This study aimed at assessing the influence of different seasons of the year (dry and rainy) on urea nitrogen (MUN) concentration of buffalo milk in a commercial herd from Rio Grande do Norte state. The region is characterized by a rainy tropical climate with a dry and wet season from August to January and February to July, respectively. Samples were collected monthly from the cooling tank between February 2010 and February 2011, in the morning. Next, they were homogenized and packed in 40-mL plastic flasks, containing the preservative Bronopol® and later sent to the laboratory for urea nitrogen analysis. Although March 2010 exhibited greater ureanitrogen concentration (25.4 ± 4.4 mg/dL) and November the lowest mean (12 ± 0.4 mg/ dL), there was no significant variation in milk urea nitrogen in samples collected from cooling tanks during the rainy and dry seasons.

In order to quantify the growth, accumulation and exportation of macronutrients by carrot ‘Forto', and obtain equations that best represent them, it was conducted an experiment in the São Gotardo (MG), from May to September 2004. Samples were taken at 40, 50, 60, 70, 80, 90, 100, 110 and 120 days after sowing (DAS) to determine dry matter and accumulation of macronutrients in leaves and roots. At 40 DAS, five days after thinning, the plants had 0.18 g and 0.04 g in dry leaves (LDM) and of roots (RDM), respectively. From then, until 88 DAS, the partitioning of photoassimilates and accumulation of matter in the shoots were more pronounced. The RDM was low until 80 DAS, which corresponded to two thirds of the crop cycle, from when the amount of material allocated in this part of the plant had strong growth, surpassing, at 88 DAS, the amount of LDM. The nutrient accumulation was small in the first 60 DAS, coinciding with the period of lower dry matter accumulation. The order of decreasing macronutrient accumulation by the crop were: K > N > Ca > P > S > Mg, in the amounts of 906.7, 438, 155.46, 87.4, 58 and 37.63 mg plant-1, respectively. The root participated with 60.5% of the accumulation of N, 86.1% of P, 58% of K, 25.5% of Ca, 55.6% of Mg and 65.5% of S. Considering a population of 590,000 plants per hectare, the total quantity of nutrients by the crop of carrots was 258.3, 51.6, 534.8, 91.7, 22.2 and 34.2 kg N ha-1, P, K, Ca, Mg and S, respectively.

With purpose of evaluating the salinity’s effe cts of the nutrient solution at different stages of development of the culture of pepper grown in a hyd roponic system, an experiment was conducted in a pr o- tected environment at the Department of Environment al Sciences, Federal University of the Semi - Arid (UFERSA). The experimental design was completely ra ndomized design with 15 treatments and three replic a- tions. The treatments consisted of five levels of s alinity of the nutrient solution (1.2, 3.49, 5.69, 7.07 and 9.23 dS m -1 ), applied at three stages of crop development (24, 85 and 120 days after the transplanting) .The leve ls salt obtained by mixing two sources of water (water supply (AB) and waste water desalination (RD)) .Th e nu- tritive’s solution salinity above 1,2 dS m -1 reduced the growth and yield of pepper grown in c oconut fiber sub- strate. The nutrient solutions prepared with water saline waste can be used in the pepper’s grown nutr ition in coconut fiber substrate with the lowest yield loss for increment the electrical conductivities (CEs), when ap- plied at 85 and 120 days after the transplanting , corresponding to fruiting phase.

The objective of this work was to obtain informatio n about the best sources and doses of nitro- gen and potassium fertilizers for obtaining vigorou s rootstocks umbuzeiro in Northeastern Brazil. In s eparate experiments, we tested two sources of nitrogen, ure a and ammonium sulfate and five N rates (0, 350, 70 0, 1400 and 2800) mg.dm -3 , and two sources of potash fertilizer (potassium c hloride and potassium sulfate) in five doses of K20 (0, 1.800, 3.600, 5.400 and 7.200) mg. dm -3 substrate. The experimental design was in random- ized blocks in factorial 2 (sources) x 4 (doses), w ith ten treatments and four replications and ten pl ants per plot. Parameters were evaluated for the growth of seedlin gs. Doses of nitrogen and potassium applied to soi l had a negative influence in the survival of seedlings, shoot length, stem diameter and root fresh weight of seedlings.

Some techniques can be used in order to promote the recovery of degraded areas like riverine ecosystems, and those with low impacts present a fast regeneration, through an ecological succession with no need for human intervention. It is necessary to study the use of techniques that contribute to the recovery of these ecosystems, such as soil bioengineering, which involves the use of biologically active elements working on soil stabilization, combined with inert elements such as concrete, wood, polymers, and geotextiles made with synthetic material or plant fibers. This work was carried out in order to evaluate planted species develop- ment and endemic species in the ecological succession, along the Paramopama river margin, located at the mu- nicipality of São Cristóvão, in Sergipe State, submitted to soil bioengineering techniques. Two types of geotex- tiles (Fibrax and Syntemax and 400 TF) arranged in two blocks and three treatments were tested, and the be- havior of the vegetation and efficiency of geotextiles were observed for a period of 11 months monitored by the floristic survey. The abundance of the species Crotalaria spectabilis and Calopogonium muconoides was stud- ied, and subsequently classified according to vegetation succession stage. The study revealed that the use of geotextile Syntemax 400 TF on the left bank promoted the greatest abundance of species, resulting in a greater vegetation cover, and consequently better protection of the slope. The geotextile Syntemax 400 TF was the most appropriate among the tested types, to promote the floristic recovery in the studied area and probably in those with similar soil-climatic conditions.

The crisphead lettuce is a greenery adapted to grow in regions with mild temperatures and lack of rain. The objective of this work was to evaluate the performance of crispheadlettuce cultivars (Del ícia, Teresa, Lucy Brown, Raider Plus, Mauren, Angelin), under tropical climate in city Cáceres-MT, in two h arvest times.The experiment followed the randomized comple te block , with four replications, were arranged in 6 x 2 factorial, being, six cultivars in the crisphead le ttuce and two harvest time. Was evaluated the total and com- mercial production, commercial dry matter mass, com pactness, plant diameter, “head” diameter, health a nd was estimated the proportion of stem in the “head”. The cultivars Teresa and Delícia exhibit the total pro duction upper in relationship the other cultivars evaluated in the experiment, with productions of 631.1 and 5 89.3 g plant -1 , respectively. The second harvest, at large, has w as upper in relationship first, with 607 g plant -1 . The cultivar Teresa, in the second harvest, exhibit the upper result from the commercial production with 4 79.6 and 483.6 g plant -1 , in the first and second harvest, respectively. Th e cultivar Teresa, in the second harvest, exhibit the upper evaluate from compactness. The cultivars Teresa and Delícia were the most suitable for culti vation from weather of Cáceres - MT, and the harvested mus t be performed at 67 days after sowing.

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 replacement of the natural systems by sugar cane leads to fundamental alterations in soil carbon and nitrogen stocks and consequently in the global cycle of these elements. This study was conducted in the municipality of Capim, Paraiba State, and the objective was to evaluate carbon and nitrogen stocks in soils of a natural forest in comparison to sugar cane with and without vinasse. The studied soil was a Dystrophic Gray Argisol. The soil samplings were performed in five replicates (five profiles) at the depths of 0-5, 5-10, 10- 20 e 20-40 cm. The systems were selected namely, native forest; sugar cane with vinasse and cane sugar with- out vinasse. The carbon and nitrogen contents and stocks decrease after the change of native forest to plant sugar cane. In general, there is not significant difference in the carbon and nitrogen contents and stocks be- tween the environments of cane sugar. The systems of cane sugar with and without vinasse are functioning as C -CO2 emitter when compared with the native forest.

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.

The whitefly is the major pest of tomato due to direct damages caused by sucking and indirect damages related to viruses transmition. Was evaluated the distribution and incidence of whitefly nymphs in tomato by using of mineral and organic fertilization in greenhouse. The experiment was carried out at the Experimental Farm of São Luis, Maranhão State University in a greenhouse during the period november 2010 to december 2011. The experimental design was completely randomized plots with five treatments and six replications T1-Soil + NPK, T2-Soil + NPK + micro-nutrient, T3-Soil + NPK + manure, T4-Solo + manure + NPK + micro-nutrient, T5-Solo + manure + rock phosphate + Biofertilizer. Irrigation was performed manually, based on the weight and field capacity of each pot. The number of nymphs of B. tabaci was evaluated by counting performed at 45, 60 and 75 days after transplanting. In the process of sampling three leaflets were removed by plant been each of plant strata lower, middle and top. The use of organic fertilization showed lower incidence of nymphs of B. tabaci in tomato and distribution of this insect pest is higher in middle and apical strata of the plant.