguis-cati and explores their links with aboveground parameters at five infested sites spanning both riparian and inland vegetation. Tubers were abundant in terms of density (~1000 per m2), although small in size and low in level of interconnectivity. M. unguis-cati also exhibits multiple stems per plant. Of all traits screened, the link between stand (stem density) and tuber density was the most significant and yielded a promising bivariate relationship for the purposes of estimation, prediction and management of what lies beneath the soil surface of a given M. unguis-cati infestation site. The study also suggests that new recruitment is primarily from seeds, not from vegetative propagation as previously thought. The results highlight the need for future biological-control efforts to focus on introducing specialist seed- and pod-feeding insects to reduce seed-output.



2012 ◽  
Vol 58 (No. 12) ◽  
pp. 560-568 ◽  
Author(s):  
E.W. Mbuthia ◽  
J.H. Shariff ◽  
A. Raman ◽  
D.S. Hodgkins ◽  
H.I. Nicol ◽  
...  

Shelterbelts are important for the sustainability of agriculture because they provide a variety of benefits to farmers and the society. Several published papers demonstrate that integration of shelterbelts with agroecosystems offers positive outcomes, such as better yield, more congenial microclimate, and greater organic matter levels. Nonetheless, soil biological diversity, the driver of greater organic matter levels, has not been convincingly tested and verified yet. In addressing this gap, we measured abundance and diversity of populations of arthropods and fungi in three<br />11-year old shelterbelts integrated with pasture to determine whether a correlation exists between the abundance of and diversity in populations of arthropods and fungi in two seasons: late autumn-early winter (May&ndash;June 2011) and late winter-early spring (August&ndash;September 2011). Litter from the soil surface and soil from two depths were sampled at increasing distance from the midpoint of shelterbelts for the extraction of arthropods and isolation culturing of fungi. The relationship among distance, depth and biodiversity of different groups of arthropods and fungi was analysed using linear regression. We found that over both seasons arthropod abundance in the litter and soil declined with increasing distance from the midpoint of the shelterbelts, and with soil depth. However, fungi abundance in either season was not affected by proximity to the shelterbelt but increased with greater soil depth. Distance from the shelterbelt midpoints did not bear an impact on the diversity richness of both arthropods and fungi.



1959 ◽  
Vol 12 (4) ◽  
pp. 205 ◽  
Author(s):  
William A. Williams ◽  
Burgess L. Kay


1951 ◽  
Vol 2 (4) ◽  
pp. 377 ◽  
Author(s):  
AJ Anderson ◽  
KD McLachlan

A study was made of the residual effect of superphosphate applied to pasture on acid soils on the Southern Tablelands of New South Wales. The effect of the superphosphate on the development of clover and subsequent changes in soil fertility and development of grass was examined. Only a limited proportion of the phosphorus applied was taken up by the pasture over the period of the experiments, but the evidence obtained suggests that this cannot be ascribed merely to phosphate fixation in the soil. The residual phosphorus was little, if any, less effective than current dressings over a number of years. The total yield of pasture was dependent almost entirely on the amount of superphosphate applied, and frequency of application had little or no effect on the total yield. A single dose at the commencement of the trials was as effective in increasing the total yield and the uptake of phosphorus as were annual dressings. High fertility and grass dominance were achieved by heavy annual dressings of superphosphate or by application of the bulk of the phosphorus in the early years. Lighter annual dressings resulted in clover dominance. Some advantages of heavier, less frequent application of superphosphate are discussed. Competition for phosphorus was an important factor in suppression of the clover by the grass. Evidence was presented in support of a hypothesis that grass or clover dominance is dependent both upon the vigour and fertility requirements of the species and upon the relation between the nitrogen demand of the pasture unit and the soil nitrogen status.



Sign in / Sign up

Export Citation Format

Share Document