Variabilidade espacial da textura de um argissolo vermelho amarelo sob cultivo de pastagem e vegetação nativa

The study of the spatial variability of soil attributes under different crop helps the study of changes due the management. This research was carried out to determine spatial variability the particle-size distribution, using of the classic statistic and geostatistics, of a soil cultivated with pasture and native vegetation. Soil samples were collected in the layer 0-0.20m, at the crossing points of a regular grid with 10m-intervals, summing up 64 samples points in each area. In the pasture area the fractions of coarse and total sand presented larger mean values in relation to the native vegetation, and negative correlation with the altitude of the points samples in the two areas. All of the fractions presented moderate to high spatial dependence in the two areas and with the defined still, with exception of the fine sand and the silt in the pasture. Much of this variability occurs as a function of water erosion.

Adubação nitrogenada e idade de corte na produção de matéria seca do capim-elefante no Cerrado

The objective of this study was to investigate the effect of the application of N fertilizer and the cutting age on the dry biomass production of elephant grass. The experiment was performed with the variety Paraiso and planted in a Ferralsol in 2008 in the district of Gurupi (State of Tocantins). Four different rates of urea application were tested (0, 50, 100 and 150 kg ha(-1)) and harvests were made at 120, 150 or 180 days after germination (DAG) of the setts. The dry matter and total N accumulation were evaluated. Dry matter production increased with dose of N, the greatest effect being observed at 180 DAG. There was a linear increase in dry matter (R-2 = 0.75**) and N accumulation (R-2 = 0.96**) permitting a productivity of 34 t ha(-1) of dry matter and an accumulation of 471 kg N ha(-1). The N utilization efficiency (biomass production per unit of applied N) increased with plant age. The higher efficiency of N use favored the quality of biomass production for energy production owing to the higher fibre content.

Variabilidade espacial de atributos químicos em um Argissolo sob pastagem

Studies show the importance of knowing the variability of soil attributes for a more efficient management. This work was carried out to evaluate the spatial variability of the chemical attributes of an Ultisol, cultivated with Brachiaria decumbens pasture in Alegre - ES. Soil samples were collected at a depth of 00-0.2 m, at the crossing points of a regular grid with 10 m-intervals, comprising a total of 64 points. Data were submitted to descriptive statistics, geostatistics and kriging interpolation analysis. The coefficient of variation was low for pH, high for Al and m%, and medium the other attributes. The attributes pH, P, H+Al and m% presented strong dependence, and the other moderate dependence. The attributes presented a spatial dependence structure, allowing their mapping by geostatistics techniques.

Qualidade tecnológica da cana-de-açúcar sob adubação com torta de filtro enriquecida com fosfato solúvel

The study had the objective to evaluate the effect of the fertilization with filter cake enriched with soluble phosphate on the sugar yield. The experiment carried at Presidente Prudente-SP, used a randomized complete block design, in the factorial scheme 5 x 4, where the first factor consisted of doses of filter cake (0; 0.5; 1.0; 2.0 and 4.0 t ha(-1)) and the second, doses of phosphorus fertilizer (0, 50, 100, 200 kg ha(-1) of P2O5), with 4 replicates, totaling 80 plots. The results indicated that phosphorus applied in planting furrows improves the quality of sugarcane raw matter by increasing the levels of soluble solids, total reducing sugars and sucrose in the stalks. The phosphorus also increases the productivity of sugar. The filter cake applied in planting furrow has the potential to partially replace the chemical fertilization with phosphate aiming to improve the quality and the productivity of sugar. The best combination was filter cake at dose between 2.6 and 2.7 t ha(-1) combined with dose between 160 and 190 kg P2O5 ha(-1) for obtaining best response of soluble solids and productivity of sugar.

Adubação organomineral e biofertilização líquida na produção de frutos de pinheira ( Annona squamosa L.) no submédio São Francisco, Brasil

The organic production systems based on natural processes do not allow the use of synthetic fertilizers with a high solubility, so it is required the use of technologies in accordance with the organic production legislation in order to make the technical, economical and environmental sustainable activities viable. To evaluate the effects of the usage of mineral and organic natural fertilizers, associated with liquid biofertilizers (BLE= enriched liquid biofertilizer and BF= leaf biofertilizers) on the production of the sugar apple fruit crop Annona squamosa L., replacing totally the chemical fertilizers, used by conventional farming systems, a nine year old orchard was driven in the irrigated plot n degrees 1295, irrigated project Nilo Coelho, district of Petrolina - PE. The experiment was carried out from September 2005 to February 2006. The experimental design was done through randomized blocks with eight treatments and four replications in plots of three plants each, with 96 plants in total. The treatments were the following: T(1) - plants with no fertilizer; T(2) - 60 g de N + 32 g de P(2)O(5) + 48 g de K(2)O; T(3) - 90g de N + 32 g de P(2)O(5) + 48 g de K(2)O; T(4) - 30 g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 15 L de BLE + BF a 5 %; T(5) - 60g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 30 L de BLE + BF a 5 %; T(6)- 90g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 45 L de BLE + BF a 5 %; T(7) - 120g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 60 L de BLE + BF a 5 %; T(8) - 150 g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 75 L de BLE + BF a 5 % The fruit growth analyses (diameter and average length), total yield, productivity, average fruit weight, average number of fruits, fresh weight of the skin and pulp and dry weight of the fruits were used to evaluate the experiment. The results were relevant to the total production, fresh weight of the skin and dry weight of the fruits. The use of organominerals associated with liquid fertilizers increased significantly the productivity in values ranging from 10.44% (T(5) = 1.98 t ha(-1)) to 24.52 % (T(7) = 12.34 %). The treatment T(3) stood out (90g de N + 32g de P(2)O(5) + 48g de K(2)O) with a higher production than the control. The fruit weight increased in the fertilized treatments, with values increasing from treatment (T(2) = 5.26 %) to the treatment (T(7) = 12.34 %) in relation to the control. The fruit development was characterized by an average growth increase of 82 % in length and 84 % in diameter until the 56(th) day, with a sigmoidal growth pattern.

Estoque de carbono orgânico no solo afetado por adubação orgânica e sistemas de culturas no Sul do Brasil

Organic carbon is a major component of soil organic matter and its stock is influenced by the management system adopted. This study aimed to examine the effects of cropping systems and nutrient sources (mineral and organic) on the concentrations and storage of soil organic carbon in no-tillage system. The experiment was carried out in Mercedes, Parana, Brazil, in an Nitossolo Vermelho (Alfisol) from October 2007 to September 2009. The treatments consisted of four crop succession systems: (1) soybean/wheat/corn/wheat; (2) soybean/black oat/corn/black oat, (3) soybean/radish/corn/radish and (4) soybean/common vetch/corn/common vetch and by two sources of nutrients (mineral and organic), arranged in a to split plot randomized block design with four replications. Soil samples were collected in layers of 0.0-0.05, 0.05-0.10, 0.10-0.20 and 0.20 to 0.40 m deep in the first and the second years of cultivation. Different cropping systems does not affect the content and the stock of soil organic carbon in the first two years of adoption of the systems. The organic fertilization with manure increased soil organic carbon stock, with an annual contribution of C, layer 0.0 to 0.20 m, 1.15 Mg ha(-1) yr(-1). Cropping systems fertilized with mineral fertilizers provide the greatest losses of soil organic carbon, resulting in negative balance of C in soil.

Adubação fosfatada, produção e qualidade de sementes de populações de amendoim

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos da adubação com manipueira sobre o rendimento e qualidade dos frutos de tomate

The objective of this research was to evaluate the residue from cassava, known as manipueira, as an alternative for tomato (Lycopersicon esculentum) fertilization. This experiment was carried out in UNESP with the cultivar Rio Grande. The experimental design was a completely randomized blocks in a 3 × 3 factorial arrangement with five blocks. Treatments constituted the following: 1) witness; 2) 54 m3/ha of manipueira; 3) 108 m3/ha of manipueira; 4) half recommended mineral fertilization; 5) half recommended mineral fertilization + 54 m3/ha of manipueira; 6) half recommended mineral fertilization + 108 m3/ha of manipueira; 7) recommended mineral fertilization; 8) recommended mineral fertilization + 54 m3/ha of manipueira and 9) recommended mineral fertilization + 108 m3/ha of manipueira. Tomato yield, number of fruits per plant, fruit diameter and lenght, total soluble solids (TSS), total titratable acidity (TTA) and the ratio TSS/TTA were evaluated. The results obtained indicated that manipueira contributed significantly to yield and quality of pos-harvested tomato fruits.

Adubação verde em Citrus: Influência na porosidade e retenção de água de um latossolo vermelho-escuro do noroeste do estado de São Paulo

The objective of this research was to study the porosity, bulk density and retention of water of an Oxisol, located in the Northwestern region of Sn̄o Paulo state, Brazil. The soil was cultivated with Citrus sp., to which green manure was applied between rows for three years. Each of six species of green manure crops (Crotalaria juncea L., Mucuna deeringiana Steph. & Bart., Canavalia ensiformis L. DC., Cajanus cajan L., Lablab purpureum L. and Ricinus communis L.) were seeded for three years (1995, 1996 and 1997) between Citrus rows, plus a treatment with a mix of all six species and a control (natural regrowth af vegetation). The experimental design was a randomized complete block design, with four replications for each of the eight treatments. Water retention, microporosity, macroporosity, total porosity and bulk density were analyzed in the beginning (1995) and end (1997) of the experiment, at three depth ranges (0-0.10; 0.10-0.20 and 0.20-0.40m). We concluded that there were statistically significant differences for bulk density, macroporosity, total porosity and retention of water among the different soil depth ranges; there were no significant differences among treatments though.

Uso da adubação foliar nitrogenada e potássica no algodoeiro

The present work was conducted in Selvíria county (MS-Brazil), in the agricultural year of 1998/99, for evaluating nitrogen and potassium foliar application to supplement sowing fertilization on cotton (IAC 22) crop. A randomized complete block design with 13 treatments and four replications was used. The treatments were constituted by a control (without foliar application) and nitrogen and/or potassium foliar applications two, four, six or eight weeks after beginning of flowering. The urea was used as source of N and potassium chloride as source of K. Urea in the concentration of 10% and potassium chloride at 4% were applied at a rate of 250 L.ha-1. Height of plants, nodule number, number of reproductive branches, boll per plant, 30 boll mass, yield and fiber percentage were evaluated. It is concluded that the N doses increased the yield and decreased the fiber percentage. There was no evaluated response to the application of K or NK.

Plasticidade fenotípica da morfologia externa de Lippia alba (Mill.) N. E. Br. ex Britt. & Wilson (Verbenaceae) em resposta a níveis de luminosidade e adubação

The objective of this paper was to evaluate the phenotypical plasticity of external morphology of Lippia alba in response to two luminosity level and four organic-mineral fertilization level. The morphological plasticity was quantified by the phenotypic variation intensity of the morphological characters (ramifications, leafs, inflorescences, flowers, height, stem diameter, leaf blade length, foliar blade breadth and space between branches). It was possible to verify significant effect as a consequence of luminosity and substratum variations. However, the interaction between these factors was not observed suggesting that they act independently. The majority of characters revealed high magnitude of phenotypical plasticity. The results obtained suggest that luminosity intensity and substratum quality contribute to amplify the phenotypical expression of Lippia alba.

Disponibilidade, composição bromatológica e consumo de matéria seca em pastagem consorciada de Brachiaria decumbens com Stylosanthes guianensis

The objective of this work was to evaluate the herbage availability, nutritive value, dry matter intake and grass and legume percentage in diet of crossbred Holstein-Zebu cows, in pasture with Brachiaria decumbens cv. Basilisk, Stylosanthes guianensis var. vulgaris cv. Mineirão and tree legumes. To estimate the fecal output, it was used 10 g cow -1 day -1 of chromium oxide during ten consecutive days. Extrusa samples were used to determine the chemical composition and in vitro dry matter digestibility. B. decumbens availability varied with climatic conditions, while S. guianensis availability decreased linearly along the experimental period. Dry matter intake was higher in May/2001 (1.9% body weight) and did not differ among other months (1.5% body weight). Low dry matter intake values were related to low in vitro dry matter digestibility coefficients (42.1 % to 48.0%) and high neutral detergent fiber content (70.2% to 79.4%). Dry matter intake was directly related to legume percentage in the pasture. This observation could indicate the potential of mixed pasture for improving nutritive value in dairy cattle diet.

Teores de nutrientes na folha e nos grãos de aveia-preta em função da adubação com fósforo e potássio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parcelamento da adubação nitrogenada na cultura do milho irrigado em sistema plantio direto

The purpose of this study was to evaluate the best time for application of N for an irrigated corn crop in a no-tillage system in the State of Alagoas. Three corn hybrids were used (TORK, FORT and BRS-3003) with four application times (days after sowing - DAS) for fertilizing with nitrogen as top dressing, consisting of the following treatments: 1) 120 kg ha-1 at 15 DAS, 2) 60 kg ha-1 at 15 DAS and 60 kg ha-1 at 30 DAS, 3) 120 kg ha-1 at 30 DAS, 4) 60 kg ha-1 at 30 DAS and 60 kg ha -1 at 45 DAS and 5) control treatment without N fertilization. The experimental design was in randomized blocks with four replications in a subdivided plot scheme. The components of the production studied were: final population of plants ha-1, numbers of corn ears ha-1 length of corn ears and number of rows of grains of corn and mass of 1000 grains. The productivities of grains obtained did not present significant differences among the treatments that received fertilization with nitrogen, independent of the time of application and number of split applications. It is concluded that in the notillage system in Alagoas spliting the manuring with nitrogen (top dressing) is not necessary.