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.

In agricultural areas of Cerrado, where there is no possibility of making two cultivation to the year, areas before cultivated with soybeans or corn, remain in fallow until the next crop year, where weed inci- dence is high. In this research was aimed assess the potential for weed suppression by cover crops, when sown in the off season of annual crops. The experimental design was a randomized block with eight treatments (Urochloa ruziziensis, Pennisetum glaucum, Crotalaria juncea, Crotalaria spectabilis, Styzolobium aterrimum, Canavalia ensiformes, Cajanus cajanand Stylosanthes macrocephala + Stylosanthes capitata) in four replica- tions. The evaluations were performed at 45, 90, 135 and 180 days after the sowing (DAS), with determination of dry mass, plant density and vegetal cover over the soil afforded by cover crops and weeds. The population dynamics was evaluated by means of phytosociological parameters. It is conclude that the weed community presents variations during the development cycle of the cover crop and the greater biomass production, soil cover vegetal and weed suppression was obtained with the U. ruziziensis.

The biocontrol of soilborne plant pathogens represents a promising approach from the environ- mental and practical points of view. Fluorescent pseudomonad rhizobacteria are well known by their antagonis- tic capacity towards several plant pathogens due to a diversity of antimicrobial metabolites they produce. This study was conceived to select and characterize rhizobacteria having antagonistic potential towards the patho- genic fungi Rhizoctonia solani and Sclerotium rolfsii. A total of 94 bacterial strains isolated from the rhizospheres of four vegetable species under organic cultivation were evaluated. Twenty-two strains which predominate in lettuce and rudbeckia rhizospheres showed identical biochemical profiles to Pseudomonas fluo- rescens, while in kale and parsley rhizospheres identical profiles to Pseudomonas putida (subgroups A and B) strains prevailed. Two types of antagonism were verified in vitro and defined as competition and inhibition of mycelial growth. Sixty percent of the evaluated strains showed antagonistic potential and, among those, 24 strains expressed antagonism to both target fungi, with P. fluorescens being the most representative bacterial species. This work clearly identified a number of strains with potential for use as plant growth-promoting and biocontrol of the two soilborne fungal pathogens in vegetable crops production systems.

This work was carried out to evaluate the functional response of Cryptolaemus montrouzieri Mulsant, 1850 (Coleoptera: Coccinellidae) fed with Planococcus citri Risso, 1813 (Hemiptera: Pseudococcidae) reared on a pumpkin hybrid (Cucurbita maxima x Cucurbita moscata) (Cucurbitaceae), seedlings of Rangpur lime (Citrus limonia) Rutaceae) and potato (Solanum tuberosum) (Solanaceae) at two temperatures. The predation rate of C. montrouzieri was measured using Petri dishes of 15 cm diameter with 1, 2, 4, 8, 16 and 24 adults of P. Citri. One third instar larva, one fourfh instar and one newly emerged adult (without differentiation of sex) of C. montrouzieri were added to each plate. The study was conducted in climatic chambers at temperatures of 25 and 30 º C and photophase of 12 hours. The predation rate was evaluated after 24 hours of prey exposition to the predator, by counting the number of preys trapped in the different treatments and control. The statistical design was completely randomized with four treatments x 6 subplots with 7 repetitions, the two temperatures. The values obtained were subjected to analysis of variance, to relate the number of scales preyed by larvae and adults of C. montrouzieri set up in different substrates. The amount of prey consumed by larvae and adults of the predator increased with increasing the prey density until it reaches a plateau, characterizing functional response type II. In general, the number of scales preyed by larvae and adults of C. montrouzieri was higher on potato and under temperature of 30 °C.

This study aims to provide doses of P 2 O 5 rates in Regolithic Neossoil, and evaluate the phos- phorus waste (P) in the soil and leaf content in three successive cowpea - beans crops. The experiment was car- ried out at field conditions, in Areia city – PB, in the period January to December 2007 in a randomized block with six treatments (0, 100, 200, 300, 400 and 500 kg ha - 1 P 2 O 5 ) and four replications. The first crop production variables (green beans per plant (PGVP), productivity of pods (PV) and dry beans (PGS) as a function of the above treatments, and in the last two harvests, the same variables in the production function were evaluated residual phosphorus in the soil. Phosphorus content after the first crop (49.53 mg dm - 3 ), corresponding to a residue (38.33 mg dm - 3 ) was higher initially to that in soil (11.2 mg dm - 3 ) before the first crop. Foliar - P for the highest values were observed for the first crop. Already the third crop, introduced himself as one of lower con- centration of P in the leaves, 1.56 g kg - 1 . The dose of 280 kg ha - 1 P 2 O 5 gave residue in P sufficient for the maxi- mum production of green beans per plant of 252 g, the second crop soil's estimated maximum yield of pods, 6.3 to 7.3 t ha - 1 at the first and second crops were obtained with Keywords : Vigna unguiculata . Phosphorus waste. yield.