Thisstudy aimed toevaluate theperformance agronomic ofgrain sorghumas a functionof Nand- P2O5, as well as the economic analysis in the municipality of Mossoró-RN. The treatmentsconsisted of the combinationof fourN rates(30,60, 90and120 kgha-1) andfourdoses ofP2O5 (30,60, 90and120 kgha-1) and acontrol treatment.The experimental design wasa randomized complete blockwith four replicationsin a factorial design. The characteristicsevaluatedwere:plant height,stem diameter, paniclelength, paniclediameter, dry matter, grain yield, nitrogen and phosphoruscontentinleafnitrogen content, phosphorus in the soil, gross receipts, expendi- tureson fertilizerand net income. Theincreased availability ofnitrogen andphosphorus in thesoil influencethe variables studied, except the nitrogen contentin soil.While mostproductiongrainhas beenestimated for theappli- cation of87.62 kgha-1 N +120 kgP2O5ha-1, the maximumdoserecommendedenvironmentalandeconomic effi- ciencywere60 kgNha-1+ 120kgha-1P2O5.

Several microorganisms produce polysaccharides, deemed to protect the bacteria from several environmental stresses. This paper aims to evaluate the protective effect of exopolyssacharides to different abi- otic stresses in bacterial isolates from “sabiá” ( Mimosa caesalpiniifolia ) nodules. 303 fast growing isolates were qualitatively evaluated for exopolyssacharide production and tested in vitro for tolerance to two levels of acidity, joint aluminum and acidity, three salinity levels; 11 antibiotics and three herbicides. Most isolates re- sisted media acidity, acidity with aluminum, salinity, and ampicillin, cefotaxime, gentamicin and vancomycin antibiotics and 2,4D herbicide, while being sensitive to ciprofloxacin, chloramphenicol, streptomycin, kanamy- cin, nalidixic acid, rifampicin and tetracycline antibiotics and paraquat and glyphosate herbicides. There was no connection between exopolyssacharide production and abiotic stress tolerance.

The objective of this study was to propose monthly average values of Class “A” pan (Kp) for the Pajeu Middle region, as well as analyze the theirs effects in the estimate of agricultural crop evapotranspira- tion (ETc). Evaporation values of class "A" pan and daily weather data from a series of 1999 to 2011 were used. From the daily values of odd-numbered years were obtained monthly values of reference Kp (Kpref). That series was used in the implementation of six methods of estimation of the Kp. The values found have been sub- jected to an analysis of variance and t-test (p > 0.05). The performance of the Kp values was done by estima- tion of the accumulated ETc values of the six agricultural crops. It was verified that the Kpref provided the best statistical indexes and minor errors in the estimate of ETc. The methods of Pereira et al. and the FAO case A should the best estimates among those evaluated. On the other hand, the Snyder and FAO case B methods were those of the worst performances. The performance of the estimation of the ETc in the Middle Pajeu, using the evaporation values of Class "A" pan, is conditioned by the time of year and crop to be explored.

In semiarid regions the irrigation is essential for obtaining high yields and fruit quality of pine- apple. The objective of this work was to evaluate the vegetative characteristics, fruit and slips production and fruit quality of pineapple, under different drip irrigation depth. The experiment was conducted in a randomized block design with five treatments replacement of class A evaporation pan (PAN), with 4 replications. The vege- tative growth, flowering, production and fruit quality and slips production were evaluated. The plants of pine- apple that have received regarding the irrigation at 30, 50, 70, 100 and 150% of PAN do not differ for the char- acteristics of productivity, fruit weight with and without crown diameter and fruit length, skin color, total solu- ble solids (TSS), total titratable acidity (TTA), TSS / TTA and pH of the pulp. The pineapple 'Perola' has greater vegetative growth in irrigation depth applied between 67,1 and 79,1% of PAN. The natural flowering cumulative total is greater in depth corresponding to 70% of PAN. The slips production per plant and slips pro- ductivity is greater in depth corresponding to 85% of PAN.

For applications in water management, estimation of evapotranspiration is a critical term in the water balance, to establish a sustainable development of activities that requires such action. So it is necessary to more accurately estimate the reference evapotranspiration (ETo). The objective of this study was to evaluate the performance of daily ETo values obtained for 12 empirical methods by comparing them with the Penman- Monteith FAO. The meteorological data used for the empirical models were measured in the National Institute of Meteorology automatic meteorological station installed at the experimental station in Rafael Fernandes, Federal Rural University of Semi-Arid, Mossoró, RN. Even with some methods presenting divergences from the standard method in the months of the highest water demand with an absolute error of approximately 0.99 to 1.67, it could infer that the most suitable methods based on the performance index greater than 0.76 were: Benevides and Lopez (1970), Linacre (1983), Bruin (1979), Jensen and Hayse (1963) and Priestley and Taylor (1972), in that order, thus it may represent satisfactorily the ETo. The methods that require fewer climatic elements such as Benevides and Lopez (c = 0.85) and Linacre (c = 0.79) performed better than more complex to estimate ETo in daily periods at any time of year.

The “araçá” (Psidium spp) is a wild plant with potential for direct and indirect use, and it is found spontaneously in the Semiarid region of the State of Bahia. Thus, the aim of this work was to character- ize and evaluate the genetic diversity for rescuing of 37 accessions of “araça” from the counties of Campo For- moso, Senhor do Bonfim, Jacobina, Morro do Chapéu and Uauá using botanical, morphological and physic- chemical descriptors in plants of different phenological phases. Size of plant, trunk shape, leaf color, floral morphology, fruit transversal diameter, rind color of fruit, fruit mass, fruit longitudinal diameter, fruit shape, soluble solids, titratable acidity, maturation index and C vitamin were the descriptors used. The diversity among the accessions of “araçá” was estimated using the method of Tocher as well as the inverted Tocher start- ing of the integration of data. Three species were determined (P. schenckianum, P. guineense e P. grandi- folium) and it was found great variation for all descriptors used and it was also found plants of the same size of guava plants. Using Tocher and inverted Tocher it was found variation within the same species, among differ- ent species as well as among accessions of different counties and within counties. The descriptors that gave the major contribution were C vitamin (70,88%) and fruit mass (25,66%). The variation found for the descriptors used show that there is genetic diversity among the “araçá” accessions from the five counties of the Semiarid of the State of Bahia and they present potential to be conserved and for future uses.

The objective of this work was to evaluate management systems for the control of Black Siga- toka in the cultivation of banana D'Angola cultivar. The experiment was installed and carried out at Embrapa Acre, Rio Branco - AC with the treatments distributed in randomized complete blocks with six replications consisting of different planting densities, corresponding to T1 - (1.111 plants ha-1; T2 - 1.666 plants ha-1; T3 - 2.000 plants ha-1; T4 - 1.333 plants ha-1; T5 - 2.500 plants ha-1 and; T6 - 1.111 plants ha-1 under rubber trees. The evaluations were carried out during two cycles of production. Plants of cv. D'Angola (AAB) cultivated in 3.0 x 3.0 m, shaded by the rubber trees, presented higher plant height, higher number of functional leaves at flowering and harvest, higher average bunch weight, greater weight of the bunches, longer cycle production and reduced severity of black sigatoka. Highest yields were obtained when we adopted higher densities. The banana intercropping with rubber trees proved to be a good alternative to permit cultivation of cv. D'Angola (long banana).

Three castor ( Ricinus communis ) genotypes were studied regarding tolerance to high exchange factorial distribution of five doses of exchangeable aluminum added to the soil (0, 0.15, 0.30, 0.60, and 1.20 cmol c dm - 3 ) and three castor genotypes (BRS Nordestina, BRS Paraguaçu, and Lyra). The plants were raised in pots in a greenhouse. At 53 days after emergence, data were taken on plant height, leaf area, dry mass of shoot and root, and leaf tissue content of macronutrients. The most sensitive genotype was the cv. BRS Nordestina, in which the shoot and root dry weight in the highest aluminum content were reduced to 12.9% and 16.2% of the control treatment, respectively. The most tolerant genotype was the hybrid Lyra, in which the shoot and root dry weight in the maximum content of aluminum were reduced to 43.5% and 42.7% of the control treatment, respectively.The increased exchangeable aluminum affected the leaf nutrient content, and the intensity of the response was different among cultivars. The aluminum toxicity increased N, Ca, and Mg contents and reduced on P, K, and S contents. The cv. BRS Nordestina had a drastic shoot dry weight reduction associated with an intense increment in the N leaf content. Thus, the N increment was caused by a concentration effect caused by the limited growth.

The ginger culture was planted in Espirito Santo State on a commercial scale for just over 10 years as an alternative income for farmers family based submitted high yield potential, but requires studies to their best advantage due to the great variability of climatic conditions of the State. The aim of this study was to evaluate the yield of fresh rhizomes, the dry mass of leaves and rhizomes and the extraction and accumulation of N, P and K of the culture depending on the application of increasing doses of P, in a dystrophic Ultisol . The experiment was conducted on a farm in the municipality of Santa Maria de Jetibá (ES) between the months of August 2006 and June 2007. Experimental model adopted was randomized blocks with four treatments and four replications. The treatments consisted of control (no P fertilization), and doses of 60, 120 and 240 kg ha - 1 of P 2 O 5 applied at planting. The plants showed continuous growth up to 180 days after planting (DAP) and the phase of the plant where there was greater uptake of N, P and K in the flowering cycle was at 240 DAP. Analy- zing the contents of N, P and K, in the rhizome and leaves over the cultivation cycle, it was observed that, in general, most of the accumulation occurred in the rhizome.

The correct time to make the ridging and spacing of plants in the rows are factors that affect the development of potato culture and its effects need to be better known to assist in establishing best management alternatives. The study was conducted on the campus of Universidade Estadual do Centro Oeste (Unicentro) in Guarapuava, Paraná State, Brazil. The objective was to evaluate the effects of different times of ridging and spacing of plants on the rows in characteristics of the vegetative development of potato plants, Ágata, to estab- lish the best alternative for managing these factors. The design was completely randomized in a factorial 4 x 4, composed by four management of ridging (at planting, at 10 days after the emergency of plants (DAE), 20 DAE and without ridging) and four spacing of plants in the row (16, 22, 28 and 34 cm). It was concluded that ridging in the planting and the largest spacing of plants in the row in the range between 16 and 34 cm are the best management options for these factors, due to its decrease in the occurrence of mechanical damage in the canopy and further development of vegetation potato plants.