Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-18T12:17:53Z No. of bitstreams: 1 FRANCISCO JARDEL RODRIGUES DA PAIXÃO - TESE PPGEA 2010..pdf: 23499841 bytes, checksum: e5e0e832bb68cb2b2be44e69ac4304b6 (MD5) / Made available in DSpace on 2018-06-18T12:17:53Z (GMT). No. of bitstreams: 1 FRANCISCO JARDEL RODRIGUES DA PAIXÃO - TESE PPGEA 2010..pdf: 23499841 bytes, checksum: e5e0e832bb68cb2b2be44e69ac4304b6 (MD5) Previous issue date: 2010-07 / Objetivando desenvolver tecnologias de cultivo agrícola adaptadas à região semiárida, capazes de fornecer uma produtividade economicamente viável a nível de pequeno e médio produtor e uma melhoria na qualidade do produto vendido revertendo-se em capital, propõe-se nesta pesquisa obter conhecimento sobre os efeitos da torta de mamona como matéria orgânica fornecedora de diferentes níveis de nitrogénio e de diferentes níveis de irrigação na cultura da mamoneira precoce, cultivar BRS Energia, nas condições do semiárido brasileiro. O experimento seguiu um delineamento em blocos casualizados distribuídos em parcelas subdividas em faixas, sendo os fatores: 4 níveis de nitrogénio via torta de mamona (TM) (TM1 = 0, TM 2 = 90, TM 3 = 180 e TM 4 = 270 kg N ha"1) e 4 níveis de irrigação baseados no conceito de água disponível no solo monitorado duas vezes ao dia com o uso do TDR (água disponível - AD) (ADI = 20%, AD2 = 40%, AD3 = 60% e AD4 = 80%), com 4 repetições, totalizando 64 parcelas. O espaçamento de plantio foi na configuração de 1,4 x 0,4 x 0,36 m, em fileira dupla continua para obter um melhor aproveitamento da área em função do sistema de irrigação por gotejamento. A adubação com P e K seguiu a recomendação para o Estado do Ceara. Os componentes de crescimento e de produção da mamoneira, cultivar BRS energia aumentaram com o incremento dos níveis de água disponível no solo e de adubação orgânica via torta de mamona; entretanto, o efeito positivo da adubação orgânica ocorreu somente até o nível de adubação de 180 kg N ha"1 ' inclusive quando associado ao nível de disponibilidade de água no solo de 80%. O nível de adubação orgânica de 180 kg ha"1, associado a 80% de água disponível no solo promoveu um incremento de 58,84 % na produtividade da mamoneira, em relação ao tratamento com este mesmo nível de disponibilidade de água no solo, mais sem adubação orgânica. O nível de água disponível no solo de 80% associado a uma adubação orgânica de 180 kg ha"1, promoveu um incremento de 22,11 % na produtividade da mamoneira, em relação ao tratamento com este mesmo nível de adubação orgânica e com o nível de água disponível no solo de 20%. / Aiming to develop technologies of agricultural cultivation adapted to the semiarid área, capable to supply a productivity economically viable to levei of small and médium producer and to favor an improvement in the sold product quality, being reverted in capital, this research had the purpose to obtain knowledge on the effects of the castor oil plant pie as organic matter supplier of different leveis of nitrogen and of different irrigation leveis in the culture of the precocious castor oil plant, cultivar BRS Energy, in the conditions of the Brazilian semiarid. The experiment followed a randomized blocks design distributed in split plots, being the factors: 4 leveis of nitrogen through castor oil plant pie (TM) (TM1 = 0, TM 2 = 90, TM 3 = 180 and TM 4 = 270 kg N ha"1) and 4 irrigation leveis based on the concept of available water in the soil monitored twice a day with the use of TDR (available water - AW) (AW1 = 20%, AW2 = 40%, AW3 = 60% and AW4 = 80%), with 4 repetitions, totaling 64 plots. The planting spacing was in the configuration of 1.4 x 0.4 x 0.36 m, in continuous double row to obtain a better use of the area in function of the drip irrigation system. The manuring with P and K followed the recommendation for the State of Ceara. The growth and production components of the castor oil plant, cultivar BRS energy, increased with the increment of the leveis of available water in the soil and of manuring organic via castor oil plant pie; however, the positive effect of the organic manuring only happened until the levei of manuring of 180 kg N ha"1 , inclusive when associate with the levei of available water in the soil of 80%. The levei of organic manuring of 180 kg ha"1 , associate to 80% of available water in the soil promoted an increment of 58,84% in the productivity of the castor oil plant, in relation to the treatment with this same levei of available water in the soil, but without organic manuring. The levei of available water in 80% associate to an organic manuring of 180 kg ha"1 promoted an increment of 22,11% in the productivity of the castor oil plant, in relation to the treatment with this same levei of organic manuring and with the levei of available water in the soil of 20%.

Submitted by RENAN JOSE PARECIDO null (renanjparecido@hotmail.com) on 2016-09-14T02:13:02Z No. of bitstreams: 1 DISSERTAÇÃO Renan-FINAL.pdf: 2751419 bytes, checksum: 77b761a96ce4657834f44a8281d103ca (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-16T21:24:01Z (GMT) No. of bitstreams: 1 parecido_rj_me_bot.pdf: 2751419 bytes, checksum: 77b761a96ce4657834f44a8281d103ca (MD5) / Made available in DSpace on 2016-09-16T21:24:01Z (GMT). No. of bitstreams: 1 parecido_rj_me_bot.pdf: 2751419 bytes, checksum: 77b761a96ce4657834f44a8281d103ca (MD5) Previous issue date: 2016-07-28 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Na fase inicial da cultura do café arábica (Coffea arabica L.), as exigências nutricionais aumentam rapidamente com a entrada em produção (primeira safra), época em que se deve ter cuidado na nutrição das plantas, pois os cafeeiros produzem muito, ainda com pouca folhagem (baixa relação folha/fruto). O nitrogênio (N) é o nutriente mais exigido pelo cafeeiro. O silício (Si) desempenha diversos efeitos benéficos às plantas, e supõe-se que possa melhorar o aproveitamento do N fornecido. Dessa forma, objetivou-se com o presente trabalho avaliar o efeito da aplicação de Si via foliar e doses de N via solo no crescimento, nutrição e produtividade inicial da cultura do café arábica. O experimento foi conduzido em uma área cultivada com cafeeiro arábica, cultivar Catuaí IAC 99, localizado no município de Manduri-SP, em um solo Latossolo Vermelho Amarelo distrófico. Foi adotado o delineamento em blocos casualizados, em esquema fatorial 4 x 2, com quatro repetições. Os tratamentos foram constituídos por quatro doses de N (0, 75, 150 e 300 kg ha-¹) com presença e ausência de aplicação Si via foliar. A fonte de N utilizada foi o nitrato de amônio. O Si foi aplicado na dose de 2 L ha-¹do produto Silamol®. O experimento foi conduzido durante o período de 39 meses após o plantio dos cafeeiros no campo. A adubação nitrogenada aumentou a altura da planta, o número de nós nos ramos plagiotrópicos e colaborou na manutenção do enfolhamento das plantas, na fase de formação da lavoura. A aplicação das maiores doses de N atrasou a maturação dos frutos e incrementou a produtividade e o tamanho dos grãos da cultura do café. Nas duas primeiras safras, a produtividade de grãos beneficiados da cultura do café arábica foi incrementada até doses de N que variaram de 246 a 300 kg ha-¹. A aplicação de Si via foliar proporcionou maior altura das plantas e número de nós nos ramos plagiotrópicos, especialmente na ausência da aplicação de N em cobertura. Na presença das maiores doses de N, o fornecimento de Si via foliar proporcionou maiores teores de N na folha e maior produtividade de grãos na cultura do café arábica. / In the initial phase of the Arabica coffee (Coffea arabica L.), the nutritional requirements increase rapidly with the entry into production phase (first harvest), the time when one should be careful in plant nutrition, because the coffee plants produce a lot, even with little foliage (low leaf/fruit ratio). Nitrogen (N) is the nutrient most required by the coffee plant. Silicon (Si) plays various beneficial effects to plants and it is assumed that can improve the use of N provided. Thus, the aim of the present study was to evaluate the effect the foliar application of Si and N rates applied to soil on growth, nutrition and initial bean yield of Arabica coffee crop. The experiment was conducted in an area cultivated with Arabica coffee, cultivar Catuaí IAC 99, located in the municipality of Manduri-SP, in a dystrophic Red Yellow Latosol. The experimental design was a randomized blocks in a factorial 4 x 2, with four replications. The treatments consisted of four N rates (0, 75, 150, and 300 kg ha-¹) and presence and absence of foliar application of Si. Nitrogen source used was ammonium nitrate. The Si was applied at the rate of 2 L ha-¹ Silamol® product. The experiment was conducted during the period of 39 months after planting of coffee plants in the field. Nitrogen fertilization increased the plant height, number of nodes in plagiotrophycal branches and collaborate in maintenance of leafiness of plants in the crop formation phase. The Application of N rates largest delayed the ripening of the fruit and increased yield and the size of bean of the Arabica coffee crop. In the first two harvests, the hulled green-bean yield of Arabica coffee crop was increased by N rates ranging from 246 to 300 kg ha-¹. The foliar application of Si provided greater plant height and number of nodes in plagiotrophycal, especially in the absence of N fertilization. In the presence of higher N rates, the supply of Si via foliar provided higher concentrations of N in leaf and higher grain yield of Arabica coffee crop.

Made available in DSpace on 2014-07-29T15:13:38Z (GMT). No. of bitstreams: 1 TESE GABRIELA CIENCIA ANIMAL.pdf: 1463173 bytes, checksum: 395aac03a18f82f95770c0584036defe (MD5) Previous issue date: 2010-04-12 / The dry matter yield and quality aspects of forage millet are still poorly understood, as well as specific information handled by this grass and nitrogen fertilization. Experiment was conducted to evaluate the productive potential and chemical composition of the dry mass of three cultivars of pearl millet (Pennisetum glaucum (L.) R. Brown) (ADR-7010, ADR- 500 and BRS-1501), submitted to sources of phosphorus (superphosphate and fused), nitrogen (0, 40, 80 and 160 kg ha-¹) in the form of urea in three cuts in the UFG / Goiânia-GO . The experimental design was completely factorial arrangement 2 x 3 x 4 with four replications. The parameters evaluated were dry matter production (DMP) of the whole plant, while the dry matter (DM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF) were determined for the whole plant and its fractions (leaf and stem). Only the whole plant was given the apparent conversion efficiency of nitrogen (NACS), apparent nitrogen recovery (NAR) and nitrogen accumulated in the plant (NA) and protein fractions (A, B1, B2, B3 and C). All tests were accomplished using the SAS program (2007). Statistical analysis revealed no significant interactions between the variables studied in this way, these were discussed in isolation. Among the evaluated cultivars the highest yield (P <0.05) was the cultivar ADR-7010 (1175 kg ha-1 DM). The increment of N increases in production. NA increased with the increase of N rates with maximum value of 42.70 kg. The NACS and RAN decreased with the addition of the nutrient, with a peak of 10.77 kg ha-1 and 33.44%. The DM content of whole plant and leaf differed (P <0.05) and stem fraction only differed among genotypes. The CP content of whole plant did not differ (P> 0.05), but increased with the succession of cuts. The leaf blade was no difference (P <0.05) reduction of CP in terms of cuts. The CP concentration of stem ranged from 8.90% to 14.04%. ADF whole plant increased due to the succession of cuts and leaf blade varied between the cultivars, the highest contents of ADF were found in the stem. The NDF in the whole plant did not differ between the N levels, however all values were below 60%. The greatest amount recorded in the leaf was 63.81%. The higher NDF were identified in the stem fraction (55.54% to 68.03%). The contents of HEM differ between courts and for all plant cultivars and their fractions. There was no significant difference (P> 0.05) for the nitrogen fractions among all treatments. The contents determined for fraction C were all lower than 10%. Cultivar ADR-7010 showed the best results as well as the source superphosphate. The sources of phosphorus and nitrogen fertilization influenced the parameters. / A produção de massa seca e aspectos qualitativos de milheto forrageiro ainda são pouco conhecidos, assim como informações específicas dessa gramínea manejada com fertilização fosfatada e nitrogenada. Foi conduzido experimento para avaliar o potencial produtivo e composição bromatológica da massa seca de três cultivares de milheto (Pennisetum glaucum (L.) R. Brown) (ADR-7010; ADR- 500 e BRS-1501), submetidos à fontes de fósforo (superfosfato simples e termofosfato), doses de nitrogênio (0; 40; 80 e 160 kg.ha-¹) sob a forma de uréia em três cortes na UFG/Goiânia-GO. O delineamento experimental foi inteiramente casualizado com arranjo fatorial 2 x 3 x 4, com quatro repetições. Os parâmetros avaliados foram produção de massa seca (PMS) da planta inteira, enquanto que os teores de matéria seca (MS), proteína bruta (PB), fibra em detergente ácido (FDA) e fibra em detergente neutro (FDN) foram determinados para a planta inteira e suas frações (lâmina foliar e colmo). Somente para a planta inteira foi determinada a eficiência de conversão aparente de nitrogênio (ECAN), recuperação aparente do nitrogênio (RAN) e nitrogênio acumulado na planta (NA), assim como as frações de proteínas (A, B1, B2, B3 e C). Todas as análises foram realizadas com auxílio do programa computacional SAS (2007). A análise estatística não revelou interações significativas entre as variáveis pesquisadas, dessa forma, as mesmas foram discutidas isoladas. Entre os cultivares avaliados a maior produção (P<0,05) foi do cultivar ADR-7010 (1.175 kg.ha-1 de MS). O incremento de N promoveu aumentos na produção. O NA aumentou em função da elevação das doses de N com valor máximo de 42,70 kg. A ECAN e RAN diminuíram com o acréscimo do nutriente, com valores máximos de 10,77 kg.ha-1 e 33,44%. Os teores de MS da planta inteira e lâmina foliar diferiram (P<0,05) e a fração colmo somente diferiu entre os cultivares. Os teores de PB da planta inteira não diferiram (P>0,05), porém, aumentaram com a sucessão dos cortes. Na lâmina foliar houve diferença (P<0,05) com redução do teor de PB em função dos cortes. Os teores de PB do colmo variaram de 8,90% a 14,04%. Os teores de FDA da planta inteira aumentaram devido à sucessão dos cortes e na lâmina foliar variaram entre os cultivares, os maiores conteúdos de FDA foram verificados no colmo. Os teores de FDN na planta inteira não diferiram entre as doses de N, entretanto todos os valores foram inferiores a 60%. O maior teor registrado na lâmina foliar foi de 63,81%. Os maiores valores de FDN foram identificados na fração colmo (55,54% a 68,03%). Os teores de HEM diferiram entre cortes e cultivares para planta inteira e suas frações. Não verificou-se diferença significativa (P>0,05) para as frações nitrogenadas entre todos os tratamentos. Os conteúdos determinados para a fração C, foram todos inferiores a 10%. O cultivar ADR-7010 apresentou os melhores resultados, assim como a fonte superfosfato simples. As fontes de fósforo e fertilização nitrogenada influenciaram os parâmetros avaliados.

Factors currently at the forefront of human in vitro fertilization (IVF) that collectively influence treatment success in the form of blastocysts development were investigated during early mammalian embryology with concentration on infertile patients presenting with diminished ovarian reserve or preliminary ovarian failure. A novel experimental technique, Graft Transplant-Embryonic Stem Cells (GT-ESC) was introduced in the mouse model, as the first inclusive approach for embryo selection in IVF treatments resulting in successful graft integration of sibling cells, stage-dependent (day 4) blastocysts. E-Cadherin-catenin bonds play an integral role in trophectoderm cell viability and calcium removal, inducing disruption of cell-to-cell bonds at the blastocyst stage was detrimental to continued blastocyst development. One of the leading methods for embryo selection for uterine transfer in human IVF is application of pre-implantation genetic screening (PGS) methods such as next generation sequencing (NGS). Female patients <35 y do not benefit from this treatment when outcome is measured by presence of fetal heart beats at 10 weeks of gestation. Patients 35-37 y benefit from PGS with no significant difference of outcome based on form of PGS method utilized. Therefore, small nucleotide polymorphism array (snp-array) or targeted-NGS should be selected for this age range to lessen the financial burden of the patient. Embryos from women >40 y have a higher rate of mosaic cell lines which can be detected by NGS. Therefore NGS is most beneficial for women >40 y. Additionally, ovarian stimulation of the patient during human IVF can notably influence outcome. Anti-Müllerian hormone (AMH) is a more conducive indicator of blastocysts development per treatment compared to basal follicle stimulating hormone (FSH). Actionable variables included in a decision tree analysis determined a negative influence (0% success, n=11) of high dose gonadotropin use (>3325 IUs) in good prognosis patients (>12 mature follicles at trigger, AMH >3.15 ng/mL). A positive relationship exists (80% success, n=11) between poor responders (AMH <1.78 ng/mL, <12 mature follicles at trigger) and high dose gonadotropin use (>3025 IUs). Utilizing the decision tree during IVF treatment can be beneficial to treatment success. Moreover, a parallel relationship of the fundamental principles of culture medium pH, pCO2 and pO2 was found with respect to blastocyst development. Human infertility patients' gametes predisposed to primary stressors (i.e., age, genetics and etiology) are negatively impacted (~30% success, n=7) for cleavage stage (day 3) embryo development when primary culture medium has pCO2 <30mmHg given age >31 y and <14 oocytes retrieved. When day 3 embryo development is measured at >65% good quality embryos per treatment (based on SART grading criteria), blastocysts development success is highest when secondary culture medium pO2 is 69-88 mmHg (~90% success, n=12). Thus, IVF treatment outcome can be optimized with utilization of predictive model analyses in the form of decision trees providing greater success for the IVF laboratories, ultimately decreasing the emotional and financial burden to infertility patients.

Resumo: O objetivo deste trabalho foi avaliar respostas do capim-tifton 85 a doses de nitrogênio (N) associadas a doses e fontes de boro (B). Em casa de vegetação, conduziu-se um experimento fatorial 3 ' 3 ' 3 {três doses de N (0, 100 e 200 mg kg-1), três doses de B (0, 1,3 e 2,6 mg kg-1) e três fontes de B [colemanita fundida ao termofosfato (CF), colemanita em mistura com termofosfato (CM) e ácido bórico (H3BO3)]} em delineamento inteiramente ao acaso. As plantas cresceram em vasos preenchidos com amostra de um Latossolo Vermelho distrófico. Elas foram avaliadas em três ciclos de crescimento. O N foi aplicado no início de cada ciclo e o B apenas antes do plantio. A aplicação de N aumentou a massa seca da parte aérea e o número de perfilhos do capim nos três ciclos. A aplicação de B, isolada ou associada à de N, não teve influência nesses atributos, embora o solo tivesse baixo teor de B disponível. O suprimento de N aumentou também os teores de carboidratos de reserva na raiz da planta nos dois ciclos em que foram avaliados (primeiro e terceiro). O suprimento de B aumentou o teor desses carboidratos na base do caule no primeiro ciclo. Os fornecimentos de N e B aumentaram seus respectivos teores na parte aérea do capim no três ciclos, exceto no caso do teor de B no terceiro ciclo. Todas as fontes de B aumentaram o teor de B disponível no solo, mas a CM e o H3BO3 aumentaram mais do que a CF. O efeito mais evidente da aplicação conjunta de N e B ocorreu no acúmulo de B na parte aérea da planta, aumentando mais com a combinação das duas aplicações. O teor inicial de B no solo (0,15 mg dm-3) foi suficiente para atender as necessidades do capim-tifton 85 nos três ciclos de crescimento. / Abstract: The objective of this work was to evaluate responses of Tifton 85 bermudagrass to nitrogen (N) rates associated with boron (B) rates and sources. In greenhouse, it was carried out a factorial experiment 3 ' 3 ' 3 {three N rates (0, 100 and 200 mg kg-1), three B rates (0, 1.3 and 2.6 mg kg-1) and three B sources [colemanite fused to termophosphate (CF), colemanite in mixture with termophosphate (CM) and boric acid (H3BO3)]} in complete randomized design. The plants grew in pots filled with sample of a Typic Haplustox. They were evaluated during three growth cycles. The N was applied at the beginning of each cycle and the B just before the planting. The N application increased both top dry mass and tiller number of the grass in the three cycles. The B application, isolated or associated with N application, did not have influence on these attributes, though the soil had low available B content. The N supply increased reserve carbohydrates contents in plant root in the two cycles in which they were evaluated (first and third). The B supply increased the content of these carbohydrates in the stem base in the first cycle. The N and B furnishings increased their respective contents in top grass in the three cycles, except in the case of the B content in the third cycle. All the sources increased the available B content in soil, but CM and H3BO3 increased more than CF. The most evident effect of the N and B applications together occurred in the B accumulation in top plant, increasing more with the combination of the two applications. The initial B content in soil (0.15 mg dm-3) was enough to attend necessities of Tifton 85 bermudagrass in the three growth cycles. / Orientador: Edson Luiz Mendes Coutinho / Coorientador: Edemo João Fernandes / Banca: Mara Cristina Pessôa da Cruz / Banca: Cassio Hamilton Abreu Junior / Banca: Takashi Muraoka / Banca: Renato de Mello Prado / Doutor

Orientador: Antonio Ismael Inácio Cardoso / Banca: Giuseppina Pace Pereira Lima / Banca: João Nakagawa / Banca: Sérgio Antonio Lopes de Gusmão / Resumo: Devido à escassez de informações relacionadas ao efeito da adubação na produção e qualidade de sementes de hortaliças, nota-se a necessidade de determinar a demanda nutricional e a dose dos nutrientes para auxiliar na recomendação que proporcione a melhor produtividade de sementes de boa qualidade. Este trabalho foi conduzido em vaso na Fazenda Experimental São Manuel - UNESP/FCA, São Manuel/SP, com o objetivo de avaliar a resposta a doses de composto orgânico, com e sem fósforo adicionado ao solo, na produção e qualidade de sementes de alface crespa cultivar Verônica. O delineamento experimental foi em blocos casualizados, com dez tratamentos (0; 20; 40; 60; 80 t ha-1 de composto orgânico, com e sem 400 kg ha-1 de P205) e quatro repetições. Foram avaliadas características vegetativas das plantas, teor dos nutrientes no caule + folhas + hastes florais, acúmulo e teor de nutrientes nas sementes, produção de sementes (massa e número) por planta e a sua qualidade (germinação e vigor). Os dados foram submetidos às análises de variância e de regressão. A aplicação de fósforo aumentou a produção de sementes. Na presença de fósforo, a dose de 33,4 t ha-1 de composto orgânico, e na ausência de fósforo, a dose de 49,21 t ha-1 proporcionaram maior massa de sementes por planta. A qualidade das sementes não foi afetada tanto pela adubação com composto orgânico como com fósforo. A ordem decrescente dos nutrientes acumulados pelas sementes foi: nitrogênio > fósforo > potássio > cálcio > magnésio > enxofre > ferro > manganês > zinco > boro > cobre. / Abstract: Due to the scarcity of information regarding the effect of fertilization on yield and quality of vegetable seeds, there is a need to determine nutrient demand and the level of nutrients to support the recommendation that gives the best yield of good quality seeds. This study was conducted out in pots at the Experimental Farm São Manuel - UNESP / FCA, São Manuel / SP, in order to evaluate levels of organic compost, with and without phosphorus added to soil, on yield and quality of lettuce seeds cultivar Veronica. The experimental design was randomized blocks with ten treatments (0, 20, 40, 60, 80 t ha-1 of organic compost, with and without 400 kg ha-1 P205) and four replicates. It was evaluated vegetative characteristics of plants, nutrients content in stems + leaf + flower stalks, accumulation and nutrient content in seeds, seed production (weight and number) per plant and quality (germination and vigor). The data were submitted to analysis of variance and regression. Phosphorus application increased seed production. In the presence of phosphorus the level of 33, 4 t ha-1 of organic compost and in the absence of phosphorus the level of 49,21 t ha-1 resulted higher seed weight per plant. The quality of seeds was not affected by fertilization with organic compost on with phosphorous. The order of nutrient uptake by seeds was: nitrogen> phosphorus> potassium> calcium> magnesium> Sulfur> iron> manganese> zinc> boron> copper. / Mestre

No description available.

Soybean (Glycine max [L.] Merr.) has become one of the main agricultural grain crops produced in the United States. Soybean production continues to increase in high-yield environments throughout the U.S. New innovations are required to sustain gains in soybean yield potential. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS in 2014 and 2015 to evaluate soybean aboveground biomass and grain yield response to supplemental N fertilization in a high-yielding environment on two soil textures commonly cropped to soybean in Mississippi. Greenhouse studies were conducted in 2016 at the Delta Research and Extension Center in Stoneville, MS to evaluate the influence of supplemental N fertilization on nodule formation and belowground biomass of soybean on two soil textures commonly cropped to soybean in Mississippi.

Master of Science / Department of Agronomy / Scott A. Staggenborg / 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.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Steven J. Keeley / Non-structural carbohydrates (NSC) are important for plant health and recovery from stress. Controlled-release N sources may moderate turfgrass vegetative growth, thereby maximizing NSC levels. Three studies were conducted to determine the effect of N source/timing on NSC levels, turfgrass visual quality, and color of ‘Midlawn’ bermudagrass and turf-type tall fescue. Additionally, the effect on low temperature tolerance of bermudagrass and brown patch incidence on tall fescue was investigated. Nitrogen sources included two polymer-coated ureas (PCU), a polymer-sulfur coated urea (SCU) and urea formaldehyde (UF). Total annual N was applied in either late summer or spring for bermudagrass, and either late summer or split between late summer and spring for tall fescue. Urea, applied at traditional timings, was a control in all studies. NSC status was determined at regular intervals by extracting two cores from each plot, defoliating, and measuring regrowth in a dark growth chamber. Turfgrass color, visual quality and brown patch incidence were rated monthly during the growing season. Bermudagrass low temperature tolerance was evaluated by subjecting plugs to a freezing regime and evaluating regrowth. Over the 2-yr study, N source did not have a significant effect on bermudagrass or tall fescue NSC levels, color, or visual quality. Timing of application, by contrast, did have a significant impact. For bermudagrass, August-applied N resulted in higher overall NSC levels and improved fall color. For tall fescue, split Sept/March applications improved color; but split Sept/ May applications reduced NSC compared to a single Sept application. Brown patch incidence was unaffected by N source or timing, though disease pressure was low. Timing of PCU application did not affect low temperature tolerance of bermudagrass, but PCU improved low temperature survival compared to urea.