This study was conducted to evaluate the yield of two maize varieties cropped with organic and mineral fertilizations either associated or unassociated. The randomized experimental design was used under a factorial scheme 2 x 3 x 2, with four replicates. The first factor corresponds to two maize varieties (Nitrodent and Nitroflint), whereas the second one represents three levels of mineral fertilization: without mineral fertilizer; 300 kg/ha of 4-14-8 + 100 kg/ha ammonium sulfate (S.A.); and 600 kg/ha of 4-14-8 + 200 kg/ha S.A. The third factor represents two organic fertilization levels: without organic fertilizer; and 40 m3/ha organic compound. The experimental plot consisted of eight plant rows with 8m length each one and 1m spacing from each others, so totaling 64 m2 area. The yield of the maize grains by plot were evaluated, and the data were subjected to variance analysis (test ¿ 5%). The averages were compared by Tukey test at 5% probability level. Both varieties Nitrodent and Nitroflint only cropped under the organic system reached more than 6.500 kg/ha. The exclusive organic cropping system provided higher yields of maize grains, compared to the conventional system. No significant differences were found between the exclusive organic system and the combination of both organic and conventional systems upon the grain yield of the Nitrodent variety.

The soil fertility and plant nutrition are influenced by electrochemical reactions occurring on the surface of soil colloids. The point of zero salt effect (PZSE) is an important parameter to study the surface charge of those colloids, since, it allows to determine the net surface charge of soil particles. This paper aimed to determine the PZSE and the net electrical charge of twelve soils from Paraíba State, which samples were collected at the depth of 0-30 cm. The point of zero salt effect was determined using program computational PZSE for Windows version 1.0. The method adopted was the potentiometric titration with different ionic strength using electrolyte NaCl in concentrations 0.1; 0.01 and 0.001 M. The use of the program has a better analysis and accuracy of the values obtained for the PZSE, which ranged from 3.06 to 5.41. All soils had values of PZSE smaller than the pH in water, being, therefore, electronegative. All soils had the potential and the electrical charge negative, possibly due to the effect of organic matter once it presented significant correlation with PZSE.

In environmental studies is important to know the adsorption process of heavy metals in clay minerals, since they are able to immobilize these metals. Knowing the cations adsorption is influenced for several factors, the objective of this research was to study the zinc adsorption process by bentonite clay and to evaluate the particle size of clay and pH influence on this process. In order to quantify the adsorbed zinc, 2 g of bentonite clay, dried at room temperature and sieved at 0.5 and 2-mm-mesh, were equilibrated for 24 hours with 20 mL of water containing different quantities of zinc (10, 15, 20, 30, 50, 100, 150 and 200 mg L-1) as background solutions of pH values 4 and 6. Langmuir's adsorption equation in its linearized form was applied and the values of the maximum capacity and those of the constant related to the bonding energy were obtained. The results showed that Langmuir equation was adequate to describe zinc adsorption at different pH values and particle size of bentonite clay. Zinc adsorption in bentonite clay depended on pH and particle size, decreasing as they increased. The maximum retention capacity, 3.24 mg g-1, was obtained in pH 4 using particle size of bentonite clay < 0,5 mm.

The work was developed in a greenhouse, with the objective to evaluate the behavior of Sudan sorghum in one normal and another saline-sodic soil treated with increasing concentration solutions of calcium chloride. Two samples of Alluvial Soil proceeding from the half-barren part of Paraíba, Brazil, with salinity and sodicity problems had been used. The physical and chemical characterization of soil samples was carried and was mounted an experiment in randomized block type, at 2 x 6 factorial arrangement, being two soils and six solutions of calcium chloride with increasing concentrations, in three replicates. The soil had been conditioned in polyethylene vases with 5,0 kg of capacity, being submitted to the ticket of the solutions during sixty days, being then made a sampling for determination of the exchangeable sodium and the calculation of ESP. After this period, was planted one sorghum tolerant cultivar to salinity, being continued the ticket of the solutions under daily irrigation. At 60 days of application of calcium chloride solutions, it was observed that it had a reduction of the ESP, which continued being reduced until the 120 days, mainly for the saline-sodic soil, correcting the sodicity partially. The effect of the salinity had been evident in sorghum cultivated in saline-sodic soil, with problems since the germination in the treatments of lesser calcium chloride concentration, with improvement in the growth of the plants in the intermediate levels and decrease in the last level, probably, for the raised saline concentration, reflecting in the height of the plants and the production of dry matter.

Hydroponics is a method of culture which offers producers a larger number of cycles throughout the year, and value aggregated to vegetables. Empiricism, however, in the use of nutritive solutions, and the non-adoption of harvest times at which lower nitrate content can be achieved, may lead to a drop in produce quality due to the accumulation of nitrate. An experiment using a hydroponic method, the NFT, was conducted in the spring of 2003, in Jaboticabal, SP, aimed at evaluating nitrogen concentration in the nutritive solution (60,8; 121,6; 182,5; 243,5 mg L-1), rocket cultivars (Cultivada, Folha Larga and Selvática) and harvest time factors (7 a.m., noon and 5 p.m.) in nitrate content of rocket. The experiment was carried out in a randomized blocks design and a 4 x 3 x 3 factorial design, with four replications. For nitrogen concentration in the nutritive solution of 93 mg L-1, which showed higher MFPA, nitrate content was 598,4 mg kg-1 NO3 - fresh matter for rocket harvested at 7 a.m.

The purpose of this study was to assess the seedling growth of cashew and tamarind rootstocks with nitrogen fertilization. To this end, two experiments were conducted in the Production Sector of the State University of Mato Grosso do Sul (UEMS), at the University Unit of Cassilândia (UUC), Brazil. Five nitrogen levels were tested: 0, 400, 800, 1600 and 3200 mg/dm3 of N in the substrates. The experimental design was in randomized blocks with 4 repetitions and ten plants per parcel. 20 ml of urea solution were added to each application from each treatment containing 45% nitrogen. The application was repeated four times. Ninety days after planting, we assessed plant height (cm), number of leaves/seedling, plant diameter (mm), roots, aerial part, root and total dry matter (g/seedling). Nitrogen fertilizer in doses of up to 2000 mg/dm3 of N in the substrate ensures better cashew and tamarind rootstock seedling quality. A 3200 mg/dm3 dose of N in the substrate had a growth depression effect on the rootstock seedlings.

Brazil possesss potential for attainment of great amounts of apicultural products, what it differentiates it of the too much countries that, normally, harvests an only time per year. However despite the diversity of the apicultural flora and the high existing food concentration in the rainy period, during the dry station, a scarcity of apicultural grass e occurs, consequently, of food for the bees being necessary a complementary feeding of this form assuring the productivity and the profits. The feeding of the bees of course is very selective, them is adapted in the adult phase to an feeding eliminates, however, these unbalanced fluids little is concentrated and its composition with predominance of sugars, thus needing complementing in the diet with a rich food in proteins as form is pólen.Dessa is necessary to know foods conventional and alternative for the period of between harvest diminishing the loss of the brief produção.Esta revision presents excellent aspects of the feeding of the bees relating its chemical composition, nutritional value and functional properties.

This study evaluated the effect of bovine manure in the agronomic performance of salad rocket cv. Cultivada. The completely randomized design was used, with six treatments and four repetitions, with each recipient constituting a parcel. The treatments had consisted of differents amounts of bovine manure incorporated to the soil (20, 40, 60, 80, 100 t.ha¯¹), and the witness. The evaluated characteristics had been: height of plant (cm), leaf number for parcel, mass of the green substance (g) and mass of the dry substance (g) for parcel. The amount of 60 t.ha¯¹ promoted greater height of plants, greater leaf number, greater mass of the green substance and greater of mass of the dry substance.

The present work has as objective to determine and compare the variation of basic density of peroba's wood throughout the Aspidosperma polineuron, that specie belongs to Apocynaceae's family, known popularly as Peroba. The sample was carried in three selected trees at random form in dense Ombrófila¿s forest in Apiuna and President Nereus Ramos/SC. The trees were knocked and they had their changeable dendrometrics measured. The basic density was determined in samples of 1,5 x 1,5 x 5 cm, removed of the internal part of the record (cerne) and the external part (alburnum), having been these collected the height of chest (DAP), 0%, 10%, 50%, 75% and 95% of morphologic inversion's point. Above this, two samples with branches called G1 and G2 were colleted. The basic density was gotten through the relation between the dry weight and the green volume of samples, revealing increasing of the base for the top of the tree. In the accomplishment of variance's performance (ANOVA) was not able to be verified significant differences between the averages of densities throughout the log and the branches. The average basic density was 0, 66 gcm3. The uniformity found for basic density throughout the stem is a characteristic that confers the specie stability and security for its use in structural projects, however it´s necessary deeper studies to better scientific fundaments of its physical and technological properties.

The study area covers all the territory of the municipality of Boa Vista, located in the Microrregião Homogênia dos Cariris Velhos, semi-arid region of the State of Paraíba. The main objective of this study was to elaborate space-temporal thematic maps of the land degradation expansion in the municipality of Boa Vista for the period 1987/2004, based on TM/Landsat-5 image analysis and field work data. The Landsat images digital processing was carried on the SPRING, v.4.2. The results had shown that in the study area are presented degradation levels varying from low to the very serious. The degradation levels very low, low, moderate and serious had their occurrence diminished in 2.59%, 11.80%, 12.86% and 0.88%, respectively during the period since 1987 to 2004. In opposing way, the areas of moderate serious and very serious degradation levels had increased in the period, with increments of 20.14% and 7.65%, respectively. The process of land degradation is more present in the neighborhoods of the rural houses and along the rivers, where the humidity of the ustifluvents soils guarantees better security for dry land agriculture and for the fodder plants for feeding live stocks in dry period. In the municipality the land degradation is resultant of a lack of conservation practical in the use of agricultural soils by the farmers, of a lack of an infrastructure for mitigating the drought effects and of a lack of public polices for a sustainable life in the semi-arid region.