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.

This work aimed to evaluate the repellent and deterrent effect of the application of concentra- tions of neem and chinaberry oil on bean leaves on the leaf beetles Diabrotica speciosa (Germar) and Cero- toma arcuata (Olivier). The concentrations of neem oil tested were 0.625, 1.25, 2.50, 5.00, 10.00 and 20,00 mL, corresponding respectively to 1, 2, 4, 8, 17 and 33 ppm of azadirachtin A and the concentrations of china- berry oil used were the same used to neem oil, corresponding, however, to 1.875, 3.75, 7.50, 15.00, 30.00 and 60.00 mg mL-1 of chinaberry extract, respectively. For the free-choice tests, glass containers were used as are- nas, whereas for the no-choice tests Petri dishes were used, where in both one insect per treatment was released in the center. Attractiveness was evaluated in predetermined time periods, in addition to the leaf consumption, at the end of the experiment. Neem oil is repellent to D. speciosa and C. arcuata, with more efficient results at the 5.00, 10.00 and 20.00 mL concentrations. All concentrations of neem oil reduce leaf consumption of both insects, except in the no-choice test with D. speciosa, in which only the 10.00 and 20.00 mL concentrations are deterrent. Chinaberry oil provides high repellent activity on both leaf beetle species, and the 10.00 and 20.00 mL concentrations stood out. The 10.00 and 20.00 mL concentrations of chinaberry oil are deterrent to D. spe- ciosa and C. arcuata.

The feeding programs for naked neck chickens in semi-intensive production system from brazilian equatorial semi-arid environment, must consider regional food availability and respective nutritional values. Thus, to evaluate the digestibility and metabolizable energy of alternative forages, it was used 240 naked neck pullets (Isa Label lineage) receiving water and ration ad libitum, pair-housed in cages for total collection of excreta on conventional warehouse. It was used a completely randomized design with factorial arrangement (5x2): one control ration (corn and soy meal) and other four experimental rations with silk flower hay (Calotropis procera), cassava leafs hay (Manihot esculenta), kills pasture hay (Senna obtusifolia) or leucaena leafs hay (Leucaena leucocephala), and all rations were balanced for two growing phases, between 8 and 10 weeks (young pullets) and between 14 and 16 weeks of age (old pullets). The values of apparent digestibility of nutrients for all experimental rations were lower than control ration (P <0.05) and it was observed general means of 72.18% for dry matter, 78.12% for crude protein, 66.90% for ether extract, 28.08% for neutral detergent fiber, 18.51% for the acid detergent fiber, 71.64% for gross energy and availability of 15.61% for mineral matter. The general mean of apparent and corrected metabolizable energy of alternative forages was 1217 kcal/ kg and 1108 kcal/kg, respectively, and the higher value was determined for leucaena hay and the lower value for silk flower hay (P <0.05).

The management of wastewater in agricultural crops in order to explore fully their potential of water and nutrients, have proved a viable alternative for irrigated agriculture, especially in semiarid regions. The objective of this work was to study the quality of ornamental sunflower (cv. Sol Noturno) with increasing doses of cattle manure and types of water. The experiment was conducted in a completely randomized block design in factorial scheme (4 x 2), with four replications and five plants per replication, testing two types of water (supply water and treated wastewater) and four doses of cattle manure (5, 10, 15 and 20% in on weight basis) In determining the quality of sunflowers morphological and growth variables were analysed. The manure doses ranging from 15 to 16.7% provided the best morphological and growth characteristics of sunflowers. The nanure dose less than 8.4% provided early onset and opening of buds of the sunflower and the highest number of flower buds was obtained with the manure dose equivalent to 14%. The types of water, as well as the interaction between the factors did not significantly influence the quality of sunflowers (cv. Sol Noturno).

Drip irrigation is one of the most efficient method s forapplyingwaterto a crop, capable of deliv- ering water at a rate close to the demand. Many eff orts have been required to estimate the amount of w ater needed by plants. Therefore studying soil water ext raction by plants linked to mathematical modeling f or be- havior prediction, and linked to computational reso urces to allow complex mathematical procedures to b e real- ized in a short space of time, becomes a powerful a nd necessary alternative for the understanding and quantifi- cation of the involved processes. Simulations were performed through a computational model, with the purpose of estimating the crop coefficient (K c ) of watermelon in the region of Mossoró-RN, using a three-dimensional macroscopic root water uptake model, which solves t he sink term of the Richards equation. The simulati ons results were compared with an experiment that estim ated the K c using lysimeter. The results of Kc estimated by the model showed a good agreement with lysimeter re sults in all chosen statistical indexes, indicating that the model can serve as a tool for predicting transpirat ion and evaporation of soil water under certain con ditions, and as a tool to aid the irrigation management.

This study was carried out during April to August of year 2009, in field conditions at the horti- culture department Centro de Ciências Agrárias – Universidade Federal da Paraíba, in Areia – PB, aiming to evaluate the effect of nitrogen rates in the presence and absence of bovine manure in the sweet potato yield. The experimental design used was randomized blocks, with four repetitions in factorial scheme 6 x 2, being six nitrogen doses ( 0, 50, 100, 150, 200, 250 kg ha-1 of nitrogen) in the presence and absence of bovine manure. The evaluated variables were commercial roots average weight, commercial roots production plant-1 and com- mercial productivity of roots. The average weight of commercial roots, depending on nitrogen doses in the presence of bovine manure has increased in a linear way in order 0,31 g each kg of nitrogen applied, with maxi- mum weight 233,6 g with 250 kg of nitrogen ha-1. In bovine manure absence it was achieved average weight of 192,1 g. The maximum productivity of commercial roots plant-1 in the presence of bovine manure was 235,42 g, obtained with 243,75 kg ha-1 of nitrogen. In organic fertilizer absence, it was achieved the average of 127,1 g of commercial roots plant-1, depending on nitrogen doses. The dose of 183 kg ha-1 of nitrogen was responsible by maximum productivity of 13,6 t ha-1 of commercial roots, in the presence of bovine manure, while in its absence was achieved medium productivity of 7,9 t ha-1. The cattle manure increased the efficiency of nitrogen production characteristics of sweet potato and set nitrogen use in coverage and cattle manure at planting pro- vides marketable yield of sweet potato than the national average.

The aim of this work was compare the buffaloes and cow’s milk quality. The samples were from cross buffaloes (Jaffarabadi x Murrah) and cow’s (Frisian x Zebu), collected from 2012 April to June.Was determined milk chemical composition (lactose, fat, protein, total solid and milk solids), physical characteris- tics (pH, density and milk acidity). The data were submitted to variance analyze, using F - test (P<0.05). The buffaloes present more level of the fat, protein, lactose, milk solids than cows. In relations to hipercholester- olemics fatty acids, the buffaloes presented hight level to the C16:0 and Lower levels of c12 and c14 than cows. Higher levels to the vacenic and rumenic acid were observed in buffaloes Milk than cows. In spite of a higher content of saturated fatty acids, the milk of water buffaloes showed lower ratio n6/n3 and lower choles- terol when compared to cow. The milk of buffalo and cow showed adequate nutritionally These results indi- cate the need for the creation of specific legislation for the buffalo milk.

It characterization of the variability of soil attributes is necessary so that we can interpret the possible causes of variations in crop yields, because the soil has, naturally, heterogeneity its attributes. Thus, the objective of this study was analyze the spatial variability and dependecy, through the tool GS+, the physical attributes of a typic fluvia underwent two systems use and management of soil: disking and mowing lines. The area managed by disking for over 10 years has 0.5 ha and the area mowing between the lines 13 years ago has 2.3 ha both located on the systematic plan of Experimental Farm in the Valley Curu, Pentecoste. Soil samples were taken in both disturbed and undisturbed areas obeying the spacing of 15 x 15 m, 21 in the area with har- rowing and 78 in the area by mowing between the rows. The density was the only attribute which there wasn’t spatial dependence structure. The other attributes (sand, clay, silt, micro and macroporosity and gravimetric soil moisture and the mechanical resistance to penetration) showed spatial dependence of medium until high. It was observed in the mowing area is made between the lines showed lower values macroporosity and high penetra- tion resistance, the constraint condition for the growth of roots.

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).