Siga este link para ver outros tipos de publicações sobre o tema: Phosphorus in agriculture.
Teses / dissertações sobre o tema "Phosphorus in agriculture"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Phosphorus in agriculture".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
1
Bujatzeck, Baldur. "Decision support system for alleviating phosphorus contamination." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22032.
Texto completo da fonteResumo:
The management of natural resources has greatly improved over the past decade. Despite advances in modelling the fate of nutrients or in modelling socio-economic effects of different farm management strategies, tools that integrate the advances made in these fields are still lacking. To develop a tool to overcome this gap, this research focused on the development of a multi-objective decision support system (MODSS) to alleviate phosphorus (P) contamination from agricultural fields and small watersheds. A decision supporting framework was designed to allow technical and public users to run the MODSS. The MODSS consists of the following elements: nonpoint source pollution models, an expert system to analyse the output of a qualitative P model, a scenario creation routine, a routine to estimate percentage and load based P reduction, a cost/benefits routine and a trade off analysis routine. Throughout the development of the MODSS, it was necessary to design a modified P Index for Southern Quebec. During the design process, the risk class 'controlled subsurface drainage' was introduced into the parameter subsurface drainage. The risk class was included due to findings that suggested that subsurface drainage is an important pathway for P loss in Southern Quebec. The modified P Index was coupled with a pre-screening routine to shorten the P Index analysis. The MODSS was applied to the Castor watershed, Quebec, Canada. The analysis showed that contributing distance, modified connectivity and P application rates are most likely probable causes for P movement from the fields in the Castor watershed. Additionally, the analysis showed that if BMP to reduce P loss are adopted the farmers could generate a surplus income.<br>La gestion des ressources naturelles s'est considérablement améliorée pendant la décennie passée. Malgré les avances dans la modélisation du destin des nutriants ou dans le domaine de modélisation des effets socio-économiques de différentes stratégies de gestion agricole, il nous manque toujours les outils d'intégrer les avances dans ces domaines. Afin de créer un outil d'integration de ces avances, cette recherche s'est concentrée sur le développement d'un système de soutien à la décision à objectifs multiples pour alléger la contamination de phosphore (P) à partir des champs agricoles et des petites lignes de partage. Le système inclut une interface de soutien à la décision permettant aux utilisateurs techniques et au grand public d'utiliser le MODSS. Le MODSS est composé des éléments suivants: plusieurs modèles de pollution diffuse, un système spécialisé pour analyser le produit de sortie d'un modèle de phosphore qualitatif, une routine de création de scénario, une routine pour estimer la réduction du phosphore en termes de pourcentage et de charge, une routine d'analyse avantages-coûts et une routine d'analyse d'échanges. Le développement du MODSS nécessitait la proposition d'un index du phosphore adapté au sud du Québec. Une nouvelle classe de risques a été introduite dans le paramètre de drainage souterrain: le drainage souterrain contrôlé. Cette classe de risques a été ajoutée, puisque des résultats de recherche extérieurs suggéraient que le drainage souterrain constitue une voie importante de perte du phosphore dans le sud du Québec. L'index modifié du phosphore a été couplé avec une routine d'examens préliminaires afin de raccourcir l'analyse. Le MODSS a été appliqué au bassin-versant de Castor au Québec, Canada. L'analyse a démontré les causes probables du mouvement de phosphore provenant des champs du bassin-versant de Castor : la distance par rapport au point d'origine, la connectivité$
2
Cooperband, Leslie Rose. "Soil phosphorus dynamics in a humid tropical silvopastoral system /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487777901660164.
Texto completo da fonte
3
Donkor, Joseph. "Evaluation of the Potential for Direct-Fed Microbials to Enhance Utilization of Phosphorus in Broiler Chickens." Thesis, Tennessee State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10641460.
Texto completo da fonteResumo:
<p> Feed accounts for about 60–68% of the total cost of poultry production. Chicken cannot efficiently absorb organic or phytin-bound phosphorus, thus about 70–80% of dietary or plant based phosphorus is excreted in the manure of broiler chickens. The goal of this research was to identify microbes with the potential to improve utilization of a plant source of phosphorus in the gastrointestinal tract (GIT) of broilers. </p><p> A total of 8,082 sequences were obtained using a metagenomic approach, with 61% of those sequences representing 5,030 species of various bacterial organisms. The highest proportion of bacteria was Massilia which represented 46% of the total dominant microbial population, Bacteroides (9%), Streptomyces (6%), Bacillus (6%), and 18 different species each constituting less than 5% of these dominant microbes. Three microbes Lactobacillus, Enterococcus, and Bifidobacterium (LEB) with the potential to hydrolyze free phosphorus were isolated and characterized. The isolated microorganisms maintained the ability to grow at all the different pH ranges (1–5), and bile concentrations of 0–3.5%. Also, the ability of the bacteria to hydrolyze free phosphorus was evaluated in-vitro. The effect of the three bacteria on performance of 400 day- old Ross broilers was evaluated during an eight-week period. The results indicated that broiler chickens fed probiotic bacteria at the rate of 100 or 150 mg/kg of feed consumed 12.0% and 17.8% more feed, respectively, and increased body weight gain by 5.9% and 8.4%, respectively, when compared with the control birds. Broiler chickens fed diets containing the probiotics at 100 or 150 mg/kg of feed retained 15.2% and 17.5% of phosphorus as against 8.6 % for the birds on the diets without the bacteria. Except for birds on dietary treatment LEB-150, which had a higher mortality (7.3%), the remaining six dietary treatments had mortality ranging from 2.0–3.3% which was less than that of the controls birds (4.5%).</p><p>
4
Cucarella, Cabañas Victor. "Phosphorus recycling from wastewater to agriculture using reactive filter media." Licentiate thesis, KTH, Land and Water Resources Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4449.
Texto completo da fonteResumo:
<p>This thesis focused on testing the suitability of reactive filter media used for phosphorus (P) removal from wastewater as fertilizers, thus recycling P to agriculture. The work compared the P sorption capacity of several materials in order to assess their suitability as a source of P for plants. The selected materials (Filtra P, Polonite and wollastonite) were saturated with P and used as soil amendments in a pot experiment. The amendments tended to improve the yield of barley and ryegrass compared with no P addition. The amendments also increased soil pH, P availability and cation exchange capacity in the studied soils. The substrates studied here can be of particular interest for acid soils. Of the materials studied, Polonite appears to be the most suitable substrate for the recycling of P from wastewater to agriculture</p>
5
Cucarella, Cabañas Victor. "Phosphorus recycling from wastewater to agriculture using reactive filter media /." Stockholm : Mark- och vattenteknik, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4449.
Texto completo da fonte
6
Pierzynski, Gary Michael. "The chemistry and mineralogy of phosphorus in excessively fertilized soils /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487670346875087.
Texto completo da fonte
7
Creekmore, Cathy E., and J. L. Stroehlein. "Phosphorus Response in Wine Grapes." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/215732.
Texto completo da fonte
8
Yibirin, Humberto Peluffo. "Effects of daily applied nitrogen forms and phosphorus on corn production /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487856076413367.
Texto completo da fonte
9
Thompson, Christopher. "The Effect of Phosphorous Placement & Rate on Phosphorus Uptake, & Growth & Yield of Tomatoes." TopSCHOLAR®, 1990. https://digitalcommons.wku.edu/theses/2931.
Texto completo da fonteResumo:
Research was undertaken in the summer of 1989 to determine the effect of phosphorus placement on the yield and quality of field grown tomatoes Lycopersicon esculentum. A subsequent study was undertaken in the winter of 1989 to determine the effect of phosphorus rate and placement on the early growth and phosphorus uptake of young tomatoes in the greenhouse.
The purpose of this study was to attempt to find the most efficient placement and rate of supplemental phosphorus when growing tomatoes. It has been shown that placing phosphorus in a concentrated zone in contact with plant roots results in more growth and fruit yield. The current trial involved the application of phosphorus at different rates and use of different methods of application. The methods of application included broadcasting phosphorus, placing phosphorus in a concentrated band, and combinations of the two.
It is of great interest to the tomato producer to know the most efficient rate and placement of fertilizer phosphorus. Availability of phosphorus is necessary for the proper development of the tomato and a good supply is needed for adequate yield and quality. If improved application methods are developed, perhaps higher yields and improved fruit quality can be realized. This could possibly result in higher production for the producer and more satisfaction for consumers.
The results of the field study were not statistically significant. One reason for the lack of any yield response was the greatly reduced yields caused by hail damage and fungal disease.
Surprisingly, the greenhouse study showed that significant growth increase resulted from phosphorus broadcast treatments. One explanation may be the small volume of soil used in this study. The plant roots were distributed throughout the entire soil volume in contrast to the situation with widely spaced field grown tomatoes. Thus, the broadcast treatments achieved more root-fertilizer contact in the greenhouse pot cultures.
10
Seiler, Lauren Katherine Kaye Jason P. "Exploring potential soil phosphorus movement in four organic agriculture forage systems." [University Park, Pa.] : Pennsylvania State University, 2009. http://honors.libraries.psu.edu/theses/approved/WorldWideIndex/EHT-44/index.html.
Texto completo da fonte
11
Herman, Melissa C. "Laboratory Evaluation and Soil Test Phosphorus Trends in Ohio." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1308336863.
Texto completo da fonte
12
Norton, E. R., J. C. Silvertooth, and L. J. Clark. "Phosphorus Fertility Evaluation in Graham County." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/197714.
Texto completo da fonteResumo:
A series of three phosphorus (P) fertility experiments were conducted in 2001 in Graham County. These studies follow similar experiments conducted over the past three seasons. Results from 2001 were consistent with previous results indicating a positive relationship between yield and P fertilizer applications in relation to soil test indices. Modest yield increases were observed from a minimum of 25 to 80 lbs. lint per acre with an application of approximately 70 lbs. of P as P₂O₅ per acre. Yield differences from previous years have been as great as 170 lbs. of lint per acre. With the increased use of UAN-32 as a primary fertilizer source and a reduction in the application of P fertilizers, which is typically associated with a rotation of small grains, a depletion of soil P is a potential result. A continuation of this research with varying rates of P fertilizer will take place in 2002 in an attempt to relate soil test P levels to yield increases observed in recent years. The results of this research demonstrate the possible need for a return to use of fertilizers with supplemental P for optimum yields that would be predictable based on soil test results.
13
Norton, E. R., and L. J. Clark. "Phosphorus Fertility Evaluation in Graham County." College of Agriculture, University of Arizona (Tucson, AZ), 2003. http://hdl.handle.net/10150/197930.
Texto completo da fonteResumo:
A field study was implemented in 2002 in the Upper Gila River Valley of Safford to investigate the effects of varying phosphorus (P) fertilization rates on yield and quality of Upland cotton. This study is a continuation of work performed in this valley that began in 1998. This study was organized in a randomized complete block design with four treatments including four rates of 10-34-0 fertilizer, 0, 15, 30, and 45 gallons per acre (gpa) replicated 4 times. Lint yield results indicate a positive response to the application of 10-34-0 fertilizer with yield increasing linearly up to 30 gpa. The 45 gpa treatment resulted in a slightly lower yield than the 30 gpa treatment. This was likely due to the high level of nitrogen (N) fertilizer and excessive vegetative growth at the expense of reproductive growth (yield) that occurred in treatment 4.
14
Dupas, Rémi. "Identification et modélisation des processus à l'origine des transferts de phosphore dissous dans un bassin versant agricole." Thesis, Rennes, Agrocampus Ouest, 2015. http://www.theses.fr/2015NSARD078/document.
Texto completo da fonteResumo:
Le phosphore (P) est un facteur de contrôle de l’eutrophisation. Sa présence dans les masses d’eau est liée en partie à des émissions diffuses agricoles. L'objectif de cette thèse a été d'identifier et de quantifier les mécanismes à l'origine des transferts de P diffus, par une démarche intégrant analyse de données d'observations multi-échelle et modélisation.L'analyse d'une chronique de chimie de l'eau à l'exutoire d'un petit bassin versant agricole a révélé que les formes particulaires et dissoutes du P avaient des origines différentes dans le paysage, et étaient transférées de manière indépendante. Le P particulaire provient des sédiments du cours d'eau, de l'érosion des berges et occasionnellement d'épisodes érosifs dans les versants. Le P dissous provient des sols de la zone riparienne; il est transféré par écoulement de subsurface lorsque les fluctuations de nappe créent une connexion hydrologique avec la rivière.Un suivi multi-site de la concentration en P dans l'eau des sols ripariens a permis de mettre en évidence que la nappe agissait non seulement sur le transfert, mais aussi sur la solubilisation du P. Deux moments importants ont été identifiés : la période de sécheresse estivale est favorable à la constitution d'un pool de P mobile dans les sols, exporté à l'automne; lorsque la nappe stagne dans les sols, la dissolution réductrice des oxydes de Fer provoque un second relargage de P. Un modèle couplé hydrologie-biogéochimie a permis de préciser le rôle de la nappe, de la teneur en P des sols et des variations d'humidité et de température. Une analyse de l'<br>Phosphorus (P) is a controlling factor of eutrophication. Its presence in water bodies is partly due to agricultural diffuse emissions. The objective of this thesis was to identify and quantify the processes controlling diffuse P transfer, with an approach combining analysis of multi-scale observation data and modelling.Analysis of a water chemistry time series acquired at the outlet of a small agricultural catchment revealed that particulate and dissolved P forms had different spatial origin within the landscape, and were transferred through distinct mechanisms. Particulate P originates from stream bed sediments, bank erosion and occasionally from erosion on hillslopes. Dissolved P originates from riparian soils; it is transferred via subsurface flow when the water table fluctuations create a hydrological connection with the stream.Multi-site monitoring of P concentration in the soil pore water of the riparian zone evidenced that groundwater fluctuations controlled not only P transfer, but also its solubilisation. Two critical moments were identified: the summer dry period is favourable for the build-up of a pool of mobile P forms in soils, which is transferred in the autumn; when groundwater stagnates in soil in anoxic conditions, reductive dissolution of iron oxides causes a second P release. A coupled hydrological-biogeochemical model confirmed the hypotheses regarding the role of groundwater fluctuation, the soil P content and variability in soil temperature and moisture. An assessment of the information content in the data and the propagation of uncertainty enab
15
Martin, Kent Lee. "Effect of phosphorus placement in reduced tillage crop production." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1223.
Texto completo da fonte
16
Sen, Amrita. "Techno-Economic and Life Cycle Analysis of Phosphorus Circularity schemes in Agriculture." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619111447316257.
Texto completo da fonte
17
Gilbert, Jennifer. "Characterizing dissolved phosphorus transport through vegetated filter strips." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 209 p, 2008. http://proquest.umi.com/pqdweb?did=1597617901&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonte
18
Tickes, Barry, and Mike Ottman. "The Effect of Phosphorus on Alfalfa Yield." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/201366.
Texto completo da fonte
19
Silvertooth, J. C., T. A. Doerge, G. W. Thacker, S. W. Stedman, and J. E. Malcuit. "Effects of Banded Phosphorus Fertilizer on Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/204814.
Texto completo da fonteResumo:
Four field experiments were established in 1988 in Arizona to evaluate the effects of banded phosphorus (P) fertilizers on cotton. 2 sites involved upland cotton (Gossypium hirsutum L.) and 2 sites with pima (G. barbadense L. var Pima S-6), with 1 of each located near Marana, AZ (Vinton Anthony sandy loam). A site with 1 of each kinds was also located near Coolidge, AZ (Mohall sandy loam). At the Marana studies, P was applied 6 inches directly below the zone of seed placement at the time of listing and at the Coolidge sites, P was applied 6 inches below and 2 inches to the side of the zone of seed placement after listing but before planting. In all cases, the P source was 10-34-0 at rates of 0, 30, and 65 lb. P₂O₅ acre⁻¹. At the Marana location, a treatment of banded 10-34-0 at 30 lb. P₂O₅ acre⁻¹ plus a foliar application of 10 lb. P₂O₅ acre⁻¹ (early bloom) as 10-34-0 was included in both the upland and the pima experiments. Plant measurements for plant height, flower numbers, node numbers, boll numbers, and nodes to first fruiting branch were taken to evaluate plant response throughout the season. Plant tissue samples were also taken for leaf petiole PO₄-P and leaf blade total P analysis. Lint yield measurements were also taken. No statistically significant (P < 0.05) differences were found among any of the treatments for any of the measured parameters, except in the petiole PO₄-P levels from the upland study at Coolidge on the second sampling date.
20
Mejias-Bassaletti, Jaime. "Phosphorus leaching from manure-impacted soils affected by fluctuating water tables." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Dissertations/Summer2005/j%5Fmejias%5F060705.pdf.
Texto completo da fonte
21
Baon, John Bako. "Role of mycorrhizas in the assessment of phosphorus efficiency in cereals." Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phb221.pdf.
Texto completo da fonte
22
Croat, Samantha Jo. "Phosphorus Dynamics and Crop Productivity in Bakken Crude-Oil Remediated Soils." Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/29169.
Texto completo da fonteResumo:
Thermal desorption (TD), a remediation method used to remove hydrocarbons from contaminated soils, may cause changes in soil properties that threaten soil function and plant productivity. The goal of this research is to better understand the effect that TD treatment has on soils intended for agricultural use. A series of soil phosphorus (P) sorption and desorption experiments were conducted on soils before and after TD treatment to determine P availability for plant uptake and risk for run-off. TD-treated soils retained more P, likely due to mineral transformations of Fe- and Al-oxides. In addition, a three-year field study using mixtures of topsoil (A), crude-contaminated soil (SP), and TD-treated soils (TDU) was conducted. Yields were significantly greater in plots that included A in the mixture compared to SP and TDU soils alone. TD-treated soils can be a replacement for topsoil, but the addition of topsoil will reduce the time to successful reclamation.
23
Lansford, Vernon D. "Economic and environmental implications of a phosphorus standard : 160-sow representative farm in Montgomery County, Missouri /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036837.
Texto completo da fonte
24
Gardner, B. R., and T. C. Tucker. "Effect of Phosphorus Fertilizer Application on Cotton Yields." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204087.
Texto completo da fonte
25
Stroehlein, J. L., M. M. Janat, and C. E. McGuide. "Response of Grape Cultivars to Nitrogen and Phosphorus." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/215733.
Texto completo da fonteResumo:
The response of 11 different varieties of grapes treated with different levels of N was studied over a seven-year period Phosphorau fertilizer was applied midway through the study. Tissue samples were tested for total P and NO₃-N content, and yield determined annually. The results showed a positive interaction in tens of increased yield between N and P when sufficient quantities of both nutrients were provided
26
Sachdeva, Vanita. "Biochar-induced soil stability influences phosphorus retention in the agricultural field in Quebec." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121318.
Texto completo da fonteResumo:
Surface runoff from agricultural fields is the largest non-point source of phosphorus (P) that pollutes surface water in humid temperate regions. Best management practices have attempted to reduce P loading and improve P retention in agricultural soils but significant losses continue to occur, emphasizing the need for novel solutions. The objective of this research project was to determine whether biochar amendments in an agricultural soil could reduce P loss in surface runoff by increasing water infiltration or by improving soil stability. Experimental plots were established in St-Francois-Xavier-de-Brompton, Quebec, Canada on an agricultural field amended with three types of biochar (Dynamotive, Pyrovac, and Basques) applied at two application rates (5 and 10 t ha-1), and one unamended control plot. First, a 30-minute rainfall simulation was conducted using the Cornell Sprinkle Infiltrometer to assess runoff volume, time-until-ponding, infiltration rate, and water holding capacity (WHC), as well as P concentration and load in runoff. Second, soil samples from the experimental plots were fractionated using a wet-sieve method to determine the proportion of macro- and micro-aggregates. Each fraction was analyzed for total organic C and total P to locate biochar presence and determine whether additional P was retained in macro- or micro-aggregate fractions of biochar-amended soils. Water dynamics in the rainfall simulation showed no significant differences, however, runoff contained significantly less ortho-P in soil amended with Dynamotive biochar at 5 t ha-1 (p=0.048) and significantly less particulate P from soil amended with Pyrovac biochar at 5 t ha-1 (p=0.012) and Dynamotive and Basques biochars at 10 t ha-1 (p=0.024 and p=0.047, respectively). Soils amended with biochar at 5 t ha-1 and 10 t ha-1 also had significantly greater microaggregate stability (p=0.032 and p=0.046, respectively), which corresponded to significantly more organic C content (p=0.013 and p<0.01, respectively). Macroaggregates from biochar-amended soils also contained significantly higher organic C and total P concentrations (p<0.05 for both biochar rates) than the control soil. This suggests that the reduction in particulate P concentration in runoff is the result of biochar integration within the microaggregate structure, which indirectly promotes P retention in macroaggregates.<br>Les eaux de ruissellement associées aux champs agricoles sont la plus grande source de charges diffuses de phosphore (P) affectant l'eau de surface en régions tempérées. Les pratiques de gestions optimales tentent de réduire la charge en polluants phosphorés ainsi que d'améliorer la rétention de P dans les sols agricoles, mais malheureusement, des pertes significatives continues d'être recensées, accentuant le besoin pour de nouvelles solutions. L'objectif de cette recherche était de déterminer si des amendements de biocharbon dans les sols agricoles pourrait réduire la charge en phosphore par ruissellement en augmentant l'infiltration de l'eau dans les sols et en améliorant la stabilité des sols. Des parcelles expérimentales ont été établies à St-Francois-Xavier-de-Brompton, Québec, Canada dans un champ agricole amendé avec trois types de biocharbon (Dynamotive, Pyrovac, and Basques) utilisant deux différentes doses d'application (5 et 10 t ha-1), et un sans biocharbon. Premièrement une simulation de précipitation de pluie de 30 minutes a été effectuée à l'aide de Cornell Sprinkle Infiltromètre pour mesurer les niveaux de ruissellements, la durée avant le début du ruissellement, le taux d'infiltration, la capacité de rétention de l'eau, ainsi que la teneur et la charge total de P dans l'eau de ruissellement. Deuxièmement, des échantillons de sols des différentes parcelles on été fractionnées selon la technique de tamisage humide pour déterminer la proportion de macros et micros agrégats. Chacune des fractions a été analysé pour leur quantité de C organique ainsi que le niveau total de P afin de localiser la présence de biocharbon et afin de déterminer si plus de P a été retenu dans les fractions contenant les macro ou les micros agrégats de sols amendés avec du biocharbon. La dynamique de l'eau dans la simulation de précipitation a démontré aucune différence significative, cependant le contenue du ruissellement avait significativement moins d'orthophosphate dans le sol amendé avec le biocharbon Dynamotive à 5 t ha-1 (p=0.048) et il y avait significativement moins de P particulaire avec le sol amendé avec le biocharbon Pyrovac à 5 t ha-1 (p=0.012), le biocharbon Dynamotive et le biocharbon Basques à 10 t ha-¬1 (p=0.024 et p=0.047, respectivement). Les sols amendés avec du biocharbon à 5 t ha-1 et à 10 t ha-1 avaient aussi, de façon significative, des micros agrégats plus stables (p=0.032 et p=0.046, respectivement), ce qui correspond à une plus grande quantité de C organique (p=0.013 et p<0.01, respectivement). Les macros agrégats des sols amendés en biocharbon avaient des concentrations de C organique et P totales plus élevées (p<0.05 pour les deux concentrations de biocharbon) que le sol témoin. Cela suggère que la réduction de la concentration de P particulaire dans l'eau de ruissellement est la conséquence de l'intégration du biocharbon dans la structure des micros agrégats, ce qui encourage la rétention dans les macros agrégats.
27
Ottman, Michael J., Thomas L. Thompson, M. T. Rogers, and Scott A. White. "Alfalfa Response to Forms of Phosphorus Fertilizer." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204090.
Texto completo da fonteResumo:
Many agricultural workers feel that 10-34-0 is a superior fertilizer for alfalfa since it is thought to move deeper in the soil with irrigation, be more available to the plant, and result in higher yields at equivalent rates compared to 11-52- 0. We found in our study with 24 cuttings over 3 years that alfalfa yields were similar if fertilized with 10-34-0 or 11-52-0 at equivalent rates. Total plant P was not affected by P fertilizer form or method of application. Broadcast 11- 52-0 resulted in higher soil P levels than water-run 10-34-0 and moved deeper in the soil profile. Broadcast 11-52-0 and water-run 10-34-0 appear to be equally effective P fertilizers for alfalfa in the irrigated southwest.
28
Abdulnour, Jihad. "Micropropagation of 'John Franklin' rose and its phosphorus uptake." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69582.
Texto completo da fonteResumo:
Nodal sections of the winter-hardy 'John Franklin' rose cultivar from field-grown plants were cultured on a modified Murashige and Skoog (MS) nutrient medium. Very high levels of contamination from the surface of the initial sections required that plants be grown under greenhouse conditions. Rose plantlets obtained from subsequent subcultures were used for the first time in a radiotracer experiment with $ sp{32}$P to study the kinetics of phosphorus (P) uptake as a function of temperature of the nutrient medium. P uptake increased with time for rooted and non-rooted plantlets in a linear fashion that did not reach an equilibrium value even after 96 hours of exposure. An analysis of variance revealed that the plantlets with roots absorbed significantly greater amounts of P at the 0.01 level compared with non-rooted plantlets at 22$ sp circ$C. P uptake was significantly higher at the 0.05 level, for rooted versus non-rooted plantlets at 33$ sp circ$C. There was no significant difference in P uptake by rooted and non-rooted plantlets at 3$ sp circ$C. Interaction between time of exposures and rooting was found to be significant at 22$ sp circ$C and 33$ sp circ$C at the 0.01 level. The results indicated that the root system, previously thought to be inefficient in the nutrient absorption, played a key role in absorbing P from the nutrient medium at optimum temperature.
29
Payne, Steven George. "The phosphorus availability of feed phosphates in broilers." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1859.
Texto completo da fonteResumo:
Thesis (MscAgric (Animal Sciences))--University of Stellenbosch, 2005.<br>Broiler diets are supplemented with feed phosphates to ensure that adequate available phosphorus is provided in the diet to meet the bird’s requirements. These feed phosphates make a considerable contribution to the total available phosphorus in the diet and small differences in their availability may have significant effects on whether the bird’s requirements are met or not. The variation in availability of phosphorus between feed phosphates belonging to different classes and between feed phosphates of the same generic class is well documented.
30
Mokase, Tsakani Joyce. "Phosphorus release characteristics and quantification of microbial population at different stages of phospho-compost production." Thesis, University of Limpopo, 2016. http://hdl.handle.net/10386/1834.
Texto completo da fonteResumo:
Thesis (M. Sc. Agriculture (Soil Science)) -- University of Limpopo, 2016<br>This study aimed at assess phosphorus (P) solubility and bioavailability from non-reactive Phalaborwa ground phosphate rock (GPR) using thermophilic co-composting technology. Two types of organic wastes (Cattle, CM and poultry manure, PM) were used to produce different mix ratios (5:5, 7:3, 8:2 and 9:1) of phospho-composts. Control compost of both manures without GPR addition were included. Samples of each compost heap were taken at mesophilic, thermophilic, cooling and maturity stages and used for bioquality and chemical tests. Microbial counts, enzyme activity, molecular analysis, and the quatification of different P forms and fractions were carried out on all compost samples. Results showed that the concentration of P measured in the different phospho-composts differed significantly (p < 0.05). The 8:2 mix ratio gave quantitatively higher P concentration in both CM- and PM-based phospho-composts. Organic P form had the lowest concentration when compared to other P forms and fractions while water soluble-P had the highest concentration as compared to other P fractions. The content of actinomycetes showed correlated positively with EC, phosphatase β-glucosidase, fungi and bacteria but negatively correlated with organic P, Ca-P water P and pH. There was a positive and significant correlation between electrical conductivity, enzyme activity (phosphatase, dehydrogenase and β-glucosidase), fungi, actinomycete and P fractions (Bray P1, Ca-P and Pi value). Acid phosphatase activity correlated negatively with water extractable P, organic P and Ca-P contents but revealed a positively significant correlation with bacteria, fungi and actinomycete counts.
Generally higher microbial counts were measured in CM- than PM-based phospho-composts but the concentrations varied with each microbial species. Highest fungi (7.27 CFU g-1) and actinomycete (6.83 CFU g-1) counts were generally recorded in the control composts, which was quantitatively higher in CM- than PM-based phospho-composts. Quantitatively higher enzyme activities were measured across compost types and mix ratios during the cooling phase phospho-compost production; but were statistically comparable to measured values at maturity phase. Acid phosphatase and β-glucosidase enzymes were predominately higher at maturity phase in all cattle manure-based phospho-compost excluding the 5:5 mix ratio. In PM-based phospho-compost, both β-glucosidase and phosphatase were higher at initial phase with PM5:5 , PM9:1 and PM10:0. Dehydrogenase activities were predominately higher at thermophilic and cooling phase from both PM- and CM-based phospho-compost. Results of molecular analysis revealed that Bacillus sp. and Acholeplasma cavigenitalium sp. were dorminant in PM-based phospho-composts while Pseudomonas sp. and Acholeplasma pleciae dorminated the CM-based phospho-composts. In conclusion, results of this study revealed that the type of manure used exerts great influence on the bioquality parameters and the amount of P released.
Key words: Phospho-compost, Compost quality, Enzyme activities, Nutrient cycling, Ground phosphate rock, Phosphorus forms and fractions
31
Shepherd, Jessica Grace. "Ochre and biochar : technologies for phosphorus capture and re-use." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28907.
Texto completo da fonteResumo:
Despite recent instability in the global supply of phosphate-rock derived fertiliser and the potential for this to continue into the future, the recovery of phosphorus (P) from wastewater treatment systems, where P is abundant and accessible, is well below maximum potential. Considerable resource is spent on removing P from wastewater in order to comply with environmental standards and to protect aquatic ecosystems from eutrophication, yet there is little emphasis on capturing the P in a way that is optimised for re-using it as agricultural fertiliser. To address this lack of innovation in the face of climate change and food insecurity, a concept for a material capable of capturing P from wastewater was developed, with an emphasis on the utilisation of otherwise waste materials and the use of carbon neutral or negative production technologies. Based on the demonstrated P capture properties of coal minewater treatment waste (ochre) and biochar made from anaerobically digested feedstocks, a range of biochars were designed and produced using different mixtures of ochre (“OC”), sourced from the UK Coal Authority Minto minewater treatment scheme in Fife, Scotland and anaerobically digested sewage sludge (“AD”), sourced from the Newbridge wastewater treatment plant in Edinburgh. A first generation of materials consisting of either AD or a 1:1 mixture (dry weight basis) of OC and AD were produced in a small-scale batch pyrolysis unit at two pyrolysis highest treatment temperatures (HTTs) (450 and 550°C) to give the biochars AD450, AD550, OCAD450 and OCAD550. These were tested for their P capture properties in repeated P-exposure experiments with pH buffering in comparison to unpyrolysed ochre, activated carbon and a natural zeolite. After 5 days of repeated exposure to a P solution at a wastewater-relevant concentration (20 mg P l-1) replenished every 24 h, relatively high masses of P were recovered by ochre (1.73 ± 8.93×10-3 mg P g-1) and the biochars OCAD550 (1.26 ± 4.66×10-3 mg P g-1), OCAD450 (1.24 ± 2.10×10-3 mg P g-1), AD450 (1.06 ± 3.84×10-3 mg P g-1), and AD550 (0.986 ± 9.31×10-3 mg P g-1). The biochar materials had higher removal rates than both activated carbon (0.884 ± 1.69×10-2 mg P g-1) and zeolite (0.130 ± 1.05×10-2 mg P g-1). To assess the extractability of recovered P and thus potential plant bioavailability, P exposure was followed by repeated extraction of the materials for 4 days with pH 7-buffered deionised water. The AD biochars retained 55% of the P recovered, OCAD biochars 78% and ochre 100%. Assessment of potentially toxic element (PTE) concentrations in the biochars against guideline values indicated low risk associated with their use in the environment. A second generation of materials were produced to examine the scalability of the concept. Mixtures of AD and OC were pelletised with a lignin binder (89.1:9.9:1.0 ratio, dry weight basis) and AD was pelletised with binder (99:1 ratio, dry weight basis). The pelletised feedstocks were pyrolysed in a bench-scale continuous flow pyrolysis kiln at the same two HTTs to give the pelletised biochars PAD450, PAD550, POCAD450 and POCAD550. Analysis of digested biochar samples compared to the previous generation of biochars showed general similarities between the two groups, apart from the substantially lower Fe content. Sub-samples of the pelletised biochars were exposed to a 20 mg l-1 P solution over 6 days, with the solution replaced every 24 h to give the P-exposed biochars EPAD450, EPAD550, EPOCAD450 and EPOCAD550. To probe the mechanisms of P capture by these materials and how feedstock preparation and pyrolysis conditions affected these, spectroscopic analysis using laser-ablation (LA) ICP-MS, X-ray diffraction, X-ray photo-electron spectroscopy (XPS) and scanning electron microscopy coupled with energy dispersive X-ray was performed. The results highlighted the general importance of Fe minerals in P capture and subsidiary roles for Al, Ca and Si. A 3-week barley (Hordeum vulgare) seedling growth experiment was conducted using the pelletised and P-exposed biochars, in comparison with other biochars produced using feedstock which contained high amounts of PTEs. The biochars were also extracted using a range of different methods used to assess the bioavailability of PTEs and nutrients in soils, and the results compared to digests of barley leaves to identify whether any of these could reliably predict plant bioavailability in biochar. The above ground biomass and its total P concentration of barley grown in a 5% mixture of EPOCAD550 in sand was significantly higher than the control (p < 0.05 and p < 0.01, respectively). A significant positive correlation between mean leaf P mass and dry weight leaf yield (R2 = 0.865, p < 0.001) was found, indicating that dry weight yield could be used as an indicator for the P fertilising capability of biochar for barley seedlings. Element concentrations in unbuffered and buffered and (pH 7) 0.01 M CaCl2 biochar extractions were significantly positively correlated with plant leaf concentration for 6 of the 18 elements investigated, more than any of the other extractions. A longer barley growth experiment was conducted, using rhizoboxes, to test the bioavailability of P in the biochars compared to conventional fertiliser. The pelletised and Pexposed biochars were applied to a sandy loam soil with P constraints. Biochar application rates were based on 2% formic acid extractable P, calculated for summer barley using Index 0 soil. Analysis of total leaf length at harvest (12 weeks), dry weight yield, leaf P concentration and leaf P mass showed no significant differences between the biochar treatments, NPK fertilised and NK fertilised controls. This shows that biochar, when applied at low total application rates based on extractable P, is as effective as conventional fertiliser. Now that AD biochar materials have been shown to have useful phosphorus recycling properties in laboratory experiments, additional work is required to optimise their use in wastewater and agricultural systems. The next stage of research should determine their performance in flow-through filtration systems with simulated and real wastewater effluent, as well as their performance in field trials with different crops of interest to demonstrate their potential as viable alternative fertilisers.
32
Stroehlein, Jack, Lee Clark, and Edith DeRosa. "Response of Alfalfa to Phosphorus Fertilizer Sources." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203794.
Texto completo da fonteResumo:
A field study was carried out to determine the effects of different fertilizers on yield and quality of alfalfa. Two harvests over a period of four cuttings did not reveal any differences due to treatment. While alfalfa often responds to phosphorus (P) fertilizer application, conditions in this study provided adequate P as well as nitrogen (N) and potassium (K).
33
Olson, Jeremy Ray. "Phosphorus fertilization of corn using subsurface drip irrigation." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8703.
Texto completo da fonteResumo:
Master of Science<br>Department of Agronomy<br>Scott A. Staggenborg<br>In recent years, subsurface drip irrigation (SDI) acres have increased substantially. The use of SDI on corn (Zea Mays L.) in the Great Plains has increased due to increased land costs, reduced irrigation water availability, and higher commodity prices. Applying phosphorus (P) fertilizer through a SDI system becomes a major advantage, but further investigation of the interaction between water and fertilizer is needed. Sub-surface drip irrigation systems can be used to better improve the application efficiencies of fertilizers, applying in wet soil-root zones can lead to better uptake of soil applied materials. The objectives of this study were to determine how corn responds to P fertilizer applied via SDI and to create methodologies to simulate fertilizer and irrigation water compatibility tests for use in SDI systems. A plot sized SDI system was installed near Manhattan, KS to evaluate P treatments. Eight separate P fertilizers were applied via SDI mid-season at a rate of 34 kg P2O5 ha-1 and split-plots were created with 2x2 starter band at planting. Nitrogen was a non-limiting factor, with 180 kg N ha-1 applied as urea. Both starter fertilizer and injected fertilizer affected corn grain yield as indicated by the starter by treatment interaction. Split applying starter fertilizer at planting increased yield. A secondary laboratory study was conducted to evaluate the water and fertilizer interactions. A filtration system was used to simulate field conditions and each fertilizer/water mix was filtered through a 400 mesh filter paper to evaluate fertilizer precipitant formation. Sixteen common fertilizers were analyzed with different rates of Avail. Differences were observed between fertilizer treatments, visually and quantitatively. A secondary P soil movement field study was performed to quantify P concentrations around the SDI emitter. Soils were sampled in a 30.5 cm by 30.5 cm square adjacent to the emitter on a control treatment and a fertilized treatment, in both years of the study. Visual and quantitative differences were observed between the two treatments in both years of the study. When P fertilizers were added to the SDI system, higher P concentrations were found very close to the emitter orifice. Control treatments exhibited lower P concentrations around the emitter than fertilized treatments.
34
Lamba, Jasmeet Srivastava Puneet Fang Xing. "Surface and subsurface transport of phosphorus from surface and subsurface-applied poultry litter." Auburn, Ala., 2009. http://hdl.handle.net/10415/1964.
Texto completo da fonte
35
Hu, Yaqiong. "The effects of oxidation-reduction potential on the solubility of phosphorus in agricultural water management systems." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19252.
Texto completo da fonteResumo:
Previous field studies have shown that dissolved phosphorus (P) concentrations are higher in subsurface drainage water from agricultural fields under water table management (WTM) than under conventional tile drainage. Anaerobic conditions have been shown to alter the Oxidation-Reduction Potential (Eh) of soils. The reducing conditions caused by anaerobic conditions result in the reduction of Fe (III), Mn (III), Mn(V) and other metal phosphates. These reductions cause dissolved P once held in metal phosphates to become mobile. The objectives of this research were to confirm the relationship between Eh and dissolved P and to determine whether Eh could be responsible for higher concentrations of dissolved P in drainage water from water table management (WTM) compared to conventional free outlet tile drainage (FD). A field experiment determined that the Eh of drainage water from WTM differs from that of FD. In the field experiment, concentrations of dissolved P in water samples from WTM and FD were compared, and pH, Eh, dissolved Fe and Mn measurements were taken. The relationship between the Eh and dissolved P was further confirmed in two laboratory experiments. In the laboratory experiments, the effects of Eh on the solubility of P was determined by manipulating Eh, using glucose in one experiment and incubation periods in another, and measuring resulting Eh, concentrations of dissolved P, and dissolved Fe and Mn. The field experiment showed that the concentration of dissolved P is much higher and the Eh is much lower in WTM than in FD. In the two laboratory experiments, soils from three depths (0-25 cm, 25-50 cm and 50-75 cm) were examined. The laboratory results for the top soil (0-25 cm), and the field experiment results all d<br>Plusieurs études dans le passé ont démontré des concentrations de phosphore (P) dissolved supérieures dans les eaux de drainage souterrain avec le contrôle de la nappe phréatique (CNP) comparé au drainage libre conventionnel. Il a été observé que les conditions anaérobiques influencent le potentiel d'oxydo-réduction (Eh) du sol. Les conditions réductrices causées par les conditions anaérobiques engendrent la réduction du Fe (III), Mn (III), Mn (V) et d'autres phosphates métalliques. La réduction cause la séparation du P dissolved et des métaux. Les objectifs de cette recherche étaient de confirmer la relation entre le Eh et le P dissolved et de déterminer si le Eh pourrait être la cause des concentrations de P dissolved accrues dans les eaux de drainage avec le contrôle de la nappe phréatique (CNP) comparé au drainage libre. Les résultats d'une étude sur le terrain ont montré que le Eh diffère dans les eaux de drainage avec CNP comparé au drainage libre. Sur le terrain, des échantillons d'eau ont été recueillis dans les parcelles soumises au CNP et au drainage libre pour comparer les concentrations de P dissolved, de métaux (Fe et Mn) dissous et le pH. La relation entre le Eh et le P dissolved a été confirmée par deux expériences en laboratoire. En laboratoire, l'effet du Eh sur la solubilité du P a été déterminé en manipulant le Eh, à l'aide de glucose dans la première expérience, et à l'aide des périodes d'incubation dans la deuxième expérience. Les concentrations de P dissolved et de métaux dissous (Fe, Mn) ont été mesurées dans les échantillons édaphiques dans chaque traitement. Les eaux de drainage avec CNP avaient des concentrations de P dissolved sensiblement sup
36
Silvertooth, J. C., E. R. Norton, and A. Galadima. "Evaluation of Potassium and Phosphorus Fertility in Arizona Soils." College of Agriculture, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/211298.
Texto completo da fonteResumo:
Two field experiments were conducted during the 2000 growing season to address fertility recommendations for fertilizer phosphorus (P) and potassium (K). A K fertility study was conducted near Tonopah, AZ consisting of two treatments, an untreated control and a treatment receiving a total of 20 gallons of K-Sul/acre. No significant differences were observed in leaf blade K concentrations between treatments. Plant growth and development estimates revealed that fruit retention (FR) levels remained consistently higher in the untreated control versus the treated plots. A second study involved treatments consisting of both P and K fertilizers was conducted near Cibola, AZ. Four treatments in this experiment included an untreated control plus treatments of 11-52-0, 0-0-60, and 4-17-40 at 100, 200, and 300 lbs. fertilizer/acre respectively. Plant growth and development estimates were similar among treatments during the season. At the end of the season the untreated control had a slightly higher FR level than the other treatments, which also produced a significantly higher yield. No other differences in yield among the fertilized treatments were observed.
37
Ward, Nicholas Charles. "Impact of avail® and jumpstart® on yield and phosphorus response of corn and winter wheat in Kansas." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3519.
Texto completo da fonte
38
Knight, Jonathan James. "Chemical phosphorus removal and its influence on sewage sludge particulates and metal availability." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324631.
Texto completo da fonte
39
Lukhele, Nomagugu Precious. "Site-specific environmental risk assessment for phosphorus runoff." Thesis, University of Limpopo, 2014. http://hdl.handle.net/10386/1291.
Texto completo da fonteResumo:
Thesis (MSc. Agriculture (Soil Science)) -- University of Limpopo, 2014<br>Phosphorus (P) runoff from agricultural sites and the subsequent loading into surface water
bodies contribute to eutrophication. Environmental concerns associated with P loading in
soil have motivated the need for the development of a proper tool that will allow farmers to
identify agricultural areas or management practices that have the greatest potential to
accelerate eutrophication. The objective of the study was to determine the spatial variability
of soil test P, soil loss potential of the farm, P application rate and methods, and map P runoff
risk across the field. This study was conducted in Vierfontein Boerdery in Kriel,
Mpumalanga province, South Africa (longitude 29.11258833 and latitude -26.27104340). The
field was under dryland cultivation and planted to yellow maize that was rotated with
soybeans. Soil samples were taken at georeferenced locations in a 100 x 100 m grid for soil
analysis. Spatial layers of soil P distribution, soil loss potential as well as application rate and
method were created in ArcGIS software. These layers were used as input factors in a P
index model to identify areas in the farm that are vulnerable to P runoff. Results indicated a
variation in soil test P. Although soil test P variation was not statistically different at P≤0.05,
variation had both agronomic and environmental implications. This variation could be
attributed to differences in site-specific conditions and management practices. Furthermore,
soil loss potential across the study site predicted by the Revised Universal Soil Loss
Equation (RUSLE) showed variation with a range of 3-15 tons/ha/yr. This variation was
attributed to differences in topographic variations in the study site. There is a need for best
management practices that control soil erosion to minimize P runoff into water bodies.
KEYWORDS: Eutrophication, Geographic Information System, Phosphorus best
management practises, Phosphorus runoff index, Soil erosion, Site-specific management.
40
De, Villiers Chris Johan. "The effect of Phosphorus on the growth, plant mineral content and essential oil composition of Buchu (Agathosma betulina)." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019.1/1867.
Texto completo da fonte
41
Gichangi, Elias Maina. "Enhancing phosphorus availability in some phosphate fixing soils of the Transkei region, South Africa using goat manure." Thesis, University of Fort Hare, 2007. http://hdl.handle.net/10353/80.
Texto completo da fonteResumo:
Low availability of soil phosphorus (P) caused by strong sorption of P is a major constraint to agricultural production in most South African soils, particularly those from the high rainfall areas. The aim of this study was therefore to investigate whether combined addition of goat manure with inorganic P fertilizers could enhance P availability in some P fixing soils of the Transkei region, South Africa. The study addressed the following specific objectives (i) to assess P sorption capacities and requirements of selected soils and their relationship with selected soil properties and single point sorption test, (ii) to assess the effects of goat manure and lime addition on P sorption properties of selected P fixing soils (iii) to assess the temporal changes in concentration of inorganic and microbial biomass P fractions following application of inorganic fertilizer P with goat manure in a laboratory incubation experiment, and, (iv) to assess the effects of goat manure application with inorganic phosphate on inorganic and microbial biomass P fractions, P uptake and dry matter yield of maize. Sorption maxima (Smax) of seven soils examined ranged from 192.3 to 909.1 (mg P kg-1) and were highly and positively correlated with sorption affinity constant (r = 0.93, p = 0.01) and organic C (r = 0.71, p = 0.01). The amount of P required for maintaining a soil solution concentration of 0.2 mg P l-1 ranged from 2.1 to 123.5 mg P kg-1 soil. Soils collected from Qweqwe (a Cambisol), Qunu (an Acrisol), Ncihane (a Luvisol) and Bethania (a Ferralsol) had lower external P requirement values and were classified as lower sorbers, whereas soils from Ntlonyana (a Planosol), Chevy Chase (a Ferralsol) and Flagstaff (a Ferralsol) were classified as moderate sorbers. The results suggested that P availability could be compromised in 43 percent iii of the soils studied and that measures to mitigate the adverse effects of P sorption were needed to ensure that P is not a limiting factor to crop production, where such soils are found. Goat manure addition at varying rates (5, 10 and 20 tha-1 dry weight basis) to two of the moderately P fixing soils from Chevy Chase and Flagstaff, reduced P sorption maxima (Smax) compared to the control treatment. Phosphate sorption decreased with increasing amounts of goat manure in both soils but the extent of reduction was greater on Chevy Chase soil than on Flagstaff soil. The relative liming effects of the different rates of goat manure followed the order 20 t GM ha-1 > 10 t GM ha-1 > 5 t GM ha-1. In a separate experiment, addition of inorganic P at varying rates (0, 90, 180, and 360 kg P ha-1) to Flagstaff soil increased labile P fractions (resin P, biomass P and NaHCO3-Pi) and the increases were greater when goat manure was co-applied. The control treatments contained only 17.2 and 27.5 mg P kg-1 of resin extractable P in the un-amended and manure amended treatments, respectively which increased to 118.2 and 122.7 mg P kg-1 on day 28 of incubation. Biomass P concentration was increased from 16.8 to 43.9 mg P kg-1 in P alone treatments but the fraction was greatly enhanced with manure addition, increasing it from 32.6 to 97.7 mg P kg-1. NaOH-Pi was the largest extractable Pi fraction and ranged from 144.3 to 250.6 mg P kg-1 and 107.5 to 213.2 mg P kg-1 in the unamended and manure amended treatments, respectively. Dry matter yield and P uptake by maize grown in the glasshouse were highly and significantly (p = 0.05) correlated with the different P fractions in the soil. The correlations followed the order resin P (r = 0.85) > NaOH-Pi (r = 0.85) > NaHCO3-Pi (r = 0.84) >> biomass P (r = 0.56) for dry matter yield at 6 weeks after planting. At 12 weeks after planting, goat manure had iv highly significant effects on resin P and biomass P but had no effect on NaHCO3-Pi and NaOH–Pi. The combination of biomass P, resin P and NaHCO3-Pi explained 75.8 percent of the variation in dry matter yield of which 63.0 percent of the variation was explained by biomass P alone. The greatest increase in biomass P occurred when added P was co-applied with 5 or 10 tha-1 goat manure. The predictive equation for maize dry matter yield (DM) was: DM (g) = 1.897 biomass P + 0.645 resin P (r = 0.73). Resin P was the fraction that was most depleted due to plant uptake and decreased by 56 to 68 percent between the 6th week and the 12th week of sampling indicating that it played a greater role in supplying plant available P. The results therefore suggested that the use of goat manure may allow resource poor farmers to use lower levels of commercial phosphate fertilizers because of its effect to reduce soil P sorption. In addition, higher increases in biomass P due to manure addition observed at lower rates of added P indicated that goat manure has potential for enhancing bioavailability and fertilizer use efficiency of small inorganic P applications.
42
Norton, E. R., and J. C. Silvertooth. "A Review of 10 Years of Phosphorus Fertility Research in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/198214.
Texto completo da fonteResumo:
Management of phosphorus (P) fertilizer in Arizona cotton production systems has been studied for many years. A series of field experiments have been conducted across Arizona since 1989 with the most recent trial conducted in 2004. These trials represent over 15 site-years of research investigating the response of upland cotton (Gossypium hirsutum L.) to the application of P fertilizers and have been conducted over a wide range of environmental conditions. A summary of these field trials is presented in this paper. All trials were structured in a similar fashion with a control being compared to various rates of applied P fertilizer ranging from 0 to over 120 lbs P₂O₅ per acre. All trials had a similar experimental design with large plots (minimum of 0.16 acres) and treatments arranged in a randomized complete block design with a minimum of three replications in all cases. All applications were made either pre-plant or shortly after stand establishment. A wide range of soil test P levels were evaluated at many locations across the State. Results indicate that the critical level for sodium bicarbonate extractable P is 5 parts per million (ppm) with a 90% probability of a positive lint yield response when soil test levels fall below the critical level. Effective (positive crop response) fertilization rates range from 60-90 lbs of P₂O₅ per acre.
43
Taylor, Astrea. "Phosphorus mass balance for hypertrophic Grand Lake St. Marys, Ohio." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347933945.
Texto completo da fonte
44
Unruh, B. L., J. C. Silvertooth, A. J. Steger, and E. R. Norton. "Nitrogen, Phosphorus, and Potassium Uptake by Upland and Pima Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1994. http://hdl.handle.net/10150/209649.
Texto completo da fonteResumo:
Several investigations of nitrogen (N), phosphorus (P), and potassium (K) uptake by Upland cotton (Gossypium hirsutum L.) have been conduced, however no investigations of this type have included American Pima cotton (G. barbadense L.). We conducted a study to describe the total N, P, and K uptake and the partitioning of each nutrient into various plant parts for both Upland and Pima cotton. During the growing seasons of 1990, 1991, and 1992 at two south-central Arizona locations, both Upland (var. DPL 90) and Pima (var. S-6) cotton were grown. Beginning 14 to 20 d after emergence, whole cotton plants were removed and cotton plants were separated into stems, leaves (including petioles), burs (carpel walls), lint, and seeds. The bur fraction, also included squares, flowers, immature bolls, and burs from mature bolls. The appropriate analyses for total N, P, and K were determined on each fraction (except lint). Regression analyses was used to model nutrient uptake as a function of both days after planting (DAP) and heat units after planting (HUAP). Regression analyses indicated that HUAP was equally good, and in most cases superior to using DAP to model total nutrient uptake and partitioning within both Upland and Pima cotton. In every case there was close agreement between the predicted and actual total nutrient uptake. For Upland cotton the actual total N, P, and K uptake was 199, 29, and 250 kg ha⁻¹ and the predicted total N, P, and K uptake was 199, 29, and 255 kg ha⁻¹, respectively. For Pima cotton the actual total N, P, and K uptake was 196, 29, and 215 kg ha⁻¹ and the predicted was 210, 29, and 229 kg ha⁻¹, respectively. The pattern of nutrient partitioning in Upland cotton were similar to the findings of others and Pima showed the same general patterns of partitioning as Upland cotton. Seeds were a major sink of nutrients. Nutrient uptake in seeds resulted in decreasing uptake in leaves and stems. Presumably, due to mobilization of nutrients from those parts to the seeds during seed development. The nutrient requirements to produce 100 kg lint ha' for Upland cotton was 15, 2.2, and 19 kg ha⁻¹ for N, P, and K, respectively and was 20, 3.0, and 22 kg ha⁻¹, respectively for Pima cotton.
45
Harwood, Eric D. "Improving the yields of late-planted winter wheat with seeding rate and phosphorus fertility." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/e_harwood_120309.pdf.
Texto completo da fonteResumo:
Thesis (M.S. in soil sciences)--Washington State University, December 2009.<br>Title from PDF title page (viewed on Jan. 25, 2010). "Department of Crop and Soil Sciences." Includes bibliographical references.
46
Thelander, A. S., and J. C. Silvertooth. "Soil Test Calibration Evaluations for Phosphorus on Upland and Pima Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/197512.
Texto completo da fonteResumo:
Numerous field experiments were conducted at a wide range of sites in Arizona from 1988 through 1999 involving phosphate (P) fertilization of cotton (Gossypium spp.). A total of 21 site-years were used to study the effects of P on both Upland (G. hirsutum L.) and Pima (G. barbadense L.) varieties. The purpose of these experiments was to evaluate University of Arizona (UA) soil fertility guidelines with respect to soil test results (NaHCO3 extractable P) and to possibly fine-tune or calibrate these guidelines in relation to soil test P, applied P, and yield for common Arizona soils used in cotton production. Results from these experiments, based on soil test information, plant measurements, and lint yield showed no significant difference (P 0.05) due to treatments for all the studies with the exception of one P study conducted in Graham County in 1998 and another P study conducted in Pinal County in 1999. The 1998 Graham County site had a preseason soil test value of 7.6 ppm NaHCO₃ extractable P. The 1999 Pinal County site had a preseason soil test value of 3.0 ppm NaHCO3 extractable P. Analysis of yield results vs. soil P show that soil test P levels greater than 5 ppm are consistently sufficient for both Upland and Pima cotton. Yield results vs. applied P (lbs. P₂O₅/acre) for both Upland and Pima did not indicate a positive response over the rates of fertilization tested (20-160 lbs. P₂O₅/acre). Based on the results from these studies, the current UA soil fertility guidelines for P fertilization of cotton appear to be valid. Furthermore, the data indicates that the UA soil fertility guidelines may be further refined to provide the following categories: < 5 ppm = high probability of response to an added P fertilization; 6-10 ppm = medium probability of response to an added P fertilization; and > 10 ppm = low probability of response to an added P fertilization.
47
Tickes, Barry R., and Tom Doerge. "Survey of Soil Phosphorus in Established Alfalfa Fields in Yuma County." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/201365.
Texto completo da fonteResumo:
A survey was conducted to evaluate the soil phosphorus levels in a cross section of established alfalfa fields in Yuma County The levels of extractable phosphorus (P) varied from 3 to 43 ppm P. All of the soils testing in the very low (below 5 ppm P) and low categories (5 -10 ppm P) were located in the Wellton-Mohawk Valley and on the Yuma Mesa. Annual soil testing in the fall should be used to identify fields which would be expected to be responsive to P fertilizer applications. Soil testing could also help identify fields less like& to respond to P additions (P values > 15 ppm). Eighty percent of the fields tested from the Yuma and North Gila Valleys were in the high and very high ranges, 16-25 ppm and > 25 ppm P respectively. These high values may reflect residual P from applications of phosphorus fertilizers to vegetable and cotton crops grown in rotation with the current alfalfa crops. Fall soil testing in these areas could help identify nonresponsive fields in order to avoid unneeded P applications.
48
Shumaker, II Paul D. "INORGANIC AND ORGANIC PHOSPHORUS INTERACTIONS WITH HYDROXY-INTERLAYERED SOIL MINERALS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/532.
Texto completo da fonteResumo:
Phosphorus (P), a necessary plant and animal nutrient, can also lead to eutrophication of fresh waters when in excess. Appropriate P management is necessary to prevent fresh water pollution. Mineralogy of soil clays has been shown to affect P adsorption, desorption, and movement through soils. Specifically, hydroxy-interlayered minerals have been shown to adsorb and retain inorganic P in soil systems. This study was designed to determine the sorption and desorption characteristics of inorganic, organic, and mixed forms of P interacting with soil hydroxy-interlayered vermiculites (HIV) and smectites (HIS), and compare the findings to sorption and desorption processes of natural aluminum (Al) and Iron (Fe) hydroxide minerals. Results indicate natural Al and Fe hydroxide minerals sorbed and retained P more strongly than hydroxy-interlayered minerals in our samples and inositol hexakisphosphate was more highly sorbed and retained than inorganic P.
49
Ottman, M. J. "Response of Wheat and Barley Varieties to Phosphorus Fertilizer, 2010." College of Agriculture, University of Arizona (Tucson, AZ), 2010. http://hdl.handle.net/10150/279396.
Texto completo da fonteResumo:
Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was conducted for the second year at the Maricopa Agricultural Center testing the response of 7 barley and 14 wheat (12 durum wheat and 2 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P₂O₅/acre). The grain yield increase due to phosphorus application averaged across varieties in 2010 was 170 lbs/acre for barley (not statistically significant) and 545 lbs/acre for wheat. The grain yield increase averaged across varieties and years was 331 lbs/acre for barley and 577 lbs/acre for wheat. The barley and wheat varieties did not differ in their grain yield increase due to phosphorus fertilizer in 2010. However, based on 2 years of results, we were able to detect differences among wheat but not barley varieties in their response to P fertilizer. The yield response to P fertilizer (100 lbs P₂O₅/acre) among durum wheat varieties varied from 331 lbs/acre for Alamo to 1063 lbs/acre for Orita. Yecora rojo, a bread wheat, did not respond to P fertilizer.
50
Chauke, Rhandu. "Mineralisation and bioavailability of phosphorus from poultry manure and sewage sludge-based phospho-composts for maize production." Thesis, University of Limpopo (Turfloop Campus), 2014. http://hdl.handle.net/10386/1171.
Texto completo da fonteResumo:
Thesis (MSc. Agriculture (Soil Science)) -- University of
Limpopo, 2014<br>Phospho-composts of different mix ratios (5:5, 7:3, 8:2 and 9:1) were produced
through thermophilic co-composting of poultry manure (PM) and sewage sludge
(SS) with ground phosphate rock (GPR). Composted PM and SS without GPR
addition were included as control. Cured phospho-composts were chemically
characterised and used for both laboratory incubation and greenhouse studies,
respectively for phosphorus (P) mineralisation and bioavailability, over a period of
42 days. Results revealed that Bray-P1 concentration measured in compost
amended soils at 14, 21 and 42 DAI differed significantly (P<0.05) and ranged
between 5.47 and 11.14 mg kg-1 and between 5.28 and 11.78 mg kg-1 in poultry
manure and sewage sludge-based phospho-composts, respectively. The maximum
amount of cumulative P mineralised of 16.06 and 9.98 mg kg -1, respectively in PM
and SS-based phospho-composts were obtained from the 8:2 mix ratio. The
content of the acid detergent fibre of the different phospho-composts showed
positive and significant correlation with cellulose, lignin and total organic carbon
(TOC). Similarly, cellulose as well as C:P ratio showed significant correlation with
both lignin and TOC. The polynomial relationship between cumulative P mineralised
and the various GRP and manure mix ratios revealed significant and positive R2-
values of 0.731 and 0.613 for PM and SS-based phospho-composts, respectively.
The maximum amount of maize tissue P uptake of 0.12 and 0.11 mg pot-1 in PM and
SS-based phospho-compost respectively were also obtained from the 8:2 mix ratio
while the least amount of 0.04 mg P pot-1 was obtained from GPR and unamended
pots. Maize tissue P uptake following the phospho-compost application was
significantly affected by the differences in soil type. Tissue P uptake was 0.06 and
0.11 mg P/pot, respectively in low potential and high potential soils with a
significantly higher value. The use of the different phospho-composts showed great
potential for amelioration of P-deficiency problems in crops while thermophilic cocomposting
improved the solubility and bioavailability of P from non-reactive GPR.
Keywords: Ground phosphate rock; poultry manure; sewage sludge; phosphocomposts;
phosphorus mineralisation; soil fertility management.