Atributos físicos de um Latossolo Vermelho distrófico degradado em resposta à aplicação de biossólidos

Sewage sludge, waste with high organic matter content and rapid decomposition, combined with sawdust, rich in carbon and slow decomposition, are suitable components for the study of degraded areas. In order to test the interactions of these residues in the recovery of a degraded soil in Selvíria - MS, four doses of sewage sludge (0, 8, 16 and 24 t ha -1, dry basis ) and four doses of sawdust particles (0, 8, 16 and 24 t ha-1, dry basis ) were tested in February 2009, in a completely randomized block design (4 × 4 + 1 factorial), with four replications. As indicators of the effects, the penetration resistance, gravimetric moisture and soil bulk density (0-0.10, 0.10-0.20; 0.20-0.40 m) were used. Significant effects were observed for the factors (sewage sludge and sawdust) and control treatment for penetration resistance in the soil depths studied, for gravimetric moisture in the intermediate layer and for the soil density in the surface and intermediate layers. Considering the type of soil and the short period of study (24 months), the use of organic wastes presented improvement in physical properties of soil in relation to control. However, it is necessary to study them for a longer period.

Características agronômicas do feijão caupi inoculado em função de lâminas de irrigação e de níveis de nitrogênio

The aim of this study was to evaluate the effect of different irrigation depths and nitrogen levels on the agronomic characteristics of inoculated cowpea. The experiment was arranged in splitplots, with the levels of nitrogen in the plots and the depth of irrigation in the splitplots, in a randomized block design, with two repetitions. The irrigation depth corresponded to 578 mm (L1), 512 mm (L2), 429 mm (L3), 299 mm (L4) and 240 mm (L5), and the nitrogen levels of 0, 30, 60 and 90 kg ha-1 of N. The nitrogen levels showed significant effect on the yield components of cowpea. The irrigation depth showed significant effects on productivity of bean cowpea, with the depth of 426.21 mm estimated for obtaining the maximum productivity of 2820.03 kg ha-1.

Danos do complexo broca-podridão à produtividade e à qualidade da cana-de-açúcar fertirrigada com doses de nitrogênio

The objective of this work was to evaluate the effect of nitrogen-fertigation on the damage caused by the borer-rot complex to the productivity and quality of fertigated sugarcane. The experiment was carried out in field, using a randomized complete block design, with four replicates and five N doses (0, 50 100, 150, and 200 kg ha-1) applied through drip irrigation. The following variables were determined: number of holes caused by Diatraea saccharalis (Lepidoptera: Crambidae); number of internodes infected with red rot; incidence percentage of red rot; stalk productivity; and sugar content. In laboratory, the attractiveness and the consumption of culm fragments by fourth instar caterpillars, in trials with or without choice, were evaluated. Nitrogen fertigation increased the incidence of D. saccharalis and red rot. The number of holes produced by the larvae was correlated with the occurrence of red rot. Sugar percentage reduced with the increase in the number of red rot affected internodes. Nitrogen doses did not affect the attractiveness of sugarcane culm fragments; however, higher N doses increased the consumption of these fragments by D. saccharalis caterpillars. Despite the damages to quality, nitrogen fertilization expressively enhanced the productivity of stalks and sugar.

Source-driven remobilizations of nutrients within stem wood in Eucalyptus grandis plantations

Nutrient remobilizations in tree ligneous components have been little studied in tropical forests. A complete randomized block design was installed in Brazilian eucalypt plantations to quantify the remobilizations of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) within stem wood. Three treatments were studied: control with neither K nor Na addition (C), 3 kmol ha-1 K applied (+K), and 3 kmol ha-1 Na applied (+Na). Biomass and nutrient contents were measured in the stem wood of eight trees destructively sampled at 1, 2, 3 and 4 years after planting in each treatment and annual rings were localized on discs of wood sampled every 3 m in half of the trees. Chemical analyses and wood density measurements were performed individually for each ring per level and per tree sampled. Nutrient remobilizations in annual rings were calculated through mass balance between two successive ages. Our results show that nutrient remobilizations within stem wood were mainly source-driven. Potassium and Na additions largely increased their concentration in the outer rings as well as the amounts remobilized in the first 2 years after the wood formation. The amount of Na remobilized in annual rings was 15 % higher in +Na than in +K the fourth year after planting despite a 34 % higher production of stem wood in +K leading to a much higher nutrient sink. A partial substitution of K by Na in the remobilizations within stem wood might contribute to enhancing Eucalyptus grandis growth in K-depleted soils. © 2013 Springer-Verlag Berlin Heidelberg.

Rendimento e qualidade de melancia cultivada sob proteção de agrotêxtil combinado com mulching plástico

The ground cover is an agricultural practice that is designed mainly to control weeds, while the nonwoven prevents the attack of pests. The objective of this study was to evaluate the yield and fruit quality of watermelon grown under nonwoven textile protection combined with plastic mulching. The experiment was conducted at the WG Fruits Company, Baraúna, RN. A randomized block design was used in a factorial 3 x 3 + 1 with four replications, and 36 plants per plot, with the first factor of color of plastic used in mulching (black, silver and white) and the second factor nonwoven textile with different times of use (first and third crop nonwoven under textile and without nonwoven) and an absolute control (no mulching and without nonwoven). The production variables evaluated were: yield (commercial, noncommercial, and total fruit yield), and fruit quality (soluble solids - SS, titratable acidity - TA and SS/TA). The use of mulching and protection of plants with nonwoven textile provided a higher yield of watermelon fruits in relation to bare soil with and without nonwoven textile protection. Fruit quality was not affected by the use of mulching and nonwoven.

Parâmetros genéticos entre caracteres quantitativos no girassol como critério de seleção para produtividade de aquênios

Two experiments were conducted in southern Brazil in no-tillage system, in order to estimate genetic parameters and the direct and indirect effects of components for achene yield as a selection criterion in sunflower. We analyzed eight sunflower hybrids at two locations, in a randomized complete block design with four replicates, determined through quantitative descriptors: insertion height of the head, and head stem diameter, weight of 1000 achenes, number of achenes per head, mass by achene head and yield achene. Estimates of genetic parameters were based on combined analysis, decomposing interactions in genetic and environmental components. Considering the coefficient of genetic variation, indirect effects of components and heritability, there are higher possibilities for responses to selection in sunflower achenes by descriptors mass and mass of achenes per head, with its indirect association interrelated pathways for the increase in the achenes of yield.

Desenvolvimento corporal de novilhas leiteiras suplementadas com minerais inorgânicos e orgânicos em pastejo na época das águas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistemas de manejo e efeito residual do potássio na produtividade e nutrição do feijão-caupi

Cowpea [Vigna unguiculata (L) Walp] have great social and economic importance for the Para State. It grows well in areas with low precipitation and two crop cycles can be obtained annually. This study aimed to assess the effect of the residual fertilization from a previous culture (Sorghum bicolor L. Moench) and crop systems on cowpea yield and macronutrient concentration on leaves of three cowpea cultivars (BRSMilênio, BRS-Urubuquara e BRS-Guariba). The study was conducted at the UFRA. The treatments were two crop systems (minimum tillage and conventional), four levels of potassium (50, 100, 200 e 300 kg de KCl ha-1 applied to a previous sorghum culture) and the three cowpea cultivars. Treatments were organized as a three (4 x 2 x 3) factor experiment on a randomized complete block design. The soil was a yellow latosol. In each experiment plot five plants were selected to determine shoot dry matter and foliar nutrient concentration. Grain yield was determined after harvesting all plants on the experiment plot. The residual KCl fertilization affected foliar nutrient content, but did not affect shoot dry mass or yield of grain. Yield was higher in the minimum tillage system. Highest yield (1590 kg ha-1) was recorded int the cv. 'Guariba' when 100 kg of KCl ha-1 had been used in the previous crop. The highest content of leaf N and K was found in cowpea under minimum tillage system. The amount of P and Mg were higher in the conventional system whereas the amount of Ca did not change.

Formas de aplicación de zinc para las plantas de maíz que crecen en Oxisol: Efectos sobre el suelo, la nutrición de las plantas y la productividad

The way of applying zinc can influence the zinc uptake and productivity of crops, especially cereals that have high demand for this nutrient. The aim of this study is to evaluate methods of Zn application on soil, nutritional status and productivity of maize. For this, an experiment was undertaken at FCAV/UNESP, Jaboticabal-SP, in Oxisol clay (DTPA on Zn: 0.5 mg dm-3) with maize (hybrid Simple Impact), from December through May 2009. Nine treatments with three doses of Zn in soil banded application (in furrows) and three doses of Zn by incorporation in soil (0-20 cm depth), foliar application, seed application and control (no Zn). The treatments were arranged in a randomized block design with four replications. Regardless of the method, Zn application promoted higher contents of this micronutrient in soil and higher accumulation in the shoots as well as increasing Zn in the maize grain. However, it did not affect the nutritional status and yield of the maize. The Zn application in the soil resulted in a greater Zn uptake by plants and maize yield, compared to Zn application in the plant by seed or foliar.

Comportamento do noni à salinidade da água de irrigação em solo com biofertilizante bovino

Salt excess in soil and water used for irrigation can cause significant loss of production and growth in cultivated plants. Among some options for reduction of negative effects of salts to plants in cultivated areas, fermented bio fertilizer has been used to grow vegetables and fruit tree irrigated with saline water. The study aimed at evaluating the behavior of the noni plant to salinity of the irrigation water in substrate with and with no bio fertilizer. Treatments were arranged in a randomized block design with four replications, using a 5 × 2 factorial arrangement. Five levels of electrical conductivity of irrigation water (0.5, 1.5, 3.0, 4.5, 6.0 dS m-1) were used in substrates with and with no bio fertilizer. Parameters were evaluated as follows: plant height, stem diameter, number of leaves, leaf area, shoot dry matter and water consumption. All evaluated variables were negatively affected by the increase in salt concentration of the irrigation water, but always with less intense effects in treatments with bio fertilizer.The bio fertilizer does not eliminate, but mitigates the negative effects of salts in noni plants.

Produção de bovinos de corte em pastagem de aveia preta e azevém submetida à adubação nitrogenada

We evaluated animal production on black oats (Avena strigosa Schreb.) and italian ryegrass (Lolium multiflorum) pasture submitted to nitrogen top fertilization of 0; 150 and 300 kg ha-1, in the form of urea. We used 36 calves with average age and average weight of 10.5 months and 180 kg, respectively, as test-animals. The grazing system used was continuous with variable stocking rate. The block design was completely randomized with three replicates (paddock). Average weight gain was similar for the levels evaluated (0.925; 0.969 and 1.045 kg day-1, respectively). Stocking rate and live weight gain per hectare showed a linear relation with nitrogen levels. The efficiency of animal production was 2.040 and 1.766 kg of weight gain per kg of nitrogen used for the dose of 150 and 300 of N, respectively. The stocking rate and live weight gain per hectare of beef calves increased with the nitrogen levels, from 0 to 300 kg of N ha-1. However, the best efficiency in weight gain per unit of nitrogen applied was obtained with the dose of 150 kg of N ha-1.

Sorghum grain yield, forage biomass production and revenue as affected by intercropping time

Sorghum is an excellent alternative to other grains in poor soil where corn does not develop very well, as well as in regions with warm and dry winters. Intercropping sorghum [Sorghum bicolor (L.) Moench] with forage crops, such as palisade grass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] or guinea grass (Panicum maximum Jacq.), provides large amounts of biomass for use as straw in no-tillage systems or as pasture. However, it is important to determine the appropriate time at which these forage crops have to be sown into sorghum systems to avoid reductions in both sorghum and forage production and to maximize the revenue of the cropping system. This study, conducted for three growing seasons at Botucatu in the State of São Paulo in Brazil, evaluated how nutrient concentration, yield components, sorghum grain yield, revenue, and forage crop dry matter production were affected by the timing of forage intercropping. The experimental design was a randomized complete block design. Intercropping systems were not found to cause reductions in the nutrient concentration in sorghum plants. The number of panicles per unit area of sorghum alone (133,600), intercropped sorghum and palisade grass (133,300) and intercropped sorghum and guinea grass (134,300) corresponded to sorghum grain yields of 5439, 5436 and 5566kgha-1, respectively. However, the number of panicles per unit area of intercropped sorghum and palisade grass (144,700) and intercropped sorghum and guinea grass (145,000) with topdressing of fertilizers for the sorghum resulted in the highest sorghum grain yields (6238 and 6127kgha-1 for intercropping with palisade grass and guinea grass, respectively). Forage production (8112, 10,972 and 13,193Mg ha-1 for the first, second and third cuts, respectively) was highest when sorghum and guinea grass were intercropped. The timing of intercropping is an important factor in sorghum grain yield and forage production. Palisade grass or guinea grass must be intercropped with sorghum with topdressing fertilization to achieve the highest sorghum grain yield, but this significantly reduces the forage production. Intercropping sorghum with guinea grass sown simultaneously yielded the highest revenue per ha (€ 1074.4), which was 2.4 times greater than the revenue achieved by sowing sorghum only. © 2013 Elsevier B.V.

Seletividade de herbicidas à cultura da mandioca

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise comparativa da produtividade de híbridos de mamoneira (Ricinus communis L.) obtidos por meio da hibridação convencional e do método de híbridos crípticos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aplicação de calcário, silicato e gesso em soqueira de cana-de-açúcar sem despalha a fogo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)