In order to analyze the morphological variability in natural populations, fourteen accesses of Manihot pseudoglaziovii were studied, collected in the Curimataú Paraibano micro-region, in Paraiba State, besides an esculent M. Cranz access (cassava) and a natural hybrid between these two species. Five plants of each access were multiplied through cutting and then cultivated in an experimental area of the PPGZ/CCA/UFPB under standardized conditions, aiming a homogeneous externalization of each genotype. For the morphometric analyses, 20 morphology characters were studied from which analyses of variance and t-test were done, for each character separately. Pearson correlation analyses between pairs of characters were also carried out, once the occurrence of significant correlation justifies the use of multivariate analyses. The cassava access differed regarding the accesses of maniçoba and manipeba, according to the first canonic axis of the multivariate variance analysis. On the other hand, the presumed hybrid between the cassava and maniçoba differed from the others regarding the second canonic axis. The 14 maniçoba accesses presented variation, but they did not differ among themselves, although accesses 1, 2, 8 and 13 revealed themselves distant regarding the other accesses of this species.

This work aimed to evaluate nodular occupancy rate of rhizobium strains inoculated in different cowpea accesses (Vigna unguiculata (L.) Walp) from Brazil, USA and Nigeria and their relationship with the symbiotic specificity. The identification of strains in nodules was done using Enzyme-Linked ImmunoSorbent Assay (Indirect-ELISA). It was observed that the nodule number and weight were influenced by the origin of cowpea accesses. The inoculation was able to promote a significant increase in the number of nodules occupied by serogroup of inoculant strain. In agreement with the cowpea accesses origin, the Brazilian accesses presented the largest of nodule occupancy rates, followed by those of Nigeria and USA. The largest occupation percentage, in 6 of the 10 tested cowpea, was due to the innoculation with the BR 3273 strain, and the smallest one was due to BR 3269 strains, in 8 of the 10 cowpea accesses. These data suggests that specificity exists between rhizobium inoculant strains and cowpea accesses.

The objective of this work was to evaluate the residual nitrogen contents behavior in a soil fertilized with four different nitrogen sources (ammonium sulfate, calcium nitrate, urea and monoamonium phosphate) at dosage of 80 kg.ha-1, divided in 2, 3, 4 and 5 parcels, applied through drip irrigation on the melon production, in field conditions, at the Fazenda Cajazeiras, located in Tibau, RN, Brazil. A 4 x 4 factorial, completely randomized block split-plot design, with four replications was used. Soil samples were collected before planting and 40 days after the first nitrogen use to the depth intervals of 0-15, 15-30, 30-45 and 45-60 cm, on which total mineral nitrogen, NH4 +, NO3 - e NO2- was determined. A differentiated behavior of the nitrogen sources regarding the ammonium furnishing to the soil was observed, existing a decreasing tendency of the ammonium contents with the increase of the fertilization partitioning and soil depth. For nitrate the highest concentrations were found on the surface interval and no effect of the fertilizer partitioning was observed. The highest concentrations of nitrite were found on the 30 - 45 cm depth interval and the total mineral nitrogen was concentrated mainly on the root absorption region. The biggest accumulation of total mineral nitrogen in the soil was originated from employment of MAP and ammonium sulfate and the lesser accumulation was due to urea use.

To evaluate the mandacaru (Cereus jamacaru P. DC.) consumption for goats in the drought period in the caatinga, they were selected to the 18 animals in the community of the Alto the Angico, Petrolina, PE, in the period of august to november of the 2004. The phytomass from mandacaru (Cereus jamacaru P. DC.) and the portion consumed by animals in the supplement period was determined. The animals were separate in two groups, and a group stayed in continuous pasture in the caatinga and the other received supplement with mandacaru in the period of 80 days. The animals consumed, on the average, 324.98 kg the mandacaru. The daily consumption the mandacaru for animal was of 5.16 kg/dia. The animals that received supplement had the period, while the other animals lost, on the average, 5.25% of the alive weight in relation to the initial weight.

The physiologic activity of two corn varieties regarding nitrogen accumulation and remobilization in the vegetative phase was evaluated by the activity of the nitrate reductase enzyme (NR), and NO3 - contents of the N-amino and soluble sugars in leaves, hems and stems of the plants. The varieties were selected according to their agricultural characteristics: BRS 4157 (Sol da Manhã), an improved variety used in familial agriculture and BRS 1010, an exotic variety, a simple hybrid used in extensive agriculture. The plants were cultivated in a greenhouse, in pots containing a Red-Yellow Argissol submitted to two doses of N-NO3 - (130 and 1300 mg of N per pot). Harvests were made at the first two stages of the vegetative development, at 32 and 60 days after germination (DAG). The Sol da Manhã variety, efficient in nitrogen use, adapted itself to the condition of low nitrogen due to its higher capacity in accumulating NO3 - in the leaves in the first development stage, and remobilizing it during the second stage. This resulted in a higher free amino-N concentration in the leaves and hems when compared to the simple hybrid BRS 1010, described as a high potential in productivity under low nitrogen conditions.

It was characterized the rural producers and their lands of the Municipal districts of Itambé, Caruaru and Serra Talhada, Pernambuco. The producers were interviewed in Organizations and/or Rural Producers Associations and in free markets of Itambé, Caruaru and Serra Talhada. Informations about the rural producers and lands, the cattle activity and the forest management were collected. The population mean age is above 50 years old with low scholar education, except to Itambé. Small pasture lands prevailed and the cattle activity was the more practiced by the rural producers, with animals grazing during all the year. The proprietors, in majority, don't accomplish forage conservation and they don't have information about agroforest systems and plan of forest management . The largest use of species was for firewood, coal and stake in Serra Talhada, Caruaru and Itambé, respectively, and the producers of Itambé and Caruaru are the largest importers of forest products. The three township present potentialities for silvipastoril system aplication, which besides supplying fodder plant the animals can also offer lumber and energy products for the agricultural prorietors.

The withdrawal of the natural vegetation in order to implement an agriculturist system provokes disequilibrium in the soil. This study had as objective: evaluate changes in the chemical and physical characteristics of the ground and in the total organic carbon level of a ground that has experienced different systems of use: remainder of Atlantic Bush, cacao (Theobroma cacao), and pasture (Brachiaria decumbens). For each use, samples were collected, in the depths of 0 - 10 and 10 - 20 cm. The chemical and physical analyses had been proceeded, and the determination of the total organic carbon, nitrogen and match in the soil. The substitution of the natural vegetation for the cacao and pasture systems caused changes in the level of clay in the layer of 0 ¿ 10 cm and in the levels of clay and silte in the second layer 10 - 20 cm. To the chemical characteristics evaluated (0-10 cm), it was observed that the levels of Ca+2, Mg+2 and P were higher, and in the cacao system, while the pasture showed higher pH and levels of K+ and lower CTC. The attributes Al+3 and m decreased and V increased. 10-20cm the cacao and pasture systems showed changes just related to the level of Ca+2, and for the cacao system,higher P level. The TOC and chemical attributes in the second layer showed significant correlations just for the pasture area.

The tebuthiuron residue, used in the sugar-cane culture, can be found in soil until two or more years after its application. Recent researches are being done using the phytoremediation in the attempt of removing it from the soil. The purpose of this work was to evaluate the effectiveness of the green manure use in the phyitoremediation of the tebuthiuron herbicide. The evaluated species were: Cajanus cajan, Canavalia ensiformis, Dolichos lablab, Pennisetum glaucum, Estizolobium deeringianum, Estizolobium aterrimum and Lupinus albus. These were sown and cultivated in pots containing soil treated with different doses of tebuthiuron (0.0; 0.5; 1.0; and 1.5 kg.ha-1). A control treatment without green manure, submitted to the same dosages, was kept. Sixty days after planting, green manure aerial part of all plants were harvested and soybean was sowed in the same pot, to bioassay accomplishment. Sixty days after sowing, the soybean plants were harvested, being the following evaluations carried out: height of plants, phytotoxicity symptoms and plants above ground dry biomass and leaf area. Until 0.5 kg.ha-1 tebuthiuron dosage, the species that better phytoremediated this herbicide was L. albus. When the soil was treated with tebuthiuron at 1.0 kg.ha-1, the C. ensiformis, followed by L. albus and S. aterrimum, they were the treatments that better phytoremediated tebuthiuron because results in highest plant height, above ground dry biomass and lesser phytotoxicity symptoms and still the biggest foliar area of the soybean plants. When the tebuthiuron was applied at 1.5 kg ha-1 dosage, it was impossible to evaluate the phyitoremediation, as the tested plants were eliminated.

This study had the objective of surveying the apicultural potential in the municipality of Petrolina flora (9o9'S; 40o22'W), aiming at identifying the nectariferous or polliniferous species visited by Apis mellifera. The observations were carried out from January 2004 to May 2005, in areas of hyperxerophilous Caatinga native vegetation and of irrigated fruit crops of Embrapa Tropical Semi-Arid. Fifty one species were observed, belonging to 42 genera and 25 botanic families. The families Leguminosae, Anacardiaceae, Convolvulaceae, Rubiaceae and Sterculiaceae were the most visited species by Apis mellifera, including 47.08% of the total visited plants. Among the species visited by Apis mellifera, 41.17% are herbaceous, showing the importance of this stratum as an apicultural source. Regarding the flora resource used as food source by the bees, it was found that A. mellifera made several visits for exclusive nectar extraction to 72.55% of the plants considered nectariferous. Among the remaining plants, it was found that in 19.60% the bee collecte pollen, being these species considered polliniferous, and in 7.85% there was pollen and nectar withdrawal. Among the herbaceous species, Borreria verticillata (L.) G.Mey., Diodia teres Walter (Rubiaceae), Waltheria rotundifolia Schrank (Sterculiaceae), Merremia aegyptia (L.) Hallier, Jacquemontia confusa Meisn. (Convolvulaceae), Hypenia salzmanni (Benth.) Hanley (Lamiaceae) distinguished as nectariferous source during the raining season, while the arboreal species Schinopsis brasiliensis Engl. and Myracrodruon urundeuva Allemão. are considered apicultural source for the dry season.

Aiming to evaluate seedling emergence of black sapote (Diospyros ebenaster Retz.) it was developed an experiment with seeds, collected on mature fruits, proceeding from Germoplasm Bank of Horticulture Department, University of São Paulo State, Jaboticabal, Brazil. Immediately after extracted, the seeds were washed, dried in paper and put in plastic box filled with the substrate studied, thus characterizing four treatments, as follows: Plantmaxâ; Coconut fiberâ; Sand; Soil mix [soil + sand + bovine manure (3:3:1)]. It was observed emergence percentage (E%) and rate of emergence speed (RES). The different substrates had statisticalinfluence on variable studied. The highest E% was obtained on soil mix, Plantmaxâ and Coconut fiberâ substrates and the best RES was observed on soil mix and Plantmax? substrates.