Doses, fontes e épocas de aplicação de nitrogênio em arroz de terras altas cultivado em sistema de semeadura direta

The crop demand by nitrogen varies from one crop to other as well as the amount and application time, and this nutrient can be lost by leaching, volatilization and erosion. The objective of this study was to evaluate doses, sources and times of nitrogen application in rice of high lands cropped in no till system. The work was conducted in Selviria, State of Mato Grosso do Sul, Brazil, in a soil originally under Cerrado vegetation. A randomized blocks design, with the treatments disposed in a factorial scheme 5x3x2 was used. The treatments were constituted by five nitrogen doses (0, 50, 100, 150 and 200 kg ha(-1)), three nitrogen sources (urea; ammonium sulfonitrate plus nitrification inhitor and ammonium sulfate) and two application times (at sowing or at flower bud differentiation), with four repetitions. The sources of nitrogen, as well as the application times had similar effects for most of evaluations. The N doses influenced linearly or with quadratic adjustment the plant height, N leaf content and grains yield, in the two growing seasons. The chlorophyll content and the number of ears m(-2) were affected only, in the first year. The highest yield in the growing season of 2007/08 was obtained with the dose of 149 kg ha(-1) of N. In 2008/09 growing season the increase of N doses provided increment in the grains rice yield, until the maximum dose evaluated (200 kg ha(-1) of N).

MORPHOGENESIS AND PRODUCTION OF TANZANIA, MOMBACA AND MULATO GRASSES UNDER NITROGEN FERTILIZATION

A field trial was conducted designed in a completely randomized block in a 4 x 3 factorial arrangement to evaluate the application of nitrogen doses (N) (0, 40, 80 and 160 kg/ha) on the morphogenical characteristics and dry matter partition of three forage grasses (Panicum maximum cvs. Mombasa and Tanzania and Brachiaria sp. Hybrid Mulato). The leaf appearance (LAR, leaf/day) and stretching (LER; mm/day) rates, the number of green leaves per tiller (NLT) and the average weight of tillers (MTW; g) presented s positive linear response to the N dose while the phyllochron (Phil; day/leaves) showed a negative linear response. The highest LER, IAL and final leaf length (FLL; cm) occurred in the Mombaca and Tanzania grasses, while the highest LAR occurred in the Mulato grass. There was a negative quadratic effect of the N dose on the stem elongation rate (SER; mm/day) and LF. The Mombaca and Tanzania grasses presented the highest SER; however, in just two forages. The production of total dry matter (TDM; kg/ha), leaves (LDM; kg/ha) and stems (SDM; kg/ha) increased linearly and quadratically with the N dose, respectively, for the Mombaca and Tanzania grasses. There was a high positive correlation among DM, LDM and SDM and the Mombaca grass MTW. The dry matter production and morphogenic characteristics were influenced by the nitrogen fertilization as a result of the substantial increase in the flow of tissues stimulated by fertilization, proving the importance of N for forage biomass accumulation.

Valor nutritivo do capim Piatã adubado com diferentes doses de biofertilizante

The aim of this study was to verify the influence of different doses of biofertilizers made from waste produced by cattle and pigs at growing-finishing on nutritive value of Piatã grass. The experiment was carried out at green house using a split plot design with a completely randomized factorial. Plots were divided into eight treatments: four doses of two biofertilizers, and four different periods of subplots cut. Biofertilizers were applied at a single dose, after the cut to standardize the plots, using doses of Nitrogen of 0, 100, 200 and 300 kg ha-1 . The results showed no significant difference among types of biofertilizer and also, the biofertilizer x dose interaction was not significant, making possible to recommend both of biofertilizers, with no risk of plant injure. Contents of neutral detergent fiber, acid detergent fiber, cellulose, hemicellulose and lignin showed negative linear behavior as a function of increasing doses of nitrogen. Contents of crude protein and “in vitro” dry matter digestibility coefficients replied linearly and positively to nitrogen doses. It also observed the effect of cut periods, since plants that were cut in summer showed nutritive value superior to those plants that were cut in autumn.

Primary and secondary metabolites production in signal grass around the year under nitrogen fertilizer

Plants produce a number of substances and products and primary and secondary metabolites (SM) are amongst them with many benefits but limitation as well. Usually, the fodder are not considered toxic to animals or as a source having higher SM. The Brachiaria decumbens has a considerable nutritional value, but it is considered as a toxic grass for causing photosensitization in animals, if the grass is not harvested for more than 30 days or solely. The absence of detailed information in the literature about SM in Brachiaria, metabolites production and its chemical profile enable us to focus not only on the nutritive value but to get answers in all aspects and especially on toxicity. The study was conducted in the period of december 2013 to december 2014; in greenhouse FZEA-USP. B. decumbens was used with two cutting heights (10 and 20 cm) and nitrogen doses (0, 150, 300 and 450 kg ha-1) in complete randomized block design. The bromatological analysis were carried out on near infrared spectroscopy. Generally, the application of 150 kg ha-1 N was sufficient to promote the nutritional value in B. decumbens but above it the nitrogen use efficiency decline significantly. The highest dry matter yield (99.97 g/pot) was observed in autumn and the lowest was in winter (30.20 g/pot). While, as per nitrogen dose the average highest dry matter yield was at 150 kg ha-1 (79.98 g/pot). The highest crude protein was observed in winter (11.88%) and the lowest in autumn (7.78%). By the cutting heights; the 10 cm proved to have high CP (9.51%). In respect of fibrous contents, the highest acid detergent fiber was noted in summer (36.37%) and lowest in winter (30.88%). While the neutral detergent fiber was being highest in autumn and lowest in spring (79.60%). The highest in vitro dry matter and organic matter digestibilities were noted at 300 kg ha-1 N; being 68.06 and 60.57%; respectively; with the lowest observed in without N treatments (62.63% and 57.97), respectively. For determination of the classes, types and concentration of SM in B. decumbens, phytochemical tests, thin layer and liquid chromatography-mass spectrometry and nuclear magnetic resonance analysis were carried out. Height, nitrogen and seasons significantly (P <0.0001) affected the secondary metabolic profile. A new protodioscin isomer (protoneodioscin (25S-)) was identified for first time in B. decumbens and is supposed to be the probable toxicity reason. Its structure was verified by 1D and 2D NMR techniques (1H, 13C) and 1D (COSY-45, edited HSQC, HMBC, H2BC, HSQC -TOCSY, NOESY and 1 H, 1 H, J). All factors influence the metabolic profile significantly (P <0.0001). The lowest phenols were at 300 kg ha-1 while the lowest flavones were at 0 kg ha-1. Season wise the highest phenols occurred in autumn (19.65 mg/g d.wt.) and highest flavones (28.87 mg/g d.wt.) in spring. Seasons effect the saponin production significantly (P <0.0001) and the results showed significant differences in the protodioscin (17.63±4.3 - 22.57±2.2 mg/g d.wt.) and protoneodioscin (23.3±1.2 - 31.07±2.9 mg/g d.wt.) concentrations. The highest protodioscin isomers concentrations were observed in winter and spring and by N doses the highest were noted in 300 kg ha-1. Simply, all factors significantly played their role in varying concentrations of secondary metabolites.

Doses de nitrogênio e potássio na produção de grama esmeralda

O nitrogênio e potássio são os nutrientes requeridos em maiores quantidades pelas gramas e no Brasil não se tem informação da quantidade a ser aplicada para se obter a formação de tapete em menor tempo possível. Dois experimentos foram instalados em vasos em casa de vegetação, com o objetivo de avaliar o efeito de doses de nitrogênio e de potássio na produção de tapetes de grama esmeralda (Zoysia japonica). O delineamento utilizado para cada experimento foi fatorial com doses de N ou K e épocas de avaliação. Foram aplicadas quatro doses de nitrogênio (0, 200, 400 e 600 kg ha-1) e quatro doses de potássio (0, 100, 200, e 300 kg ha-1). As doses de nitrogênio e potássio foram aplicadas parceladamente em cobertura. O aumento das doses de N influenciou a taxa de cobertura do solo pela grama (TCS) permitindo a formação do tapete com a dose de 408 kg ha-1 de N aos 198 dias após a colheita do tapete anterior, tempo menor quando comparado com as demais doses. A concentração de N na folha e da cor verde da grama foram influenciadas pelas doses de N podendo ser utilizadas para auxiliar na recomendação das doses de N. O aumento das doses de K não influenciou na TCS pela grama, sendo o teor no solo (1,4 mmol c dm-3) suficiente para a produção dos tapetes de grama esmeralda.

Straw and early nitrogen fertilization affect soil properties and upland rice yield.

The presence of cover crop straw and early application of total N at sowing may provide significant changes in the microbial population, reflecting on the N dynamics in the soil and in upland rice plants. This study aimed at determining the effect of the early application of nitrogen doses as mineral N and microbial biomass carbon in the soil, as well as in the activity of nitrate reductase, and grain yield of upland rice plants cultivated under notillage system (NTS). A randomized blocks design, in a split-plot scheme, with four replications, was used. The treatments consisted of N doses (0 kg ha-1, 40 kg ha-1, 80 kg ha-1 and 120 kg ha-1) and the presence or absence of U. brizantha cover straw. Maintaining the straw on the soil surface reduces the ammonium levels and increases the microbial biomass carbon content of the soil. The application of increasing doses of N in the soil provides increases in the levels of nitrate and ammonium in the soil up to 28 days after emergence. The activity of the nitrate reductase enzyme in the plants increases and the contents of ammonium and nitrate in the soil decrease with the crop development. The number of panicles and grain yield of upland rice increase with the increase of the nitrogen fertilization, but decrease in the presence of U. brizantha straw. Thus, it is recommend the use of early N fertilization in upland rice crop.

Effect of nitrogen fertilization on soil microbial biomass in an Oxisol cultivated with irrigated barley in the Brazilian Cerrado.

Abstract:The aim of this study was to evaluate the effect of different nitrogen doses and five period of sample collection, on soil microbial biomass - nitrogen (SMB-N), total nitrogen (total N) and percentual ratio of the microbial biomass and total N (SMB-N/total N) in a Oxisol cultivated with barley (Hordeum vulgare L.). The experiment was installed in June, 2005, in an area located at Embrapa Cerrados, Federal District. The experimental design was a randomized block, with three replicates. The plots received doses of nitrogen: 20 - 40 - 80 kg ha-1 N and a control without it and the subplots were period of soil sample. Three applications of N were realized: 10 kg ha-1 on the 5th day (06/14) after sowing; the rest of N was parceled in two applications with fertigation, on tillage, on the 27th (07/08) DAP, e no 43rd (07/22) DAP. Soil samples layer (0 - 10 cm deep) were collected for (SMB-N) determination and total N in six periods: 02 days before of the first fertigation; 02 days after of the first fertigation; 04 days before of the last fertigation and 04 days after of the last fertigation; on flowering stage and after harvesting. There was effect of the doses of N and the period of soil collection on the SMB-N, total N and in the ratio SMB-N/total N. The average values of total N revealed steadier in short-term (cycle of the culture) and this was not a good parameter to evaluate the behavior and N transformations in the soil-plant system. Resumen: El objetivo de este estudio fue evaluar el efecto de diferentes dosis de nitrógeno y cinco período de muestreo en la biomasa microbiana del complejo suelo - nitrogeno (BMS-N), nitrógeno total (N total) y la relación porcentual de la biomasa microbiana y N total (BMS-N/N total) en un Oxisol cultivado con cebada (Hordeum vulgare L.). El estudio se inició en junio de 2005 en la estación experimental de la Empresa de Pesquisa Agropecuaria (Embrapa-Cerrados), Distrito Federal, Brazil. El experimento se dispuso en bloques al azar con tres repeticiones. Las parcelas recibieron dosis de nitrógeno: 20 - 40 - 80 kg/ha de N más un control sin N, y las subparcelas fueron el periodo de muestro. Las aplicaciones de N se realizaron de la forma siguiente: cinco días después de la siembra (dds) se aplicaron 10 kg/ha y el resto de la dosis se aplicó con fertirrigación en dos dosis 27 y 43 dds. Las muestras de suelo (0-10 cm de profundidad) para determinar BMS-N y N total fueron tomadas, 2 días antes e igual número de días después de la primera fertirrigación y 4 días antes y después de la última, en floración y después de la cosecha. No se encontró efecto de las dosis de N y el período de muestreo en el BMS-N, N total y en la relación BMS-N/N total. Los valores medios de N total fueron más estable en el corto plazo (ciclo de la cultivo) lo que indica que éste no es un buen parámetro para evaluar la dinámica del N y sus transformaciones en el sistema suelo-planta.

Influence of macro- and micronutrient fertilization on fungal contamination and fumonisin production in corn grains

The aim of this study was to investigate the effects of nutrients (nitrogen, zinc and boron) on fungal growth and fumonisins production in corn samples obtained at the beginning of grain formation and at harvest. Three nitrogen doses were applied to the corn plants through soil in combination with three zinc doses and two boron doses during sowing. Mycological analysis of grains, using Dichloran Rose-Bengal Chloramphenicol Agar, collected at the beginning of formation demonstrated a fungal population predominantly of yeasts. Analysis of freshly harvested corn revealed a higher frequency of Penicillium spp. (72%) and F verticillioides (27%). High Performance Liquid Chromatography analysis revealed that 100% of grains were contaminated with fumonisins B, at levels ranging from 0.3 to 24.3 mg/kg and 93% contaminated with fumonisin B(2) at levels ranging from 0.05 to 5.42 mg/kg. Nitrogen (50 kg/ha) in combination with boron (0.5 kg/ha) resulted in an increased fumonisin B2 production. (c) 2007 Elsevier Ltd. All rights reserved.

Produtividade de híbridos de cebola em função da população de plantas e da fertilização nitrogenada e potássica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nitrogênio em cobertura na cultura do milho em preparo convencional e plantio direto consolidados

O nitrogênio é o nutriente exigido em maior quantidade pela cultura do milho, sendo o que mais frequentemente limita a produtividade de grãos. O objetivo do trabalho foi avaliar, em área com vinte anos (1985-2005) de estudo de sistemas de manejo de solo, na Universidade Estadual Paulista, Campus de Botucatu (SP), a resposta do milho à produtividade, características agronômicas e eficiência de uso de nitrogênio (N), em função da adubação nitrogenada em cobertura, nos sistemas de preparo convencional e plantio direto. O delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. As parcelas foram representadas por preparo convencional do solo e plantio direto e as subparcelas por doses de adubação nitrogenada em cobertura (0 kg ha-1, 40 kg ha-1, 80 kg ha-1, 120 kg ha-1 e 160 kg ha-1). A adubação nitrogenada de cobertura promoveu acréscimos significativos nas características agronômicas e nutricionais do milho, com a produtividade máxima de grãos obtida com 151 kg ha-1 de N. Nas doses de 90 kg ha-1 e 145 kg ha-1 de N em cobertura, os valores da eficiência agronômica e de recuperação foram semelhantes, para o preparo convencional do solo e plantio direto, respectivamente. As produtividades de grãos e as características agronômicas e nutricionais do milho não foram afetadas pelo tipo de preparo do solo.

Características agronômicas de arroz de terras altas sob plantio direto e adubação nitrogenada e potássica

O objetivo do presente trabalho foi avaliar o efeito da adubação nitrogenada e potássica em cobertura na cultura de arroz de terras altas, utilizando um delineamento estatístico inteiramente casualizado, com 15 tratamentos, em esquema fatorial 5 x 3, representados por cinco doses de nitrogênio (0, 25, 50, 75, 100 kg ha-1) e três doses de potássio (0, 25, 50 kg ha-1), com três repetições. Os resultados mostraram que diversas características produtivas foram influenciadas positivamente pela adubação nitroggenada e potássica. A melhor combinação de doses estaria em torno de 65 kg ha-1 de N e 20 kg ha-1 de K2O, resultando em maiores valores de produtividade e proteína bruta por hectare.

Mecanismos de abertura do sulco e adubação nitrogenada no cultivo do feijoeiro em sistema plantio direto

Algumas culturas têm pouca adaptação ao sistema plantio direto, em vista da maior compactação da camada superficial do solo e, nesse caso, o mecanismo utilizado na semeadora para a abertura dos sulcos para deposição do fertilizante pode ter grande importância no sentido de facilitar a penetração das raízes. Este experimento foi desenvolvido em Selvíria (MS), com o objetivo de avaliar a produtividade do feijão de inverno cultivado em sistema plantio direto, em função da utilização de mecanismos de abertura para distribuição de fertilizantes na semeadura e da adubação nitrogenada em cobertura. O delineamento experimental utilizado foi em blocos casualizados, utilizando-se esquema fatorial 2 x 6, constituído por mecanismos de distribuição de fertilizante (haste escarificadora e disco duplo) e doses de N em cobertura (0, 25, 50, 75, 100 e 125 kg ha-1), com quatro repetições. Recomenda-se o uso da haste escarificadora como mecanismo de distribuição do fertilizante, para o cultivo do feijoeiro de inverno. A adubação nitrogenada em cobertura proporciona incrementos à produtividade do feijoeiro de inverno.

Produtividade e qualidade industrial do arroz de terras altas em função da disponibilidade hídrica e adubação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adubação nitrogenada na cultura do milho safrinha irrigado em plantio direto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resposta de soqueiras de cana-de-açúcar à aplicação de nitrogênio em sistema de colheita sem queima

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)