Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil)

The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil), in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean) and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5). In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation) as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient). After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped) was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

Ruzigrass affecting soil-phosphorus availability

The objective of this work was to evaluate the effectiveness of ruzigrass (Urochloaruziziensis) in enhancing soil-P availability in areas fertilized with soluble or reactive rock phosphates. The area had been cropped for five years under no-till, in a system involving soybean, triticale/black-oat, and pearl millet. Previously to the five-year cultivation period, corrective phosphorus fertilization was applied once on soil surface, at 0.0 and 80 kg ha-1 P2O5, as triple superphosphate or Arad rock phosphate. After this five-year period, plots received the same corrective P fertilization as before and ruzigrass was introduced to the cropping system in the stead of the other cover crops. Soil samples were taken (0-10 cm) after ruzigrass cultivation and subjected to soil-P fractionation. Soybean was grown thereafter without P application to seed furrow. Phosphorus availability in plots with ruzigrass was compared to the ones with spontaneous vegetation for two years. Ruzigrass cultivation increased inorganic (resin-extracted) and organic (NaHCO3) soil P, as well as P concentration in soybean leaves, regardless of the P source. However, soybean yield did not increase significantly due to ruzigrass introduction to the cropping system. Soil-P availability did not differ between soluble and reactive P sources. Ruzigrass increases soil-P availability, especially where corrective P fertilization is performed.

Produtividade, qualidade fisiológica e composição química de sementes de crambe em diferentes doses de fósforo

The crambe is a brassica with high content of oil used for biodiesel production and that has aroused interest in the short cycle and low production cost. However, there are doubts about their response to phosphated fertilization. The objective of this study was to evaluate the effect of different doses of phosphorus on yield, physiological quality, chemical composition and oil content of crambe seeds. The treatments consisted of five doses of phosphorus (0, 25, 50, 75 and 100 kg ha(-1)) applied at sowing. There was no effect of phosphorus on mineral composition and oil content of the seeds of crambe that showed the following averages: 30.11 N, 7.46 P, 7.35 K, Ca 10.06, 6.58 mg and 8.98 g kg(-1) S; 36.25 Cu, Fe 169.40, 36.75 Mn 73.60 mg kg(-1) Zn and 30.22% oil. It was concluded that the productivity of crambe increases with phosphorus rates of up to 100 kg ha(-1), but its use does not affect the survival rate of plants, dry mass, the mass of thousand seeds, the physiological quality, chemical composition and oil content of the seed.

Uso de torta de filtro enriquecida com fosfato natural e biofertilizantes em Latossolo Vermelho distrófico

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

Efeitos da fosfatagem em pré-plantio nas condições químicas do solo e no desenvolvimento da cultura da cana-de-açúcar

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Fosfato decantado e calagem no perfilhamento e produção de massa seca do capim-marandu

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Andropogon grass consortium with stylo in two times: the forage response and sources of phosphorus rates

The use of legumes intercropped with forage in the Brazilian savannah (Cerrado) region is an alternative to reverse the process of pasture degradation. The natural phosphorus deficiency in this region and the high retention capacity of this nutrient in the soil are factors that directly affect the sustainability of the production system. The objective of this study was to evaluate the effect of a phosphate with medium solubility (Arad) compared to more soluble sources such as triple superphosphate and mono-ammonium phosphate, on the formation and maintenance of pastures of Andropogon gayanus with or without the introduction of Stylosantes guianensis in pasture already established in the Brazilian savannah. Two experiments were carried out under field conditions in an Oxisol using a randomized block design with split plots, plots with two sources of phosphorus (Arad and super-triple or MAP) and subplots with different levels of phosphorus. The study showed that andropogon grass, even though characterised as forage requiring low fertilization, responded to increased fertilization, especially with the use of more soluble sources of P at planting. From the second year on, with the introduction of Stylosantes guianensis, verified effects were seen on legumes in their efficiency of utilization of residual fertilization from the first year; however, this didn't affect legume dry matter production resulting from the P sources used for the andropogon grass. The mixed stands of andropogon grass and Stylosantes guianensis made it more advantageous to increase the P sources using phosphate fertilizer with lower solubility (Arad), when compared to MAP.

Crescimento e produção do maracujazeiro amarelo, sob diferentes fontes e doses de fósforo em cobertura

Brazil is the largest world producer of yellow passion fruit, a fruit crop which is exigent in nutrients, although little studied in relation to phosphorus fertilizing, fundamental on plant establishment. An experiment was carried out during the period of March/2010 to April/2011 in Remigio County, Paraiba State, Brazil, in order to evaluate the vegetative and productive attributes of yellow passion fruit plants under different sources and doses of phosphorus. Treatments were distributed in randomized blocks in tree replications and twelve plants by plot using the factorial design 2 x 5 referring the sources of superphosphate triple and superphosphate simple at levels P2O5 of 0, 12, 18, 24 and 30 g cave(-1). The following variables were recorded: stem diameter, number of productive branches, number of fruits per plant, fruit mass and fruit yield. The sources and doses of phosphorus affected growth and fruit production of yellow passion plants. The triple superphosphate is the most phosphorus efficient source for growth and fruit production of yellow passion fruit. The triple superphosphate dose which promoted the maximum yield of yellow passion fruit is 42.86 g.

Técnicas intervencionistas de recuperação ecológica em áreas florestais e influências nas características físicas, químicas e isotópicas dos solos

Pós-graduação em Engenharia Civil e Ambiental - FEB

Crescimento, características nutricionais e fisiológicas de progênies de Eucalyptus grandis W. Hill. Ex Maiden sob diferentes doses de fósforo

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Doses de superfosfato simples na produção da berinjela ‘ciça’ em cassilândia (MS) Brasil

The objective of this experiment was to evaluate the answer of the eggplant (Solanum melongena L.) submitted to different applied match doses in the planting hole. The treatments were composed by four doses of simple superphosphate (0, 1000, 2000, 3000 kg.ha-1), the experimental design was randomized block, with five repetitions, tends each unit experimental four plants. The phosphorus fertilized soil propitiated increase of the diameter of the lap of the adult plant, of the number of fruits for plant and productivity of fruits; could be used doses among 1814 to 2054 kg ha-1 of simple superphosphate in the conditions of Cassilandia (State of Mato Grosso do Sul - Brazil).

Adubação nitrogenada e fosfatada no desenvolvimeno de mudas de uvaia (Eugenia uvalha)

Considering the reduced number of works with fertilization of Eugenia uvalha in national literature and being overcome as base the results of the research with fertilization of other fruitful ones, the present work had as objective to study the effect of nitrogen fertilization and phosphorus, in the culture of the Eugenia uvalha. The work was lead in the Department of Agriculture of the Federal University of Lavras, Lavras - MG, in the first semester of 2005. The experiment was adopted the experimental delineation of randomized blocks in factorial project 4 X 4, with four repetitions and 5 plants for parcel, having been 4 doses of phosphorus: 0 kg m(-3); 2,5 kg m(-3); 5,0 kg m(-3); 10,0 kg m(-3); using itself as seasoning source the triple superphosphate. Already for nitrogen, the applications proceeded from 10 in 10 days had been used 4 doses in covering being, had been carried through 4 applications. The applications consisted of a solution with urea, in the doses: 0; 0,8; 1,6 e 3,2 Kg m(-3), in each application had been added to the polyethylene bags, 20 mL of solution contend the N. had been evaluated the following characteristics: height of the dumb one (cm); root length (cm); leaf number; dry substance of the root and the aerial part (g). For the production of changes of Eugenia uvalha of quality, incorporation to the substratum of up to 1,30 kg m(-3) of P(2)O(5) sends regards to it.

Adubação nitrogenada e fosfatada na cultura da mamona cultivada na safrinha em sistema de semeadura direta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adubação nitrogenada, fosfatada e potássica na cultura do eucalipto (clone i144 - E. urograndis)

Pós-graduação em Agronomia - FEIS

Modificações na produtividade e nas características físicas e químicas da madeira de Eucalyptus grandis causadas pela adubação com lodo de esgoto tratado

O Eucalyptus grandis é uma das espécies mais cultivadas no Brasil devido à sua produtividade e qualidade da madeira. Avaliaram-se o efeito da aplicação de lodo de esgoto tratado (0 a 40 t ha-1 base seca) e uma dose de adubo mineral nos atributos físicos e químicos da madeira de Eucalyptus grandis de árvores com cinco anos de idade, no Município de Itatinga, São Paulo, Brasil. O tipo de solo foi caracterizado como Latossolo Vermelho-Amarelo Distrófico (argila = 120 g kg-1 na camada de 0-20 cm) e o clima, como mesotérmico úmido (Cwa), segundo a classificação de Köeppen. O delineamento experimental foi o de blocos ao acaso, com seis tratamentos e quatro repetições. O diâmetro à altura do peito (DAP), a altura das árvores e o volume de madeira foram obtidos em todas as parcelas de oito árvores com DAP na classe de maior freqüência. As caracterizações físicas e químicas da madeira foram realizadas de acordo com as normas da ABTCP, TAPPI e ABNT. O lodo de esgoto diminuiu a densidade básica da madeira, mas não afetou os teores de celulose, lignina, extrativos e o poder calorífico da madeira. O decréscimo de densidade da madeira pela adubação com lodo de esgoto foi compensado pela maior produtividade de madeira.