Bibliografie tematiche / Soils Australia Nitrogen content

Indice

Articoli di riviste
Tesi
Libri
Capitoli di libri
Atti di convegni

Letteratura scientifica selezionata sul tema "Soils Australia Nitrogen content"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 4 febbraio 2022

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili

Scegli il tipo di fonte:

Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Soils Australia Nitrogen content".

Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.

Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.

Articoli di riviste sul tema "Soils Australia Nitrogen content"

Paul, K. I., P. J. Polglase, A. M. O'Connell, J. C. Carlyle, P. J. Smethurst e P. K. Khanna. "Soil nitrogen availability predictor (SNAP): a simple model for predicting mineralisation of nitrogen in forest soils". Soil Research 40, n. 6 (2002): 1011. http://dx.doi.org/10.1071/sr01114.

Testo completo

Abstract (sommario):

A new empirical model (SNAP) combines a simple laboratory measurement of the basal rate of N mineralisation with the modifying effects of daily temperature and water content to predict seasonal and annual rates of mineralisation of forest soils. Short-term (20-60-day) aerobic incubations of either undisturbed or bulked and mixed soil were found suitable for prediction of the basal rate of N mineralisation. Data from laboratory incubations of a range of soils were used to calibrate empirical relationships describing the effects of temperature (Tm) and water (Wm) on rates of N mineralisation. Submodels for predicting daily average temperature (STUF) and water content (SWUF) for up to 3 surface soil layers were developed and used to provide inputs to the Tm and Wm functions, respectively. Inputs required for SNAP are restricted to variables whose values are easily obtained. In addition to the amount of N mineralised during a short aerobic laboratory incubation, other soil properties required are bulk density, gravel and clay content, and upper and lower limits of soil water content. Climatic data required included daily air temperature, rainfall, and solar radiation. Other inputs are slope, leaf area index of the stand, and approximate mass and height of litter. Predicted rates of N mineralisation have been verified using data from 9 native forests, 12 radiata pine plantations, and 12 eucalypt plantations from across southern Australia. Despite the wide range of forest types, soil types, climatic regions, and management systems, predicted annual rates of N mineralisation were in close agreement with those observed in the field, regardless of whether daily soil temperature and water content were predicted (R2 = 0.76, P < 0.001, n�=�127) or observed (R2 = 0.78, P < 0.001, n = 68). Sensitivity analysis showed that it was most important to minimise analytical error in inputs used to calculate the basal rate of N mineralisation (i.e. soil temperature, water content, and N mineralised during laboratory incubation). The model was more sensitive to daily soil temperature than to daily soil water content.

Gli stili APA, Harvard, Vancouver, ISO e altri

Ewing, MA, AD Bathgate, RJ French e CK Revell. "The role of crop and pasture legumes in rotations on duplex soils". Australian Journal of Experimental Agriculture 32, n. 7 (1992): 971. http://dx.doi.org/10.1071/ea9920971.

Testo completo

Abstract (sommario):

Duplex soils are prominent in southern Australia and are generally low in fertility. Their agricultural performance is, therefore, suboptimal in most circumstances without an exogenous source of nitrogen. This is often supplied by legumes which are grown in rotation with non-leguminous crops. Both crop and pasture legumes are now widely used in southern Australia and the contribution that they make to the non-legume phase of rotations is through nitrogen fixation and through other mechanisms such as cereal disease breaks. We use a mathematical programming model, MIDAS (Model of an Integrated Farming Dryland Agricultural System), to investigate the role of legumes in the low rainfall wheatbelt of Western Australia. The impact of legumes on farm profitability is assessed with a special focus on the contribution of legumes grown on a duplex soil. By using the model, the sensitivity of rotation choice on this duplex soil to changes in biological and economic parameters is explored. We conclude that crop legumes, in particular, have a firmly established role on sandy-surfaced duplex soils in low rainfall regions and that substantial increases in both the productivity and legume content of pasture would be required to outperform rotations which include crop legumes.

Gli stili APA, Harvard, Vancouver, ISO e altri

O'Sullivan, Cathryn A., Steven A. Wakelin, Ian R. P. Fillery e Margaret M. Roper. "Factors affecting ammonia-oxidising microorganisms and potential nitrification rates in southern Australian agricultural soils". Soil Research 51, n. 3 (2013): 240. http://dx.doi.org/10.1071/sr13039.

Testo completo

Abstract (sommario):

Ammonia-oxidising archaea (AOA) have recently been described as having an important role in soil nitrification. However, published data on factors which influence their distribution and their impact on a soil’s potential nitrification rates (PNR) are sparse, particularly compared with the amount of information available regarding ammonia-oxidising bacteria (AOB). This study had two aims. First, to investigate which environmental factors affect the AOA : AOB ratio in soils from two agricultural regions, and second, to explore whether the abundance of either AOA or AOB correlated with PNR. Samples were collected from 45 sites within the cropping regions of Western Australia and South Australia. Soils were tested for pH, NH4+/NO3–, organic carbon (C), total nitrogen (N), C : N ratio, PNR, and electrical conductivity. Climate data were obtained from the Queensland Climate Change Centre for Excellence SILO website. Abundances of AOA and AOB were measured using real-time PCR quantification of the gene encoding the ammonia monooxygenase enzyme (amoA). Multivariate statistical analysis was applied to assess correlations between PNR, soil properties, and abundance of AOA or AOB. In the majority samples AOA were present, but their abundance, and the AOA : AOB ratio, varied considerably between sites. Multivariate analysis showed that the distribution of AOA and AOB and the AOA : AOB ratio were strongly correlated with climatic and seasonal factors. Sites where samples were collected during dry, hot periods tended to be AOA-dominated, whereas samples collected during cool, wet periods tended to be AOB-dominated or have equal abundances of AOA and AOB. The PNRs were correlated with total N content, organic C content, and soil pH. There was no clear correlation between AOA or AOB and PNR. This study shows that both AOA and AOB are widespread in Western Australian and South Australian soils and their abundance and ratio are affected by climate and season. It also shows that PNR is more strongly influenced by soil fertility factors than by the AOA : AOB ratio.

Gli stili APA, Harvard, Vancouver, ISO e altri

Spain, AV. "Influence of environmental conditions and some soil chemical properties on the carbon and nitrogen contents of some tropical Australian rainforest soils". Soil Research 28, n. 6 (1990): 825. http://dx.doi.org/10.1071/sr9900825.

Testo completo

Abstract (sommario):

Concentrations of carbon, total nitrogen, total phosphorus, soil pH, the sum of the exchangeable basic cations, clay and dithionite-extractable iron were examined in the surface soils of 72 rainforest sites from north-eastern tropical Queensland. Soils derived from basalt had higher levels of most of the above properties than those formed on other parent materials. Differences between the carbon status of soils formed from basalt and those formed from other parent materials may be related to the higher free iron levels and phosphorus status of the former group. Excluding the soils of basalt origin, both carbon and nitrogen are positively related to clay content. In contrast, within the soils of basaltic origin, carbon concentrations are negatively related to clay contents through interactions with free iron oxides. Separate univariate regression relationships were established between carbon and nitrogen concentrations and site temperature and precipitation for soils derived from basaltic and combined granitic and acid volcanic parent materials. Coefficients relating both nitrogen and carbon to temperature differed between these groupings. The importance of topography in controlling carbon levels is demonstrated in soils that are poorly drained or formed on ridges, while the importance of soil age is demonstrated by a juvenile soil formed on weakly weathered basalt.

Gli stili APA, Harvard, Vancouver, ISO e altri

Baldock, J. A., B. Hawke, J. Sanderman e L. M. Macdonald. "Predicting contents of carbon and its component fractions in Australian soils from diffuse reflectance mid-infrared spectra". Soil Research 51, n. 8 (2013): 577. http://dx.doi.org/10.1071/sr13077.

Testo completo

Abstract (sommario):

Quantifying the content and composition of soil carbon in the laboratory is time-consuming, requires specialised equipment and is therefore expensive. Rapid, simple and low-cost accurate methods of analysis are required to support current interests in carbon accounting. This study was completed to develop national and state-based models capable of predicting soil carbon content and composition by coupling diffuse reflectance mid-infrared (MIR) spectra with partial least-squares regression (PLSR) analyses. Total, organic and inorganic carbon contents were determined and MIR spectra acquired for 20 495 soil samples collected from 4526 locations from soil depths to 1 m within Australia’s agricultural regions. However, all subsequent MIR/PLSR models were developed using soils only collected from the 0–10, 10–20 and 20–30 cm depth layers. The extent of grinding applied to air-dried soil samples was found to be an important determinant of the variability in acquired MIR spectra. After standardisation of the grinding time, national MIR/PLSR models were developed using an independent test-set validation approach to predict the square-root transformed contents of total, organic and inorganic carbon and total nitrogen. Laboratory fractionation of soil organic carbon into particulate, humus and resistant forms was completed on 312 soil samples. Reliable national MIR/PLSR models were developed using cross-validation to predict the contents of these soil organic carbon fractions; however, further work is required to enhance the representation of soils with significant contents of inorganic carbon. Regional MIR/PLSR models developed for total, organic and inorganic carbon and total nitrogen contents were found to produce more reliable and accurate predictions than the national models. The MIR/PLSR approach offers a more rapid and more cost effective method, relative to traditional laboratory methods, to derive estimates of the content and composition of soil carbon and total nitrogen content provided that the soils are well represented by the calibration samples used to build the predictive models.

Gli stili APA, Harvard, Vancouver, ISO e altri

Wong, M. T. F., e K. Wittwer. "Positive charge discovered across Western Australian wheatbelt soils challenges key soil and nitrogen management assumptions". Soil Research 47, n. 1 (2009): 127. http://dx.doi.org/10.1071/sr08098.

Testo completo

Abstract (sommario):

Nitrogen management in Western Australia (WA) and in cropping areas elsewhere in Australia assumes that soil contains negligible or no positive charge and is therefore unable to retain nitrate against leaching. The amount of water needed to displace nitrate is thus assumed to be the drainable volume of water held by the soil (1 pore volume), and in sandy soils about 100 mm drainage is assumed to be required to displace nitrate by 1 m. The clay mineralogy of the highly weathered soils of the WA wheatbelt is dominated by kaolinite and iron and aluminium oxides. This mineralogy suggests likely occurrence of positive charge and anion exchange capacity (AEC), since these minerals can carry positive charge under normal acidic field situations. We measured AEC of soils sampled widely across the WA wheatbelt by independent leaching and batch equilibration methods of charge measurement. This showed widespread occurrence of positive charge and AEC in these soils. AEC ranged from 0 to 2.47 mmolc/kg and is linearly correlated with the potassium chloride or monocalcium phosphate extractable sulfate content of the soil. This correlation provides a rapid screening method to identify soils with positive charge. Application of ion-chromatographic theory showed that AEC has a large effect in delaying nitrate leaching by up to 12.5 pore volumes. The most highly charged soil (2.47 mmolc/kg) thus needed 12.5 times more water to displace nitrate than currently assumed. This potentially large delay in nitrate leaching affects the optimum amount and time of fertiliser application, rates of soil acidification attributed to nitrate leaching and the benefit of ameliorating subsoils to allow roots access to subsoil water and leached nitrate. It also calls into question the use of anions such as bromide to trace water flow and estimate recharge in these soils.

Gli stili APA, Harvard, Vancouver, ISO e altri

Moata, Melinda R. S., Ashlea L. Doolette, Ronald J. Smernik, Ann M. McNeill e Lynne M. Macdonald. "Organic phosphorus speciation in Australian Red Chromosols: stoichiometric control". Soil Research 54, n. 1 (2016): 11. http://dx.doi.org/10.1071/sr15085.

Testo completo

Abstract (sommario):

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.

Gli stili APA, Harvard, Vancouver, ISO e altri

Latta, R. A., e A. Lyons. "The performance of lucerne - wheat rotations on Western Australian duplex soils". Australian Journal of Agricultural Research 57, n. 3 (2006): 335. http://dx.doi.org/10.1071/ar04016.

Testo completo

Abstract (sommario):

In field experiments on duplex soils in the south-eastern and central Western Australian wheatbelt, lucerne (Medicago sativa L.) was compared with subterranean clover (Trifolium subterraneum L.) in pasture–crop rotations. Comparative pasture plant densities and biomass, soil water content, available soil nitrogen, wheat grain yield, and protein content were measured during 2 and 3 years of pasture followed by 2 and 1 year of wheat, respectively. Lucerne densities declined by 60–90% over the 3-year pasture phase but produced up to 3 times more total annual biomass than weed-dominant annual pastures and similar total annual biomass when annual pastures were legume dominant. Lower soil water contents were measured under lucerne than under annual pastures from 6 months after establishment, with deficits up to 60 mm in the 0–1.6 m soil profile. However, significant rain events and volunteer perennial weeds periodically negated comparative deficits. Wheat yields were lower following lucerne (1.3 t/ha) than following an annual pasture (1.8 t/ha) in a low-rainfall season, higher (3.7 v. 2.9 t/ha) in a high-rainfall season, and much higher when the previous annual pastures were grass dominant (3.4 v. 1.5 t/ha). Grain protein contents were 1–2% higher in response to the lucerne pasture phase. Overcropping wheat into a lucerne pasture of 19 plants/m2 reduced wheat grain yields, but a lucerne density of 4 plants/m2 reduced yields only where rainfall was low. The study has shown that lucerne–wheat rotations provide a productive farming system option on duplex, sodic soils in both the south-eastern and central cropping regions of Western Australia. This was most evident in seasons of above-average summer and growing-season rainfall and when compared with grass-dominant annual pastures.

Gli stili APA, Harvard, Vancouver, ISO e altri

Lewis, DC, e LA Sparrow. "Implications of soil type, pasture composition and mineral content of pasture components for the incidence of grass tetany in the South East of South Australia". Australian Journal of Experimental Agriculture 31, n. 5 (1991): 609. http://dx.doi.org/10.1071/ea9910609.

Testo completo

Abstract (sommario):

The occurrence of grass tetany related deaths in cattle grazing pasture in the South East of South Australia is related to soil type. The greatest losses occur on the solodised solonetz soils, with few, if any, on the rendzina or siliceous sand soils in the region. Pastures from 3 soil types were sampled on 2 occasions during the growing period, and soils were sampled once. Comparisons were made for the pasture components of potassium (K), calcium (Ca) and magnesium (Mg) concentrations in soils, and K, Ca, Mg, nitrogen (N) and sulfur (S) concentrations in plants. In the July sampling, the mean herbage K/(Ca + Mg) ratio for both annual and perennial grass species grown on the solodised solonetz soils exceeded 2.2 but was below 2 for the other 2 soil types. At the same time the mean K/(Ca + Mg) ratio for soil-extractable cations was 0.10 for the solodised solonetz soils but only 0.058 and 0.025 for the rendzina and siliceous sand soils. A critical value for the K/(Ca + Mg) ratio for the soil extractable cations of 0.07-0.08 is suggested. Of the 22 sites in the investigation, grass tetany deaths had occurred on 9 within the previous 5 years; all of these were classified as solodised solonetz soils. Deaths were reported in late autumn and winter, and in all cases the dominant pasture species growing at these sites in July were grasses. It is suggested that deaths ceased in spring because there was either a change to legume dominance or an increase in air temperature.

Gli stili APA, Harvard, Vancouver, ISO e altri

Bauhus, J., PK Khanna e RJ Raison. "The effect of fire on carbon and nitrogen mineralization and nitrification in an Australian forest soil". Soil Research 31, n. 5 (1993): 621. http://dx.doi.org/10.1071/sr9930621.

Testo completo

Abstract (sommario):

The causes of onset of nitrification in a soil collected under an ashbed which was produced when heaped slash was burned, and for its absence in an unburnt soil, were investigated for an acid forest soil from south-eastern Australia. The occurrence of nitrification in ashbed soils was assessed in laboratory incubations extendig to 151 days to determine if it could be attributed to (a) an increase in pH, (b) an additional supply of P, (c) the removal of chemical inhibitors, and (d) the lack of competition with heterotrophs killed during soil heating. The treatments were: percolated and unpercolated ashbed soil from 0-5 and 5-10 cm depth; unburnt soil from 0-5 cm untreated and with added lime or added P; and burnt and unburnt soil from 5-10 cm depth. In addition, each treatment had an identical where the soil was inoculated with nitrifying garden soil. Compared with the unburnt surface soil (0-5 cm), ashbed soil had higher pH (3.6 units), higher mineral N (3 times) and slightly elevated NaHCO3-extractable P. During 151 days of incubation, microbial respiration in surface ashbed soil, measured as CO2 evolution, initially exceeded the values obtained in unburnt soil but then decreased to only 72% of unburnt soil at the end of the incubation period. In ashbed soil, the microbial biomass N content was low but its C/N ratio was high. Net N mineralization (Nmin) in ashbed soil was not significantly different from unburnt or phosphate fertilized soils (13.1, 14.7 and 17.8 mg N,in kg-' respectively) but was lower than in limed soil (59.3 mg Nmin kg-1). Percolation of surface ashbed soil with distilled water removed high amounts of salts and increased microbial respiration and N mineralization. Inoculation of soils with a slurry from a nitrifying garden soil induced nitrification in every treatment, regardless of their ammonium content, pH or other limiting component. Nitrification was also stimulated in unburnt surface soil on the addition of lime and P. Autotrophic nitriflers were active only in surface ashbed soils and probably in limed soils. P addition promoted heterotrophic nitrification. It was concluded that soil heating reduced competition between autotrophs and heterotrophs for ammonium and that ash supplies nutrients, such as K and Ca which stimulate nitrification. Low pH was not a limiting factor for nitrification but a high pH may promote the establishment of autotrophic nitrifiers.

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Tesi sul tema "Soils Australia Nitrogen content"

Lotfollahi, Mohammad. "The effect of subsoil mineral nitrogen on grain protein concentration of wheat". Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phl882.pdf.

Testo completo

Abstract (sommario):

Copy of author's previously published work inserted. Bibliography: leaves 147-189. This project examines the uptake of mineral N from the subsoil after anthesis and its effect on grain protein concentration (GPC) of wheat. The overall objective is to examine the importance of subsoil mineral N and to investigate the ability of wheat to take up N from the subsoil late in the season under different conditions of N supply and soil water availability. Greenhouse experiments investigate the importance of subsoil mineral N availability on GPC of wheat and the factors that contribute to the effective utilisation of N. The recovery of N from subsoil, the effect of split N application on GPC and short term N uptake by the wheat at different rooting densities are also studied.

Gli stili APA, Harvard, Vancouver, ISO e altri

Hoyle, Frances Carmen. "The effect of soluble organic carbon substrates, and environmental modulators on soil microbial function and diversity". University of Western Australia. School of Earth and Geographical Sciences, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0050.

Testo completo

Abstract (sommario):

[Truncated abstract] The principal aim of this thesis was to examine the response of the microbial community to the addition of small amounts (<50 μg C g-1 soil) of organic C substrates (‘trigger molecules’) to soil. This addition is comparative to indigenous soluble C concentrations for a range of soil types in Western Australia (typically measured between 20 and 55 μg C g-1 soil). Previously it has been reported that the application of trigger molecules to European soils has caused more CO2-C to be evolved (up to six fold) than was applied . . . Findings from this study indicated that there was an additional CO2 release (i.e. greater than the C added) on application of organic C substrates to some soil treatments. However, findings from this study indicate that the response of the microbial community to small additions of soluble C substrate is not consistent for all soil types and may vary due to greater availability of C, and supports the premise that microbial responses vary in a yet to be predicted manner between soil type and ecosystems. Differences in microbial response to the addition of soluble organic C are likely attributable to differences in soil attributes and environmental factors influencing both the diversity of microbes present and the frequency of food events. Theoretically, trigger molecules could also provide a possible control mechanism for microorganisms in arable farming systems. These mechanisms include stimulating either targeted pathogenic microorganisms that starve after depletion of a suitable substrate; or stimulating beneficial microorganisms to manipulate nutrient cycling, by targeting specific functional groups and altering mineralisation and immobilisation turnover rates.

Gli stili APA, Harvard, Vancouver, ISO e altri

Lalor, Briony Maree. "An assessment of the recovery of the microbial community in jarrah forest soils after bauxite mining and prescription burning". University of Western Australia. School of Earth and Geographical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0037.

Testo completo

Abstract (sommario):

[Truncated abstract] Recovery of soil nutrients, microbial populations and carbon (C) and nitrogen (N) cycling processes are critical to the success of rehabilitation following major ecosystem disturbance. Bauxite mining represents a major ecosystem disturbance to the jarrah (Eucalyptus marginata) forest in the south-west of Western Australia. Mining has created a mosaic of mined areas in various stages of succession surrounded by non-mined forest areas. Initial site preparations within rehabilitation areas such as contour ripping alter soil structure (creation of mound and furrows) and over time also influence the distribution of vegetation and litter. Current performance criteria developed by industry, government and other stakeholders have determined that before post-bauxite mined areas of jarrah forest can be integrated back into normal forest management practises they should be functional and demonstrate resilience to normal forest disturbances such as fire. Furthermore, resilience should be of a manner comparable to non-mined analogue forest sites. Currently little is known of the resilience of microbial communities and C and N cycling in rehabilitation sites to normal forest disturbances such as prescription burning. As such, before rehabilitated jarrah forests can be successfully integrated into broad scale forest management regimes, a more thorough knowledge of the potential impacts of burning practises on the soil microbial community and C and N cycling processes in these systems is required. ... While there are similar rates of C and N cycling the underlying microbial community structure was distinctly different; implying a high degree of functional redundancy with respect to C and N cycling. Differences in the C and N cycling and structure of the microbial communities were likely to be due to differences in soil environmental conditions (i.e. soil alkalinity/acidity, soil moisture) and C substrate availability which influence the physiological status of the microbial community and in turn are related to successional age of the forests. Results also suggest that the measurement of CLPP can be a useful approach for assessment of changes in the functional ability of microbial communities. However, the interpretation of how well these rehabilitation forests have recovered heterotrophic abilities was greatly affected by the methodological approach used (e.g. MicroRespTM or Degens and Harris, 1997). Importantly, results from Chapter 4 and 5 suggested that the effects of a moderate prescription fire on C and N processes, CLPP and microbial community structure of 18 year old rehabilitation forests are likely to be short-lived (< 2 years). Furthermore, the effects of the moderate spring prescription fire were not large enough to decouple C and N cycling processes over the short-term (< 1 years) which suggests that by 18 years of age rehabilitation forests demonstrate comparable functional resilience to a moderate prescription burn.

Gli stili APA, Harvard, Vancouver, ISO e altri

Baethgen, Walter E. "Plant nitrogen availability in selected Virginia soils". Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90907.

Testo completo

Abstract (sommario):

Surface and subsoil samples were collected from agriculturally important soils of Coastal Plain, Piedmont and Ridge and Valley regions of Virginia for the purpose of determining the contribution of different soil N fractions to plant available N. Soil samples were analyzed for exchangeable and non-exchangeable NH₄⁺-N, NO₃⁻-N, total N, and organic matter contents. The samples were also subjected to the anaerobic incubation procedure as an index of organic N availability. Plant available N was measured by N uptake of successive wheat crops grown in the greenhouse. Multiple linear regression models for different groups of samples were used to determine the contribution of the different soil N fractions to the plant available N supply, and to predict N uptake by wheat. Best models were selected considering fit, significance of the regression coefficients, and predictive ability. Due to the high correlation among the different soil N fractions, important collinearity was present and affected the linear models. These effects were reduced by utilizing biased techniques. All the soils provided significant amounts of N to the wheat in both the first and second crops. Exchangeable NH₄⁺-N and NO₃⁻-N were the major initial sources of plant available N. Non-exchangeable NH₄⁺-N was also a significant contributor to the plant available N supply for most soils. The results of the biological and chemical indices of organic N availability were highly correlated among each other, and with plant N uptake by the first and second wheat crops. Plant N uptake was associated with the variation observed in the different soil N fractions, indicating that wheat is a good indicator crop for plant N availability experiments. The procedures used to detect and combat collinearity were effective in producing more stable models with better predictive ability. Further research should be conducted under field conditions to study the contribution of non-exchangeable NH₄⁺-N to plant N availability.
M.S.

Gli stili APA, Harvard, Vancouver, ISO e altri

Mehdi, Bano B. "Soil nitrate-N and plant nitrogen distributions under different tillage practices". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/MQ44220.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Sarmah, Ajit K. "Persistence and mobility of triasulfuron, metsulfuronmethyl, and chlorsulfuron in alkaline soils". Title page, abstract and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs2461.pdf.

Testo completo

Abstract (sommario):

Bibliography: leaves 157-174. This study examined the fate of three common sulfonylurea herbicides in highly alkaline soils through a series of laboratory and field experiments to determine if existing leaching models could be used to describe their field behaviour under Australian climatic conditions. A liquid chromatographic method was developed to simultaneously determine levels of triasulfuron, metsulfuronmethyl, and chlorsulfuron in soil and water. The investigation of base hydrolysis for the herbicides in aqueous buffer and soil solutions determined that it was unlikely to be a major loss pathway for sulfonylureas in alkaline soils. The herbicides were found to have low sorption, very little retardation and high mobility, moving at a marginally slower rate than water. Degradation did not follow first-order kinetics, but rather a two-stage process appeared to be involved. Both VARLEACH and LEACHM models predicted the measured concentration of the herbicides reasonably well in profile under low rainfall conditions but were less adequate under high rainfall. Forecasts with the LEACHP model predicted levels of the herbicides for a dominant soil type of the cereal belt of southern Australia with median rainfall after a year.

Gli stili APA, Harvard, Vancouver, ISO e altri

Fotovat, Amir. "Chemistry of indigenous Zn and Cu in the soil-water system : alkaline sodic and acidic soils". Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phf761.pdf.

Testo completo

Abstract (sommario):

Copies of author's previously published articles inserted. Bibliography: leaves 195-230. In this study the soil aqueous phase chemistry of Zn and Cu in alkaline sodic soils are investigated. The chemistry of trace metal ions at indigenous concentrations in alkaline sodic soils are reported. Metal ions at low concentrations are measured by the graphite furnace atomic absorption spectrometry (GFAAS) technique.

Gli stili APA, Harvard, Vancouver, ISO e altri

Haskin, Catherine Marie. "Nitrogen availability and soil microclimate after clearcutting lodgepole pine". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24677.

Testo completo

Abstract (sommario):

Long term management of lodgepole pine depends, in part, on the nutrient capital of the site. Harvesting has been shown to increase the availability of nitrogen and other nutrients for a limited period of time. This increase, or nutrient flush, following cutting has been attributed to several factors including changes in organic matter quantity and quality, soil moisture and temperature regimes, and competition for nutrients. Knowledge of the duration and the magnitude of the nutrient flush would be valuable for management decisions. A consequence of lodgepole pine clearcuts was studied for soil nitrogen availability and microclimate. Mineral soil and forest floor samples were anaerobically incubated and analyzed for ammonium-nitrogen (ppm). The mineral soil showed a flush lasting about 12 years, peaking by year 8, while the forest floor material showed no trend. The size of the increase from year 2 to year 8 was about 52%. Temperature (air and soil), soil moisture, solar radiation, and precipitation data were collected, and a soil water budget was calculated using a simple water balance model. The average calculated soil water deficit was 119 mm, but this may have been an over-estimate. Windrowing following cutting may have depleted the site nitrogen reserve which in turn reduced the amount that was mineralized during incubation. The interaction between the soil temperature and moisture may have further limited nitrogen availability to the lodgepole pine trees. It is concluded that the dynamics of nitrogen availability following clearcutting are important for the establishment and growth of lodgepole pine. The summer moisture deficit appears to limit the nitrogen mineralization rate as well as seedling growth.
Forestry, Faculty of
Graduate

Gli stili APA, Harvard, Vancouver, ISO e altri

Simon, John J. "Wastewater application to soils: hydraulic and nitrogen considerations". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71186.

Testo completo

Abstract (sommario):

Land application of domestic and industrial wastewaters provides an effective means of recycling water and its components into the ecosystem. Successful treatment by soil requires that wastewater is applied in quantities that both maintain infiltrative capacity of the soil and do not exceed the capacity of the soil-plant system to assimilate biological and chemical contaminants. Application of N-rich wastewaters requires that consideration be given to both the ability of the soil to transmit the hydraulic load and remove sufficient N to maintain groundwater quality standards. A textile wastewater containing high concentrations of organic N was spray-irrigated to tall fescue (Festuca arunindinacea) to determine optimum N application levels. Nitrogen balances were determined at each N level and and the potential for predicting the leaching component of the excess N applied was investigated. Historically on-site wastewater disposal systems (OSWDS) for treating septic tank effluent (STE) have been designed on a hydraulic loading basis with N pollution potential essentially ignored. Many soils have been deemed unsuitable for application of STE because of textural, water table, or landscape restrictions. The relations between soil properties, hydraulic performance of OSWDS, and N distribution around OSWDS are evaluated. Wastewater from a nylon processing plant was applied to 'Ky 31' tall fescue at total Kjeldahl nitrogen (TKN) levels of approximately 250, 430, and 1900 kg ha⁻¹ during 1982 and 1983. Fescue yield and N removal was comparable to agricultural yields at similar N application levels. Nitrogen balances indicate that plant uptake efficiency decreased with increasing organic N levels above the 250 kg ha⁻¹ level and that maximum uptake occurred at the 450 kg ha⁻¹ level. Most of the N not recovered in plant tissue mineralized rapidly to the nitrate NO₃⁻ form and leaching was noted during the winter and spring. This data is evaluated with quasi-transient analytical solution of the convection-dispersion equation. The movement of the solute center of mass is predicted on the basis of assumptions of piston flow as well as alternative assumptions of mixing via plate layer theory. Prediction of the location of the center of solute mass (α) provides a moving lagrangian coordinate solution around which dispersion of solute is calculated. The assumptions made about the sequence of evaporation and infiltration events significantly influence the prediction of α and hence the agreement between predicted and measured solute distribution. Both approaches give results which are within experimental error and provide a rational basis for predicting leaching losses and carry-over NO₃⁻ available to future crops. Prototype OSWDS with low pressure distribution installed in three clayey limestone-derived soils were dosed with STE at flux densities ranging from 0.4 to 3.6 cm d⁻¹ on a trench bottom area basis. Ponding was noted in OSWDS at all sites dosed at the 3.6 cm d⁻¹ flux due to both underlying hydraulic restrictions and resultant anaerobic conditions. It is concluded that clayey B horizons low in swelling clays but moderately well structured can be dosed at flux densities up to 2 cm d⁻¹ if low pressure distribution of STE is used. Nitrification was found to be quite limited in soils where effluent was ponded above a restrictive layer but occurred readily within 30 cm below trenches which were freely drained or had matric potentials of at least 40 cm of water. Ratios of NO₃⁻ to Cl⁻ indicate that only limited denitrification can be expected and that substantial NO₃⁻ does leach from below OSWDS in the direction of water flow.
Ph. D.

Gli stili APA, Harvard, Vancouver, ISO e altri

Melkamu, Teshome. "Intercropping in corn : soil physical quality and soil inorganic nitrogen levels". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ44098.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Libri sul tema "Soils Australia Nitrogen content"

Subasinghe, Ranjith. Increasing productivity and water use efficiency in Australia's rice industry through nitrogen management. Barton, A.C.T: RIRDC, 2009.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Alexander, John D. Nitrogen-loss potential ratings for Illinois soils: By John D. Alexander. [Illinois: University of Illinois at Urbana-Champaign, College of Agriculture, Agricultural Experiment Station in cooperation with the Soil Conservation Service, U.S. Dept. of Agriculture], 1987.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

D, Alexander John. Nitrogen-loss potential ratings for Illinois soils: By John D. Alexander. Illinois: University of Illinois at Urbana-Champaign, College of Agriculture, Agricultural Experiment Station in cooperation with the Soil Conservation Service, U.S. Dept. of Agriculture, 1987.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

J, Hatch D., a cura di. Controlling nitrogen flows and losses. Wageningen: Wageningen Academic Publishers, 2004.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Taylor, C. M. A. Nitrogen deficiency in Sitka spruce plantations. London: HMSO, 1990.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

N, Mishustin E., a cura di. T͡Sikl azota v pochve i ėffektivnostʹ udobreniĭ. Moskva: "Nauka", 1989.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Zhongguo tu rang xue hui. Tu rang nong ye hua xue zhuan ye wei yuan hui e Zhongguo tu rang xue hui. Tu rang sheng wu he sheng wu hua xue zhuan ye wei yuan hui, a cura di. Wo guo tu rang dan su yan jiu gong zuo di xian zhuang yu zhan wang: Zhongguo tu rang xue hui tu rang dan su gong zuo hui yi lun wen ji. Beijing: Ke xue chu ban she, 1986.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Poletschny, H. Vergleichende Erprobung verschiedener Stickstoffbestimmungsmethoden in Böden. Münster-Hiltrup: Landwirtschaftsverlag, 1989.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

International Symposium on Nitrogen Economy in Tropical Soils (1994 Trinidad and Tobago). Nitrogen economy in tropical soils: Proceedings of the International Symposium on Nitrogen Economy in Tropical Soils, held in Trinidad, W.I., January 9-14, 1994. Dordrecht: Kluwer Academic Publishers, 1996.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Più fonti

Capitoli di libri sul tema "Soils Australia Nitrogen content"

Dalal, R. C., W. M. Strong, E. J. Weston, J. E. Cooper, K. J. Lehane e A. J. King. "Comparison of legumes and fertilizer nitrogen for wheat production in subtropical Australia". In Nitrogen Economy in Tropical Soils, 363–69. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1706-4_35.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Németh, T., A. Abd El-Galil, L. Radimszky e Gy Baczó. "Effect of plant residues on ammonium and nitrate content of soils during incubation". In Progress in Nitrogen Cycling Studies, 109–14. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_17.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Russow, R., e M. Körschens. "Nitrous Oxide Formation in Black Earth Soils Depending on the Soil Water Content". In Progress in Nitrogen Cycling Studies, 607–11. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_99.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Slattery, J. F., W. J. Slattery e B. M. Carmody. "Influence of Soil Chemical Characteristics on Medic Rhizobia in the Alkaline Soils of South Eastern Australia". In Highlights of Nitrogen Fixation Research, 243–49. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4795-2_49.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Anderson, G. C., e I. R. P. Fillery. "Sulphate and nitrogen net mineralisation in coarse-textured soils in western Australia". In Plant Nutrition, 944–45. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/0-306-47624-x_460.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Anton, A., L. Radimszky, T. Szili-Kovács, G. Füleky e F. Gulyás. "Effects of environmental factors and Mn, Zn, Cu trace elements on the available N content of two soils". In Progress in Nitrogen Cycling Studies, 173–77. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_27.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Gordon, D. M. "Diurnal water relations and the salt content of two contrasting mangroves growing in hypersaline soils in tropical-arid Australia". In Towards the rational use of high salinity tolerant plants, 193–216. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1858-3_21.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Dziamski, A., M. Banach-szott, M. Drag e Z. Stypcyñska. "Content of Organic Carbon and Nitrogen as Well as Root Mass in Meadow Soils Under a Combined Slope and Flood Irrigation System". In Functions of Natural Organic Matter in Changing Environment, 319–22. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-5634-2_58.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Maun, M. Anwar. "The Ammophila problem". In The Biology of Coastal Sand Dunes. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780198570356.003.0012.

Testo completo

Abstract (sommario):

Even a cursory look on foredune plant communities shows vigorous dense stands of dune species in areas with moderate recurrent sand accretion levels specific for each plant species (Disraeli 1984; Maun and Baye 1989; Maun 1998). The phenomenon has been well documented in species of Ammophila arenaria (Carey and Oliver 1918; Tansley 1953), Corynephorus canescens (Marshall 1965), A. breviligulata (Eldred and Maun 1982) and Calamovilfa longifolia (Maun 1985). Burial has a positive influence on growth and flowering of plants and debilitated populations of foredune plant species can be rejuvenated by sand deposition (Maun 1998). Clear evidence of this phenomenon was presented by Maze and Whalley (1992a), who examined population dynamics of Spinifex sericeus in five zones receiving different amounts of sand deposition on a coastal dune system of Australia: the sea side of the first dune ridge, crest of first dune ridge, swale, Acacia thickets and stable hind dunes. In the very dynamic area on the sea side or toe of the first dune ridge (high beach) with regular burial or erosion of up to 1 m or more the plants produced very vigorous stolons with long internodes. On the crest of the dune ridge with sand deposition of about 17.5 cm per year even though plants had fewer stolons, they responded to burial by growing upwards with long internodes. In Acacia thickets in spite of very little sand deposition, plants were vigorous with little or no dead material, produced stolons and grew upwards with some long and some short internodes, probably because of greater nitrogen content in the soil. However, in the swale (slack) with little or no sand deposition, plants showed strong clumping tendency with very short internodes, a large amount of dead material on the surface and very low vigour. Unburied nodes usually died. Similarly, in the stable sand dunes with little or no sand deposition debilitated low-vigour clumps with very few stolons were abundant. Another example of this decline was presented by Martin (1959) on a shoreline along the Atlantic coast of North Carolina. He measured deposition and deflation of sand on two transects and showed that as one moved inland from the shoreline the total deposition of sand decreased.

Gli stili APA, Harvard, Vancouver, ISO e altri

Knicker, Heike, e Rüdiger Fründ. "Characterization of Nitrogen in Plant Composts and Native Humic Material by Natural-Abundance 15N CPMAS and Solution NMR Spectra". In Nuclear Magnetic Resonance Spectroscopy in Environment Chemistry. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097511.003.0022.

Testo completo

Abstract (sommario):

Soil organic matter (SOM) provides one of the major deposits for carbon and nitrogen on the surface of the Earth. It is continuously produced, mainly from dead plant material, by composting and humification processes. During these processes microorganisms thoroughly convert the starting material, which consists mostly of insoluble lignocelluloses. The end products of these processes in average middle-European soils, that contain typically 1 to 5% w/w of organic material, are clay–SOM complexes which are insoluble in all the usual organic and inorganic solvents. The standard aqueous sodium hydroxide extraction procedure dissolves at most 40% of the total organic carbon in all the soils tested by our group. The insoluble majority, the humin fraction, remains as poorly defined aluminosilicate- SOM complexes. During the decomposition and conversion processes the carbon to nitrogen ratio–decreases. Compared to the starting material, SOM is enriched in nitrogen. Under natural conditions, i.e., without the artificial addition of nitrogen in the form of manure or fertilizer, SOM provides the major part of the nitrogen available for plant growth. The chemical characterization of this ubiquitous but ill-defined material has only been partly successful until now. For characterization of the organic carbon in complete soils and extracts, nuclear magnetic resonance (NMR) methods appear to be most promising, especially since the application of high-resolution solid-state methods has become almost a laboratory routine. The combination of proton–carbon cross polarization with high-speed magic angle rotation (the CPMAS technique) permits the study of complete native soils, and thus provides detailed information about the gross chemical structure of the total SOM, without introducing any of the chemical modifications that could result from aggressive chemical extraction procedures. It has been shown by 13C CPMAS and high-resolution (HR) solution 13C NMR studies of a series of typical European soils, in which the concentration of paramagnetic metal ions was fairly low and which contained humic material with an aromatic carbon content ≤20%, that the carbon could be quantitatively assigned. The measurement of the 13C CPMAS spectra of complete native soils with a carbon content in the region of 1 % w/w is rather instrument-time consuming, and appeared to be at the limit of sensitivity.

Gli stili APA, Harvard, Vancouver, ISO e altri

Atti di convegni sul tema "Soils Australia Nitrogen content"

Lehane, Barry M., J. Antonio H. Carraro, Nathalie Boukpeti e Sarah Elkhatib. "Mechanical Response of Two Carbonate Sediments From Australia’s North West Shelf". In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23340.

Testo completo

Abstract (sommario):

The carbonate sediments found offshore on the North West Shelf of Australia can generally be described as silts with varying proportions of clay-sized and sand-sized carbonate particles. This paper investigates the undrained shearing response (as measured under simple shear and triaxial conditions) of two sediments with different grading curves. The importance of the fines content in controlling the density and hence dilatancy and undrained strength of the materials is demonstrated. The paper discusses the importance of fabric to the behavior of these soils and provides guidance on how undrained strengths of soils of this nature may be assessed with a knowledge of a material’s in-situ water content (or void ratio) and composition.

Gli stili APA, Harvard, Vancouver, ISO e altri

ADAMOVICS, Aleksandrs, e Liena POIŠA. "EVALUATION OF CHEMICAL CONTENT IN DIFFERENT ENERGY CROPS". In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.143.

Testo completo

Abstract (sommario):

For energy crops (reed canary grass and timothy grass), it is important to evaluate the sulphur and carbon content, and the harvested dry matter dependency on the fertilizer norm. Sulphur and carbon are important elements of a combustible material, and carbon is directly important as it forms the burning component. On the other hand, sulphur is an unwelcome element in combustible materials as it promotes environmental pollution. The field trials were carried out in sod calcareous soils in 2011–2013. A research was conducted to investigate the chemical content of two grasses: reed canary grass var. ‘Bamse’ (Phalaris arundinacea L.), and timothy grass ‘Jumis’ (Phleum pratense L.). Fertiliser norms (kg ha-1) applied in the research were: N0P0K0 (control), N30, N60, and N90. The harvest yield is one of the most important factors to obtain biocombustible materials; however, it does not mean that the amount of the harvest yield guarantees also a good quality of grasses. The research showed that the trial year had the most significant influence on both the sulphur yield and content in dry matter, the fertiliser norm essentially influenced the sulphur (η=30.1%) and carbon (η=6.5%) yield, but for the sulphur yield, a 6% interaction effect was established between the trial year and the nitrogen fertilizer norm.

Gli stili APA, Harvard, Vancouver, ISO e altri

Offriamo sconti su tutti i piani premium per gli autori le cui opere sono incluse in raccolte letterarie tematiche. Contattaci per ottenere un codice promozionale unico!