Aiming at assessing the growth of sweet peppers (Ca psicum annum L.), submitted to different controlling strategies of weeds in the no-trillage and conventional planting systems, an experiment wa s carried out in UFERSA’s experimental orchard in Mossoró-RN. The split-plot scheme was used, which was distribu ted within the experimental design, in randomized block s with four replications. The planting systems (no- trillage and conventional) were assessed in the plots, and t hree weed handling strategies (soil covering with p olyethyl- ene film, with hoeing, and without hoeing) were ass essed in the subplots. Within each subplot, assessm ents were made on 0, 21, 42, 63, 84, 105, 126, and 147 d ays after transplanting (DAT) for the purpose of de termin- ing the following features of the sweet pepper: lea f area, leaf area index, dry mass of leaves, of ste m, of fruits, and the total dry mass per plant, leaf area ratio, leaf weight ratio as well as the rates of absolute and relative growth and of net assimilation. On the 30th and 90t h DAT, the weeds’ density was assessed in the treat ments without hoeing. It was found that the no-trillage s ystem displayed a decrease in the incidence of weed s as com- pared to the conventional planting system. The no-t rillage system decreased the incidence of weeds com pared to the conventional planting systems. The weed inte rference in treatments without hoeing reduced the g rowth of pepper in both systems and the no-trillage with hoeing system showed higher indices than the other manage- ment strategies of plants in both planting systems.

The objective this work was to study the drying of integers grains of pumpkin, grains without tegument and grain flour of pumpkin in an oven with forced air circulation at temperatures of 40, 50, 60, 70 and 80 °C and adjust the mathematical models of the Diffusion Approximation, Two Term Exponential, Hen- derson and Pabis, Logarithmic and Page, to the experimental values. The fit of the mathematical models to data from the drying kinetics was performed using analysis of nonlinear regression, through Quasi-Newton method, using the software Statistica 5.0. As a criterion for adjustment of the models the coefficient of determination and mean-square deviation were used. It was observed that processing influenced the time of drying, where the samples of grain flour of pumpkin demanded a shortest time to reach equilibrium. For samples of integers grains of pumpkin and grains without tegument, the model that best fitted the experimental data was of the Dif- fusion Approximation at all temperatures studied; for samples of grain flour, the logarithmic model was the best fit to drying curve.

This work aimed to evaluate strategies for weed management on the quality of watermelon in the subsequent growing melons in no-tillage (NT) and conventional (SPC). The experiment was conducted in split plot in randomized block design with four replications. The plots were evaluated both tillage systems (no tillage and conventional tillage) and sub-plots, nine strategies for weed management (covering with polyethylene film, with weeding at 14 days after transplanting (DAT) at 14 and DAT 28, 14 and 42 DAT, at 14, 28 and 42 DAT, the DAT 28, at 28 and 42 DAT, the DAT 42 and a control without weeding). We evaluated density and weed dry weight at 14, 28 and 42 DAT and at harvest of watermelon (80 DAT). For watermelon, were evaluated for fruit quality characteristics (longitudinal and transverse length, pulp thickness, firmness, pH and soluble solids). The SPD reduced the density and dry mass of weeds, requiring the completion of only one weeding between 28 and 42 DAT, whereas the SPC was necessary to carry out weeding at 14 and 28 DAT. The SPD and the polyethylene film in the conventional tillage system allow the realization a second crop in the area in succession to the melon, reducing weed interference and providing satisfactory results in the quality characteristics of watermelon.

The main goal aim of this work was study the parameters that influence in the spatial variation of the chlorophyll "a" in the surface water of the Orós reservoir, Ceará state, Brazil. It was studied the compari- son of the water in that reservoir, too. Twelve water samples were taken in seven different sites in the reservoir. They were sampled every two months from April/2008 to April/2010. Total phosphorus, water temperature, water transparency and the chlorophyll "a" production were analyzed. To assessment the eutrophication be- tween the sampled sites it was used the Hierarchical Cluster Analysis. Results showed that the eutrophicationallowed observes that the water temperature, water transparence and total phosphorus are influential in the chlorophyll "a" production. The increasing of the water temperature increase the chlorophyll "a" concentration. Hierarchical Cluster Analysis showed that the sampled sites 1 and 2 are similar in relation to water eutrophication and it separates the water in two different groups. The group 1 was formed because of the both high sedi- ment concentration and the low levels of chlorophyll “a” and the group 2 was formed because of the both highwater temperature values and high chlorophyll "a" concentration.

Ni was the last nutrient characterized like essenti al for plants. Its essentiality is due to participa - tion as constituent of urease enzyme, which makes i t extremely important for the metabolism of N. Thus , the objective of this study was to investigate the grow th, content and accumulation of urea and nutrients in cowpea bean plants ( Vigna unguiculata (L.) Walp.) ‘IPA 206’ according to nickel rate and two soil types. The experi- ment was carried out in a greenhouse at Universidad e Estadual do Norte Fluminense Darcy Ribeiro, using a 5 x 2 factorial scheme in a randomized block design wit h four replications. Treatments consisted of foliar applica- tions of five nickel concentrations (0, 20, 40, 60 and 100 mg L -1 Ni) in the form of NiCl 2 .6H 2 O and two soils, a Typic Quartzipsamment and a Tb dystrophic Red-Yello w Ultisol. Ni rates promoted Ni toxicity symptoms j ust on young leaves of bean. These symptoms were charac terized by small reddish spots that have not progre ssed during the time and did not influence on the plants development. The foliar application of Ni increase d levels of this micronutrient in stems, mature leaves, youn g leaves and pods of cowpea bean, indicating high m obility of this micronutrient in the plant, but did not alt er the urea contents, indicating no effect on the a ctivity of urease enzyme. The dry mass of the shoots and the c ontent of others nutrients were not affected by fol iar appli- cation of Ni. Plants grown in Ultisol showed higher growth and higher content of urea and Cu in mature leaves; K and B in mature leaves, young leaves and twigs an d Zn in mature leaves and stem.

This research aimed to evaluate the tannins extracted content of Anadenanthera colubrina (Vell.) Brenan var. cebil (Gris..) Alts. bark in aqueous solution of sodium hydroxide, sodium sulfite and hydroxide + sulfite having as comparison the amount extracted in distilled. A total of 25 g of dry sawdust and 3% of chemicals were used with relationship to dry weight of sawdust. To compare the effect of water with one of the other used solutions it was found that the addition of sodium hydroxide, sodium sulfite or hydroxide + sulfite caused an increase in solid total contents (TST) of 60,17%, 28,45% and 60,17%, in condensed tannin contents (TTC) of 34,5%, 20,02% and 18,02% and of no-tannins of 117,34%, 47,3% and 146,6% and a reduction in the Stiasny’s index of 15,62%, 5,53% and 24,51%, respectively. Statistical analyzes showed that the sodium hydroxide solution extracted a larger amount from tannic substances when compared with the water, having the sodium sulfite and the hydroxide + sodium sulfite solutions presented middlemen results. The distilled water extracted a lower solid total content than other solutions, but the extract contained a greater Stiasny’s index than those obtained by other solutions.

Diazotrophic bacteria play important role on economy nitrogen fertilizer in forage glasses and environmental sustainability. With the objective of evaluate the occurrence of diazotrophic bacteria associated associated with native forage at two different times and identify isolates with potential for fixing N2 in the semiarid region. Was conducted in the Soil Laboratory of the Centro de Saúde e Tecnologia Rural in Federal University of Campina Grande, Campus de Patos, Paraíba. A study was carried out at the Soil Laboratory of the Centro de Saúde e Tecnologia Rural of the Federal University of Campina Grande, in Patos, Paraíba. The objective this study was to verify in the native diazotrophic endophytic bacteria associated with forage glasses and to identify isolates in NBF hability, during the rainy and dry seasons in semiarid region. Root samples of three forage grasses [Andropogon gayanus Kunth (Andropogon), Panicum maximum Jacq. cv. Tanzania (Tanzânia) and Cenchrus ciliaris L. (Buffel)] cultivated in the field experiment was utilized. The bacteria were isolated in NFb culture media free-N specific for Azospirillum spp., the isolates was quantified, phenotypically characterized, purified. From caracterized after, was evaluated for their nitrogenase activity in vitro. The resultas show diazotrophics bacteria growth in the three forage grasses tested. The ocorrency diazotrophics bacteria be influencied by genotipic plant and seasonal variation. A more density of NSDB of the genus Azospirillum associated in the root grasses were obtained in dry season. The NSDB isolates, show a high potencial for new studies on the genetic caracteristcs and avaliation the inoculo potential to (BNF) associated on grasses in semiarid region.

The adoption of management practices that reduce water losses is essential to conserve moisture and improve soil temperature, especially in arid and semiarid environments of the Brazilian Northeast, characterized by high evapotranspiration and the adoption of irrigation with saline water, which harms growth and yield of commercial crops. Given these factories, an experiment was conducted in Nova Floresta, Paraíba, from August 2010 to February 2011 in Oxisoil, in order to evaluate the production of bell pepper and soil moisture in grooves with side trim, and application of biofertilizer and mulch cattle. The experimental design was randomized blocks with four replications using a factorial 2 x 2 x 2 for the ground beef with and without biofertilizer, with and without residues of sisal fiber (Agave sisalana), with and without the side facing the grooves, to reduce lateral water losses by infiltration of water with polyethylene plastic film. From the results, the lining of the lateral grooves provided higher values of soil moisture, number of fruits, fruit mass, plant production and productivity, bell pepper plants. It was also found that the combination of biofertilizer and mulch the ground beef remained wetter in the first 15 cm depth.

The cowpea is a plant of great importance for small producers of the Brazilian Northeast, in particular the region of the Vale of Pajeú. The destination of this plant for the production of green beans constitutes an important source of income for family farmers and presents itself as a good alternative for industrial processing. The objective of this study was to evaluate the potential of cultivars of the cowpea for production of green beans in the conditions of Serra Talhada - PE. The experiment was conducted on the campus of Uni- versity Federal Rural of Pernambuco (UFRPE) / Academic Unit of Serra Talhada (UAST) in the period from August to November 2011. We used five developed improved cultivars: BRS-Tucumaque, BRS-Caumé, BRS- Itaim, BRS-Guariba and BRS-Potengi, and three local cultivars: Corujinha, Paulistinha and Sempre-verde. The experimental design was randomized blocks with four replications, where each cultivar was considered a treatment. The characteristics evaluated were: number of days to beginning of flowering (NDIF), plant size (PP), days to maturity of green pods (DMVV), period of production of green pods (PPVV), length of green pods (CVV) number of grains of green pods (NGVV), grain weight of green pods (PGVV), yield of green pods (PRO.VV), productivity of green grains (PRO.GV), index of green grains (IGV). Cultivars BRS-Potengi, BRS- Tucumaque, BRS-Guariba, BRS-Itaim, BRS-Caumé and Paulistinha and showed potential for the production of green beans in Serra Talhada-PE, under irrigated condition.

The aim of this work was to study the physiological responses of three contrasting cultivars of sugar cane subject to water stress and rewatering, The experiment was carried out in a greenhouse, where the cultivars SP83-2847, SP80-1842 and SP81-3250 were grown in pots. The first assessment was done after 85 days of planting, then two treatments were implemented, i.e. without water stress (-D) and with water stress (+D) by withholding water for 15 days and rewatering imposed for 12 days after the stress period. Cultivars SP81-3250 and SP80-1842 showed a higher decline in the Fv/Fm ratio, leaf relative water content (RWC), leaf water potential (Ψw), SPAD index and photosynthetic pigments due to water deficit. Drought caused less damage in the physiology of the variety SP83-2847, and it still showed rapid recovery during rewatering, including for the stomatal conductance (gs), so this variety had better adaptation under this condition. The traits Fv/Fm, Ψw, RWC, SPAD index and photosynthetic pigments present as potential physiological indicators in order to select tolerant sugar cane cultivars to water deficit. The trait gs is more effective in differentiating the tolerant cultivars during rewatering.