Review of Australian phosphate rock research

1997 ◽  
Vol 37 (8) ◽  
pp. 845 ◽  
Author(s):  
D. C. Lewis ◽  
M. D. A. Bolland ◽  
R. J. Gilkes ◽  
L. J. Hamilton
Keyword(s):  
Western Australia ◽  
Phosphate Rock ◽  
Relative Effectiveness ◽  
Growing Season ◽  
Water Soluble ◽  
Hydrogen Ions ◽  
Laboratory Studies ◽  
Applied Current ◽  
The Poor ◽  
Rapid Dissolution

Summary. Most of the research on the effectiveness of phosphorus (P) fertilisers in Australia has involved comparing phosphate rock (PR) or partially acidulated PR (PAPR) with superphosphate (SP) or other water-soluble P fertilisers. There are many estimates of effectiveness (current relative effectiveness or CRE) which compared freshly-applied (current) PR and freshly-applied (current) SP. The CRE values for PR range from <0.1 to 2.5, with a mean value for apatite PR of 0.26 and 0.43 for calcined calcium iron aluminium PR (Calciphos). As measured in field experiments in the years after application, and using current SP as a basis for comparison, the residual effectiveness of PR (residual value or RV) is low and constant for up to 11 years after application. Phosphate rock is 5–30% as effective as current SP. The average value of RV for SP declines by about 40% in the first year after application, followed by a further 15% in the second year, and a further 30% over the remaining 6 years. Values of relative effectiveness and RV, and the rate of decline in RV differ substantially between sites and sometimes between plant species. Laboratory studies of reactions between PR and soil have shown that the poor effectiveness of PR is primarily due to the limited extent and rate of dissolution of these fertilisers compared with the almost complete and rapid dissolution of water-soluble P fertilisers. Many Australian soils are only moderately acid (pH in water >5.5) with low pH buffering capacities and they cannot quickly contribute a large supply of hydrogen ions to promote rapid dissolution of PR. Soils are commonly sandy and have low water-holding capacities; in the strongly seasonal Mediterranean climate of south-western and southern Australia, the fertilised surface soil rapidly dries between rains thereby restricting PR dissolution. This restricted dissolution contributes to the poor agronomic effectiveness of PR fertilisers. Studies in Western Australia have shown that the effectiveness of current and residual PR relative to current SP generally decreases with increasing level of application. Therefore, relative to current SP, PR fertilisers become less effective per unit of PR as more is applied to the soil. Consequently, PR fertilisers frequently cannot support the same maximum yield as current SP. Published work indicates that PR fertilisers cannot be regarded as economic substitutes for SP for most agricultural applications in Australia. However, much Australian research has used low reactive PRs in conditions that are not likely to favour even highly reactive PRs. The soils dry out between rains during the growing season and have insufficient hydrogen ions to cause rapid, extensive dissolution of even reactive PR. Research elsewhere has suggested that reactive apatite PRs can be as effective as SP for suitable soils and environments. These are soils that remain wet for the whole growing season and which contain sufficient hydrogen ions to cause rapid dissolution of reactive PR. Laboratory studies, in which there is no P leaching, on 254 different soils collected from throughout south-western Australia showed that 29 soils, all collected from >800 mm average annual rainfall areas, dissolved >40% highly reactive North Carolina PR, suggesting that in the field these soils could be suitable for highly reactive PRs. Insufficient research has been conducted in the high rainfall areas of Australia, where the environment is more likely to favour highly reactive PR, and PAPR made from highly reactive PR. Therefore, a national program was undertaken in 6 Australian states to identify circumstances under which PRs, including reactive PR and PAPR made from reactive PR, may be economic fertilisers for acidic soils in the high rainfall areas of Australia where agricultural production is largely based on pasture production.

Management of excess water in duplex soils

1992 ◽  
Vol 32 (7) ◽  
pp. 857 ◽  
Author(s):  
DJ McFarlane ◽  
JW Cox
Keyword(s):  
Groundwater Recharge ◽  
Water Flow ◽  
Western Australia ◽  
Soil Structure ◽  
Wind Erosion ◽  
Growing Season ◽  
Water Levels ◽  
Storm Runoff ◽  
Cereal Crops ◽  
Excess Water

Excess water in duplex soils can be removed by drains. In soils in which drainage is impractical, some success has been obtained by deep ripping and by gypsum amendment. These practices can increase profile storage or drainage. Interceptor drains are suitable for duplex soils with slopes of more than about 1.5%. On more gentle slopes, relief drains are used to remove excess water. Subsurface tube and mole drains have been used successfully to drain cereal crops in Victoria, but in Western Australia open drains are preferred because they can carry storm runoff as well as seepage waters. The greatest cost of open drains is the land removed from production. Over 35% of the rain falling during the growing season has been removed by drains in Victoria and Western Australia in wet years. Drainage was almost entirely downslope of monitored interceptor drains in Western Australia, which is not predicted from the theory. Simulation of water levels between drains and of drain flows using the DRAINMOD model indicated significant, preferred pathways for water flow to drains. The pathways explain the predominantly downslope effect of interceptor drains and the wide drain spacings which can be used. Deep ripping and the incorporation of gypsum can reduce waterlogging in some soils, but has had no effect in several others. The effect of deep ripping on recharge is unclear. Drains may decrease groundwater recharge, water and wind erosion, and soil structure decline. Their effect on phosphate export from catchments is unclear.

scholarly journals COMPOSITION, MICROSTRUCTURE AND PROPERTIES OF QUATERNARY CLAYS OF THE PRIKHANKAYSKAYA DEPRESSION (PRIMORYE)

2019 ◽  
Vol 14 (1) ◽  
pp. 20-34
Author(s):  
T. G. RYASHCHENKO ◽  
N. N. UKHOVA ◽  
S. I. SHTELMAKH ◽  
N. I. BELYANINA ◽  
P. S. BELYANIN
Keyword(s):  
Clay Minerals ◽  
Laboratory Data ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Climatic Conditions ◽  
Water Soluble ◽  
Laboratory Studies ◽  
Microstructural Parameters ◽  
Physical Chemical ◽  
Study Results

The article considers the study results of composition, microstructure and physical-chemical properties of the quaternary clays of the Prikhankayskaya depression in district of the lake Khanka (Primorye) on the example of air-dry samples of geological borehole 45-b in the range of 18–62 m. The objective of research was to obtain new information about the properties of widespread clay sediments in this area using geologic-lithological materials and laboratory data. The schematic geologic-lithological column was composed with the selection of various zones in the quaternary clay sediments section and the border with sediments of the Neogene System. The methodological scheme of laboratory studies of clays was proposed. This scheme includes the determination of chemical and microelement composition, clay minerals, contents of carbonates, water-soluble salts, mobile forms of aluminum oxide, humus, as well as microstructural parameters (method «Microstructure») and some physical-chemical properties. Geochemical coefficients (Kz, CIA, CIW, ICV) determined the degree of chemical maturity of clays and confirmed the results of palynological studies reflecting the fluctuations of the climatic conditions of their formation. For the group of toxic microelements for the first time the special indicator (Zc) was calculated. Which was the criterion for a degree of pollution of the clay sediments section. Clay minerals of the quaternary clays are represented by smectite and hydromica. The clear change in the mineral association was found when passing to the Neogene sediments (kaolinite prevails). The method «Microstructure» revealed the aggregated type of clays microstructure, the domination of the particles of coarse dust fraction among the primary (free) particles and the almost complete absence of the particles of fine-grained sand fraction, the participation of various fractions in the composition of aggregates. The variants of the formation of certain types of aggregates (on sizes) in the fluviolacustrine «khankayskiy» clays are presented. Solid part density, water resistance (soaking time), sedimentation volume, plasticity, relative swelling (samples-pastes) were determined using standard methods for clays. By special methods, the cation exchange capacity was measured and the calculated values of the plasticity index were obtained from forecasting formulas using the yield limit. The proposed methodological scheme of complex laboratory studies of clay sediments can be recommended for problematic geologic-lithological and engineering-geological sections.

The forms of potassium and potassium adsorption in some virgin soils from south-western Australia

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 695 ◽  
Author(s):  
Y. Pal ◽  
R. J. Gilkes ◽  
M. T. F. Wong
Keyword(s):  
Western Australia ◽  
Agricultural Soils ◽  
Clay Mineralogy ◽  
Sorption Isotherms ◽  
Clay Content ◽  
Water Soluble ◽  
X Ray Diffraction ◽  
Exchangeable K ◽  
The North ◽  
Southern District

This investigation was undertaken to determine the potassium (K) status and adsorption behaviour of 227 samples from horizons of 41 representative virgin soil profiles, extending from Geraldton in the north to the Great Southern district of Western Australia. X-ray diffraction analysis of random powder of whole soil indicated that quartz is the dominant mineral and some soils contain significant amounts of feldspars. Clay mineralogy is dominated by kaolinite but minor quantities of illite are present in some soils. Most south-west Australian agricultural soils contain little available K: NaHCO3-extractable K (NaHCO3-K, median value 0·09 cmol K/kg, equivalent to 35 mg K/kg soil), HNO3-extractable K (HNO3-K, median value 0·30 cmol K/kg, equivalent to 117 mg K/kg soil), and total K (XRF determined K, median value, 17 cmol K/kg, equivalent to 6630 mg K/kg soil). The proportion of water-soluble K (H2O-K) ranges from 0 to 3·5% of total K, 0 to 76% of HNO3-K, and 0 to nearly 100% of exchangeable K. Exchangeable K ranges from 0 to 100% (median value 37%) of HNO3-K. These are relatively high proportions of H2O-K and exchangeable K compared with soils from many other parts of the world. The amounts of all forms of K variously increase or decrease downwards in the soil profile depending on both clay content and mineralogy. The commonly assumed increase in K with clay content alone is invalid. The soils mostly have low-to-moderate values of K sorption capacity, ranging from 5% to 67% (median value 14%) of added K (initially 4·1 mM K/L, equivalent to 4·1 cmol K/kg). otassium sorption isotherms conform well to the Freundlich equation. The inability of the Langmuir equation to describe the data may indicate that there are several types of K sorption sites in these soils. The Gapon coefficient KG varied widely from 0·04 to 29·8 (L/mol) ½ [median value 5·4 (L/mol) ½ ].

Changes in the total amount of water-soluble antioxidants in the blood serum of Duroc boars depending on the duration of their fattening

2020 ◽  
Vol 1 (12) ◽  
pp. 112-118
Author(s):  
O. A. Voronina ◽  
◽  
A. A. Savina ◽  
N. S. Kolesnik ◽  
N. V. Bogolyubova ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Blood Serum ◽  
Water Soluble ◽  
Laboratory Studies ◽  
Blood Samples ◽  
Amperometric Method ◽  
Significant Difference ◽  
Total Antioxidant ◽  
First Time

The influence of fattening conditions on the digestive and metabolic processes in animals is actively studied to increase the production of animal food. The aim of the study was to estimate the total amount of water-soluble antioxidants in the blood serum of Duroc boars depending on the duration of fattening. Experiments were conducted on 102 animals to confirm the results of laboratory studies, as well as determination of the total antioxidant activity of pig blood serum by amperometric method. For the first time, a significant difference in antioxidant activity was found in blood samples of Duroc boars with the duration of their fattening from 81 to 101 days.

Innovative Strategies for Lipid-Based Drug Delivery

2018 ◽  
pp. 60-84 ◽  
Author(s):  
Navneet Sharma ◽  
Sabna Kotta ◽  
Mohd Aleem ◽  
Shubham Singh ◽  
Rakesh Kumar Sharma
Keyword(s):  
Drug Delivery ◽  
Drug Absorption ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Water Soluble ◽  
Absorption Process ◽  
Innovative Strategies ◽  
The Poor ◽  
Water Soluble Drugs ◽  
Selection Of

In the last decade, there has been a mounting concern in lipid-based formulations to deliver water-soluble drugs. Lipid-based drug delivery systems are one of the budding and promising technologies designed to tackle the poor bioavailability problems. This chapter stresses the different mechanisms of lipophilic drug absorption along with its advantages and limitations. It points out the different mechanisms of how lipid-based excipients and the different formulations interact with the absorption process. This review provides a comprehensive summary about the lipid formulation classification scheme (LFCS), a guide for the selection of appropriate formulation and commonly used excipients for lipid-based formulations, along with the important factors to be considered in formulation design and excipient selection. This review also focuses on the formulation of solid lipid-based formulations, important evaluation aspects, and commercial formulations available for the purpose.

scholarly journals Effects of Temperature, Concentration, Age, and Algaecides on Phytophthora capsici Zoospore Infectivity

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 54-60 ◽  
Author(s):  
L. L. Granke ◽  
M. K. Hausbeck
Keyword(s):  
Water Temperature ◽  
Irrigation Water ◽  
Phytophthora Capsici ◽  
Growing Season ◽  
Laboratory Studies ◽  
Inoculum Concentration ◽  
Pickling Cucumbers ◽  
Effects Of Temperature ◽  
Water Treatments ◽  
Zoospore Suspension

Controlled laboratory studies were undertaken to determine the effects of water temperature (2, 9, 12, 19, 22, and 32°C), inoculum concentration (1 × 102, 1 × 103, 5 × 103, 1 × 104, 2 × 104, and 4 × 104 zoospores/ml), and zoospore suspension age (0, 1, 3, and 5 days old) on infection of pickling cucumbers (Cucumis sativus) by Phytophthora capsici. Zoospore motility and mortality in response to commercial algaecides were also investigated. Cucumbers became infected at all temperatures tested, except 2°C, and the highest infection incidence was observed for cucumbers incubated in suspensions held at ≥19°C. Fewer fruit (<40% at ≥19°C, 0% at ≤12°C) became infected when water contained 1 × 102 zoospores/ml. Almost 100% of fruit were infected when water contained ≥5 × 103 zoospores/ml at temperatures ≥12°C. While the incidence of fruit infection declined with the zoospore suspension age, infection still occurred when 5-day-old suspensions were used. Commercial algaecides inhibited zoospore motility and caused significant zoospore mortality in laboratory assays, and show promise for treatment of infested irrigation water. Avoidance of infested irrigation water throughout the growing season is warranted until effective and economically acceptable water treatments are developed for field use.

Effectiveness of some copper compounds applied as foliar sprays in alleviating copper deficiency of wheat grown on copper-deficient soils of Western Australia

1990 ◽  
Vol 30 (5) ◽  
pp. 687 ◽  
Author(s):  
RF Brennan
Keyword(s):  
Grain Yield ◽  
Western Australia ◽  
Copper Deficiency ◽  
Relative Effectiveness ◽  
Grain Yields ◽  
Foliar Sprays ◽  
Cu Deficiency ◽  
Copper Compounds ◽  
The Difference ◽  
The Relationship

The effectiveness of copper oxychloride (CU2Cl(OH)3, 52% Cu) and chelated Cu (Cu-EDTA, 15% Cu) were compared with the effectiveness of copper sulphate (CuSO4, 25% Cu) as foliar sprays for alleviating Cu deficiency and obtaining maximum grain yields of wheat (1.93-2.5 t/ha). The experiments were conducted over 4 years at 4 sites in the Lake Grace and Newdegate districts, about 300-350 km south-east of Perth, Western Australia. Each source was sprayed at 6 or 7 rates of Cu to define the relationship between grain yield and the amount of foliar Cu applied for wheat grown on soils where Cu had not been previously applied. The levels of Cu sprayed in experiment 1 were 0, 21, 63, 125, 250, and 375 g/ha, and for experiments 2,3 and 4, the levels of Cu were 0, 25, 50, 100, 200, 400 and 800 g/ha. The relative effectiveness of foliar-applied chelated Cu and CU2Cl(OH)3, compared with CuSO4, was 1.72-2.24 and 0.47-0.63, respectively. Although the relative effectiveness of each product was different, similar quantities of each were required to achieve maximum wheat grain yield because of the difference in the Cu contents of each source of Cu. The amounts of Cu product sprayed for maximum grain yields of wheat varied within the ranges 0.9-1.8 kg/ha, 0.8-1.2 kg/ha and 0.8-1.8 kg/ha for CuSO4, chelated Cu and CU2Cl(OH)3, respectively.

An analysis of the frequency and timing of false break events in the Mediterranean region of Western Australia

2001 ◽  
Vol 52 (3) ◽  
pp. 367 ◽  
Author(s):  
R. Chapman ◽  
S. Asseng
Keyword(s):  
Western Australia ◽  
Mediterranean Region ◽  
Meteorological Data ◽  
Seasonal Pattern ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dormancy Release ◽  
The Poor ◽  
Time Periods ◽  
The Mediterranean

Historical meteorological data were used to estimate the frequency and timing of false break events at 10 locations in the annual pasture and wheat producing area in the Mediterranean climatic region of Western Australia. The seasonal pattern of false breaks identified by this analysis was compared with the dynamics of dormancy release in a field population of subterranean clover (Trifolium subterraneum L.) to determine the influence that these events may have on the legume content of annual pasture communities in this region. False break events were estimated to occur on approximately 2 of every 3 years (611–72% of years) with no significant differences across the area investigated. Changes in the risk of false break events were examined over discrete time periods. The period of greatest risk was predicted to occur during early autumn (early March to mid April). Seed softening is virtually complete in subterranean clover at this point. The seed bank strategy of this species is, therefore, not well adapted to withstand the effects of false breaks. This might largely explain the poor persistence of subterranean clover in the annual pasture communities in the Mediterranean region of Western Australia. The legume content of these pastures might be improved by selecting species with late dormancy release strategies that will give better protection from false breaks.

Severity of root rot in mature subterranean clover and associated fungal pathogens in the wheatbelt of Western Australia

2009 ◽  
Vol 60 (1) ◽  
pp. 43 ◽  
Author(s):  
Tiernan A. O'Rourke ◽  
Tim T. Scanlon ◽  
Megan H. Ryan ◽  
Len J. Wade ◽  
Alan C. McKay ◽  
...  
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Fungal Pathogens ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Growing Season ◽  
Root Diameter ◽  
Root Disease ◽  
Soil Dna ◽  
Tap Root

Pasture decline is considered to be a serious challenge to agricultural productivity of subterranean clover across southern Australia. Root disease is a significant contributing factor to pasture decline. However, root disease assessments are generally carried out in the early part of the growing season and in areas predominantly sown to permanent pastures. For this reason, in spring 2004, a survey was undertaken to determine the severity of root disease in mature subterranean clover plants in pastures located in the wheatbelt of Western Australia. DNA-based soil assays were used to estimate population density in the soil of a variety of soil-borne pathogens known to commonly occur in the Mediterranean-type environments of southern Australia. The relationships between severity of disease on tap and lateral roots and root diameter, root length, nodulation, and total rainfall were determined. The survey showed, for the first time, that severe root disease is widespread in spring across the wheatbelt of Western Australia. There was a positive correlation between rainfall and tap root disease, and between tap root disease and average root diameter of the entire root system. Despite the high levels of root disease present across the sites, the DNA of most root disease pathogens assayed was detected in trace concentrations. Only Pythium Clade F showed high DNA concentrations in the soil. DNA concentrations in the soil, in particular for Phytophthora clandestina and Rhizoctonia solani AG 2.1 and AG 2.2, were higher in the smaller autumn sampling in 2006. This study suggests that the productivity of subterranean clover-based pastures is severely compromised by root rot diseases throughout the growing season in the wheatbelt of Western Australia.

Seed production and persistence of Carnamah and other early strains of Trifolium subterraneum in the wheatbelt of Western Australia

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Early Flowering ◽  
The Other ◽  
Factors Affecting ◽  
Seed Yields

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

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