The weed control procedures are known to affect the soil physical attributes and the nutrient amount taken up by weed roots. This work hypothesis is that weed control methods might also affect soil chemical attributes. Four experiments were carried out, three with maize (E-1, E-2 and E-3) and one with cotton (E-4), in randomized complete blocks design arranged in split-plots, with five replications. In E-1 experiment, the plots consisted of two weed control treatments: no-weed control and weed shovel-digging at 20 and 40 days after sowing; and the subplots consisted of six maize cultivars. In the three other experiments, the plots consisted of plant cultivars: four maize cultivars (E-2 and E-3) and four cotton cultivars (E-4). And, the subplots consisted of three weed control treatments: (1) no-weed control; (2) weed shovel-digging at 20 and 40 days after sowing; and (3) intercropping with cowpea (E-2) or Gliricidia sepium (Jacq.) Walp. (E-3 and E-4). In all experiments, after harvest, eight soil samples were collected from each subplot (0-20 cm depth) and composed in one sample. Soil chemical analysis results indicated that the weed control by shovel-digging or intercropping may increase or decrease some soil element concentrations and the alterations depend on the element and experiment considered. In E-2, the weed shovel-dug plots showed intermediate soil pH, lower S (sum of bases) values and higher soil P concentrations than the other plots. In E-4, soil K and Na concentrations in plots without weed control did not differ from plots with intercropping, and in both, K and Na values were higher than in weed shovel-dug plots. Maize and cotton cultivars did not affect soil chemical characteristics.

The culture of the popcorn comes as a promising culture for region of the Brazilian northeast, however they are still scarce studies to make possible the expansion of this culture, especially as the fertilization. This experiment was accomplished in the department of Environmental Sciences of the Rural Federal University of the Semi-arid (UFERSA), Mossoró, RN, with the objective of evaluating the effect in different ammonium:nitrate ratios in the initial development of the popcorn. The design was used randomized entirely with five treatments and four repetitions, with the treatments being constituted of ratios different NH4 +: NO3 - (0/100, 25/75, 50/50, 75/25 and 100/0) and the experimental unit acted by a plant/vase. To the 45 DAS the plants were collected and appraised, as for the height, number of leaves, leave area, diameter the stem and matter total dry. The results obtained in this work evidence that plants of popcorn present a larger development when the supply of nitrogen is accomplished with application of this nutritious one in the form ammonium.

The objective of the present experiment was evaluate the effect inter cropping systems with the culture of the maize on the production components, aiming at to maximize the grain production and to increase availability of pastures for animal feeding. The treatments had consisted of the culture of DKB-950 maize (Hybrid Simple Modified), on three grassy species of (Brachiaria decumbens, Brachiaria brizantha and Panicum maximum cv. Tanzania) inter cropping systems and conventional tillege of soil. In foundation one applied 0, 35, 50 and 4 kg ha-1 of N, P, K and Zn respectively in the sulphate form of ammonium, simple superphosphate, potassium sulphate and zinc Sulphate. In covering it applied if 120 kg ha-1 of N. the used espaçamento was of 0,80 x 0,20 m, The experiment was arranged in a randomized complete block design, with four repetitions. The components of the production of the maize had not been affected by the studied systems of inter cropping, except for the number of spikes and production of grains, where the maize cultivated inter cropping systems with Brachiaria decumbens (4.787 kg ha-1) was better that the Tanzania (3.683 kg ha-1). The accumulation of dry mater presented significant difference between the treatments, in the which Tanzânia presented greater accumulates of dry mater.

Random regression models (RRM) allows considering heterogeneous residual variances to describe the growth for each age. However, this feature increases the number of parameters to be estimated in the maximization likelihood function process. Searching for more parsimonious RRM, several approaches have been suggested. One of them is the use of different structures of residual variances modelled through step function in different classes with similar variance or through variance functions. A total of 7,369 records of body weight of partridges, measured from birth to 210 days of partridges born from 2000 to 2004 were used in this research. The random regression models applied to the data set considered different structures of residual variances and were performed by the restricted maximum likelihood method. The residual variances were modeled using classes of 210 (R210) and 30 (R30) ages and variance functions with orders ranging from quadratic (VF2) to nine (VF9). The R30 considered birds weighted in the same week. The random effects included were the genetic additive direct and the permanent environment effects of the animal. It was not possible to include the maternal effects in the models. All random effects were modelled by sixth order regression on Legendre polynomials. The models were compared by the likelihood ratio test, the Akaike's information criterion and the Schwarz's Bayesian information criterion. Best results were showed by the models R210 and VF5. In conclusion, the most parsimonious model was VF5 and should be applied to fit growth records of partridges.

In the cemented plots, between July/93 and August/94, in the campus of the Federal University of Paraíba, in João Pessoa (lat 7o 02' 30'' S and long 3o 45' 06' W), experiments were carried out as follows: in the plots A, B and C podzolic soil was put into them and amended with 25kg of sugarcane bagass and added 80 earthworms (A), 10kg of bagass and 80 earthworms (B) and unamended and added 40 earthworms (C). The results showed that the sugarcane bagass improved same soil properties, by raising the pH and Ca++, organic C, S.O.M., and N levels. Microbial biomass (BM), in mg CO2-C.100g-1 of soil and microbial activity (MA), in g.year-1, showed a means: (A) BM= 7.88mg and AM= 1.54g; (B) BM= 10.44mg and AM= 1.59g; (C) BM= 3.29mg and AM= 1.25g. Ratio Cmic : Corg were higher in the plots with greater amount of sugarcane bagass (0.84% in A, 0.64% in B, and 0.33% in C). Earthworms population density (individuals.m-2) was initially 13 in the three plots and increased to 35 in A, 40 in B, and to 30 in C respectively. The results obtained here suggest that 10kg of sugarcane bagass enhanced soil microbial biomass and activity, and the earthworm population assayed.

For proposition of the better recovery practice is necessary to identify the main characteristics of index fingers soil of environmental degradation. For so much, it should seize upon chemical, physical and biological analyses. Thus, the goal of this work was to study some chemical indicators of environmental degradation in soils terms of semiarid. The soils were collected in the pilot's area JICA Project located in the municipal district of Pedro Avelino-RN, the choice of the area was due to your desertification degree. The analyses were accomplished in Soil, Plant and Water Analyses Laboratory of the University Semi-arid Rural Federal. The samples were collected in the layers of 5, 10, 20, 30 and 50 cm. The accomplished chemical analyses were: pH in water (1:2,5); Electric Conductivity (CE) in the extract 1:5; Ca+2,Mg+2, Na+ and K+ exchangeable, and P available. By the results, it verified that pH and CE increased with the depth, with regard to the contents of In the Na+ in the soil there was variation with the increase of the depth. To the thwart of the majority of the analyzed elements the K+ tended to decrease your content in the soil with the increase of the depth, The sodium elevated contents should be carried in consideration for the implantation of the recovery project, using itself preferentially resistant plants of sodicity.

The study was carried out in Fazenda Pau Ferro, Itaperuna - RJ, to evaluate soil quality attributes in pastures areas, Braquiária (Brachiaria brizantha (Hochst. ex A. Rich.) Stapf), Suázi (Digitaria swazilandensis Stent) and Tifton 85 (Cynodon spp. cv Tifton 85) cultivated in hill relief. Soil samples were collected at 0-10 and 10 -30 cm depth in two times; dry period (August of 2004, May of 2005 and August of 2005) and in the rainy period (December of 2004) in different sections: at the hillside shoulder (TS), backslope (TM) and footslope (TI) positions. In the samples soil chemical and physical analyses were accomplished. Were evaluated the soil aggregate stability; the bulk density (BD) and the total volume of pores (TVP), total organic carbon (TOC) and soil fertility. To study the multidimensional effect of soil attributes the Principal Component Analysis (PCA) was applied. The pastures areas showed a good aggregation levels, in the different times and depths evaluated. The grasses Tifton 85 and Braquiária propitiated a higher TOC contribution in the depth of 0-10 cm and also larger aggregate weight in the class> 2,0mm, in the dry period. Higher values of BD were observed in the TI. In the rainy period it was observed a BD reduction and TVP increase, mainly for the Suázi areas. In a general way, the positions of the hillside TS and TM were the ones that showed the higher values for the physical and chemical attributes indicating a better soil quality in these areas. In the TI area the lowest levels of soil quality were observed, possibly for the accentuated steepness of this last position of the slope in relation to the other positions. The PCA separated the areas in function of seasonal variation. The dry season presented the higher correlation values with soil quality attributes such as the aggregation indexes and TOC. The aggregate weight distribution in function of the size classes, especially > 2,0 mm, MGD, MWD and TOC were a indicative sensitive to the effects of the treatments, grasses types and seasonal variation.

Aiming the characterization of genotypes and estimate the genetic divergence through morphological markers of the sweet-potato, an experiment was developed, in the year 2007, in the municipality of Junqueiro, in the Alagoas State, composed of nine clones and two local varieties, in the randomized complete block design with three replications. Were evaluated fourteen characteristics of the aerial part and seven of the roots through morphological descriptors. For the assessment of genetic divergence was used the methodology of the principal components made by the group and the methodology of Tocher. It was wide phenotypic variability among genotypes based on morphological markers. The results showed that the first three components of the variables of aerial part explain 77.08% and in the first two components of the root system of variables explain 72.13% of the variability exists. Six groups were formed, being that group I restrained three genotypes, the groups II, III and IV have been formed by two genotypes each, and the groups V and VI contain a genotype each. The results indicate; using the two methodologies, have wide phenotypic and genotypic variation among genotypes of sweet potato-based on morphological descriptors, indicating prospects for the breeding program of this culture.

The Brazilian northeast region is the main melon producer of Brazil, however in the rainy period there is a significant fall in the quality and amount of melon produced. This work aimed to evaluate the quality and the shelf-life of 'Frevo' yellow melon produced rainy time and stored under cold storage. The completely randomized design was used, in factorial scheme 5 x 4, with five replications. The treatments resulted of the combination of five storage times (0, 7, 14, 21 and 28 days) and four storage temperatures (7, 9, 11 and 13 ºC). In each storage time the fruits were analyzed 48 hours after the withdrawal of these of the cold chambers to simulate the market conditions. The evaluated characteristics were flesh firmness, soluble solids, weight loss, chilling injury and internal and external appearances. The fruits kept at 13ºC and 11ºC temperatures had a postharvest shelf-life of 21 days, however, temperatures around 7ºC and 9 ºC favored the development of chilling injury, being apparent at 14º day. The temperatures and the time studied are not determinative for the increase or reduction in the soluble solid content.

This work had the purpose evaluate physiological quality and incidence of fungi in twelve cowpea seeds cultivars, produced in the state of Ceará, Brazil, in 2005. The physiological quality was evaluated through the germination standard and vigour tests (First germination count) and sanity quality was evaluated through the method paper filter (blotter test) being used four repetitions of 100 seeds. In relation physiological potential of cultivars, it was observed that the cultivars presented low vigour, like Galanjão (0 %), Costela de Vaca (11,49 %) and Parambú (16,6 %). The germination index were low too, except Sempre Verde with 70,33 % the germination of seedlings normal. In respect the incidence of fungi in the seeds, the Fusarium spp. was detected in 0,5 a 0,6 %, Colletotrichum only in Corujinha (0,5 %), Pingo de Ouro 3 (2 %) and Macrophomina phaseolina was detected only in Costela de vaca and Pingo de ouro (0,5 %) and Galanjão (7 %). The incidence of Aspergillus spp. was verified in all you cultivars and Penicillium sp. was detected only in Galanjão, Pingo de Ouro and Costela de Vaca (12 %). Others fungi like Curvularia sp., Phoma sp., Trichoderma sp. and Alternaria sp. were detected in low incidence. The seeds evaluated shown a low physiological quality and the most frequent fungi were those of storage.