The municipal district of Mossoró - RN is inserted into the Caatinga biome and like other coun- ties its vegetation is notably mischaracterized. Thus a phytosociological study of forest remnants was conduct- ed in Mossoró, seeking knowledge of forest wealth for possible conservation. Bibliographic and cartographic materials were consulted, as well as maps were used for better spatial visualization of forest remnants. Areas where there are forest remnants were highlighted and four sites were chosen to characterize the vegetation. At these sites, the phytosociological study was conducted by installing plots of 20 x 20 m, within which were esti- mated height and diameter at breast height (DBH) of all living individuals of the shrub and herbs layers. The phytosociological parameters considered were: Margal ef and Menhinick Diversity Index, Frequency, Density, Dominance and Coverage and Importance Percentage Index. It was found that Poincianella pyramidalis (Tul.) and Croton sonderianus Mull. Arg. have excelled in number of individuals, frequency and density. Poincianel- la pyramidalis (Tul.) was the one that stood out in most of the analyzed parameters. Species that stand out in an area are found at low frequency in the other. This variation can be probably explained by several factors, one of them may be the anthropic level among the studied areas. Diversity indices indicated that Point 4 showed the greatest diversity and the lowest point 3. However, the Caatinga vegetation of the areas analyzed has low diver- sity, probably by the effects of human disturbance, but with proper planning and managements could avoid its complete disappearance.

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).

The present study verified the consumption capacity of Ceraeochrysa cubana when fed nymphs of Aleurocanthus woglumi. The experiments were conducted at the Laboratory of Entomology, Departamento de Fitotecnia e Ciências Ambientais, Universidade Federal da Paraíba – Areia/PB. Was used a completely randomized design in a factorial arrangement. The research was conducted in climatic chamber, regulated to 26 ± 2ºC, 70 ± 10% relative humidity and 12 hours photophase. The predation of C. cubana was evaluated for the three larval instars (1st, 2nd and 3rd), and as prey, nymphs of 1st, 2nd, 3rd or 4th instars of A. woglumi, with 10 repetitions per treatment. The larvae were individualized in Petri dishes (9.0 x 1.5 cm), with as standard food (control) Sitotroga cerealella eggs. The consumption among the predator instar among nymphs was higher and increasing for the first instar nymphs of A. woglumi. The total predation among the predator instar was higher when fed with nymphs of first instar of A. woglumi. The predator when fed with second instar nymphs of A. woglumi had higher intake in the 3rd larval stage. The green lacewing C. cubana is promising as a control agent of A. woglumi in biological control program, considering the infestations with nymphs of first instar of A. woglumi.

The optimization of nutritional efficiency is critical to increase productivity and reduce produc- tion costs. However, the identification of lines with greater efficiency and responsiveness to phosphorus is of great importance, with the in intention to join the hybrid, these traits at once and, moreover, the best way to select them. Thus, the objective of this study was to evaluate which characters should be considered in the se- lection of genotypes efficient and responsive to phosphorus in sorghum. The correlations were split into direct and indirect basic variables of efficiency and responsiveness to phosphorus through path analysis. The character that most influenced the efficiency of sorghum lines to phosphorus was harvest index to utilization efficien- cy and dry matter to absorption efficiency and use, under conditions of stress. Under conditions of adequate phosphorus fertilization, the trait with the greatest influence for evaluation of responsiveness was dry grain mass to the apparent recovery efficiency, physiological and agronomic.

This study was developed with the aim of evaluating the performance and land use efficiency of different arrangements of intercropping with maize and forage. The field experiment was conducted in Tangará da Serra/MT. The experimental design was a randomized block in factorial scheme 3x2 +1, were as three arrangements of intercropping, two species of forage and an additional treatment with maize monoculture in four replication. In maize monoculture and intercropping were evaluated: plant height and ear insertion height, plant population, weight of 100 grains, productivity, number of grain rows and number of grain per row. In forages intercropping with maize were evaluated plant population and dry matter accumulation. The arrangements with Maize + Forage sown in the line and Maize + Forage sown in two rows between rows with the species Urochloa hybrid promoted best corn yields. The modality and species affect both the productivity of maize as forages species. Grain yield of maize is higher in monoculture. The higher dry matter accumulation of Urochloa hybrid occurs in the Maize + Forage sown in one row between rows, while, for the Urochloa brizantha the arrangements studied do not affect their yields. The arrangement with best land use efficiency is Maize + Forage sown in two rows between rows for both study forage species.

Fueron conducidos dos experimentos individuales en el municipio de Mossoró, Rio Grande do Norte, Brazil. Se empleó dos cultivares de melón, ‘Olimpic express’ (del tipo Cantaloupo) e ‘Iracema’ (del tipo Amarillo), para evaluar el crecimiento y la acumulación de macronutrientes, bajo el diseño de bloques al azar con siete tratamientos (épocas de muestreo) y tres repeticiones. Los muestreos de plantas fueron realizados a los 14, 21, 28, 35, 42, 49 y 56 días después del trasplante (DDT). El crecimiento fue lento hasta 28 DDT en ambos cultivares evaluados, intensificándose en el periodo siguiente, alcanzando a los 56 DDT, 246.4g planta-1, en ‘Olimpic express’,y 266.9 g planta-1, en ‘Iracema’, siendo la materia seca (MS) de los frutos correspondientes a 60% y 64% de la MS total, respectivamente. Mayores acumulaciones de N, P y K fueron obtenidos en los frutos, mientras de Ca, Mg y S en las hojas. Al final del ciclo, en ‘Olimpic express’, cuya productividad fue de 32 t ha-1, fueron acumulados 173.4, 110.1, 101.1, 26.9, 15.6 y 13.5 kg ha-1 de K, Ca, N, Mg, S y P, respectivamente, y en ‘Iracema’, cuya productividad fue de 38 t ha-1, fueron acumulados 136.0, 93.9, 84.1, 22.6, 15.4 y 9.5 kg ha-1 de K, N, Ca, Mg, S y P, respectivamente. En relación al total acumulado, las exportaciones de N, P, K, Ca, Mg y S en los frutos fueron de 61, 73, 66, 9, 35 y 39% (‘Olimpic express’)y 58, 70, 55, 6, 33 y 41% (‘Iracema’). Con una menor producción de frutos y una mayor acumulación de nutrientes, ‘Olimpic express’ ha demostrado ser menos eficiente en el uso de nutrientes que ‘Iracema’.

The systems of harvesting sugar cane can cause changes in fertility, quantity and quality of organic matter and the degree of oxidation, altering soil carbon stocks. Given this context, the objective was to evaluate the production of dry biomass (DB), soil fertility, the content of total organic carbon (TOC), the car- bon in particle size fractions (particulate organic carbon (COp) and organic carbon associated with minerals (COam)) and oxidizable organic matter fractions (F1, F2, F3, F4 and F1 / F4) in manual harvesting (CMa) and mechanized (CMe) of sugar cane. The sampling for biomass production was conducted in area of 1 m 2 at four points per plot, soil samples were collected at depths of 0.00 - 0.05; 0.05 - 0.10; 0.10 - 0.20 and 0.20 - 0.40 m. The average annual production of dry biomass in the area CMe was 17 times higher when compared to the area of CMa; The pH and phosphorus content was significantly lower in the larger depths area CMa when compared with that of Cme; the harvesting system caused significant CMe in TOC, COp and COam depth 0.00 - 0.05 m increases when compared to the CMa system; There were not significant differences in the oxidizable fractions (F1, F2, F3 and F4) of the organic carbon in the areas of CMa and CMe.

The cowpea bean (Vigna unguiculata (L.) Walp.) is often attacked by defoliator insects. There are a great number of species of these defoliator insects and they cause huge damage to the plants. The most important being: Diabrotica speciosa e Cerotoma arcuata (both Coleóptera), Spodoptera frugiperda, Mocis latipes e Spodoptera cosmioides (both Lepidoptera). Understanding the relationship between the plague infestation and the productivity of the culture is one of the keys to the success of the integrate management of the cowpea bean. Studying the artificial defoliation process in order to simulate similar insect damages to the plants is useful. There are few research studies about the artificial defoliation in the cowpea bean plant. So, this study was developed to determine the level of economical damage inflicted by defoliator insects in cowpea bean plants in the Cultivar BR-17 Gurguéia. The experiments were conducted in the do Departamento de Fitotecnia do Centro de Ciências Agrárias da Universidade Federal do Piauí. The defoliation were in the order of 0%; 25%; 50%; 75% and 100%. The experiment was taken 25 days and 40 days after planting the cowpea bean plants. The production loss threshold of the cowpea bean in local condition in Teresina-PI is R$ 61.00.ha-1, which allows, through regression analysis, the following conclusion: the level of control of defoliator insects during the vegetative state is about 60% of defoliation; while in the reproductive state it is about 47%.

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.

The establishment of pastures in Amazonia is made to replace the woody vegetation by slash and burn process in chemically poor and low available phosphorus soils. The recovery of degraded areas is required and can contribute to reducing deforestation in the region. This study aimed to evaluate the effects of doses of Arad and NPK combinations in the management of maize in soil with low productive capacity. The experiment was conducted in Santo Antonio do Taua, Pará State, in an area with degraded pasture, in a dys- trophic Oxisol. The experimental design was a randomized block split plot design with four replications. The plots were four phosphate: 50, 100, 200 and 300 kg ha-1 of P2O5 as Arad and sub-plots combination with NPK, NK, NK liming, and control ( no match ). We evaluated the growth characteristics and productivity of corn. Doses of Arad influenced the plant height and number of kernels per row cob. The application of Arad com- bined with NPK increased grain yield.