Papers by Geraldine Ritchie
Environmental Pollution, 1994
Phosphorus Phosphorus (P) (P) in in wastes wastes from from piggeries piggeries may may contribut... more Phosphorus Phosphorus (P) (P) in in wastes wastes from from piggeries piggeries may may contribute contribute to to the the eutrophication eutrophication of of waterways waterways if if not not disposed disposed of of appropriately. appropriately. Phosphorus Phosphorus leaching, leaching, from from three three soils soils with with different different P P sorption sorption characteristics characteristics (two (two with with low low P P retention retention and and one one with with moderate moderate P P retention) retention) when when treated treated with with piggery piggery effluent effluent (with (with or or without without struvite). struvite). was was investigated investigated using using batch batch and and leaching leaching experiments. experiments. The The leaching leaching of of P P retained retained in in soil soil from from the the application application of of struvite struvite effluent effluent was was determined. determined. In In addition. addition. P P leaching leaching from from lime lime residues residues (resulting (resulting from from the the treatment treatment of of piggery piggery effluent effluent with with lime lime to to remove remove P) P) was was determined determined in in comparison comparison to to superphosphate superphosphate when when applied applied to to the the same same three three soils. soils. Most Most P P was was leached leached from from sandy sandy soils soils with with low low P P reten reten tion tion when when effluent effluent with with or or without without struvite struvite was was applied. applied. More More than than 100% 100% of of the the filterable filterable P P applied applied in in struvite struvite effluent effluent was was leached leached in in sandy sandy soils soils with with low low Pretention. Pretention. Solid, Solid, inorganic inorganic forms forms of of P P (struvite) (struvite) became became soluble soluble and and potentially potentially leachable leachable at at pH pH < < 7 7 or or were were sorbed sorbed after after dissolution dissolution if if there there were were sufficient sufficient sorption sorption sites. sites. In In sandy sandy soils soils with with low low P P retention. retention. more more than than 39% 39% of of the the total total filterable filterable P P applied applied in in recycled recycled effluent effluent (without (without struvite) struvite) was was leached. leached. Soil Soil P P increased increased mainly mainly in in surface surface layers layers after after treatment treatment with with effluent. effluent. Sandy Sandy soils soils pre-treated pre-treated with with struvite struvite effluent effluent leached leached 40% 40% of of the the P P retained retained in in the the previous previous application. application. Phosphorus Phosphorus decreased decreased in in surface surface layers layers and and increased increased at at depth depth in in the the soil soil with with moderate moderate P P retention retention after after leaching leaching the the struvite struvite effluent effluent pre-treated pre-treated soil soil with with water. water. The The soils soils capacity capacity to to adsorb adsorb P P and and the the soil soil pH pH were were the the major major soil soil properties properties that that affected affected the the rate rate and and amount amount of of P P leaching. leaching. whereas whereas the the important important characteristics characteristics of of the the effluent effluent were were pH. pH. P P concentration concentration and and the the forms forms of of P P in in the the effluent. effluent. Phosphorus Phosphorus losses losses from from soils soils amended amended with with hydrated hydrated lime lime and and lime lime kiln kiln dust dust residues residues were were much much lower lower than than losses losses from from soils soils amended amended with with superphosphate. superphosphate. Up Up to to 92% 92% of of the the P P applied applied as as superphosphate superphosphate was was leached leached from from sandy sandy soils soils with with low low P P retention. retention. whereas whereas only only up up to to 60% 60% of of the the P P applied applied in in lime lime residues residues was was leached. leached. The The P P source source contributing contributing least least to to P P leaching leaching was was the the lime lime kiln kiln dust dust residue. residue. The The amount amount of of P P leached leached depended depended on on the the water-soluble water-soluble P P content. content. neutralising neutralising value value and and applica applica tion tion rate rate of of the the P P source. source. and and the the pH pH and and P P sorption sorption capacity capacity of of the the soil. soil.
Environmental Pollution, 1987
Piggery effluent may contribute to the eutrophication ofwaterways. ifit is not treated before dis... more Piggery effluent may contribute to the eutrophication ofwaterways. ifit is not treated before disposal. because of high levels of phosphorus. Limes and red muds (a residuefrom bauxite refining) were used to remove phosphorusfrom piggery effluent (41 mg litre-I total P). Lime-based amendments were more effective than the red muds at removing phosphorus when compared at the same liquid: solid ratios. Based on laboratory data. the cost ()f treating effluent increased rapidly as the final required phosphorus concentration decreased to less than 4 mg litre-I. Kiln dust was the cheapest amendment tested down to 2 mg litre-I. Hydrated lime was able to clarify andflocculate the effluent to 1 mg litre-I within 60 min. The re-useability of all limes may be determined by a simple pH test. Red mud could be used to remove phosphorus when its pH was lowered to 6,0-6,5 and it is used at liquid:solid ratios <20:1.
Environmental Pollution, 1994
The choice of management practices for the treatment of piggery effluent prior to its disposal to... more The choice of management practices for the treatment of piggery effluent prior to its disposal to waterways or land is governed by the desire to simultaneously minimise the cost of treatment whilst minimising pollution of the environment. Laboratory experiments were conducted to compare the removal of total and total filterable phosphorus (P) «0-45 pm) from ortho-phosphate solutions or piggery effluent by hydrated lime or lime kiln dust alone, or from recycled piggery e.ffluent by lime and physico-chemical treatment methods. In addition, the ability of lime to remove P from recycled piggery e.ffluent at an intensive piggery was assessed. in lime treated e.ffluent was present in the >0•45 f..Lm fraction because of the presence of unsettled Most P floes of P impregnated lime. The efficiency of total P removal by hydrated lime and lime kiln dust decreased as e.ffluent quality declined. The efficiency of removal of total filterable P by hydrated lime or lime kiln dust was not affected by e.ffluent quality. Hydrated lime was more efficient in removing P from e.ffluent or ortho-phosphate solutions, but lime kiln dust was more cost effective. More than 95% of total P was removed from recycled piggery e.ffluent when physico-chemical treatment followed settling with or without lime. The physico-chemical treatment decreased total P mainly by decreasing the number of suspended particles in the e.ffluent and by precipitating some total filterable P as iron, aluminium or calcium compounds.
Fertilizer Research, 1993
In order to manage phosphorus (P) losses from soils to waterbodies, knowledge of the mechanisms t... more In order to manage phosphorus (P) losses from soils to waterbodies, knowledge of the mechanisms through which P is retained or released from the soil is essential. Sandy soils of the Peel-Harvey catchment (Western Australia) were subjected to a range of environmental and management factors in the laboratory and field in order to gain an understanding of the mechanisms that affect the magnitude of P losses. Sandy soils accumulated P, despite having little sorption capacity, and this accumulation could be monitored by measuring an acid-extractable fraction. The potential, short-term P loss could be estimated by determination of water-soluble soil solution P prior to winter rains. An annual cycle of the change in arbitrarily defined soil-P pools is discussed in relation to environmental and management factors. Laboratory experiments indicated that P rundown and potential annual P loss in the absence of P fertilizers could be estimated using bicarbonate extractable P. Phosphorus losses were decreased by the application of fertilizers with a low content of water-soluble P. The low ability of sandy soils of the Peel-Harvey coastal catchment to retain P, when compared to other Western Australian soils, is because of low contents of clay minerals and iron and aluminium hydrous oxides.
Lime movement and subsurface soil acidity
Carbon dioxide (CO2) is a pollutant (greenhouse gas) that is emitted during winemaking but not cu... more Carbon dioxide (CO2) is a pollutant (greenhouse gas) that is emitted during winemaking but not currently regulated by the Environmental Protection Agency. While winery CO2 emissions have been modeled, they have never been measured continuously or confirmed during a commercial fermentation. As international interest increases in greenhouse gases, it is important to know the amount of CO2 release and the determining factors; yeast strain, temperature, and dissolved CO2 are potentially important parameters. The study was designed to quantify emissions and test a theoretical model for atmospheric release of CO2 during alcoholic fermentation in a commercial winery. Gas release was channeled through a manifold system with an in-line mass flow meter calibrated for CO2, providing real-time and integrated measurement of atmospheric emission. Intermittent use of a hot-wire anemometer was used as a check on the mass-flow measurements. Initial results indicate that integrated mass of CO2 releas...
Sulfur dioxide (SO 2) can be added to harvesting bins if there is a risk of spoilage due to high ... more Sulfur dioxide (SO 2) can be added to harvesting bins if there is a risk of spoilage due to high temperatures, high pH, diseased or damaged fruit, long wait times until the fruit can be minified or long transport distances to the winery. High temperatures and pH increase proliferation of microbes after infection and increase the rate of oxidation. Machine harvested or diseased and damaged berries often have ruptured skins, releasing juice which drains to the bottom of the container. Accumulation of juice in the base of the bin increases the risk of infection with microbes, as the juice is more easily accessible. The longer the journey to the winery, the greater the opportunity for spoilage. Sulfur dioxide's main role is to prevent microbial infection of the juice and thereby prevent unwanted or spontaneous fermentations by yeasts other than that planned by the winemaker and infections by undesirable bacteria (e.g., acetobacter, lactobacillus). Molecular sulfur dioxide (SO2 or H2...
Grape juice concentrate is added to juices and musts when the growing conditions have prevented t... more Grape juice concentrate is added to juices and musts when the growing conditions have prevented the grapes from accumulating optimal glucose and fructose concentrations for the desired wine style. It may also be used to adjust the sweetness of a table wine (usually just before bottling) or a sweet or fortified wine (after alcoholic fermentation or during maturation). Grape juice concentrate is a very viscous material and therefore it is important to ensure through homogenization with the juice or wine to which it is added. Adequate homogenization can be achieved by mixing the concentrate with small volumes of the juice or wine to be adjusted, in one or more stages. A 1:1 mixture is placed in another, smaller tank and carefully mixed by circulation over the top of the tank and between the bottom and racking valves. Another equal volume of the juice or wine can then be added to the small tank and the procedure repeated until the viscosity of the mixture is closer to that of the juice ...
Red grapes can sometimes have sugar contents that may be high enough to cause stuck or sluggish f... more Red grapes can sometimes have sugar contents that may be high enough to cause stuck or sluggish fermentations. At harvest, grapes may have a Brix >26 and include dehydrated or raisined berries. During fermentation, the alcohol that is produced can be sufficient to kill the yeast or severely restrict its ability to take up glucose and fructose and hence prevent the fermentation from completing to the desired level. The addition of water to the must can prevent such problems and is legal in some regions (Anon, 2002).
The concentration of dissolved carbon dioxide (DCO2) is recognized as being high during alcoholic... more The concentration of dissolved carbon dioxide (DCO2) is recognized as being high during alcoholic fermentation, but there is little data to indicate the actual concentrations and how they vary with extent of the fermentation or winemaking operations. The presence of the inert gas is important in protecting the juice or must from oxidation. In addition, carbon dioxide (CO2) is a recognized greenhouse gas, and the contribution of fermenting juice and musts to atmospheric CO2 cannot be put in perspective or modeled unless one has a better idea of DCO2 and whether supersaturation is occurring throughout fermentation or for part of the time. This study monitored DCO2 concentrations on a daily basis in four red musts during alcoholic fermentation in a commercial winery. Dissolved carbon dioxide concentrations generally peaked at around 2000 mg/L, but the maximum was not associated with a particular stage of fermentation. Musts tended to be supersaturated with DCO2 when the rate of ferment...
What is lysozyme and why is it used in Winemaking
Fortified wines, such as Port-style wines, can be made by choosing to ferment the juice or must t... more Fortified wines, such as Port-style wines, can be made by choosing to ferment the juice or must to a desired sugar concentration and then adding a sufficient amount of a distilled spirit to arrest the fermentation and raise the alcohol to a predetermined level. In order to carry this out, we have to know the amount of sugar left in the juice at anyone moment in time. In small wineries, a hydrometer is often used for this purpose, because it gives an instant answer and is economical to buy. However, using a hydrometer to estimate sugar concentration is complicated by the presence of alcohol in the juice and causes the hydrometer to sink more, thus indicating a lower Brix than is actually present. One percent v/v alcohol obscures 0.47 Brix (Rankine, 1991). The true Brix is given by: True °Brix-Obscured °Brix + Measurable °Brix Measurable Brix is that which is detected by a hydrometer. True Brix is the targeted sweetness of the resulting fortified wine. Calculations for fortification h...
Saignee (or bleeding) is the removal of juice from a red must immediately after destemming/crushi... more Saignee (or bleeding) is the removal of juice from a red must immediately after destemming/crushing. Usually, it is performed to concentrate flavors and phenols in the wine made from the remaining must, or to counterbalance water additions, made to lower the potential alcohol and allow alcoholic fermentation to proceed in a timely manner (legal in CA). Sometimes it is carried out for the sole purpose of making a Rose wine usually using white winemaking methods. When the juice is first released from a crushed red grape, it mainly contains water, glucose, fructose and acids. It contains very little flavor compounds, phenols or anthocyanins (color compounds) because the majority is found in the skins. After 30 minutes to one hour, however, the skins start to release anthocyanins, a few phenols and some flavor compounds.
Role of Dissolution and Precipitation of Minerals in Controlling Soluble Aluminum in Acidic Soils
Advances in Agronomy
Plant-Soil Interactions at Low pH: Principles and Management, 1995
A glasshouse experiment "vas conducted to investigate gypsum application and leaching on the amel... more A glasshouse experiment "vas conducted to investigate gypsum application and leaching on the amelioration of" an at uIl1inium (AI) toxic subsoil for wheat growth. Treatments included di ft'erent rates of gypsum application and amount of leaching prior to wheat being grown. Wheat shoot growth increased vvhen gypsum was applied in both the presence and absence of leaching, but growth was higher with leaching. Gypsum application led to a decrease in toxic Al as a result of a higher ionic strength and activity of A1501-ion pairs in the soil solution, and increased Al leached from the soil. Root growth may not be a good bioassay for predicting \vheat shoot responses to gypsum applications on acidic subsoils.
Plant Nutrition — from Genetic Engineering to Field Practice, 1993
A pot experiment was conducted to establish whether gypsum or lime could increase wheat growth in... more A pot experiment was conducted to establish whether gypsum or lime could increase wheat growth in an acid subsoil. Wheat (Triticum aestivum c. v. Gutha) was grown in 3 kg of soil which had been mixed with basal nutrients and different rates of gypsum and lime. Wheat in the treatment which received no gypsum or lime showed the most severe nutrient deficiency symptoms and had the lowest shoot and root dry weights. Lime treatments increased shoot and root growth 2 to 3 fold and decreased the concentration of total Al and the calculated activities of all Al species. Gypsum increased shoot dry weight to up to 50% but decreased root dry weight and root length compared with unamended soil; it had little effect on the pH and concentration of total Al in the soil solution but decreased the sum of the activity of monomeric Al ions and increased the activity of the AlSO; ion pair. Both gypsum and lime increased uptake of Ca, Mg, S, P and K in plant shoots. It is suggested that lime increased plant growth by increasing the pH and markedly decreasing the concentration of Al in the soil solution, enabling plants to take up other nutrients from the soil. It is further suggested that gypsum decreased the activity of toxic monomeric Al species and therefore enabled better nutrient uptake. The results indicate that subsurface incorporation of lime would be the best method for improving wheat growth on yellow sandplain soils in Western Australia if an economic method for incorporation of lime into the subsoil could be developed.
Journal of Soil Science
Labile A1 in the soil solution measured by 8-hydroxyquinoline (Al,,) was a better predictor of pl... more Labile A1 in the soil solution measured by 8-hydroxyquinoline (Al,,) was a better predictor of plant growth than trivalent A1 (Al : :) measured by ion chromatography (IC). HQ reacted with some organic A1 complexes which did not separate during chromatography. In the presence of oxalic acid, Al, was greater than Al : : , which was the same as the greater than A] : : , and both were greater than Al& In extracts of soils that had been acidified, A] : : was less than Al , , , which was similar to A&, when it was assumed that the only complexing ligands were OHand F-. The proportion of Ali: in the soil solutions decreased more than Al,, as the pH increased. Organic ligands appeared to form complexes with A1 at the expense of AIF complexes. Forms of A1 detected by IC differed in CaCI, extracts and soil solutions. Al,, in the CaCI, extracts and soil solution were closely correlated, although the proportion of Al,, was higher in the CaC1, extracts. predicted concentration of AI3+ (Al&), 9 whereas in the presence of citric acid, Al,, was I N T R O D U C T I O N The development of accurate soil tests for aluminium toxicity is limited partly by the ability of analytical techniques to distinguish between toxic and non-toxic forms of A1 (Whitten & Ritchie, 19916). Estimation of toxic A1 in solutions containing non-toxic inorganic A1 complexes has been possible in relatively simple solutions (Cameron et ai., 1986), but has been inconsistent in acidic topsoils. Nevertheless, labile A1 as measured by 8-hydroxyquinoline (HQ) in a short reaction time of 15 s (James et al., 1983) has been shown to be closely correlated with the growth of subterranean clover in acidic topsoils (Whitten & Ritchie, 1991~). The major forms of non-toxic A1 in soil solutions are thought to include A1 complexed with sulphate, fluoride (F) and organic ligands (Ritchie, 1989). Recently, a method has been developed using ion chromatography (IC) which separates A1 species according to charge (Willett, 1989). In solutions containing A1 and F, the concentrations of mono-, di-and trivalent A1 as determined by IC corresponded closely with the theoretical values of AIF:, AlF2+ and A13+, respectively, except that monomeric hydroxy species elute with Al ; : (Willett, 1989). Similarly, HQ, which also reacts with the monomeric hydroxy A1 species, reacted in 15 s with only a small proportion ofAl that was complexed with F, and provided a good estimate of toxic A1 in nutrient solution experiments (Noble et al., 1988). Fluoride may be an important ligand because of the presence of F (< 2% w/w) in some phosphate fertilizers (White, 1976). Measurement of uncomplexed A1 in the presence of organic ligands presents more of a problem. In the presence of citric acid, the estimated concentration of uncomplexed A1 by IC (data for Fig. 6a in Willett, 1989) was greater than the concentration of A13+ (A&) predicted from thermodynamic
Annals of botany, 1994
Unlike many plants reported in the literature, lupins do not excrete OH(-) in amounts equivalent ... more Unlike many plants reported in the literature, lupins do not excrete OH(-) in amounts equivalent to the net excess of inorganic anion uptake over inorganic cation uptake. To investigate the mechanisms involved in the maintenance of charge balance, nutrient uptake and organic anion accumulation of lupins and peas supplied with a range of NO(3)(-) concentrations, were compared. Lupins absorbed less NO(3)(-) than peas on a dry weight basis, which largely ACCOUNTED for the smaller excess of anion uptake over cation uptake in lupins than in peas at the same NO(3)(-) supply. When anion uptake exceeded cation uptake, peas excreted an equivalent charge of OH(-), whereas lupins excreted much smaller amounts of OH(-) than the excess of anion over cation uptake. It was calculated that lupins excreted significant amounts of organic anions when anion uptake exceeded cation uptake, whereas organic anion excretion from peas was negligible, regardless of their NO(3)(-) supply and cation-anion balan...
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Papers by Geraldine Ritchie