This study aimed to evaluate the spatial variability using the indicative kriging method in pre- paring probability maps of the occurrence of soil chemical properties and productivity. Data were collected in a ground area planted with soybeans in a no - till system, with a regular grid sampling of 60 x 60 m, totaling 124 points. At each point were deformed soil samples collected to determine the chemical attributes (pH, Potassi- um, Calcium, Magnesium and Aluminum exchangeable, available phosphorus, zinc, potential acidity, soil or- ganic matter, cation exchange capacity and base saturation). To determine productivity were collected all the plants within 1 m ² of the sample point. Data were categorized into binary codes on the amounts presented in the recommendation for the use of lime and fertilizer. Later it used the geostatistical analysis and attributes potassi- um, phosphorus, magnesium and base saturation that presented spatial dependence underwent kriging as inter- polation technique. Occurrence probability maps were drawn of the evaluated attributes presented spatial de- pendence. The probabilistic maps showed that the central area evaluated was more likely to need correction to the levels of potassium attributes, phosphorus, magnesium and base saturation. From the analysis of the maps, you can detect nutrient deficient areas and making corrections and use of localized management techniques, minimizing operating costs and economic that culture.

Castor produces racemes primary, secondary, tertiary, among others, whose contributions to the overall productivity differ. In this context, the aim was to evaluate the agronomic characteristics and to deter-mine the influence of the order of racemes and nutrient sources on yield of castor bean. Thus, under field con-ditions, in the municipality of Remigio, Paraíba State, an experiment with BRS Nordestina cultivar was carried out in randomized blocks design arranged in 5 (different sources of organic manure: without organic manure, compost, compost enriched with rock powders and manure and mineral complete) x 4 (orders of racemes pri-mary, secondary, tertiary and quaternary) factorial experiment, with four replications. During the experiment, plant height and insertion of racemes were evaluated, length and number of racemes, early blooming and matu-ration of racemes. After harvesting, the following variables were determined: mass of racemes, number of grains per plant, yield, weight of hundred grains, length and width of the grains and the contribution of differ-ent orders of racemes in total yield. The growth of castor bean increased with the fertilizing, especially for or-ganic compounds. The first inflorescences were emitted in castor bean plants fertilized organically. The mass of racemes, the number of grains per plant and productivity were higher in racemes of secondary and tertiary orders. The length and width of the grains was higher in primary racemes. The highest yields were obtained with the use of organic sources.

The objective of this study was to identify and determine the spatial distribution of the physiological quality of soybean seeds in a field of 39 hectares with production through precision farming techniques. Soil sampling and harvest seeds, georeferenced points for determining soil fertility, seed quality and range of spatial dependence were performed. The results were submitted to analysis of descriptive statistics, Pearson correlation, and geostatistics. The data presented coefficient of variation of 1,63% for emergency, 1,74% for germination, 1,63% for viability, 2,59% for accelerated aging and 4,28% vigor evaluated by the tetrazolium test. Soil pH was negatively correlated with germination, emergence, and viability. The grid point per hectare and a georeferenced grid sampling, spacing of 100 meters between points, was efficient in assessing the spatial variability. Physiological quality is not uniform, particularly in nexion of vigor, providing better diagnosis through interpolation maps. Precision agriculture allows one to determine the spatial distribution of seed physiological quality in a production area of soybean seeds, facilitating decision-making, in what refers to the areas to be harvested.

The development of vetiver grass (Chrysopogon zizanioides L.) has been evaluated under differ-ent levels of phosphorus on slopes of the right-side bank of the San Francisco River, in the municipality of Am-paro do São Francisco, SE. Techniques of soil bioengineering were used, characterized by the combination of vegetated riprap with stakes, seedlings of vetiver grass and sediment retainers. The experimental design was randomized blocks with five doses (0, 4, 8, 12, and 16 g pit-1 of simple superphosphate) and five replicates. The growth of vetiver seedlings were observed in periods of 30, 60, 90, e 180 days, carrying out the following pa-rameters: number of roots, external root surface, root density, root length, root length density, root and shoot dry weight, root and shoot fresh weight, and shoot length, at each evaluation period. The phosphorus doses and periods of morphological development interacted in all variables of plant biomass mentioned above. Higher superphosphate doses than 9.0 g pit-1 did not offer advantages in terms of cost-benefit for the production of vetiver seedings.

The selection of common bean lines for seed coat standard, sanitary and physiological quality seed is recent in breeding programs. The objectives of this research were to evaluate if common bean lines differ for seed coat standard, sanitary and physiological quality seed, to investigate the correlation between these characters and to select common bean lines with high seed quality. For this, 16 inbred common bean lines were evaluated in normal rainy growing season. The common bean lines showed significant difference for the weight of thousand seeds, seed coat color, lignin content, length, width and thickness seeds, Fusarium sp. incidence, germination, first germination count, accelerated ageing, length of shoot, root and total of seedling, dry matter of shoot and total of seedling and emergency of seedling in field. A positive correlation coefficient was found between emergency of seedling in field and germination (r = 0.650), first germination count (r = 0.600), accelerated ageing (r = 0.793) and electric conductivity (r = 0.635). The indirect selection by germination, first germination count and accelerated ageing is effective to identify common bean lines with the highest emergency of seedling in field and germination. The selection of TB 02-07, SM 1810, Carioca, LP 08-90, SM 1107, LP 07 -80, Pérola, CNFP 10104 and TB 02-24 lines is recommended for use in controlled hybridization programs for improvement of news common bean cultivars of high seeds quality.

The piçarra (subsoil material mainly formed by silt, sand and gravel) is commonly used in the civil construction and activities related to the onshore oil production in the Caatinga biome. The revegetation of the piçarra mines at the end of exploration cycle is mandatory and generally demands the planting of native tree species. However, there is scarce information about tree species able to grow in these degraded environments. This study aimed to evaluate the development and survival of 20 tree species, including native and exotic spe-cies, and nodulating and non nodulating species, planted in five piçarra mines located in three cities in the state of Rio Grande do Norte, Brazil. The experiment was a split-split block design, where 10 nodulating tree species were compared with ten other non nodulating species in areas with and without addition of a 20 cm topsoil layer and/or 2 L cattle manure in the planting hole. Biometric measurements were made at the end of the dry and rainy seasons (February 2008 to February 2010) up to 660 days after planting. The addition of topsoil re-duced the survival of trees, especially of non nodulating species, likely due to the vigorous herbaceous regener-ation in this treatment. Conversely, the addition of manure favored the tree growth. The nodulating species outperformed the non nodulating in respect to survival rate, total height, trunk diameter, and growth rate. The native species with the best survival and development rates were Mimosa tenuiflora, Mimosa caesalpiniifolia, Caesalpinia ferrea and Tabebuia caraiba, and among the exotics were Azadirachta indica and Pseudosamanea guachapele.

Under conditions of high stress, interactions between species can be positive. Islands of perennial vegetation can improve the conditions of the understory and facilitate the establishment of herbaceous plants. The hypothesis of this study is that islands of perennial vegetation in an area of caatinga harbor, a greater richness, diversity and density of herbaceous plants, and that individuals reach a greater height and diameter than in open spaces. The study was conducted in Petrolândia, Pernambuco, Brazil. Twenty-seven plots were installed in the center of the islands, 38 at the edge of the islands (in a total of 38 islands) and 35 in the open spaces. A total of 51 species were recorded in the center and 55 on the edge of the islands and 48 in the open spaces. The mean richness of the open spaces was lower than on the islands. The diversity was greater in the center of the island and became less on the edge of the island and in the open spaces. The mean density was lower in the open spaces than on the islands. The mean density at the edge of the islands was greater than in the center of the islands. There was no difference in mean diameter of herbaceous plants. The mean height of the individuals was higher in the center of the islands. The herbaceous community growing on the islands exhibited higher richness, diversity, density and height than in open spaces. Thus, islands of perennial vegetation facilitate the establishment of herbaceous species.

The objective of this research was to characterize the spineless forage cactus production in the semi-arid region of Paraiba State in the Northeast of Brazil. Information from 199 interviews carried out in the rural area of municipal districts in the Paraiban Cariri region was used. The interviews were conducted from February 2008 through August 2009. The data were tabulated in a spreadsheet, where a matrix with the ques- tions and answers of each interviewee was established. The production systems were defined using principal component analysis, followed by cluster grouping of quantitative variables. The first three principal compo- nents explained 61.60% of total variation. The application of cluster analysis, based on scores of the three main components, identified four cactus forage groups of producers. The livestock activity prevails on the ag- riculture and it is imposed as an appropriate activity in the production systems of the agriculture sector in the Paraiban Cariri region. The cultivation of forage cactus predominates over other cultivated forage plants, being fully incorporated into the local productive process of Paraiban Cariri region.

Due to the oil crisis and concern about the environment, global demand for biofuels has ex- panded rapidly in recent years, so the physic nut has attracted the attention of researchers for the development of research on this specie. The aim of the present work was to verify the effects of the supply of Na to replace potassium nutrition on growth and nutrition of physic nut seedlings. The experiment was conducted in green- house conditions using nutrient solution. We used the completely randomized design in five proportions of replacing K by Na: 100% (T1), 75% (T2), 50% (T3), 25% (T4) and 0% (T5). Thus, the concentrations (in mM) of K:Na in the treatments were: T1 = 0:6.0; T2 = 1.5:4.5; T3 = 3.0:3.0; T4 = 4.5:1.5; T5 = 6.0:0. The sources of K and Na used were KNO3 and NaNO3, respectively. Data were subjected to analysis of variance and means evaluated at Scott & Knott test at 5% probability. The growth and mineral nutrition variables of physic nut seedlings are influenced by the substitution of K by Na, varying according to the characteristic studied. Na re- places partially the K nutrition of physic nut seedlings and establishing a strategy to reduce the doses of K fer- tilizer applied.

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.