In agriculture practiced in Brazil, the branch of the horticulture is one of the prominences, in production and in exportation, being melon one of the more produced fruits, especially in Brazil¿s northeast. In this context, the use of a good quality substrate is essential for the development of the plants. In this study it was evaluated the growth of melon seedlings and the role of Arbuscular Mycorrhizal Fungi (AMF),Glomus clarum, associated to the use of coconut dust, as an alternative substrate, at 100, 80, 60, 40, 20, 10 and 0% concentrations, as a soil mixture (grayish Argissol). The plants were cultivated under greenhouse conditions and, at the end of a 35 days period, were analyzed the diameter of the stem, number of leaves, height of plants, shoot dry weight, microbial biomass carbon content, basal soil respiration, metabolic quotient, colonization with AMF and shoot nutrient content (N, P, K, Ca and Mg). It was observed that 100% and 80% concentration of coconut dust were the more restrictive treatments for plant development. Microbial carbon and mycorrhizal colonization were higher when the substrate was composed by 10 and 20% of coconut dust. The basal soil respiration and the metabolic quotient (2,07) were higher when 100% coconut dust was used, while the smallest value (0, 96) was found in treatment without coconut dust. The use of concentrations higher than 40% of coconut dust decreased AMF activity and growth of the melon plants.

Copaifera langsdorfii is a typical tree species very important for restoration of degraded areas. This study evaluated the effect of different temperatures and light conditions on Copaifera seed germination. The applied treatments were the temperatures of 25ºC, 30ºC and 20-30ºC and three different light expositions (constant dark, 8h of light plus 16h of dark and constant light). The tested variables were percentage, velocity and average time of germination. The treatments consisted of 200 seeds, with four replications of 50 seeds each, sown on a Germitest towel paper and maintained for 28 days on germination chamber. The completely randomized design was used and the averages compared by Tukey test at 5% probability. Germination percentage was not influenced by the treatments. The constant temperatures of 25ºC or 30ºC, independently of light regime, promoted a higher rate of germination velocity and caused the reduction of the germination average time.

The physiologic activity of two corn varieties regarding nitrogen accumulation and remobilization in the vegetative phase was evaluated by the activity of the nitrate reductase enzyme (NR), and NO3 - contents of the N-amino and soluble sugars in leaves, hems and stems of the plants. The varieties were selected according to their agricultural characteristics: BRS 4157 (Sol da Manhã), an improved variety used in familial agriculture and BRS 1010, an exotic variety, a simple hybrid used in extensive agriculture. The plants were cultivated in a greenhouse, in pots containing a Red-Yellow Argissol submitted to two doses of N-NO3 - (130 and 1300 mg of N per pot). Harvests were made at the first two stages of the vegetative development, at 32 and 60 days after germination (DAG). The Sol da Manhã variety, efficient in nitrogen use, adapted itself to the condition of low nitrogen due to its higher capacity in accumulating NO3 - in the leaves in the first development stage, and remobilizing it during the second stage. This resulted in a higher free amino-N concentration in the leaves and hems when compared to the simple hybrid BRS 1010, described as a high potential in productivity under low nitrogen conditions.

This work was conducted in order to evaluate the procedures for analysis of nodule development through non-destructive and destructive methods in the same plant set. A greenhouse experiment was carried out with cowpea grain legume. Plants were weekly measured, from seven days old to physiological maturity, for evaluation of plant height and leaf area, and to obtain digitized images of all the visible part of the rooting systems. Weekly, a plant was also collected from each block for destructive determination of plant and nodule development.Nodules area, length and diameter were measured for those hand-separated from the root system and for those visible on the vessels side. For area, length and diameter of the nodules, initially a escriptive analysis was conducted in each point and next it was determined the average, median, maximum, minimum and the sum for each variable. Both variables, leaf area and plant height, were studied by regression analysis being considered as dependent variables and plant age as independent variable. Independent regressions were conducted for data obtained through the traditional destructive methods. Results have indicated a general concordance for development curves obtained by destructive and non-destructive methods, especially regarding nodule appearing and age in which the maximum value for each variable was found.

The purpose of the present work was to determine the size sample in order to estimate soluble solid contents in yellow melon plot. Samples of fifty fruits were taken of fifteen yellows melon plots grown in Mossoró- Assu Agricultural Pole. Evaluation for total soluble solid contents was done in all fruit samples. The procedures used for sample size estimation were bootstrap method and classical expression with 5% and 10% of error limit. The sample sizes estimated by bootstrap method, in average, yielded estimates close to those observed in the classical expression with 10% of error limit, although in ten plots these sample sizes were greater in the bootstrap method. The sample size recommended to estimate the total soluble solid contents in cultivated plots of melon fruits is fifteen.

Seedling production is an important step for the tomato (L. esculentum) production system, being sometimes limited by cost and quality of the substrates used for this purpose. Use of agro-industrial residues, alone or in mixtures, may help reduce this problem. The potential of different mixtures of substrate including coconut dust treated with nitrogen, phosphorus and potassium (PC), commercial substrate TropstratoÒ and organic compound (CO) were evaluated in order to obtain the best source and combinations of substrates. These materials were used alone or in volumetric basis mixtures at the proportions of PC+SC (1:1); PC+CO (1:1) and PC+SC+CO (1:1:1), for seedling production of tomato cv. Salada. The randomized block design was used, with six treatments and six replications. Obtained data were aerial dry matter (MS), emergence speed index (IVE), colon diameter (DC), leaf number (NF) and seedling height (AP). The best results were obtained for CO and PC+CO. CO performance probably is due to its higher nutritional value, once its physical characteristics do not differ from the remaining treatments, especially when compared to SC and PC. CO was the best substrate for tomato seedling production, and its addition to PC enhanced the performance. The use of organic residues for tomato seedling substrate composition is an economic option which may reduce production costs, and represents an alternative for recycling and subproduct usage in agro-industry.

This work had as objective to evaluate spatial variability of physical characteristics of a Typical Haplocambids (CX), under papaya culture, by means of the geostatistic. The analyzed area presented 43 sampling points , where soil samples were collected, in the layer of 0 ¿ 0.2 m. In the soil samples granulometry, soil bulk density, particles density, water content at tension of 0.03 and 1.5 MPa were measured. From these analyses the total porosity and water availability were calculated. Data were evaluated by descriptive statistics and by analysis of the spatial dependence based in semivariograms adjustment. The variation coefficient indicated low variability for total and coarse sand contents, water content at tension of 0.03 and 1.5 MPa, soil bulk and particles density and total porosity; and medium for clay, silt e available water contents. Except for water content at tension of 0.03 and 1.5 MPa and particles density, the other variables presented space dependence, being the spherical and exponential models adjusted to all the semivariograms. The nugget effect had small contribution in the data total variance, indicating strong spatial dependence for fine sand and clay contents, total porosity and available water. The other variables showed moderate dependence. There was a great variation in the distance until where the physical characteristics of the ground present spatial dependence (reach).

The yield of lettuce plants cultivated under agrotextile protection was evaluated in conditions of high temperatures and intensity of radiation. The experiment was carried out at the experimental area of the Universidade Federal Rural do Semi-Árido, in Mossoró, Rio Grande do Norte State, Brazil, in a red-yellow argissol. The randomized complete blocks design was used, with four replications, in a 3 x 3 factorial scheme. The treatments consisted of the combination of three lettuce cultivars (Tainá, Babá de Verão and Verônica) with three types of plant protection (non-protected, direct-on-the-plant agrotextile protection, and nonwoven polypropylene tunnel with height of 0.5 m). The best yield performance was observed when the lettuce cultivars were grown in low tunnel.

The purpose of this work was to evaluate the effects of phosphor dosages and sources on productivity and fruit quality of yellow passion fruit. The experiment was carried out in orchards in Lavrasmunicipality, Minas Gerais, Brazil. The experimental outline used was a 2 X 5 factorial on a randomized complete block design, with four replicates. The treatments were composed by two phosphor sources (super triple phosphate and termophosphate) and five dosages (6, 30, 60, 90 and 120 g/plant). Productivity, fruit number per plant, juice yield, total soluble solids (TSS), total titratable acidity (TTA), ratio TSS/TTA and peel thickness were evaluated. There was no productivity increase or improvement of the fruit quality for the treatments, except for the increases of TTA and peel thickness when Yoorin termophosphate was used as fertilizer.

A treated sewage effluent was initially analyzed and after that an experiment was carried out to evaluate the effects of the irrigation using this effluent on some chemical properties of a Typic Quartzipsamment soil, in a greenhouse. The experiment was accomplished in a completely randomized design with two treatments and ten replications. The treatments consisted of applying normal water and treated sewage effluent in twenty experimental units (plastic bags with capacity of 2 L). Soil samples from experimental units, collected before and after experiment, tap water and treated sewage effluent samples were chemically analyzed. Results indicated that treated sewage effluent can be used for crop irrigation. When compared to water, irrigation with treated sewage effluent produced in the soil, under the study conditions: a) increase in the P and organicmatter contents in the soil; b) increase in the sodium contents, exchangeable sodium percentage and, consequently, in the soil pH; and c) increase on the sum of exchangeable basis and on the exchangeable cationic capacity.