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Mineral Nutrition versus Yield of Field Crops Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur Zinc Copper Iron Manganese Boron Molybdenum Chlorine Nickel Index
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Subsoil constraints present a substantial problem for crop production in many agricultural regions. In particular, soils in temperate grain production areas of Australia are often poorly structured due to high content of sodic clay. An... more
Subsoil constraints present a substantial problem for crop production in many agricultural regions. In particular, soils in temperate grain production areas of Australia are often poorly structured due to high content of sodic clay. An alternative to the standard practice of addition of gypsum is to incorporate organic amendments deep into the subsoil. An incubation experiment was performed for 174 days using several organic amendments. These consisted of wheat shoots, lucerne pellets, canola and chickpea stubbles, chicken manure, peat, and sawdust. Gypsum, an inorganic amendment commonly applied to sodic soil, was included for comparison. The change over 174 days in soil structural properties was measured using wet-sieving. Formation of slaking-resistant macroaggregates >2 mm was most rapid with ‘green plant material’, wheat and lucerne, while the ‘stubbles’ were markedly slower in obtaining the equivalent level of aggregation. However, the largest growth in aggregates after day...
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Summary. The dissolution of North Carolina phosphate rock (NCPR) in soil was investigated in a laboratory study using surface soils sampled from 28 permanent pasture sites. The relationships between phosphorus (P) dissolved, P... more
Summary. The dissolution of North Carolina phosphate rock (NCPR) in soil was investigated in a laboratory study using surface soils sampled from 28 permanent pasture sites. The relationships between phosphorus (P) dissolved, P availability and various soil properties were investigated using simple and multiple linear regression and the findings related to the relative effectiveness of NCPR for pasture production at the sites. The extent of dissolution of NCPR was positively correlated to P buffering capacity (r2 = 0.42). Phosphorus buffering capacity and titratable acidity together accounted for 72% of the variance in dissolution. Bicarbonate-extractable P (‘available’ P) generally increased as dissolution increased. However, the increase in available P was consistently lower for soils with higher P buffering capacity. The proportion of dissolved P that was available also decreased with increasing P buffering capacity (r2 = 0.63). Consequently, the increase in available P was highes...
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A large-scale field experiment was used to investigate the long-term effects of a single application of manure or inorganic fertiliser on microbial communities in the topsoil and subsoil of a cropping field in south-west Victoria. Poultry... more
A large-scale field experiment was used to investigate the long-term effects of a single application of manure or inorganic fertiliser on microbial communities in the topsoil and subsoil of a cropping field in south-west Victoria. Poultry litter (20 t ha–1) and fertiliser (with equivalent total nutrients to the manure) was either surface broadcast or deep ripped into the subsoil before sowing in 2014. Soil samples were collected from the 0–10 and 25–40cm horizons in each treatment immediately after harvest of the third successive crop in January 2017. Next-generation sequencing of the 16S and ITS rRNA genes was used to characterise the bacterial and fungal communities in the soil. Amendment type and method of placement had a limited effect on soil microbial community structure and diversity, three years after treatments were applied. Fungal communities exhibited weak responses to the poultry litter and fertiliser in comparison to a nil control, but none of the treatments had any det...
Research Interests: Environmental Science, Agronomy, Soil, Multidisciplinary, Manure, and 3 moreSoil health, Topsoil, and Subsoil
© 2016 The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the... more
© 2016 The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the remediation time. However, limited information is available on the effect of N form on Cd phytoextraction and associated mechanisms in plants. This study examined the effect of N form on Cd accumulation, translocation, and speciation in Carpobrotus rossii and Solanum nigrum. Plants were grown in nutrient solution with 5-15 μM Cd in the presence of 1000 μM NH4+ or NO3-. Plant growth and Cd uptake were measured, and Cd speciation was analyzed using synchrotron-based X-ray absorption spectroscopy. Shoot Cd accumulation was 30% greater with NH4+ than NO3- supply. Carpobrotus rossii accumulated three times more Cd than S. nigrum. However, Cd speciation in the plants was not influenced by N form, but it did vary with species and tissues. In C. rossii, up to 91% of ...
In this paper the question is answered about how profitable it was to incorporate 10 and 20 tonnes of poultry litter (manure) per ha to amend sodic sub-soil used for high rainfall cropping on two farms in south western Victoria over the... more
In this paper the question is answered about how profitable it was to incorporate 10 and 20 tonnes of poultry litter (manure) per ha to amend sodic sub-soil used for high rainfall cropping on two farms in south western Victoria over the four years 2009 to 2012. The subsequent four crop yield responses were measured in plots from replicated field trials on the two farms, and the costs and benefits analysed. The costs of growing crops using sub-soil manure were high. Incorporating the full rate of 20 tonnes of manure cost $1244 and $1345/ha at the two farms, with the difference resulting from the distance the manure was transported. Applying half the rate of manure at 10 tonnes/ha greatly reduced the cost of the sub-soil treatment. Despite the high costs, the practice was profitable at both sites, because significant increases in crop yields were achieved in each crop over the four years from 2009 to 2012. Incorporating 20 t/ha of manure in the sub-soil resulted in an extra annual net...
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Transpiration efficiency, the shoot biomass produced per unit of transpired water, is generally considered to be a constant property for a given crop in a given environment. To determine whether deep-banded organic amendments affect the... more
Transpiration efficiency, the shoot biomass produced per unit of transpired water, is generally considered to be a constant property for a given crop in a given environment. To determine whether deep-banded organic amendments affect the transpiration efficiency (TE) of wheat plants and to provide a possible explanation for any changes in the TE, two-column experiments were carried out under controlled environment conditions. A Sodosol soil with physically constrained subsoils and a well-structured Vertosol were subjected to treatments including a control, fertilizer nutrients alone, and fertilizer-enriched organic amendments. The addition of fertilizer-enriched organic amendments in Sodosol consistently increased the canopy TE compared to the control and inorganic fertilizer treatments. The instantaneous TE, at the leaf level, was also increased by the organic-based amendments due to greater reductions in stomatal conductance and transpiration rates during periods of moderate water-...
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Subsoil manuring is a practice that involves placing high rates of organic amendments in bands at the base of rip-lines that extend down into the subsoil to a depth of 30–40cm, in order to ameliorate poorly structured clay subsoils. The... more
Subsoil manuring is a practice that involves placing high rates of organic amendments in bands at the base of rip-lines that extend down into the subsoil to a depth of 30–40cm, in order to ameliorate poorly structured clay subsoils. The objective of this study was to determine whether the increases in crop yield from this practice, which occurred at one site in the high-rainfall zone in Victoria from 2005 to 2007, would occur at other sites and in other seasons in south-western Victoria. On-farm field experiments were therefore carried out at three sites in south-western Victoria between 2009 and 2012 to measure the yield responses to subsoil manuring. The study found that subsoil manuring with poultry litter resulted in consistent and recurring increases in estimated grain yield at these sites, with responses occurring with consecutive crops. Increases in estimated grain yield continued for 4 years, with average increases in hand-harvested yield of 3.5 t ha–1 for wheat, 1.6 t ha–1 ...
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Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the remediation time. However, limited information is available on the effect of N form on Cd phytoextraction and associated... more
Nitrogen fertilization could improve the efficiency of Cd phytoextraction in contaminated soil and thus shorten the remediation time. However, limited information is available on the effect of N form on Cd phytoextraction and associated mechanisms in plants. This study examined the effect of N form on Cd accumulation, translocation, and speciation in Carpobrotus rossii and Solanum nigrum Plants were grown in nutrient solution with 5-15 μM Cd in the presence of 1000 µM NH4 (+) or NO3 (-) Plant growth and Cd uptake were measured, and Cd speciation was analyzed using synchrotron-based X-ray absorption spectroscopy. Shoot Cd accumulation was 30% greater with NH4 (+) than NO3 (-) supply. Carpobrotus rossii accumulated three times more Cd than S. nigrum. However, Cd speciation in the plants was not influenced by N form, but it did vary with species and tissues. In C. rossii, up to 91% of Cd was bound to S-containing ligands in all tissues except the xylem sap where 87-95% were Cd-OH compl...
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Field trials examined the growth, water-use and grain production of a canola crop grown on a Sodosol that was 'subsoil manured' two years prior to the study. After three seasons of crop production, the organic-amended treatments... more
Field trials examined the growth, water-use and grain production of a canola crop grown on a Sodosol that was 'subsoil manured' two years prior to the study. After three seasons of crop production, the organic-amended treatments continued to out-perform the non-amended treatments with 50-80% additional grain yield. The yield gain was attributed to the additional nutrient uptake, and water use mostly in the subsurface layers below 40 cm deep. Furthermore, the largest change in the subsurface structure was associated with the treatment effect on growth of crop plants. Introduction The amelioration of high clay, poorly structured, sodic subsoil is quite a challenge in terms of cost and the available technology. In Australia, the use of deep-ripping with application of gypsum has resulted in increased grain and pasture yields (Clark 2004; Ellington 1986; Greenwood et al. 2006; Hamza and Anderson 2003). Rarely have these methods achieved sustained increased grain yield. The use o...
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The role of phosphorus (P) in the amelioration of aluminium (Al) toxicity to plants is still unclear. The aim of this study was to examine the amelioration of Al toxicity by P supply. The study involved growing Al-sensitive wheat... more
The role of phosphorus (P) in the amelioration of aluminium (Al) toxicity to plants is still unclear. The aim of this study was to examine the amelioration of Al toxicity by P supply. The study involved growing Al-sensitive wheat seedlings for 13 days in an acidic soil (pH 4.5 in CaCl 2) with increasing added rates of P (0, 20, 40 and 80 mg P/kg soil) and Al (0, 50 and 150 mg AlCl 3 /kg soil). The results indicated that the effects of Al toxicity in this soil could be fully alleviated by the application of P at 50 mg AlCl 3 /kg. The highest 150 mg/kg AlCl3 treatment significantly reduced root growth, but this was partially overcome by the 80 mg/kg P treatment. High P significantly reduced the concentration of Al in the apoplast, and in the root and shoot. It is possible that an insoluble Al-P complex forms in the soil and this decreases Al bound in apoplast as well as uptake into the roots. High P decreased the translocation of Al from root to shoot. Introduction Aluminium toxicity ...
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Increasing attention is being focused on the influence of rapid increases in atmospheric CO2 concentration on nutrient cycling in ecosystems. An understanding of how elevated CO2 affects plant utilization and acquisition of phosphorus (P)... more
Increasing attention is being focused on the influence of rapid increases in atmospheric CO2 concentration on nutrient cycling in ecosystems. An understanding of how elevated CO2 affects plant utilization and acquisition of phosphorus (P) will be critical for P management to maintain ecosystem sustainability in P-deficient regions. This review focuses on the impact of elevated CO2 on plant P demand, utilization in plants and P acquisition from soil. Several knowledge gaps on elevated CO2-P associations are highlighted. Significant increases in P demand by plants are likely to happen under elevated CO2 due to the stimulation of photosynthesis, and subsequent growth responses. Elevated CO2 alters P acquisition through changes in root morphology and increases in rooting depth. Moreover, the quantity and composition of root exudates are likely to change under elevated CO2, due to the changes in carbon fluxes along the glycolytic pathway and the tricarboxylic acid cycle. As a consequence...
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Benefits to crop productivity arising from increasing CO2 fertilization may be offset by detrimental effects of global climate change, such as an increasing frequency of drought. Phosphorus (P) nutrition plays an important role in crop... more
Benefits to crop productivity arising from increasing CO2 fertilization may be offset by detrimental effects of global climate change, such as an increasing frequency of drought. Phosphorus (P) nutrition plays an important role in crop responses to water stress, but how elevated CO2 (eCO2) and P nutrition interact, especially in legumes, is unclear. This study aimed to elucidate whether P supply improves plant drought tolerance under eCO2. A soil-column experiment was conducted in a free air CO2 enrichment (SoilFACE) system. Field pea (Pisum sativum) was grown in a P-deficient vertisol, supplied with 15 mg P kg(-1) (deficient) or 60 mg P kg(-1) (adequate for crop growth) and exposed to ambient CO2 (aCO2; 380-400 ppm) or eCO2 (550-580 ppm). Drought treatments commenced at flowering. Measurements were taken of soil and leaf water content, photosynthesis, stomatal conductance, total soluble sugars and inorganic P content (Pi). Water-use efficiency was greatest under eCO2 when the plant...
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Research Interests: Chemistry, Agronomy, Water Treatment, Biological Sciences, Plant Physiology, and 15 moreEnvironmental Sciences, Nitrate, Nitrogen, Carbon Allocation, Rhizosphere, Acid Soil, Soil management, Soil Acidity, Crop Yield, Water Level, Nitrate Uptake, Agricultural Soil, Field capacity, Root growth, and nitrate leaching
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Summary. The agronomic effectiveness of a partially acidulated phosphate rock (PAPR), produced by the 50% acidulation of North Carolina phosphate rock with sulfuric acid, was compared over 4 growing seasons with triple superphosphate... more
Summary. The agronomic effectiveness of a partially acidulated phosphate rock (PAPR), produced by the 50% acidulation of North Carolina phosphate rock with sulfuric acid, was compared over 4 growing seasons with triple superphosphate (TSP) and the highly reactive North Carolina phosphate rock at 22 permanent pasture sites in the National Reactive Phosphate Rock Project. The performance of PAPR as a phosphorus (P) fertiliser for permanent pasture was determined by calculating the substitution value of TSP for PAPR at 50% of the maximum yield response for TSP from the fitted annual dry matter response curves. PAPR performance varied both between sites, and between years at individual sites. Annual yield responses with PAPR were larger than those with TSP at 1 high rainfall site where water-soluble P from TSP was thought to leach from the root zone. PAPR was superior to TSP at another site and generally similar in effectiveness to TSP at 4 sites with light-textured, low or medium P-sor...