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Short-rotation woody crops are becoming important supplies of hardwood fiber, but little is known about the early nutritional needs of these systems, especially on different site types. The study objectives were, on two young (ages 3-6) sweetgum plantations with contrasting soil types, to 1) determine the plant growth and foliar nutrition response to repeated nitrogen (N) fertilizer applications, 2) determine soil N supply, plant N demand, foliar N resorption, and soil and fertilizer uptake efficiencies, and 3) test a simple N supply model. In order to expand the findings to the range of sweetgum site types, the study objectives were also to 4) evaluate rapid methods for determining N mineralization potential, 5) characterize the soils of 14 sweetgum site types in the Atlantic coastal plain, and 6) review current N fertilizer prescriptions in forestry and recommend strategies for improvement. Two young sweetgum (Liquidambar styraciflua L.) plantations on a converted agricultural field and a pine cutover site in South Carolina were fertilized biannually with three rates of N fertilizer (0, 56, 112 kg N per ha). Fertilization doubled foliar biomass and leaf area on the cutover pine site in the years fertilizer was applied, and stem biomass increased 60%. Critical values, the N concentration required for 90% of optimum growth, is approximately 1.75%. Foliar N uptake increased at both sites when fertilizer was applied. Modeled annual soil N supply was within 20% of that measured on the two plantations even though monthly N supply was not accurately estimated. Potential N mineralization was accurately estimated with a 3-day incubation of rewetted soils that were previously dried, but not by hot salt extraction or anaerobic incubation. Across a spectrum of 14 sweetgum sites, the agricultural fields had lower mineralizable nitrogen (126 kg per ha) than the cutover sites (363 kg per ha). Current N fertilizer prescriptions are not sufficient for repeated fertilizer applications to fast-growing hardwood plantations, but simple models of soil N supply and an N-balance approach may improve prescriptions. / Ph. D.

Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-01-30Bitstream added on 2014-06-13T20:09:10Z : No. of bitstreams: 1 souto_ls_me_botfca.pdf: 550271 bytes, checksum: 91706ee0d726778f1ce55e469bebe106 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente trabalho teve como objetivo estudar a resposta da cultura do milho à adição de níveis crescentes de fitomasssa de Brachiaria decumbens Stapf. e níveis de nitrogênio. Este foi conduzido em condições de túnel plástico, no Departamento de Recursos Naturais - Área de Ciência do Solo, da Faculdade de Ciências Agronômicas, Campus de Botucatu-UNESP, utilizou-se um solo classificado como Latossolo Vermelho distrófico, textura média, cultivado anteriormente com B. decumbens Stapf. O delineamento experimental utilizado foi o de blocos ao acaso, com cinco repetições, em esquema fatorial 4 x 4, constando os tratamentos de quatro níveis de fertilização nitrogenada (0, 50, 100 e 150 mg dm-3 de N na forma de Uréia) e quatro níveis de palhada de B. decumbens Stapf. (0, 5, 10 e 15 Mg ha-1 de fitomassa seca), totalizando 80 unidades experimentais. Adicinou-se litterbags (bolsas de nylon), no momento da instalação dos tratamentos com palhada de braquiária, para determinação da taxa de decomposição aos 70 dias após a emergência da cultura. As doses de N foram parceladas em três épocas, a saber: i) 1/3 na semeadura; ii) 1/3 no estádio de 4-5 folhas e; iii) 1/3 no estádio de 7-8 folhas totalmente expandidas. Um dia antes da adubação nitrogenada e uma semana após, foram realizadas leituras de clorofila com o Clorofilômetro SPAD-502. Aos 60 dias após a emergência (dae) das plântulas determinou-se a altura média de plantas, diâmetro basal do colmo, número de entrenós e diagnose foliar de nutrientes. Em seguida, coletou-se duas plantas por vaso para determinação da produção de fitomassa seca e teores de nutrientes na parte aérea, bem como a extração de N, P, K, Ca, Mg e S. As doses de N afetaram significativamente as leituras do clorofilômetro (IRC), a altura de plantas, diâmetro... / The objective of this research was to evaluate corn response to increasing levels of Brachiaria decumbens Stapf. straw and levels of nitrogen. This study was set at plastic tunnel conditions, at Recursos Naturais Departament - Soil Science Area, at Faculdade de Ciências Agronômicas, Campus de Botucatu - UNESP. The soil used was a Latossolo Vermelho distrófico an Oxisoil medium texture, previous cultivated with B. decumbens Stapf.. The treatments were set as a complete randomized experiment, with five repetitions in a factorial pattern, and the treatments were: four levels of nitrogen (0, 50, 100 and 150 mg dm-3) and four levels of B. decumbens straw (0, 5, 10, and 15 Mg ha-1). Litterbags containing B. decumbens straw were used to evaluate the decomposition rate at 70 days after corn emergence. Nitrogen was applied in three different times: i) 1/3 at planting; ii) 1/3 at 4-5 leaves stage; iii) 1/3 at 7-8 totally expanded leaves stage. Chlorophyll level was measured one day before and one week after nitrogen fertilize. At 60 days after emergence (dae) it was measured plants height, stalk basal diameter, internode numbers, and leaves were collected for foliar diagnosis analyses. At the same period two plants were collected for dry matter evaluation and for N, P, K, Ca, Mg and S extraction. Nitrogen rates affected chlorophyll levels (IRC), plants height, stalk basal diameter, internode numbers, foliar diagnosis, dry matter production, and nutrients extraction. Nitrogen at 100 mg dm-3 provided... (Complete abstract, click electronic access below)

This study compared the effects of nitrogen sources on the available inorganic soil nitrogen, nitrogen movement, nitrogen losses, and wheat yields when nitrogen fertilizers were applied to soil planted to drylond winter wheat at the Blue Creek Experimental Station in northern Utah. In the fall 1973 soil samplings, the fertilizers producing the largest mineral nitrogen contents in the 0-30 em soil depths were ammonium nitrate >ammonium sulfate > S-cooted urea, when they were broadcast at the practical rate of 56 kg N/ha. There was no increase in the mineral nitrogen at the deeper depths in the fall or at any depth in the following spring. Statistically, the three nitrogen sources did not increase grain yield significantly but did increase grain protein content and nitrogen content in grain. Ammonium nitrate and potassium bromide at the rates of 400 kg N and 200 kg Br/ha were broadcast to soil planted to winter wheat in October 1974. Nitrate-nitrogen and bromide distribution patterns in the soil profile looked alike in May 1975. These showed that their movements were similar. Considerable nitrate-nitrogen (35 percent of the added nitrogen) had moved down below the 120 em depth. The highest nitrate-nitrogen concentrations were found at the 45 to 90 em depth . There seems to be evidence that nitrate-nitrogen and bromide had moved deeper than the 150 em depth. Ammonia- nitrogen losses from nitrogen fertilized soils were conducted in the laboratory. Ammonium sulfate, ammonium nitrate, or urea applied to the soil surface lost ammonia-nitrogen differently. From noncalcareous soil, the ammonia-nitrogen loss was greatest from urea. From calcareous soil or soils receiving carbonates or high soil pH by the addition of sodium hydroxide solution, the greatest losses were from ammonium sulfate. High losses were favored by high temperatures and longer periods of moist soil. The total amounts of water lost from the soil was not closely related to the total ammonia-nitrogen loss during two weeks. No loss of ammonia-nitrogen occurred when nitrogen fertilizers were applied at a 2.5 em depth or deeper. The ammonia-nitrogen losses were also greatly reduced when nitrogen fertilizers applied to the soil surface was followed by irrigation or heavy rainfall. In the field, the higher temperatures increased the ammonia-nitrogen losses from ammonium sulfate, ammonium nitrate, and urea when applied to both a noncalcareous and a calcareous soil . However, the loss from calcareous soil was reduced by irrigation following fertilizer application. No ammonia-nitrogen was observed when ammonium sulfate was applied at a 2. 5 em soil depth, despite of the high soil temperature during the day time in moist soil. Rapid drying of the moist soil surface quickly reduced the losses per day.

Meadow bromegrass (<i>Bromus riparius</i> Rehm.) is an important forage grass in western Canada. Economical seed production is critical to its use. Seed yield usually declines rapidly after two to three seed crops. Field and growth chamber experiments were conducted to determine the influence of (a) residue removal and N fertilization on tiller density and size, panicle density, silvertop incidence, seed yield and stand longevity, (b) filler size and stand age on panicle production, and (c) daylength and temperature during primary and secondary induction on panicle production. Removing residue after harvest and applying N (100 kg ha-1 ) increased yield from 200 to 450 kg ha-1 compared to not removing residue or adding N in the second seed crop. The difference between treated and untreated plots was only 30 to 90 kg ha-1 in the third seed crop. The increase was related to an increase in panicle production, however, the correlation between panicle number and seed yield was low. Silvertop incidence (% of panicles affected) increased as the stand aged, but removing residue after harvest reduced silvertop. In pot studies, the percentage of plants that produced panicles increased as tiller basal diameter increased from one mm to three mm, regardless of the age of the stand. However, fewer large tillers were observed in older stands. Large tillers from a four-yr-old stand produced fewer particles than large tillers from a two-yr-old stand indicating that tiller size alone is not responsible for the decline in panicle production. Panicle production increased as the temperature during primary induction decreased. However, daylength during primary induction had no effect on panicle production. Varying temperature or daylength during secondary induction had no effect on panicle production; panicles were produced in 85% of plants regardless of temperature, and 67 to 77% of the plants regardless of daylength. In conclusion, residue removal after harvest and N fertilization improve seed yield in young meadow bromegrass stands. However, these practices were not effective in prolonging seed yield beyond two to three seed crops. Drought, winter injury, competition amongst tillers and silvertop incidence all play a role in reducing seed production.

The aim was compare impact of NPK with the other types of fertilization: 0, N, PK, NK and NP on plants of chosen varieties. The experiment was treated on soil less convenient to intensive planting at an altitude of 400 m and conventionally

Made available in DSpace on 2014-06-11T19:35:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-12Bitstream added on 2014-06-13T20:46:27Z : No. of bitstreams: 1 kappes_c_dr_ilha.pdf: 1718636 bytes, checksum: 955e8aa77cf657ce36d88da312d29401 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Pesquisas são desenvolvidas buscando identificar a melhor dose de nitrogênio para o milho nos mais diferenciados sistemas de manejo do solo. Contudo, não há ainda concordância nos resultados, pois a dinâmica deste nutriente é influenciada pelo manejo do solo e pela cobertura vegetal. O objetivo deste trabalho foi avaliar a influência de coberturas vegetais, sistemas de manejo do solo e doses de nitrogênio em cobertura no milho. Os experimentos foram conduzidos no município de Selvíria – MS, durante os anos agrícolas 2009/10 e 2010/11, em Latossolo Vermelho distrófico típico argiloso (20o 20’ S e 51o 24’ W, com altitude de 340 m). Foram estabelecidos trinta e seis tratamentos com quatro repetições, em blocos casualizados, resultantes da combinação entre coberturas vegetais (milheto, crotalária e milheto + crotalária), manejo do solo (escarificador + grade leve, grade pesada + grade leve e sistema plantio direto) e doses de nitrogênio em cobertura (0, 60, 90 e 120 kg ha-1 – fonte ureia). O híbrido de milho utilizado foi o DKB 350 YG®, semeado no espaçamento de 0,9 m entre as linhas e o nitrogênio aplicado no estádio V5. Os efeitos de cobertura vegetal e manejo do solo foram analisados pelo teste de Tukey e de dose pela análise de regressão. O milheto produz menor quantidade de massa seca em relação à crotalária, porém seus resíduos são mais persistentes no solo. A aplicação de nitrogênio em cobertura proporciona incremento da maioria das características morfológicas e nutricionais de plantas e dos componentes de produção do milho. A utilização de crotalária e de milheto + crotalária como antecessoras, associada à aplicação de 90 kg ha-1 de nitrogênio em cobertura do milho sob sistema plantio direto, proporciona maior produtividade / Research has been developed to identify the best nitrogen rate for maize in many types of soil management systems. However, there is no agreement on the results so far, because the dynamic of nitrogen is influenced by soil management system and cover crops. This work aimed to evaluate the influence of cover crops, soil management systems and side-dressing nitrogen rates for maize. The field trials were carried out in Selvíria, Mato Grosso do Sul State, Brazil, during the growing season of 2009/10 and 2010/11, on a clayey Rhodic Haplustox (20o 20’ S and 51o 24’ W, with altitude of 340 m). Thirty six treatments were established with four replications, in a randomized blocks design, with the combination of cover crops (millet, sunn hemp and millet + sunn hemp), soil management systems (chisel plow + levelling disking, heavy disking + levelling disking, and no-tillage system) and side- dressing nitrogen rates (0, 60, 90 and 120 kg ha-1 – urea source). The hybrid of maize used was DKB 350 YG® sown in the spacing of 0.9 m between lines and the nitrogen applied at V5 growth stage. The effects of cover crops and soil management were analyzed by Tukey test and nitrogen rates by regression analysis. The millet produces less amount of dry mass yield than sunn hemp, but its residues are more persistent on the soil surface. The side-dressing nitrogen application increases most of the morphological and plant nutritional characteristics and yield components of maize. Sunn hemp and millet + sunn hemp grown previously, associated with 90 kg ha-1 side-dressing nitrogen application of maize under no-tillage system, provides higher grain yield

Made available in DSpace on 2014-06-11T19:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-14Bitstream added on 2014-06-13T20:56:08Z : No. of bitstreams: 1 correia_ac_me_araca.pdf: 344579 bytes, checksum: 0f954ba0a1db857e840c7ba7a8a57821 (MD5) / Com o objetivo de avaliar a produção de matéria seca (MS), da parte aérea e raízes do capim Tierra Verde e os atributos químicos do solo e da parte aérea submetida à adubação com biofertilizante orgânico, realizou-se um experimento em casa de vegetação do Departamento de Apoio, Produção e Saúde Animal da UNESP, Faculdade de Medicina Veterinária, Campus de Araçatuba-SP, de janeiro a setembro de 2010. Os tratamentos foram dispostos em delineamento inteiramente casualizado, adubados com seis doses de biofertilizante (0, 33, 66, 132, 264, 528 m 3 ha -1 ) e com cinco repetições durante três cortes. Utilizou-se o modelo de parcelas subdivididas no tempo, sendo as doses de biofertilizante consideradas como tratamentos principais e os cortes como sub-parcelas. Foi observado aumento na produção de MS da parte aérea e raízes a partir das doses de 66 até 528 m 3 ha -1 de N. A adubação nitrogenada influenciou nos atributos químicos do solo nos teores da matéria orgânica, enxofre, boro e manganês. A adubação nitrogenada influenciou a composição química do capim Tierra Verde, nos teores foliares de fósforo, potássio e cobre. Os teores de proteína bruta, fibra em detergente neutro e fibra em detergente ácido não foram alterados pela influência das doses de biofertilizante orgânico aplicado ao solo / In order to evaluate the production of dry matter (DM) of shoots and roots of grass Tierra Verde and chemical attributes of soil and subjected to aerial fertilization with organic biofertilizer, an experiment was performed in house vegetation Support Department, Animal Production and Health, University of Veterinary Medicine, UNESP, Araçatuba-SP, from January to September 2010. The treatments were arranged in completely randomized design with six fertilized biofertilizer doses (0, 33, 66, 132, 264, 528 m 3 /ha) and five repetitions for three cuts. We used the model split plot in time, and the doses of biofertilizers considered as main treatments and cuts as sub-plots. We observed increase in DM yield of shoots and roots from the doses of 66 to 528 m 3 /ha of N. Nitrogen fertilization influenced the soil chemical properties in the levels of organic matter, sulfur, boron and manganese. Nitrogen fertilization influenced the chemical composition of grass Tierra Verde in foliar concentrations of phosphorus, potassium and copper. The crude protein, neutral detergent fiber and acid detergent fiber were not affected by the influence of the organic biofertilizer doses applied to the soil

Made available in DSpace on 2014-06-11T19:27:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-12Bitstream added on 2014-06-13T20:17:00Z : No. of bitstreams: 1 campana_m_me_botfmvz.pdf: 694345 bytes, checksum: 5b95a0f43e56990d64086b8a724378b9 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Com objetivo de validar o uso no campo do coletor de espuma com ácido e politetrafluoroetileno que capta amônia volatilizada e quantificar essa perda oriunda de fontes e formas de aplicação de nitrogênio (N) em pastagens, realizou-se 2 experimentos. No experimento 1, para avaliação do coletor, utilizou-se fatorial 2 x 2 - doses de N (50 e 100 kg/ha) e coletores de amônia (coletor semi-aberto e absorvedor de espuma com ácido e politretafluoroetileno). O período experimental foi de 22 dias. No experimento 2 utilizou-se delineamento de blocos ao acaso e os tratamentos foram: uréia; Super N®; uréia + 12,5% de zeólita; uréia + 25% de zeólita; uréia + 50% de zeólita; uréia em pulverização foliar; 75% de uréia + 25% de sulfato de amônio; nitrato de amônio e sem N (testemunha). A avaliação das perdas por volatilização de amônia ocorreu em 3 épocas. No verão/07 e inverno/07 utilizou-se dose de 50 kg/ha de N para adubos sólidos e 15 kg/ha de N para pulverização foliar e para o verão/08 as doses foram duplicadas. As perdas diárias de amônia foram avaliadas em onze amostragens a cada dois dias para ambos os experimentos. Para o experimento 1, não houve diferença entre os coletores na perda acumulada e diária de amônia com a dose de 50 kg/ha de N. Entretanto, na dose de 100 kg/ha de N o coletor semi-aberto captou o maior pico de volatilização diária e maior acúmulo de amônia. No experimento 2 as menores perdas por volatilização foram detectadas para nitrato de amônio aplicado a lanço e uréia via pulverização foliar. Dessa forma poderia ocorrer melhor uso do fertilizante pela planta refletindo em aumento na produção e qualidade da forragem. / With the objective of validating the field use of the foam collector with acid and polytetrafluorethylene, which captures volatilized ammonia and quantify this loss when using sources and application forms of nitrogen (N) in pastures, 2 experiments were realized. In the experiment 1, to evaluate the collector a 2 x 2 factorial – N doses (50 and 100 kg/ha) and ammonia collectors (semi-open collector and foam absorber with acid and polytetrafluorethylene). The experimental period was 22 days. In the experiment 2, the experimental design was a randomized block design and the treatments were: urea; Super N®; urea + 12,5% of zeolite; urea + 25% of zeolite; urea + 50% of zeolite; urea leaf spraying, 75% of urea + 25% of ammonium sulfate, ammonium nitrate, and without nitrogen (control). The evaluation of the volatilization losses occurred in 3 periods. On summer/07 and winter/2007 a 50 kg/ha of N dose for solid fertilizers was used and a 15 kg/ha N dose for leaf spraying and on summer/2008 the doses were doubled. The daily losses of ammonia were evaluated in eleven samplings every two days for both experiments. In the experiment 1, there was no difference between the collectors in the accumulated and daily loss in the dose of 50kg/ha of N. However, with the dose of 100 kg/ha of N the semi-open collector showed the highest peak of daily volatilization and accumulated the highest volatilization loss. In the experiment 2, the lowest volatilization losses were detected for ammonium nitrate in soil application and urea in leaf spraying application. So, in this cases might happen the better use of the fertilizer by the plant, reflecting in the increase of the forage production and quality.

Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-31Bitstream added on 2014-06-13T19:52:15Z : No. of bitstreams: 1 nascimento_fm_me_botfca.pdf: 672188 bytes, checksum: 48e970a9e0a259e419f9a68daaa916db (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O aumento do emprego do Sistema Plantio Direto, no Brasil, tem revelado de maneira inquestionável a necessidade do aprofundamento das pesquisas que avaliem os efeitos das culturas antecessoras sobre culturas de gramíneas anuais, particularmente na cultura do milho. A presente pesquisa teve como objetivo avaliar a resposta da cultura do milho em sucessão às culturas de soja + aveia e milho + aveia, havendo a antecipação da aplicação do nitrogênio na cultura da aveia, em doses crescentes, no Sistema Plantio Direto. Foram conduzidos dois experimentos em condições de campo em solo classificado como NITOSSOLO VERMELHO distroférrico, na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas da UNESP, Campus de Botucatu. No experimento nº1, foi realizada a seguinte sucessão de culturas: soja, aveia e milho; enquanto no experimento nº2, a sucessão de culturas foi: milho, aveia e milho. Nos dois experimentos foram consideradas parcelas as doses de nitrogênio aplicadas na cultura da aveia: 0, 20, 40 e 60 kg ha-1. As doses de nitrogênio aplicadas em cobertura na cultura do milho, foram consideradas subparcelas, variando nas seguintes doses: 60, 80, 100 e 120 kg ha-1, aplicados de forma parcelada em dois estádios da cultura do milho, a saber: 1ª aplicação no estádio de 3 a 4 folhas totalmente distendidas e a 2ª aplicação no estádio de 6 a 7 folhas totalmente distendidas. Na cultura da aveia foi avaliada a massa de matéria seca e calculada a relação C/N. Na cultura do milho foi calculada a relação C/N, quantificado o nitrogênio na planta antes da primeira cobertura e quinze dias após a aplicação da segunda cobertura, sendo nesta coeficientes de determinação (R2) tiveram sua significância testada ao nível de 5% de probabilidade e considerados significativos quando R2 foi superior a 60%. Os experimentos foram analisados estatísticamente separados... / The growing use of no–tillage system, in Brazil, has unquestionably revealed the need of deeper investigation to assess the effects of preceding cultures on current annual grass cultures, specially the corn ones. The main goal of this current research is to evaluate the response of corn plantation in succession on cultures of soybean + black oat and corn + black oat, with the antecipation of nitrogen applications in the black oat culture, in increasing doses, in no–tillage system. Two experiments in field conditions in soils classified as NITOSSOLO VERMELHO distroférrico were conducted, on Lageado Experimental Farm, at Faculdade de Ciências Agronômicas of UNESP, Botucatu Campus. On experiment nº1, the succession was conducted as follows: soybean, black oat and corn while on experiment nº2 the culture succession was: corn, black oat and corn. On both experiments, parcels of 0, 20, 40 e 60 kg ha-1 of nitrogen doses were applied on the black oat cultures. In relation to the corn cultures, subparcels were considered, varying on the following doses: 60, 80, 100 e 120 kg ha-1. The latter were applied gradually in two stages of the corn culture, as follows: 1st application on the stage of 3 to 4 totally unfolded leaves and the 2nd application on the stage of 6 to 7 totally unfolded leaves. On the black oat culture, the dry matter mass was assessed and the relation C/N calculated. On the corn culture the relation of C/N was also calculated; the nitrogen in the plants was quantified before the first covering and 15 days after the second At the end of the cicle, the plant and the first spike insertion heights and the stem diameter were measured and the spike indexes were calculated. After the harvest, the number of rows per spike was counted, the mass of 1000 grains was measured and the productivity was calculated. The data were submitted to the variance analysis and compared through the F test...(Complete abstract, click electronic access below)