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.

The objective of this research was to evaluate the profitability of the production of rocket ferti-lized in different amounts of roostertree biomass and times of incorporation of this green manure into the soil, in two cultivation seasons (spring-summer and autumn), in Serra Talhada, Pernambuco state, Brazil. The exper-imental design was a randomized block with the treatments arranged in a factorial 4 x 4, with three replications, with the first factor consisting of amounts of roostertree biomass (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis), and the second factor by the incorporation times into the soil (0, 10, 20 and 30 days before sowing of the rock-et). Beyond the green mass yield and production costs, were determined the following economic indicators: gross income, net income, rate of return and profit margin. The optimal agronomic performance of the rocket was obtained into monetary terms. Spending on hand labor accounted for 69% of protuction costs. Due to the increase in the daily price of rural workers, the costs of preparation of the green manure were higher in autumn. The cultivation of the rocket under fertilization with roostertree was feasible from the economic perspective, regardless the amount of green manure, time of incorporation into the soil and cultivation season. The amount of 12.2 t ha-1 of roostertree biomass promoted greater profitability for the production of rocket. The incorpora-tion of green manure at 20 days before planting the crop was considered ideal to the economic viability of the activity. The net income of the rocket was higher in the autumn season.

The objective of this Study was to evaluate the effect of organic fertilizer and cuts on the chemical composition and in vitro digestibility of the air pornunça biomass. The experimental design of randomized blocks in a split plot with four courts, two fertilization, and four replications. The cuts were made in February, June and October 2011 and February 2012. The fertilizer was with cattle and sheep manure, applied in May 2010 and March 2011 in the amount of 20 Mg ha-1 . We evaluated the structural components of the shoot, such as leaf blade, petiole, branch and full (leaf blade and petiole more branch) of pornunça. The manure beef and lamb did not influence (P>0.05) the chemical composition of the structural components of the shoot. Differences were noted between the cuts, except for dry matter (DM) of the leaf blade and the full component of ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose (HC). There was a significant (P<0.05) for the in vitro digestibility of the MS of the structural components in different cuts, with the highest digestibility for structural components in the cut made in February 2011. Lower crude protein was found in the petiole and components branch. The pornunça should be considered as an alternative food for animals according to the chemical composition of the values presented in this study, with the leaf surface of the plant part that presents the best nutritional value.

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 maintenance of a plant water status is essential for keeping of its development in environments with limited water availability. Different species have different mechanisms that provide greater ability to survive under drought conditions. The objective of this study was to evaluate physiological parameters changes of the isohydric species Beaucarnea recurvate Lem. under irrigation suspension. The study involved experiments with slow dehydration (SD) performed by withholding water followed by plants rehydration, and with rapid dehydration (RD), where individual leaves were detached and placed to dehydrate in the laboratory bench. The results showed that although of the soil water content (% H2O) reach critical values (12%) in the first days of the irrigation suspension, the plants showed maintenance of the relative water content (≅80%) over the 54-day SD period, when the net photosynthesis (PN) reached null values. Throughout SD, it was observed that the PN, stomatal conductance (gs), instantaneous carboxylation efficiency, the electrons transport rate, the potential quantum efficiency of PSII and chlorophyll content were reduced. In RD, experiment was observed a high correlation between PN and gs . The results suggest that the reduction in photosynthesis was initially caused by a stomatal adjustment that culminated in an imbalance between photochemical energy production and its consumption by biochemical apparatus of photosynthesis. However, after rehydration, all gas exchange parameters were recovered, indicating that the isohydric behavior of this species contributed to the plants did not suffer extensive damage during a prolonged period of irrigation suspension.

Watermelon is a cucurbit, grown in almost all regions of the world, and it is enjoyed by most of the population. In Rio Grande do Norte the cultivation of watermelon has been increasing, because of the good climatic conditions in the region that provides adequate light and temperature throughout the year. In this con-text, the present study aimed at evaluating the yield and quality of watermelon cultivars in different planting dates in Mossoró-RN. The experiment was conducted in the garden didactic Department of Plant Sciences, Federal Rural University of the Semi-Arid in the period between June and December 2010. The experimental design was a randomized complete block in a split plot design with four 3 x 3 repetitions. The plots consisted of three cultivars of watermelon (Crimson Sweet, Olympia and Denver) and subplots were planting (June, Au-gust and October). It is concluded that the yield and fruit quality were influenced by planting dates. The water-melon sowing in August resulted in higher average fruit weight and commercial productivity, and the fruits of lower acidity and better palatability were collected in the June planting.

The modeling for agriculture is a mathematical tool that allows us to weigh the effects of factors, environmental or management on crop productivity. Therefore, the aim of this study was to evaluate the efficiency of mathematical models, in the estimation of the productivity of maize over the need for nitrogen fertilization. Estimates of nitrogen fertilization were performed to obtain the potential productivity and depleted grain yield and silage corn genotypes. The Model 1 was based on estimates obtained in the literature and Model 2 on estimates generated by the proposed alternative model, calibrated with data observed in the experiment. To evaluate the performance of the models we used statistical indicators, such as Pearson correlation coefficient, Willmott agreement index, the performance index of Camargo, percentage deviation and medium square error. Recommendations of nitrogen generated by the models for the potential productivity and depleted much grain as silage were higher compared with the recommendations of the culture ways. The AG30A91 genotype had a higher leaf area index, reflecting higher estimates of potential productivity and depleted grain and silage. The model 2 can be used to estimate the yield of grain and silage and the need for simulation of nitrogen for grain production, however, requires adjustments to estimate nitrogen needs for the production of silage. Both models are efficient in simulating the crop cycle.

In fruit pulp industrialization often use thermal processes to (heating and/or cooling) that may cause changes in its viscosity, which causes the study of the influence of temperature on the rheological behavior of this type of product is of great importance. Data of the apparent viscosity of fruit pulp are used in equipment design and process optimization. The research objective was to evaluate the influence of temperature on the apparent viscosity of the Myrtle pulp. The rheological analysis was conducted on a Brookfield viscometer model DV - II +Pro. The apparent viscosity curves as a function of strain rate were described by rheological models Sisko, Power Law, and Falguera - Ibarz. The full Myrtle pulp was classified as non - Newtonian fluid and shear thinning. The behavior of this fluid can be well described by models Sisko, Law of Power and Falguera - Ibarz, especially the Sisko model. The effect of temperature on the apparent viscosity was described by Arrhenius equation with activation energy presenting high values at low shear rate.

Calotropis procera (Aiton) W.T. Aiton - Apocynaceae (silk-flower) is an important species for several usages: ornamental, forage, timber, textile and medicine, that justify its study. We investigated the physiological behavior and the vigor of seeds under different storage conditions. There were performed month-ly evaluations of germination, seedling emergence, speed of emergence, seedling length and weight of seedling dry matter, during 180 days. Experimental design was completely randomized with a 6x5x3x2 factorial, using combinations of six storage periods (30, 60, 90, 120, 150 e 180 days), five moisture contents (30, 24, 18, 12 e 7%), three package types (paper bags, plastic bags and PET bottles) and two environmental conditions (chamber: 16 °C a 18 °C and laboratory: 27 °C a 30 °C, both environments with 50±5%) with four replications of 50 seeds. Data were analyzed using analysis of variance using F (p≤ 0.05) test to treatments and Tukey test for averages comparison, with polynomial regression analysis considering the storage periods. There were con-cluded that silk flower seeds presented orthodox physiological behavior; the vigor decreased when stored for 180 days; silk flower seeds with 7% moisture content are preserved efficiently in paper bags and controlled environment for 90 days.

This work aimed to evaluate the growth and yield of banana cv. "Nanicão", in intercropping with live coverage crops in the semi - arid region. The experiment was analysed as a randomized complete block with four replications. The experiment used a split - plot design, and some variables were sub - subdivided over time. In the plots, factor "A", made of three management strategies of soil cover - the leguminous, calopo and tropi- cal kudzu, and bare soil (hoed soil); Factor "B", on the sub - plots, banana plants in three morphophysiological ages (different cycles and sizes) and factor "C", dates of collections in the sub - plots. The cultivation of banana cv. Nanicão in soil under live coverage with calopo and tropical kudzu in the semi - arid region promotes an increase in the number of fruits, fruit weight and bunches.