Dissertations / Theses on the topic 'Zinc - Fertilizer'

After reviewing the literature on factors influencing zinc availability in soils, it was decided to investigate further aspects of the well documented zinc/phosphate interaction for the soil/maize system and to study the migration and transformations of inorganic and organic (sludge) fertilizer zinc in soils. A conventional pot experiment with maize to look at zinc/phosphate interaction, with thorough mixing of added fertilizer, indicated that phosphate could alleviate zinc toxicity effects, but did not show whether this was a soil or plant effect. A subsequent experiment in which soils treated with zinc and phosphate fertilizers were spatially separated by nylon net provided evidence that the interaction occurred, at least in part, in plant roots. This suggests limited benefit in the field for separate placement. Under field conditions, it is unrealistic to expect the same degree of soil mixing as used in typical pot experiments. Therefore an experiment with ⁶⁵Zn was used to study the vertical movement of surface-applied inorganic zinc fertilizer. The same experiment was also used to study the changes in distribution of added zinc between a range of soil fractions (exchangeable, organic, manganese oxide, iron oxide and residual) at three soil pH values. Uptake was higher at lower pH, corresponding to greater amounts of zinc being retained on exchange sites. However, much of the added zinc was found in the manganese oxide fraction especially at higher pH. Zinc mobility during the experiment was almost negligible. Subsequently the soils left at the end of this experiment were incubated for 6 months and then used for a further pot experiment, to gain insight into residual zinc fertilizer effects. This showed a reduction in exchangeable zinc and plant uptake, with increases in zinc associated with organic matter and iron oxides.

Heavy metal contamination in food is a worldwide concern. Man-made ponds are domestic sites in the production of Procambarus clarkii and Procambarus zonangulus, two edible species of crayfish. Ponds may be constructed in former sugar cane or rice fields. Crayfish farming is an ancillary seasonal business within the rice-growing season. The use of products to control insects, pests, and weeds in rice and sugar cane production, may cause an accumulation of heavy metals in the crayfish tail within pond structures. Arsenic, cadmium, copper, and zinc are heavy metals that are absorbed through the roots of and distributed through rice products. Metabolites associated with rice products are absorbed in the human body. Research suggests that metabolites associated with heavy metals cause disease in animals and humans.

In order to investigate the effect of foliar application of organic fertilizer and micronutrients on quantitative and qualitative characteristics of Niger plant, a field experiment was conducted in a complete randomized block design with three replications at Shahrekord University Research Farm during the years 2013-2014. Treatments included three levels of humic acid (1, 3, and 6 liters of humic acid per hectare), iron (4 parts per million, ppm), zinc (4 parts per million, ppm) and control (without humic acid iron, and zinc). In this experiment, traits of the number of heads per plant, seeds number per head, 1000 seeds' weight, grain yield, and also oil and protein content were evaluated. The findings showed that foliar application of humic acid, zinc and iron resulted in a significant increase in all analyzed traits. The most significant plant response was obtained with the use of 6 liters humic acid per hectare, and the second most significant plant response was seen with the sprayed zinc treatment which was probably due to limited absorption and deficiency of these elements in the tested soil.

The effects of poultry manure versus inorganic fertilizer use on copper, zinc and manganese concentrations and the sustainability of metal contents under raspberry cultivation was investigated on two aeolian soils in the Lower Fraser Valley, British Columbia. Total elemental analysis by a teflon bomb procedure using reverse aqua regia and hydrofluoric acid was done on soils sampled at three depths (0-15 cm, 15-30 cm and +40 cm) and results were compared to metal contents extracted by the Mehlich III method. High variability of some of the soil data was attributed to mixing of the loess capping with the underlying glacio-fluvial outwash material, differences in site conditions of the test fields, variations in sampling depth, and inadequate analytical reproducibility at the low concentrations found in some of the soils. For the variables tested, differences between sites most often occurred in the first 30 cm and never at the +40 cm depth. Higher contents in the 0-30 cm depth than in the lower depths indicated an enrichment of the surface layers either by anthropogenic inputs or by bioaccumulation. Poultry manure applications had a significant effect on organic matter content, total and available manganese, and total and available zinc in both soils studied. The comparison of the manured versus the inorganically fertilized site indicated that zinc was the metal most effected by the manure application. The other metals were not significantly increased by poultry manure amendments. The comparison of the site that had been under long-term raspberry cultivation against the site that had been only recently converted to raspberries from long-term pasture cover, showed that long-term raspberry cultivation reduced metal and organic matter contents in the 0-15 cm depth and increased these variables in the 15-30 cm depth. It was hypothesised that this was in direct response to differing biocycling patterns under different land uses. Total and available manganese and zinc were strongly interconnected and their correlation to the organic matter content appeared most interesting in terms of fluxes between the various soil components. inorganically fertilized site indicated that zinc was the metal most effected by the manure application. The other metals were not significantly increased by poultry manure amendments. The comparison of the site that had been under long-term raspberry cultivation against the site that had been only recently converted to raspberries from long-term pasture cover, showed that long-term raspberry cultivation reduced metal and organic matter contents in the 0-15 cm depth and increased these variables in the 15-30 cm depth. It was hypothesised that this was in direct response to differing biocycling patterns under different land uses. Total and available manganese and zinc were strongly interconnected and their correlation to the organic matter content appeared most interesting in terms of fluxes between the various soil components.
Land and Food Systems, Faculty of
Graduate

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The determination of the appropriate levels of fertilization with micronutrients is essential for the culture to express its full productive potential, since they participate in vital functions in the metabolism of plants, participating in compounds responsible for metabolic and / or phenological processes. This research aims to evaluate the response of sugarcane (Saccharum officinalis) to fertilization with micronutrients (boron and zinc) in low fertility soils, in order to establish their adequate nutritional content. The experimental design was randomized blocks, in a factorial scheme (3 x 4) considering the application of three doses of boric acid (17% B) to provide 0, 1.0 and 2.0 kg ha-1 of boron and four doses Of zinc sulfate (20% Zn) for the supply of 2.0; 4.0 and 6.0 kg.ha-1 of zinc. The experimental area consisted, therefore, of three blocks with twelve experimental units, totaling 36 plots. In order to verify the results, the nutritional status of the plant (foliar diagnosis), soil analysis, indicators of technological quality and sugarcane production were analyzed. Through the evaluation of the results of the micronutrient contents foliar and in the soil it is noticed that there was no direct relation between the leaf contents of the sugarcane culture and different treatments applied during the conduction of the experiment. The technological attributes (Fibra, Brix, Pol and ATR) were not significantly influenced by the fertilization with boron and zinc. In cane-plant the highest yields were reached by application of 2.0 kg ha-1 of zinc represented by treatment 2, and in treatment 10, with a respective increase of 6% and 10%.
A determinação dos teores adequados de adubação com micronutrientes é fundamental para que a cultura possa expressar todo seu potencial produtivo, já que participam de funções vitais no metabolismo das plantas, participando de compostos responsáveis por processos metabólicos e/ou fenológicos. Esta pesquisa tem como objetivo avaliar a resposta da cana-de-açúcar (Saccharum officinalis) à adubação com micronutrientes (boro e zinco) em solos de baixa fertilidade, buscando estabelecer seus teores nutricionais adequados. O delineamento experimental foi blocos ao acaso, em esquema fatorial (3 x 4) considerando a aplicação de três doses de ácido bórico (17% B) visando fornecer 0, 1,0 e 2,0 kg ha-1 de boro e quatro doses de sulfato de zinco (20% Zn) para o fornecimento de 2,0; 4,0 e 6,0 kg.ha-1 de zinco. A área experimental constava, portanto, de três blocos com doze unidades experimentais, totalizando 36 parcelas. Para a verificação dos resultados foi analisado o estado nutricional da planta (diagnose foliar), a análises de solo, os indicadores de qualidade tecnológica e de produção da cana-de-açúcar. Através da avaliação dos resultados dos teores de micronutriente foliares e no solo nota-se que não houve relação direta entre os teores foliares da cultura da cana-de-açúcar e diferentes tratamentos aplicados durante a condução do experimento. Os atributos tecnológicos (Fibra, Brix, Pol e ATR) não foram influenciados significativamente pela adubação com boro e zinco. Em cana-planta as maiores produtividades foram atingidas pela aplicação de 2,0 kg ha-1 de zinco representado pelo tratamento 2, e no tratamento 10, com aumento respectivo de 6% e 10%.

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A pesquisa foi instalada em uma área experimental (latitude 6º54’59,88”S, longitude 35º09’17,86”O e altitude de 121,00 m) da Fazenda Capim II, localizada no Município de Capim/PB, com objetivo de se avaliar a cultura da cana-de-açúcar (Saccharum spp), variedade SP 79 1011, submetida a dois fatores: lâminas de água de irrigação e níveis de adubação com zinco. O delineamento experimental consistiu em blocos casualizados (DBC), com três repetições em esquema fatorial 5 x 5 analisados conjuntamente. As lâminas de irrigação foram: sequeiro, 25% da ETc (256,64 mm), 50% da ETc (513,29 mm), 75% da ETc (769,93 mm) e 100% da ETc (1026,57 mm) com as respectivas precipitações efetivas 780,06, 713,31, 487,54, 243,71 e 194,51 mm. Os níveis de zinco foram 0, 1, 2, 3 e 4 kg ha-1. O equipamento de irrigação utilizado na pesquisa foi do tipo pivô central fixo. O turno de irrigação, definido em função da análise físico-hídrica do solo, foi de nove dias utilizando 100% da água do solo. A ETo foi definida através do tanque “classe A” e a ETc foi determinada em função da idade da planta e de seu respectivo Kc. Abateu-se, do cálculo da lâmina de irrigação, a precipitação efetiva dentro do turno de irrigação. Foram determinadas as funções de resposta, em termos de crescimento e desenvolvimento fisiológico, bem como em termos econômicos, definindo-se, para tanto, os níveis dos dois fatores que proporcionam os melhores resultados econômicos. Até os sete meses de idade, a queda média de 50% no perfilhamento ocorreu independentemente dos fatores estudados ocorrendo diferenças significativas ao final do ano de cultivo. A resposta fisiológica aos fatores estudados foi significativa em altura, índice de área foliar, fitomassa total, fitomassa das folhas e fitomassa dos colmos. Do ponto de vista da qualidade da matéria-prima, o rendimento mínimo em açúcares totais recuperáveis foi de 96,57 kg t-1 e o máximo foi de 153,55 kg t-1. A cultura respondeu a lâmina de água de irrigação, em termos de produtividade, de forma significativamente diferente, sendo a mínima de 28,33 t ha-1 e a máxima de 106,47 t ha-1. Em termos de eficiência no uso da água pela cultura, o valor mínimo foi de 3,63 kg m3 e o máximo de 8,71 kg m3. Do ponto de vista econômico, foi calculado um modelo de função de resposta P(L,Zn) = a +b*L+c*L²+d*Zn+e*Zn²+f*LZn para estimar, diante do efeito conjunto dos dois fatores, qual combinação (L, Zn) resultaria em maiores produtividades (Lm, Znm) e maiores lucros brutos (L*,Zn*). De acordo com a tendência do modelo, a combinação que maximizou a produtividade em 181,26 t ha-1 foi (1.947,82 mm de lâmina total com 3,94 kg ha-1 de zinco) propiciando um lucro bruto de R$ 16,57 t-1. Ainda segundo o modelo, a combinação que maximiza o lucro bruto em R$ 21,06 t-1 é 1.628,06 mm com 1,80 kg ha-1 para uma produtividade de 168,59 t ha-1. Entretanto, a adoção da lâmina que maximiza o lucro bruto implica um volume de água maior que aquele aplicado à cultura, quando irrigada com 100% da ETc (1.221,08 mm). A cana de sequeiro conferiu ao produtor um prejuízo de R$ -1,43 t-1, independentemente da combinação. Quando foram aplicados 25% da ETc, o prejuízo foi maior, da ordem de R$ -9,64 t-1 em detrimento da combinação estudada. A combinação L50, Zn3 proporcionou um LB de R$ 5,86 t-1; para L75, Zn3 o LB foi de R$ 7,17 t-1. A combinação que conferiu o maior LB (R$ 19,60 t-1), com uma produtividade de 101,05 t ha-1, foi 1.221,08 mm de lâmina total e 3,0 kg de Zn ha-1 (L100, Zn3).
The research was conducted in an experimental area (coordinates 6º54’59,88”S; 35º09’17,86”W and 121,00m of altitude) of the Capim II Farm in the municipality of Capim/PB with the objective to evaluate the response of sugarcane crop (Saccharum spp.) variety SP 79 1011, submitted to different depths of irrigation water and fertilization levels with zinc to obtain their response functions for the growth and physiologic development, as well in economical terms. . The experimental design consisted of randomizered blocks, with three repetitions in 5 x 5 factorial scheme analyzed jointly. The irrigation depths were cultivation without irrigation, 25% of ETc (256,64 mm), 50% of ETc (513,29 mm), 75% of ETc (769,93 mm) e 100% of ETc (1.026,57 mm) with the respective effective precipitations of 780,06, 713,31, 487,54, 243,71 and 194,51 mm and the levels of zinc were 0, 1, 2, 3 and 4 kg ha-1. The irrigation equipment used in this research was a fixed central pivot . The irrigation frequency was defined in function of physical properties of soil and frequency of irrigation was of nine days using 100% of soil moisture. ETo was defined through the tank Class “A” and ETc was calculated in function of the plant age and respective Kc. The effective precipitation during the interval of irrigation was substracted from the calculation of depth of irrigation to be applied.. Until the seven months of age the mean reduction of 50% in number of plants occurred independently of the factors studied presenting significant differences at the end after one year of cultivation. The physiologic response to the studied factors, at the end of the year was significant, in plant height, leaf area index, total dry mass, dry mass of leaves and dry mass of stems. The point of view quality of the raw material. the minimum yield in recoverable total sugars (RTS) was of 96,57 kg t-1 and the maximum was of 153,55 kg t-1. The crop responded in terms of production significantly where the minimum was of 28,33 t ha-1 and the maximum was of 101,05 t ha-1. In terms of EUW (efficiency use water) for the crop, the minimum value was of 3,63 kg m-3 and the maximum was of 8,71 kg m-3. From the economical point of view, a model response function was calculations (P(L,Zn) = a+b*L+c*L²+d*Zn+e*Zn²+f*LZn) to estimate the combined effect of two factors, with combination (L, Zn) it would result in larger productivities (Lm, Znm) and larger gross profit (L*,Zn*). It was Verified that in agreement with the tendency of the model, the combination that had maximized the productivity of 181,26 t ha-1 , was 1.947,82 mm with 3,94 kg ha-1 of zinc, resulting in a gross profit (GP) of R$ 16,57 t-1. However, the same model estimated that the combination which maximizes the GP of R$ 21,06 t-1, consisted of 1.628,06 mm water with 1,80 kg ha-1 of zinc, for a productivity of 168,59 t ha-1. However, the adoption of irrigation depth that maximizes GP implicates in a larger volume of water compared to that applied to the crop when irrigated with 100% of the ETc (1.221,08 mm). the sugar cane without irrigation (control) resulted in a loss of R$ -1,43t-1 to producer, independently of the combination. When irrigation was applied equivalent to 25% of the ETc the loss was more, of the order of R$ 9,64 t-1 independently of studied combination. The combination (L50, Zn3) provided a GP of R$ 5,86 t-1. For L75, Zn3 GP was of R$ 7,17 t-1. The combination that provided highest GP (R$ 19,60 t-1) with a productivity of 101,05 t ha-1 was 1.221,08 mm with 3,0 kg ha-1 (L100, Zn3).

Sewage sludge is the product from wastewater treatment that mostly is considered as a waste material. However, it contains several nutrients, especially phosphorus, potassium and nitrogen which are excellent fertilizers. The downside is the harmful content it also carries with pathogens, heavy metals and a variety of organic pollutants that in many cases have unknown effects on the ecosystem. A possible solution to this problem could be to pyrolyse the sewage sludge and by that decrease the levels of heavy metals and also render both pathogens and organic pollutants harmless. In this thesis project pyrolysis of dried sewage sludge has been evaluated at temperatures 650 750, 850 and 950 °C with addition of chlorine in the form of PVC and straw. An energy balance for pyrolysis and drying of dewatered sewage sludge has also been suggested. The results of the pyrolysis evaluation indicate that cadmium concentration can be reduced significantly with increasing temperature in the product char. But also other heavy metals like lead and zinc are affected at the higher temperatures evaluated. Mercury is completely removed from the char residue. The more latent volatile metals copper, chromium and nickel cannot be reduced to lower concentrations at these temperatures. They are instead enriched under these conditions. Chlorine addition to the sludge enhances the evaporation of all heavy metals but copper, nickel and chromium. The energy balance over the system indicates that the drying process requires more energy than is released from the sludge into the pyrolysis gases. The energy carried by the pyrolysis gases is however larger than what is required to drive the pyrolysis process.

Philosophiae Doctor - PhD
Cape Town includes two vegetable farming areas within the city limits, the Joostenbergvlakte/Kraaifontein area and the Philippi area. Both areas supply produce to local markets and further afield. Sporadically, high levels of cadmium, copper, lead and zinc have been found to occur in some of the soils, irrigation water resources and crops. To find the sources of specifically Cd, Pb and Zn to these agricultural systems, extensive analysis of several heavy metals in inputs such as fertilizers, agrochemicals and supplementary water resources to these farming areas was undertaken. Heavy metal concentrations in soils, irrigation water resources and crops were also determined. Two mitigation techniques that could be used to remediate Cd, Pb and Zn contamination were investigated. The first mitigation method included immobilization of heavy metals as phosphate complexes by using a triple super phosphate fertilizer, while the second method involved mobilisation and thus leaching of heavy metals away from plant roots using EDTA. These mitigation methods were tested in a pot experiment using cabbage as the experimental crop and soil from these areas as growth medium. A survey of common farming practices in these two areas and farmers willingness to use remediation methods was conducted.
South Africa

Crop-available zinc is affected by P-Zn interactions in soils. Orthophosphate (OP) additions may decrease or have no effect, while pyrophosphate (PP) may increase or have no effect on Zn solubility. Mechanisms involved in the interactions are not well understood and need to be quantified on agricultural soils subjected to P fertilization.
Top and sub-samples from three Quebec agricultural soils were equilibrated with OP or PP solutions, then with Zn solutions, and finally with solutions containing neither P nor Zn. The first equilibration evaluated P sorption effects on soil cation exchange capacity (CEC), the second equilibration evaluated Zn sorption (Zn$ sb{ rm s}$) after P sorption, and the third Zn desorption (Zn$ sb{ rm D}$) as related to added P. Subsequently, Zn fractions were extracted sequentially with KNO$ sb3$ (Zn$ sb{ rm KNO3}$), NaOH (Zn$ sb{ rm NaOH}$) solutions and concentrated HNO$ sb3$ + H$ sb2$O$ sb2$ (Zn$ sb{ rm HNO3}$). Autoclaved soils were used for OP and PP comparisons, and non-autoclaved soils were used for OP determinations.
Autoclaving reduced dithionite-citrate extractable Fe and Al materials. In both autoclaved and non-autoclaved soils, one mmole sorbed P as PP or OP resulted in increases in CEC from 0.52-1.24 mmole (+). Comparison between OP and PP in the autoclaved soils indicated that the increased CEC per mmole sorbed was greater with sorbed OP than with PP, while at the same rate of P addition, the absolute increased CEC was more with sorbed PP than with OP due to greater P sorption as PP compared to OP. Both sorbed OP or PP in autoclaved soils and sorbed OP in non-autoclaved soils increased specific Zn sorption in association with oxide materials. The effect was more significant with PP than with OP, as indicated by the observations: (1) P sorption increased Zn sorption but reduced Zn desorption, (2) P sorption reduced KNO$ sb3$- but increased NaOH- and HNO$ sb3$-extractable Zn, and (3) P sorption increased the difference between Zn sorbed and Zn extracted with KNO$ sb3$. These effects were more significant in coarser than finer textured soils. Results suggested that Zn fertilizers should be separated from P fertilizers to avoid enhanced Zn sorption and reduced Zn desorption.

Master of Science
Department of Agronomy
Dorivar Ruiz Diaz
The limitation of an essential nutrient for plant growth can affect crop yield. Research has been focused mainly on macronutrients, nevertheless micronutrients are equally important. This thesis is divided into three studies, which had the purpose of assessing frequent questions that producers have about micronutrient fertilizers and their effect on several crops in Kansas. The objective of the first study was to summarize and analyze results from studies since 1962 until 2015 to verify responses to zinc (Zn) and sulfur (S) fertilization in corn (Zea mays), sorghum (Sorghum bicolor (L.) Moench), wheat (Triticum aestivum) and soybean (Glycine max (L.) Merr). The treatments evaluated consisted of fertilizer Zn or S application versus their respective unfertilized treatments. Zinc fertilization significantly increased corn yield; no significant response was found for sorghum, wheat and soybean. Sulfur fertilization did not increase yields on corn and wheat. The objectives of the second study were: (i) to evaluate soybean response to S and micronutrients boron (B), copper (Cu), manganese (Mn), and Zn fertilizer application and to assess soil test and soybean seed and tissue nutrient concentration with fertilization. Treatments consisted of an unfertilized control, micronutrient fertilizer as individual nutrient for B, Cu, Mn, S and Zn applied broadcast pre-plant, in addition to a blend of these nutrients using two different placements (broadcast and band). Secondary and micronutrient fertilization showed no significant effect on soybean yield at any of the ten locations. Zinc fertilization showed significant effects on soybean tissue and seed Zn concentration. The objective of the third study was to evaluate soybean tissue nutrient response to micronutrient fertilizers in field strips with high variability in soil properties in the area evaluated. The study consisted of two strips (with and without fertilizer) and replicated three times. The treatment with fertilizer included a blend of Cu, Mn and Zn at a rate of 11.2 kg ha⁻¹ and B at a rate of 2.8 kg ha⁻¹. Initial soil tests B, Cu, Mn and Zn were not good indicators of soybean tissue response. Within-field variability of soybean Zn and B tissue content were affected by soil pH and organic matter; and these factors may be used to help explain field variability in plant availability. The micronutrient blend treatment showed higher tissue Zn and B values compared to the control. When pH ranged from 5.5 to 7.6, B in soybean tissue was higher on the control than the micronutrient blend treatment. Copper concentration in soybean tissue did not show significant difference between treatments at any location, regardless of pH and organic matter levels.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Brazil is one of the biggest producers of cellulose, paper and vegetal coal of the world, and the activities related to planted forests contribute to 3.5 % of the Gross Domestic Product (PIB) of the country. The eucalypt is the forest essence that stands out, with a planted area of 3.75 millions of hectares, and the state of Minas Gerais has about 28 % of this planted area. In Brazil, with the intensification of the clonal sivilculture, the management of genetic materials that are more productive and more nutritional demanding has increased the appearance of symptoms of micronutrients deficiency, mainly of B, and, more recently, of Cu and Zn, especially in areas of Cerrado. The aim of this study was to evaluate three methods of determining Cu and Zn availability (Mehlich-1, Mehlich-3 and DTPA pH 7.3) to eucalypts seedlings cultivated under greenhouse conditions, in samples of six soils from Minas Gerais state (one sample from João Pinheiro, two from Vazante, one from Três Marias and two from Curvelo) and the influence of the properties of the soil in the efficiency of these extractors. Were realized two experiments, one for each micronutrient. The treatments were arranged in a randomized block design, with four replications, in a factorial scheme of 6 x 5, corresponding to six soils and five doses of micronutrient. The doses were 0, 2, 4, 8 and 16 mg dm-3 of Cu and 0, 2.5, 5, 10 and 20 mg dm-3 of Zn, in the form of Cu and Zn chloride, respectively. After 70 days of growth, the plants were cut into two distinct portions, one being apical (apical third of all the branches of the plant) and the other being basal (the rest of the plant cut down near the ground level). The criticals levels of Cu and Zn in soils from Cerrado, to the growth of eucalypts seedlings, are equal or inferiors to 0.12 and 0.23 mg dm-3 by the Mehlich-1 and are equal or inferiors to 0.09 and 0.05 mg dm-3 by the DTPA, respectively. The concentrations of Cu and Zn in the soil and in the plant, as well as the respectives contents, increase with the elevation of the additional doses of these nutrients. The concentrations and the contents of Cu and Zn in the plant show close relation to the contents extracted by the three extractors. The concentrations of Cu and Zn extracted by Mehlich-1, Mehlich-3 and by DTPA were strongly correlated. The content of organic matter and the P- remanescent are the characteristics of the soils which most negatively influence in the recovering rates of Cu and Zn by the extractors Mehlich-1 and Mehlich-3, while for the DTPA, the recovering rates are more negatively influenced by the pH. The Mehlich-1 is the most recommended extractor to evaluate Cu and Zn availability to eucalypts seedlings. First because the method is easy to handle when compared to other methods, and second because it is a method which has already been used by the great majority of the labs in the country.
O Brasil é um dos maiores produtores de celulose, papel e carvão vegetal do mundo, e as atividades relacionadas às florestas plantadas contribuem com 3,5 % do Produto Interno Bruto (PIB) do país. O eucalipto é a essência florestal que se destaca, com uma área plantada de 3,75 milhões de hectares e o Estado de Minas Gerais possui em torno de 28 % dessa área plantada. No Brasil, com a intensificação da silvicultura clonal e o plantio de materiais genéticos mais produtivos e exigentes nutricionalmente têm aumentado o aparecimento de sintomas de deficiência de micronutrientes, principalmente de B, e, mais recentemente, de Cu e Zn, especialmente em áreas de Cerrado. Este trabalho teve por objetivo avaliar três métodos de determinação da disponibilidade de Cu e de Zn (Mehlich-1, Mehlich-3 e DTPA pH 7,3) para mudas de eucalipto cultivadas em casa de vegetação, em amostras de seis solos do Estado de Minas Gerais (um de João Pinheiro, dois de Vazante, um de Três Marias e dois de Curvelo) e a influência de propriedades do solo na eficiência desses extratores. Foram realizados dois experimentos, um para cada micronutriente. Os tratamentos foram arranjados no esquema fatorial 6 x 5, correspondendo a seis solos e cinco doses do micronutriente, com quatro repetições, em blocos ao acaso. As doses foram de 0, 2, 4, 8 e 16 mg dm-3 de Cu e de 0, 2,5, 5, 10 e 20 mg dm-3 de Zn, na forma de cloreto de Cu e Zn, respectivamente. Após 70 dias de crescimento, as plantas foram cortadas em duas porções distintas, sendo uma apical (terço apical de todos os ramos da planta) e a outra basal (restante da planta cortada rente ao solo). Os níveis críticos de Cu e de Zn em solos de Cerrado, para o crescimento de mudas de eucalipto, são iguais ou inferiores a 0,12 e 0,23 mg dm-3 pelo Mehlich-1 e iguais ou inferiores a 0,09 e 0,05 mg dm-3 pelo DTPA, respectivamente. Os teores de Cu e de Zn no solo e na planta, bem como os respectivos conteúdos, aumentam com a elevação das doses adicionadas desses nutrientes. Os teores e conteúdos de Cu e de Zn na planta mostram estreita relação com os teores extraídos pelos três extratores. Os teores de Cu e de Zn extraídos pelo Mehlich-1, Mehlich-3 e DTPA são altamente correlacionados entre si. O teor de matéria orgânica e o P-remanescente são características dos solos que mais influenciam negativamente nas taxas de recuperação de Cu e de Zn pelos extratores Mehlich-1 e Mehlich-3, enquanto que para o DTPA, as taxas de recuperação são mais influenciadas pelo pH. O Mehlich-1 é o extrator mais recomendado para avaliar a disponibilidade de Cu e de Zn para mudas de eucalipto, pela facilidade operacional deste método frente aos outros e por este já ser usado na grande maioria dos laboratórios do país.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
As deficiências de boro (B) e zinco (Zn) comumente ocorrem em solos de Cerrado. Por isso, para obtenção de maiores produtividades de milho é necessário entender melhor a interação desses elementos, como se existe efeito sinérgico ou antagônico na absorção destes micronutrientes do solo, tal como o modo de aplicação mais vantajoso (via solo ou foliar) e o efeito residual destas adubações. Sendo assim, objetivou-se avaliar o efeito de doses de B aplicadas via solo e via foliar, ambos com ou sem adubação com Zn no solo sobre o estado nutricional, componentes de produção e produtividade do milho primavera/verão e o residual destas adubações via solo no milho outonal, em solo de Cerrado com baixo teor de boro. O experimento foi desenvolvido em um Latossolo Vermelho distrófico em sistema plantio direto. O delineamento experimental dos dois experimentos foi em blocos ao acaso com quatro repetições, dispostos em esquema fatorial 2 x 5, sendo: com ou sem adubação via solo com 2 kg ha-1 de Zn, na forma de sulfato de zinco aplicados na ocasião da semeadura do milho primavera/verão; e 5 doses de B (0, 1, 2, 3 e 4 kg ha-1 na semeadura do milho primavera/verão (experimento 1) ou 0, 170, 340, 510 e 680 g ha-1, que correspondem respectivamente, 0; 0,25; 0,50; 0,75 e 1% de ácido bórico na calda de pulverização aplicada via foliar na fase de pré-pendoamento do milho (experimento II). Após a colheita do milho primavera/verão, avaliou-se o residual destes tratamentos aplicados via solo no cultivo do milho outonal e foram aplicados novamente as doses de B via foliar no milho outonal, conforme mencionado anteriormente. A aplicação de Zn no solo propicia maiores teores de Zn no solo e B foliar no milho primavera/verão, independentemente da dose de B aplicada via foliar. Doses crescentes de B via foliar aumentam o teor de Zn nos grãos do milho primavera/verão, apenas quando não se adubou com Zn, e o teor de B foliar do milho outonal. A adubação com zinco no solo e o incremento das doses de boro tanto via solo como foliar não influenciam os componentes de produção e produtividade de grãos de milho primavera/verão e outonal, em solo argiloso de Cerrado com baixo teor de B.
Boron deficiencies (B) and zinc (Zn) commonly occur in Cerrado soils. Thus, for obtaining higher maize yields is necessary to better understand the interaction of these elements, as if exists synergistic or antagonistic effect on the absorption of these micronutrients in soil, such as the most advantageous mode of application (by soil or foliar) and the effect of these residual fertilizations. Therefore, it was aimed to evaluate the effect of B rates applied to soil (experiment I) and foliar application (experiment II), both with or without Zn fertilization in the soil on nutritional status, yield components and grains yield of spring/summer maize and the residual of these fertilizations in the soil in the autumnal maize, in Cerrado soil with low boron content. The experiment was conducted in an Oxisol under notillage system. The experimental design of the two experiments was a randomized block with four replications, in a factorial 2 x 5, being: with or without soil fertilization with 2 kg ha-1 Zn, in the form of zinc sulfate applied on the occasion of sowing of spring/summer maize; and 5 doses of B (0, 1, 2, 3 and 4 kg ha-1 applied at sowing of spring/summer maize (experiment 1) or 0, 170, 340, 510 and 680 g ha-1 , which correspond respectively, 0, 0.25, 0.50, 0.75 and 1% of boric acid in the spray solution applied by foliar in pre-tasseling of maize (experiment II)). After harvesting of the spring/summer maize was evaluated the residual of these treatments applied to the soil in the cultivation of autumnal maize and were applied again the B rates as foliar application in autumnal maize, as mentioned earlier. The application of Zn in soil propitiates higher contents of Zn in soil and B foliar in spring/summer maize, regardless of B rate applied as foliar application. Increasing B rates, as foliar application increase the Zn content in the grains of spring/summer maize, only without Zn fertilization, and the B leaf content of autumnal corn. The zinc fertilization in the soil and increasing boron rates in the soil and by foliar application not influence the production components and grains yield of spring/summer and autumnal maize, in clay soil of the Cerrado with low B content

Orientador: Marcelo Carvalho Minhoto Teixeira Filho
Resumo: As deficiências de boro (B) e zinco (Zn) comumente ocorrem em solos de Cerrado. Por isso, para obtenção de maiores produtividades de milho é necessário entender melhor a interação desses elementos, como se existe efeito sinérgico ou antagônico na absorção destes micronutrientes do solo, tal como o modo de aplicação mais vantajoso (via solo ou foliar) e o efeito residual destas adubações. Sendo assim, objetivou-se avaliar o efeito de doses de B aplicadas via solo e via foliar, ambos com ou sem adubação com Zn no solo sobre o estado nutricional, componentes de produção e produtividade do milho primavera/verão e o residual destas adubações via solo no milho outonal, em solo de Cerrado com baixo teor de boro. O experimento foi desenvolvido em um Latossolo Vermelho distrófico em sistema plantio direto. O delineamento experimental dos dois experimentos foi em blocos ao acaso com quatro repetições, dispostos em esquema fatorial 2 x 5, sendo: com ou sem adubação via solo com 2 kg ha-1 de Zn, na forma de sulfato de zinco aplicados na ocasião da semeadura do milho primavera/verão; e 5 doses de B (0, 1, 2, 3 e 4 kg ha-1 na semeadura do milho primavera/verão (experimento 1) ou 0, 170, 340, 510 e 680 g ha-1, que correspondem respectivamente, 0; 0,25; 0,50; 0,75 e 1% de ácido bórico na calda de pulverização aplicada via foliar na fase de pré-pendoamento do milho (experimento II). Após a colheita do milho primavera/verão, avaliou-se o residual destes tratamentos aplicados via solo no cultiv... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Boron deficiencies (B) and zinc (Zn) commonly occur in Cerrado soils. Thus, for obtaining higher maize yields is necessary to better understand the interaction of these elements, as if exists synergistic or antagonistic effect on the absorption of these micronutrients in soil, such as the most advantageous mode of application (by soil or foliar) and the effect of these residual fertilizations. Therefore, it was aimed to evaluate the effect of B rates applied to soil (experiment I) and foliar application (experiment II), both with or without Zn fertilization in the soil on nutritional status, yield components and grains yield of spring/summer maize and the residual of these fertilizations in the soil in the autumnal maize, in Cerrado soil with low boron content. The experiment was conducted in an Oxisol under notillage system. The experimental design of the two experiments was a randomized block with four replications, in a factorial 2 x 5, being: with or without soil fertilization with 2 kg ha-1 Zn, in the form of zinc sulfate applied on the occasion of sowing of spring/summer maize; and 5 doses of B (0, 1, 2, 3 and 4 kg ha-1 applied at sowing of spring/summer maize (experiment 1) or 0, 170, 340, 510 and 680 g ha-1 , which correspond respectively, 0, 0.25, 0.50, 0.75 and 1% of boric acid in the spray solution applied by foliar in pre-tasseling of maize (experiment II)). After harvesting of the spring/summer maize was evaluated the residual of these treatments applied to the s... (Complete abstract click electronic access below)
Mestre

碩士
國立宜蘭大學
環境工程學系碩士班
101
Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, significant soil fertility degradation and high operation costs are the major disadvantages of soil washing. soil Washing with a dissolved organic matter (DOM) solution has been identified as a method that can moderate the loss of nutrients in the soil and enhance metal removal. Liquid fertilizer of food waste composting can be used to prepare a dissolved organic matter (DOM) solution. This study employed DOM solutions to remediate Zn-contaminated soil (with concentrations up to 992 and 757 mg kg-1 respectively in topsoil and subsoil) and determined the factors affecting the removal of Zn, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with a DOM solution 1,500 mg L-1 twice (at pH 2.0、25°C) , 45% and 23% of Zn in the topsoil and subsoil were removed , respectively. With this treatment, the organic matter content was increased from 5.0% to 7.5%; available ammonium (N-NH4+) content ranged from 47% to 140%; available phosphorus content ranged from 63% to 65% and exchangeable potassium content ranged from 153% to 499%. Fourier Transform infrared spectrometer scope measurement that liquid fertilizer washing solution contains carboxyl group (COOH), which adsorbed positively charged heavy metal ions, as well as functional groups such as COOH and COO-, which occurred complex reaction with heavy metal ions. This verified the fact that the organic matter in the liquid fertilizer solution indeed had the function of extracting heavy metal ions in soil. The results of pot and germination experiments showed that livability of the planted seedlings approached zero when the soil used has been cleansed. In the germination experiment, germination rate was high but root system of the sprouts so rotted as to die when they contacted the soil, which was similar to the result of the pot experiment. Subsequently, soil column leaching experiment which simulated monsoon rains (pH 4.6、568mm) followed. While potassium, sodium, calcium, and magnesium in the soil was washed away, the toxicity deriving from overly low pH and the inhibition of absorption of nitrogen, magnesium, and calcium from excessive potash fertilizer in the soil reduced. As a result, this study successfully grew planted seedling and harvested the crop in the pot experiment where column-leached soil. Therefore, it is suggested that crops should not be planted in soil instantly after the soil being treated by cleansing restoration.

Cape Town includes two vegetable farming areas within the city limits, the Joostenbergvlakte/Kraaifontein area and the Philippi area. Both areas supply produce to local markets and further afield. Sporadically, high levels of cadmium, copper, lead and zinc have been found to occur in some of the soils, irrigation water resources and crops. To find the sources of specifically Cd, Pb and Zn to these agricultural systems, extensive analysis of several heavy metals in inputs such as fertilizers, agrochemicals and supplementary water resources to these farming areas was undertaken. Heavy metal concentrations in soils, irrigation water resources and crops were also determined. Two mitigation techniques that could be used to remediate Cd, Pb and Zn contamination were investigated. The first mitigation method included immobilization of heavy metals as phosphate complexes by using a triple super phosphate fertilizer, while the second method involved mobilisation and thus leaching of heavy metals away from plant roots using EDTA. These mitigation methods were tested in a pot experiment using cabbage as the experimental crop and soil from these areas as growth medium. A survey of common farming practices in these two areas and farmers willingness to use remediation methods was conducted.

Thesis (MSc. Agriculture (Agronomy)) --University of Limpopo, 2015
Agronomic field trial was planted at two sites, Ukulima and Syferkuil, in Limpopo Province, to determine the response of cowpea to variable rates and methods of zinc application under supplementary irrigation and rainfed conditions, respectively. The experiment was laid out in a split plot arrangement and fitted into a randomized complete block design (RCBD). Treatments consisted of two factors namely zinc rates (0, 5, 10, 15, 20 and 25 kg ha-1) and methods of application (soil and foliar) with white cowpea variety (IT00K-1217) seeds sown. The zinc fertilizer was applied as ZnSO4 (38.5% Zn) while basal phosphorus (30 kg P ha-1) was applied in the form of single super phosphate (10.5% P) so as to eliminate P constraints. Soil application of the zinc fertilizer was band placed near the row of cowpea plant while foliar application was done 3-5 weeks after plant emergence. Growth parameters measured included plant height, number of primary branches, canopy cover, number of trifoliate leaves, days to 50% flowering and pod formation, and fresh biomass as well as yield component attributes. Twenty young cowpea leaves and immature green pods were each harvested at approximately 75% physiological maturity. Crude protein, total nitrogen, potassium, phosphorus, zinc, and iron content and uptake were assessed in the different plant parts. Growth, yield and nutrients data collected were subjected to analysis of variance. Treatments means were separated using Tukey’s test at probability level of 5%, while the response variables were modelled using quadratic polynomial equation. Results obtained revealed that total above ground biomass yield of 6219 kg ha-1 and fresh pod weight of 142.3 g were obtained when zinc was soil applied under rainfed condition compared to 6019 kg ha-1 and 138.0 g for total above ground biomass yield and fresh pod weight, respectively when foliar applied. Soil application gave a total above ground biomass yield of 6298 kg ha-1 and pod fresh weight of 150.9 g while foliar application gave total above ground biomass yield and pod fresh weight of 4791 kg ha-1 and 124.0 g, respectively at Ukulima. Soil application also gave a significantly higher grain yield (2251 kg ha-1) than the foliar application (1503 kg ha-1) at Ukulima. A higher but inconsequential effect on grain yield was obtained with soil over foliar application at Syferkuil. Application of zinc fertilizer at a rate beyond 5 kg ha-1 resulted in a grain yield reduction of up to 22.2% and 6.6% respectively at vi Ukulima and Syferkuil. Thus, this rate appeared optimum for both grain and fodder production when soil applied at both sites. Based on the quadratic model, total biomass (4897 kg ha-1) and grain (1602 kg ha-1) yields were optimized at an estimated zinc rate of 54.7 and 33.4 kg ha-1, respectively under supplementary irrigation, while total biomass (5913 kg ha-1) and grain (2696 kg ha-1) yields were obtained at an estimated optimum zinc rate of 20.1 and 26.8 kg ha-1, respectively under rainfed condition. A scorching effect of cowpea leaves was observed following foliar application of zinc fertiliser at 25 kg ha-1 that resulted in a decreased growth and yield at Ukulima. Foliar application resulted in improve cowpea leaf zinc concentration (43.9 mg kg-1) compared to soil application (23.2 mg kg-1) at Syferkuil. It also resulted in increased crude protein, total N, P, Fe and Zn uptake compared to soil application at Ukulima. Both soil and foliar zinc application gave 28.5% zinc concentration in the fresh immature pods samples collected. Findings from this study reveal that foliar zinc sulphate application resulted in higher grain and biomass yields as well as zinc concentration in the various cowpea plant parts. Based on the quadratic model used in this study, the optimum zinc rate required to guarantee high cowpea yield and zinc-rich grain and leaf content at both trial sites is highly variable; and thus requires further study for validation. Keywords: Cowpea production, grain yield, dryland farming, leafy vegetables, foliar fertilizer, improved nutrition, zinc deficiency.

Thesis (M. Sc. Agriculture (Soil Science)) -- University of Limpopo, 2019
One of the major constraints to crop productivity in South Africa is crop nutrient deficiency especially micronutrients. Laboratory, glasshouse and field studies were carried out during the 2016/2017 growing season to assess the effects of micronutrient (Zn, B and Mo) seed priming on maize growth and yield in micronutrient deficient soils of the Limpopo province. The laboratory experiment was carried out in a completely randomized design (CRD) laid out in a 3 x 5 x 3 factorial treatment structure with three replications. The assessments of the micronutrients were made at 0%, 0.01%, 0.05%, 0.1%, and 0.5% concentrations. The seeds were primed in the solutions for 24 h, 12 h and 8 h. The glasshouse experiment was carried out in a completely randomized design (CRD) laid out in a 3 x 4 x 2 factorial treatment structure with three replications. In the field, a single factor experiment in a randomised complete block design (RCBD) with three replications and a control was used, with micronutrient concentrations as levels. The laboratory study investigated the effect of seed priming with Zn, Mo and B on germination (germination percentage (GP), germination rate (GR), the coefficient velocity of germination (CVG), days to germination (DG) and mean germination time (MGT)). The interaction between seed priming duration and concentration levels of seeds primed with B had significant effect (P < 0.05) on germination. The interaction between seed priming duration and concentration levels of seeds primed with Zn had significant effect (P < 0.05) on germination. The interaction between seed priming duration and Mo concentration levels on CVG, MGT and DE had no significant different (P > 0.05). Meanwhile, the effect on GP and GR had significant (P < 0.05) effects. Seed priming with the micronutrients and water resulted in improved GP, MGT and CVG for seeds primed with 0.01, 0.05 and 0.1% for 24 h in laboratory conditions. The glasshouse study was established to investigate the effect micronutrient seed priming on seedling establishment and growth. The effects of the interaction between Mo concentration levels and duration, Zn concentration levels and duration, B concentration levels and duration and control had no significant (P > 0.05) effect on days to emergence (DE), seedling wet weight (WW), dry weight (DW), chlorophyll, stem diameter, plant height and final root length (RL). Furthermore, seeds primed at lower concentration levels (0.05, 0.01 and 0.1%) with longer duration priming period (24 hours) for Mo, Zn and B recorded higher results on the seedling emergence and establishment parameters. The field investigation showed that priming with micronutrients solutions had no significant difference on the final values of dry biomass, prolificacy, harvest index and grain yield. Seeds primed with 0.05, 0.01 and 0.1 % concentration levels with longer duration priming period (24 hours) showed improvement in germination and seedling establishment. The grain yield and grain nutrient content was not improved, meanwhile emergence was improved. This confirms that not only micronutrients limit yields maximization and crop nutrients content retention solely, rather that the complexity of the agricultural crop production environment should be well understood by all farmers to archive their goals. Keywords: Boron, Maize, Micronutrients, Molybdenum, Nutrient seed priming, Zinc.
National Research Foundation (NRF)