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THE EFFECTS OF RATES AND DATES OF APPLICATION OF COMMERCIAL FERTILIZERS ON FOUR RANGELAND SITESBilly, Bahe, 1937- January 1970 (has links)
No description available.
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Effect of large initial applications of fertilizer on the availability and fixation of phosphorus in Tatum silt loamHall, Rhody B. January 1948 (has links)
M.S.
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Response of cotton to N and water applied via a trickle irrigation system : growth, yield, and nutrient uptakeMohamed, Abdellatif Abdellatif,1956- January 1987 (has links)
The crop growth rate (CGR); the relative growth rate (RGR); seed yield; plant uptake of N, P, K, Ca, Mg, Fe, and Na; and the water use efficiency (WUE) were studied in relation to N fertilizer and water application rate interactions in trickle-irrigated cotton. Increasing water application rate significantly increased CGR, but no significant differences were detected among the RGR values at the various water levels. Nitrogen fertilizer additions significantly increased the CGR. Nitrogen and water applications significantly increased seed yield, however, the effect of the interaction between N and water was not significant. Water levels had a positive significant effect on the cotton reproductive growth. Increased N and water significantly increased total N-uptake by cotton plants. Nitrogen additions significantly increased N% of leaves, burrs and seed. However, N% of stem was significantly reduced with high N applications. Total uptake of P, K, Ca, and Mg significantly increased with the increased application of N and water. Addition of 1.2 consumptive use (Cu) irrigation rate significantly increased P% in cotton stems, however, K% in stem was reduced. The irrigation rate of 0.9 CU and 1.2 CU significantly increased Mg% in both leaves and stems. Nitrogen application rates of 224 and 336 kg N/ha significantly decreased Mg% in leaves and stems. Increasing the irrigation rate from 0.9 CU to 1.2(1.3) CU reduced the WUE by cotton plants. However, WUE appeared to increase as N fertilizer increased up to 33 kg N/ha with water level of 0.9 CU.
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Physiological measurements of daily daylight fertigated citrus treesSchoeman, Stephanus P. (Stephanus Philippus) 12 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Daily daylight fertigation regimes (involvinq drip fertigation, on a daily basis,
during the daylight hours) are becoming widely used in the South African
citrus industry in the endeavor to enhance tree productivity. Such regimes
could provide sensitive nutrient and moisture management, reducing plant
stress in general as well as the response time to root-directed cultural
activities.
There is a need to evaluate the efficacy of daily daylight fertigation systems
relative to conventional irrigation systems. Standard horticultural evaluation of
orchard management practices is very time consuming. We opted for
physiological studies comparing plant stress levels, in an attempt to quantify
plant performance under each system. Citrus trees under daily daylight
fertigation and conventional micro-jet and drip-irrigated regimes were
monitored to establish plant stress levels as indicated by sap flow, xylem
water potential, stomatal conductance and chlorophyll a fluorescence. Plants
under a daily daylight fertigation regime are believed to have good soil water
conditions in their rooting volume, and therefore experience negligible
baseline levels of stress. The trees do, however, experience midday
depression in stomatal conductance, to a lesser degree, but not unlike trees
under conventional regimes. It appears as if a larger rooting volume of microjet
irrigation regimes enhances recovery from the midday depression. It is
recommended that producers optimise productivity during the moming hours,
by early irrigation, so that plants can function optimally, whilst environmental
conditions are most favourable for high physiological activity.
We also assessed the effect of withholding water from trees adapted to a daily
daylight fertigation regime to evaluate the risk involved with short-term water
deficits in trees adapted to this regime, as well as the usefulness of
physiological techniques for identifying water stress. Stomatal conductance
and xylem water potential indicated water stress sooner than the other
physiological parameters. Citrus trees seem to be relatively insensitive to
water deficit stress as measured by sap flow and chlorophyll a fluorescence. Sap flow is buffered by tree capacitance, and although mediated via stomatal
conductance, atmospheric conditions and not the soil water content primarily
determine it. As daily fertigation is applied to trees under DOF regimes, they
exhibit more optimal levels of xylem water potential and stomatal
conductance, compared to trees from which water is withheld. Although
alleviating it to a degree, daily irrigation did not mitigate the midday
depression in these values. Seen over a season, even small enhancements
of stomatal conductance (and with it photosynthesis and possibly, growth) and
xylem water potential, could incrementally produce higher yields. / AFRIKAANSE OPSOMMING: In die strewe na verhoogde boomproduktiwiteit, word daaglikse
sproeibemesting (deur 'n drupbesproeiingsstelsel toegedien tydens die
dagligure) al meer algemeen in die Suid Afrikaanse sitrusbedryf gebruik.
Hierdie praktyk verminder algemene plantstres deur baie spesifieke voedingsen
vogbeheer, en verkort ook die plant se reaksietyd op wortelgerigte
bewerkingsaktiwiteite.
Dit is nodig om die relatiewe voordeel van daaglikse sproeibemesting teenoor
konvensionele besproeiingssisteme te evalueer. Huidige tuinboukundige
evaluering van boord-bestuurspraktyke is baie tydrowend. In 'n poging om
plantreaksie onder verskillende praktyke te beskryf, het ons besluit om die
plantstresvlakke met fisiologiese metodes te vergelyk. Sitrusbome onder
daaglikse sproeibemesting, en konvensionele mikro- en drupbesproeiing, is
onderskeidelik gemonitor om die plant se stresvlakke vas te stel, soos
aangedui deur sapvloei, xileem-waterpotensiaal, stomatale geleiding en
chlorofil a f1uoresensie. Die plante onder daaglikse sproeibemesting
ondervind lae viakkke van waterstremming, waarskynlik weens hoë
grondvogtigheid in die wortelsone. Die bome ondervind wel, soos dié onder
konvensionele besproeiing, middagdepressie in stomatale geleiding, hoewel
tot 'n mindere mate. Dit blyk asof die groter wortelvolume van mikrospuit
besproeide bome die herstel na middagdepressie bespoedig. Produsente
word aangeraai om die oggendure optimaal te gebruik deur vroeg te besproei
sodat plantproduktiwiteit hoog is terwyl die omgewingsfaktore op hul
gunstigste is en wanneer die hoogste fisiologiese aktiwiteit voorkom.
Ons het ook die effek van wateronthouding gemeet op die bome wat
aangepas is vir daaglikse sproeibemesting. Sodoende is die risiko verbonde
aan 'n korttermyn watertekort op hierdie bome ge-evalueer, asook die
bruikbaarheid van fisiologiese tegnieke om waterstremming in sitrus te
identifiseer. Stomatale geleiding en xileem-waterpotensiaal het
waterstremming vroëer aangedui as die ander fisiologiese parameters.
Sitrusbome blyk redelik onsensitief te wees teenoor droogtestremming soos gemeet deur sapvloei en chlorofil a fluoresensie. Sapvloei word gebuffer deur
boom-kapasitansie, en alhoewel sapvloei gereguleer word deur stomatale
geleiding, is dit die atmosferiese toestande (hoofsaaklik dampdruk verskil) wat
dit primêr beïnvloed, en nie die grond-water inhoud nie. Omdat bome
daagliks sproeibemes word, het hulle meer optimale vlakke van xileemwaterpotensiaal
en stomatale geleiding in vergelyking met bome waarvan
water weerhou is. Alhoewel daaglikse sproeibemesting die middagdepressie
verlaag het, is dit nie daardeur opgelos nie. Oor die typerk van 'n seisoen kan
selfs minimale verhogings in stomatale geleiding (en daarmeesaam
fotosintese en moontlik groei) en xileem-waterpotensiaal, hoër opbrengste tot
gevolg hê.
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Adubação potássica na produção e qualidade pós-colheita do rabanete /Gouveia, Aline Mendes de Sousa, 1985. January 2016 (has links)
Orientador: Regina Marta Evangelista / Banca: Pablo Forlan Vargas / Banca: Eliane Aparecida Benato Rodrigues da Silva / Resumo: O rabanete pode ser cultivado entre o período de safra de outras culturas de ciclo mais longo, sendo uma opção interessante aos pequenos produtores rurais que enxergaram nesta hortaliça uma possibilidade de incremento na rentabilidade das suas áreas. Devido a poucas informações na literatura que mostrem os efeitos do potássio na produção, qualidade e nas características bioquímicas do rabanete, objetivou-se com este trabalho avaliar os efeitos da adubação potássica aplicado em cobertura na produção e qualidade pós-colheita da cultura do rabanete armazenado sob refrigeração. O experimento foi conduzido na Fazenda Experimental da FCA/UNESP, em São Manuel/SP e as avaliações foram realizadas no Departamento de Horticultura da Faculdade de Ciências Agronômicas (FCA/UNESP). O delineamento experimental foi em blocos ao acaso, composto por cinco tratamentos de doses de potássio (K2O) (0; 22,5; 45; 67,5 e 90 kg ha-1) na forma de cloreto de potássio em cobertura, com cinco repetições. Foram avaliadas as características vegetativas da planta, acúmulo de nutrientes na raiz e produtividade. Para as características de qualidade (físico-química e bioquímica) as raízes colhidas foram armazenadas a temperatura de 5 ± 1 °C e UR de 85 ± 5 % durante 28 dias, sendo avaliadas a cada 7 dias, quanto a perda de massa, pH, acidez titulável, sólidos solúveis, açúcares redutores, ácido ascórbico (vitamina C), compostos fenólicos, pigmentos (carotenoides e antocianinas totais) e atividade enzimática (peroxidase). Para as características de produção do rabanete, obtiveram-se respostas lineares significativas em função das doses de potássio aplicadas em cobertura para: altura de plantas, massas da matéria fresca da parte aérea, raiz e total, com incremento de 0,46 cm, 0,61 g, 1,05 g, e 2,02 g por planta para cada 10 kg ha-1 de K2O aplicados, respectivamente. Para produtividade ... / Abstract: The radish is grown in consortium with other longer-cycle crops, but now small farmers have seen in the vegetable, a chance to increase the profitability of their areas. The literature has little information as to potassium's effects on the production, quality and the biochemical Radish characteristics. This study is aimed to evaluate the effects of potassium fertilizer applied in coverage in the production and culture of post-harvest quality radish under refrigeration. The experiment was conducted at the Experimental Farm of FCA/UNESP in San Manuel / SP and the evaluations were carried out in the Department of Horticulture, Faculty of Agricultural Sciences (FCA / UNESP). The experimental design was in randomized blocks, comprising of five treatments of potassium (K2O) (0; 22,5; 45; 67,5 and 90 kg ha-1) in coverage, with five repetitions. We evaluated the vegetative characteristics of the plant, nutrient accumulation in the shoots, roots and productivity. For the quality features, physical chemistry and biochemistry harvested roots were stored at 5 ± 1 °C and RH 85 - 90 % for 28 days were evaluated every 7 days, the mass loss, pH, titratable acidity, soluble solids, reducing sugars, ascorbic acid (vitamin C), phenolic compounds, pigments (carotenoids and anthocyanins) and enzyme activity (peroxidase). For radish production characteristics, we obtained significant responses as a function of potassium doses on coverage for plant height, mass of fresh matter of the aerial part, root and total, an increase of 0,46 cm, 0,61 g, 1,05 g and 2,02 g per plant per 10 kg ha-1 K2O applied, respectively. The decreasing order of macronutrintes accumulated by the root is: K> N> Ca> P> S> Mg. For productivity, there was an increase by 1,05 t ha-1 every 10 kg ha-1 K2O applied and the dose 52,4 kg ha-1 K2O with the highest percentage (97,7 %) in marketable yield. For the physicochemical and biochemical ... / Mestre
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Criteria signaling reapplication of controlled-release fertilizer for maximum growth of Ilex crenata Thunb. 'Helleri'Shiflett, Melinda Cole 12 September 2009 (has links)
Medium solution N and electrical conductivity (EC), and foliar N levels were measured to determine criteria which signal the need for reapplication of a controlled-release fertilizer (CRF) in order to maximize growth of container-grown Ilex crenata Thunb. ‘Helleri’. Rooted cuttings of ‘Helleri’ holly were initially fertilized (7 Mar. 1991) with 8-9 month (18N-2.6P-9.9K) or 12-14 month (17N-3.1P-9.9K) Osmocote. A subset of 12 plants received a CRF reapplication (half rate) of the respective Osmocote formulation on 19 July, 2 Aug., or 16 Aug. In addition to reapplication treatments, 12 plants received a liquid fertilizer (LF) solution with each irrigation starting on 19 July. Canopy widths of plants receiving LF or CRF reapplication on 19 July and 2 Aug. were greater than those plants without supplemental fertilizer (control). At the time of the second reapplication date (2 Aug.), medium solution N and EC, and foliar N levels of control plants were = 40 mg liter⁻¹, 0.4 d m⁻¹ and 2.3%, respectively. Since growth of control plants was less than those of LF, CRF 19 July and 2 Aug. reapplications, medium solution N and EC, and foliar N values at the time of the second reapplication (2 Aug.) signaled the need for CRF reapplication or LF supplementation. There was a strong relationship between medium solution EC and N (NO₃ + NH₄) (r² = 0.91, P = 0.05), indicating that growers could use EC measurements to predict medium solution N concentration, as well as to assess the adequacy of the fertilizer regime. / Master of Science
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The technique of plot study to determine soil losses and runoff under field conditions due to fertilizer treatmentHicks, Reuben B. January 1937 (has links)
For the past ten years certain experiment stations have conducted studies dealing with soil and water losses under a wide range of conditions, but no study has been conducted on plots under actual field cultural conditions. These investigations have been very valuable in that they have revealed much needed information but they have added very little knowledge of plot technique under field cultural conditions.
The size of the experimental plots for these studies has varied considerably from the small indoor laboratory plot to the complete watershed study. The indoor laboratory plot would exist under artificial conditions and could add little to methods and technique of the field plots, whereas the watershed investigation would take into account many factors not effecting field conditions. It is evident that a plot which would permit conduct of studies on the effect of fertilizer on soil and water losses under field conditions would be valuable. Such investigation is therefore undertaken in this thesis for a Master Degree.
lt is believed that the information obtained from this investigation will have special value because it is the first of its kind to be obtained on Virginia soil and because the experiment will furnish needed data regarding the measurements of soil and water losses under the special field conditions due to fertilizer treatment.
Objects
In order to permit a more complete study of soil erosion and its causes some type of portable field plot is needed.
Thus the objects of this investigation are as follows:
(1) To develop and propose technical methods for studying soil and water losses on plots under field cultural conditions.
(2) To test the practicality and usefulness of the methods developed by conducting studies on soil and water losses from plots of different fertilizer treatments. / M.S.
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Yield, dry matter production, and nitrogen uptake of drip irrigated cottonAhmed, Sabah Kedar. January 1988 (has links)
The study consisted of two experiments conducted over two growing seasons. Urea ammonium nitrate was used as a source of N at rates of 50, 75, 100 and 150% of levels estimated to be ideal for maximum yield of cotton (Gossvpium hirsutum L.). The nitrogen fertilizer was applied through a drip irrigation system. The yield of seed cotton, flowering pattern, boll set, plant N uptake, and dry matter production were studied in relation to four N fertilizer rates and two plant populations in the 1984 study. Yield of seed cotton, plant N uptake and dry matter production were studied in relation to four N rates, three seeding rates, and three cotton cultivars in the 1985 study. Petiole nitrate patterns were studied both seasons. The effect of N applications on seed cotton yield was dependent upon the initial soil N and the yield possibility. In this study the lower rate of N appeared to be sufficient for the yields obtained. Thinning resulted in reduction of the total number of flowers and significantly decreased yield, but percent boll set was not affected. Nitrogen additions significantly increased plant N uptake and dry matter production as well as petiole NO₃-N levels during the growing season. The N need of cotton under drip irrigation was determined throughout the growing season by using petiole analysis. The levels of petiole NO₃-N for N sufficiency and deficiency which are accepted under furrow irrigation cotton were shown to be applicable for drip irrigated cotton. Yield of DPL-775 and DPL-90 cotton cultivars was significantly higher than that for DPL-41 cotton cultivar in 1985.
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Comportamento de milho (Zea Mays L.) e propriedades físicas do solo, no sistema plantio direto, em resposta a aplicação de fertilizante organomineralSantana, Cleverton Tiago Carneiro de [UNESP] 16 March 2012 (has links) (PDF)
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santana_ctc_me_botfca.pdf: 439755 bytes, checksum: e679859c91574c2de49be49c6a9834cb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta pesquisa foi conduzida com o objetivo de avaliar a resposta agronômica de Zea Mays L. à aplicação de fertilizante organomineral, aplicado via tratamento de sementes e foliar, também utilizando-se de metodologias para avaliação das raízes por meio de coleta e análise de imagens. Para tal, foi realizado um trabalho em área de plantio direto, em Latossolo Vermelho distroférrico, textura argilosa, na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas – Universidade Estadual Paulista, Município de Botucatu, SP (22º58'S e 48º23'W, 765 m de altitude média). O delineamento experimental utilizado foi o de blocos casualizados, com cinco repetições. Os tratamentos foram constituídos pela aplicação isolada ou em combinação de três biofertilizantes (Haf Plus, Haf Alfa e Haf Potassium) e por quatro épocas de aplicação (Tratamento de Semente, Estádio V3, Estádio V9 e Estádio V11). Cada parcela possuía 5,5 metros de comprimento por 3,6 m de largura. Foram feitas trincheiras para capturar imagens do sistema radicular pelo método do perfil. As imagens foram analisadas pelo software SAFIRA, resultando em área, comprimento e volume de raízes. Na mesma trincheira foram coletadas amostras de 10 cm3, com o auxílio de um cubo volumétrico, para determinar a massa de raízes secas. A aplicação de fertilizante organomineral provoca sinergismo para fósforo e antagonismo para boro e cobre. A melhor interação entre os produtos e épocas de aplicação é a utilização conjunta de Plus (TS) + Alfa (V9) + Potassium (V11), com efeito positivo nos componentes biométricos das plantas... / This research was developed to evaluate the agronomic response of Zea mays L to the application of bio-fertilizer applied as seed and foliate treatment, evaluating the roots by collecting and analyzing images. To this end, work was undertaken in an area of no-tillage in Rhodic Eutrudox (or Red Latosol), clayey soils in three growing seasons, Faculty of Agricultural Sciences, State University of São Paulo (Universidade Estadual Paulista), Botucatu, SP (22 º 58'S and 48 º 23'W, 765 m average elevation). The trial design was made up of five (5) random trial blocks. The treatments were applied individually or in a combination of three bio-fertilizers (Haf Plus, Haf Alfa and Haf Potassium) and at four different stages (seed treatment, V3 Stadium, V9 Stadium and Stadium V11). Each plot was 5.5 meters long by 3.6 m wide. Trenches were dug to capture images of the root system via the profile method. The images were analyzed by the software SAFIRA, resulting in area, root length and volume. In the same trenches samples of 10 cm3 were collected with the aid of a volumetric cube to determine the dry root mass. The application of bio-fertilizer causes phosphorus synergism and boron and copper antagonism. A better interaction between the products and application times is the joint use of Plus (ST) + Alfa (V9) + Potassium (V11) with positive effect on biometric components of the corn plants. Treatment Plus (TS), at the time of application, is the biggest contributor to increasing biometric components and mass, length, volume and area of maize roots. Plus + Alpha applied to V11, either with or without Potassium, does not produce good results for average length of the spike, number of rows per ear, dry mass, area and volume of... (Complete abstract click electronic access below)
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The environmental risks linked to different manure application periods /Cantin, Jean. January 2006 (has links)
More intensive production of hogs and cattle in Quebec during the past decade has benefited local economies, but led to over-fertilization of agricultural soils and eutrophication of waterways. Provincial ministries responded to this issue by developing regulations to control manure applications. The objective of this thesis was to determine the environmental risk associated with applying farm manure in the late fall. Spreading manure in fall after harvesting corn was a common practice for many agricultural producers in Quebec, but this period is now viewed as very risky, having more negative environmental consequences than other manure application periods. This two-year study used common diagnostic tools to compare the fertilization efficiency of solid dairy farm manure (DFM) spread in early fall, late fall and spring on a heavy clay soil used for corn production. In the first year, when DFM was the only nutrient source, there was no difference in corn yield that could be attributed to the manure application period. In the second year, each DFM plot was split and six levels of inorganic fertilizer (from 55 to 240 kg N ha-1) were applied ("Strip Split Plot") after planting. Corn tissue analysis (chlorophyll content, leaf N content at silking, cornstalk NO3 concentration) indicated that more residual N was supplied from late fall manure application than other manure application periods. Monitoring of soil NO3-N concentrations indicated that most of the NO3-N migration through the soil profile occurred after the early fall manure application. Late fall manure application appears to be the most efficient at supplying N for corn production, without deleterious environmental impacts, when DFM is applied to a heavy clay soil.
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