The vegetation features in the coastal portion of the State of Rio Grande do Norte are presented as transitional environment between Caatinga and Atlantic Forest biomes. Being an area where distinct phytoecological domains overlap and interpenetrate keep their own ecological characteristics. As there are no major human settlements and so little agricultural activities and prominent livestock, natural scenery prevails almost untouched. Because of these characteristics, this stretch of coast has been the target of heavy real estate speculation. This study was aimed to conduct a floristic and structure ecotone study which could contribute to conservation and sustainable use. For the floristic study the entire area (300 ha) was used and the method adopted was the pathway. For the phytosociological characterization a sample from an area of approximately 60 hectares was extracted, which applied the plot method, marking 100 contiguous plots of 100 m2. The phytosociological parameters were calculated using specific software. The floristic recorded 108 species in 91 genera and 49 families. For the phytosociological survey, 1960 individuals comprising of 31 species in 27 genera and 22 botanical families. The most important family was the Myrtaceae. The most abundant species were Psidium oligospermum, Eugenia luschnathiana and Pilosocereus catingicola and endangered species Aspilia procumbens, Cattleya granulosa and Melocactus violaceus. Species from the caatinga and the atlantic forest has been observed, supporting the idea of ecotone.

The use of Silicon on the plants cultivation is one the most used strategy in order to reduce the negative effects of soils salinity. The goal of this work is to evaluate the influence of Silicon on minimizing the negative impacts due to salinity of irrigation water in the Jatropha curcas plants growth. The experiment was carried out at the National Center of Cotton Research, in a completely randomized design and treatments ar- ranged in a factorial 4 x 4 x 6, performed by four levels of salinity of irrigation water (0,43; 2,5; 5,0; and 7,5 dS m - 1 ), four levels of Silicon (0; 221,76; 443,52; and 665,28 mg L - 1 ) and six evaluation periods (40, 55, 70, 85, 100 and 115 days from emergence) with three replications. The analysis of variance, the F test and the polyno- mial regression to 0.05% significance were used to evaluate the data. hight plant, diameter stem plant, number of plant leaves, leaves plant area, total dry matter, dry matter roots plants e dry mass stem plants, dry mass of shoots and roots of Jatropha curcas were not affected by salinity of water at 115 days after sowing. The leaves number and leaf area were influenced by Silicon.

It is proposed to evaluate the growth of tomato plants grown in soil covered with different types of material. The experiment was conducted at WG Fruit Farm in Baraúna-RN during the period from July to November 2008. The experimental design was a randomized complete block with four replications. The treat- ments were arranged in split plots. The plots were the types of ground cover: bare soil (control), black polyeth- ylene film (double-sided black), silver polyethylene film (double-sided black and silver), white polyethylene film (double-sided black and white) and black row cover (TNT), and the subplots sampling dates of plants of the hybrid tomato Mariana at intervals of fourteen days, from the seedling stage (14, 28, 42, 56, 70, 84 and 98 days after transplanting, DAT). The plants were harvested in the surface area of each plot, partitioned into leaves, stems, flowers clusters and fruit, and placed in an oven with forced circulation at 65 oC, until constant weight is gotten. The characteristics assessed were: dry matter accumulation of leaves, twigs, flower clusters, fruit, total leaf area and leaf area index. Based on the dry mass of leaves, twigs, flower clusters, fruit and total, it was quantified partition of treated tomato grown in different mulching. Mulching treatments affected the growth of tomato plants with black row cover, white polyethylene and bare soil registering the highest mean of total dry matter, leaf area and leaf area index. The maximum leaf area index was obtained at 71 DAT in the treatments with black row cover (2.88), non-covered soil (2.36), white polyethylene (2.21), 77 DAT in silver polyethylene (2.17) and black polyethylene (1.72). At the end of the cycle, the plant has accumulated a mean of 28.30%, 11.98%, 3.92% and 55.82% of dry leaves, twigs, flowers and fruit clusters, respectively. Key words: Solanum lycopersicon L, dry mass accumulation, assimilate partitioning, leaf area.It is proposed to evaluate the growth of tomato plants grown in soil covered with different types of material. The experiment was conducted at WG Fruit Farm in Baraúna-RN during the period from July to November 2008. The experimental design was a randomized complete block with four replications. The treat- ments were arranged in split plots. The plots were the types of ground cover: bare soil (control), black polyeth- ylene film (double-sided black), silver polyethylene film (double-sided black and silver), white polyethylene film (double-sided black and white) and black row cover (TNT), and the subplots sampling dates of plants of the hybrid tomato Mariana at intervals of fourteen days, from the seedling stage (14, 28, 42, 56, 70, 84 and 98 days after transplanting, DAT). The plants were harvested in the surface area of each plot, partitioned into leaves, stems, flowers clusters and fruit, and placed in an oven with forced circulation at 65 oC, until constant weight is gotten. The characteristics assessed were: dry matter accumulation of leaves, twigs, flower clusters, fruit, total leaf area and leaf area index. Based on the dry mass of leaves, twigs, flower clusters, fruit and total, it was quantified partition of treated tomato grown in different mulching. Mulching treatments affected the growth of tomato plants with black row cover, white polyethylene and bare soil registering the highest mean of total dry matter, leaf area and leaf area index. The maximum leaf area index was obtained at 71 DAT in the treatments with black row cover (2.88), non-covered soil (2.36), white polyethylene (2.21), 77 DAT in silver polyethylene (2.17) and black polyethylene (1.72). At the end of the cycle, the plant has accumulated a mean of 28.30%, 11.98%, 3.92% and 55.82% of dry leaves, twigs, flowers and fruit clusters, respectively.

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.

The present study was carried out to evaluate the agronomic and technological performance of common-bean crop following three straw mulch production system (sole corn, corn-Urochloa ruziziensis inter- crop and sole U. ruziziensis) and topdressing nitrogen fertilization (0, 40, 80, 120 and 160 kg ha-1 of N) in the fourth year after the no-tillage system implementation. A randomized block design, in a splitplot array, with three replications was used. The use of U. ruziziensis intercropped with maize allowed a greater straw mulch formation and a more adequate coverage of the soil surface aiming the beans cultivation in succession. The nitrogen fertilization influenced the common-bean productivity in succession to U. ruziziensis unique and maize intercropped with U. ruziziensis. The common-bean crop in succession to the straw mulch production system with U. ruziziensis allowed higher grain production and sieve yield. The grain cooking time decreased due to the rates of N used in the dry bean crop in succession of maize exclusive.

The trial was developed under greenhouse conditions in the experimental area of IFGoiano - Campus Rio Verde. The research aimed to evaluate the growth of physic nut irrigated with subsurface drip sys- tem. The experimental design was completely randomized, using two irrigation depths (100% and 50% of irri- gation depth) and two models of driplines (M1 and M2) with five replicates (containers) each treatment. Data was submitted to analysis of variance by F test, and in cases of significance, regression analysis was performed. For the data flow of the drippers, we used descriptive statistics. The application of irrigation equal to 100% using the dripper model presented a major development when compared to other treatments.

The inadequacy of sewage systems and water shortages in semi-arid Northeast is encouraging the reuse of water in the production of agricultural crops. This study aimed to analyze the effect of treated do- mestic sewage in the initial development of three melon cultivars in Mossoró-RN. The experiment was mounted on a split-plot in randomized blocks with plots cultivars of melon (Yellow Tikal, Cantaloupe type Harper and Gália) and the split-plots the proportions of water supply and domestic sewage (T1 - 100% water supply T2 - 50% of water supply and 50% of domestic sewage, T3 - 25% of water supply and 75% of domestic sewage and T4 - 100% domestic sewage) in three replicates. In the experimental period were analyzed for physico-chemical and microbiological characteristics of sewage and water supply. At 20 days after sowing was measured plant height, stem length, root length and stem diameter. The results showed that the fertirrigation of melon cultivars with domestic sewage minimizes the effect of water scarcity in semiarid. The development of cultivar Gália seedlings was not affected by application of primary domestic sewage. The T2 and T4 were the most suitable for the production of cultivar Gália seedlings.

The objective of this work was to study the effects of N and K2O doses applied through fertigation in soil fertility and nutritional status. The experiment was carried out during April, 2002 until March 2004, on Experimental Farm of the Empresa de Pesquisa Agropecuária of the State of Rio Grande do Norte (EMPARN), Brazil. The statistical design was in a completely randomized block with 4 replication, using for composition of treatments Plan Puebla III experimental matrix, treatments being composed of combination of two factors: nitrogen and potassium doses in the form of urea and potassium chloride, respectively. In all 10 treatments, defining the interval for N (256 to 4874 g plant-1 year-1) and K2O (258 to 4872 g plant-1 year-1) were applied through fertigation with microsprinkler irrigation system. The contents of nutrients in the soil presented great variation and tended to decrease with time. The doses of N decreased the pH and contents of Ca and Mg although increased the availability of P in soil and favored its absorption by plant. A negative gradient in concentration of nutrients under fertigation was observed from the soil surface. The K content in leaf 14 were increased with increase in doses of K2O via fertigation presenting high correlation with number of fruits. The application of K in soil increased the contents of Cl and Mg in leaf 14 and decreased the contents of Na, while the application of N in soil increased the contents of Mn in leaves.

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.

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.