The objective was to evaluate the growth of clones of forage cactus, subjected to different conditions of water availability in the Brazilian Semiarid, during a year of climate anomaly (biennium 2012-2013). The experiment was carried out in the first production year of the second crop cycle (March 2012 to February 2013), in the district of Serra Talhada, State of Pernambuco. The experiment was carried out in a randomized block design using a factorial arrangement 3x3 with three replications, being used three intervals of application of a fixed irrigation depth (7.5 mm), (7, 14 and 28 days), and three forage cactus clones (IPA: IPA Sertânia; MIU: Míuda and, OEM: Orelha de Elefante Mexicana). Eight biometric campaigns were performed during the experiment period for morphological analysis of the plants and cladodes along the time. It was found that water availability conditions showed no significant influence (P>0.05) on the majority of the absolute and relative values of the growth variables of the three forage cactus clones. However, when comparisons were performed among different clones, regardless of the water availability conditions, it was observed that, in terms of absolute values, the OEM had the highest means, differing only from the MIU clone. Regarding evaluations over time, there were increased growth rates in the last months of the crop cycle because of the occurrence of rainfall, which in conjunction with the application of the irrigation treatments promoted the best biometric increments for the OEM and IPA Sertânia clones.

Cropping systems modify soil attributes and may change its quality.The work had the objective to evaluate the changes in physical, chemical and biological soil under organic farming systems (soils cultivated organically for more than seven years), in conversion to organic and conventional, with reference to the soil under native forest, and identify the attributes used as indicators of soil quality. Three areas of farm crops, located in the municipalities of Areia, Remígio, and Lagoa Seca, the state of Paraíba, Brazil were selected, and soil samples deformed collected in the layers 0-10 and 10-20 cm. The data were analyzed using ANOVA, the Tukey Test, and the Principal Component Analysis. There was a reduction of soil density (Ds) and increased porosity (PT) in the system of organic farming compared to cropping systems in conversion organic and conventional. The contents of phosphorus and organic carbon (CO), the base sum (SB), cation exchange capacity (CTC), light particulate organic matter (MOPL), carbon particulate organic matter light (CMOPL), edaphic respiration (RE) and pH of soils under organic cultivation are higher than soils under conventional tillage.The growing organic basis contributes to the maintenance of soil quality under similar conditions and/or even better than the condition forest and, under the conditions of this study, the most appropriate indicators to analyze the cultivation organic basesare Ds, PT, CO, MOPL, CMOPL, pH, SB, CTC e RE.

It was objective to evaluate the influence of vegetation structure in the selection of plant species by sheep in Cerrado (Brazilian savanna). The research was conducted in an area of Cerrado sensu stricto in the north of Minas Gerais between January 2009 and March 2010. A phytosociological survey conducted the anal-ysis of the vegetation structure, using the plot method. In the tree stratum were delimited 38 continuous plots of 20 m × 20 m. In the regenerant stratum, were allocated sub-plots of 5 m × 5 m. In herbaceous stratum were made two transects in the area of pasture and every 2 m, with the movable square of 0.50 cm × 0.50 cm, 283 points for each transect (566 m).To the identification of the selected species, were used three sheep of the breed Santa Inês, which were kept by grazing in the experimental area and accompanied by observers. In the vegetation were identified 1288 tree, 102 regenerating and 1388 herbaceous individuals, grouped in 117 species distributed in 72 genera and 33 families, among these species: Tachigali rugosa, Heteropterys by sonimifolia, Astronium fraxinifolium, Lantana fucata, Evolvulus sp. e Rhynchospora sp. were important. The selected spe-cies by sheep in grazing, both in the rainy and dry season, in more than 50% species were: Casearia sylvestris, Erythroxylum deciduum, Heteropterys by sonimifolia e Ximenia americana. The feeding preference of sheep in the rainy season was by the species of herbaceous stratum, in the dry period by the species of the tree and re-generating strata. These species are structural bio-indicators of the Cerrado biome, for the grazing of sheep. It is necessary to evaluate, identify and quantify the chemical compounds of selected vegetal species because these can act as nutritional bio-indicators and potential in sheep feeding.

The treated domestic wastewater use in agricultural production has increased in research pro-jects, because providing nutritional qualities available to the plants. However, studying the challenges that this water source can cause to the this irrigation system located, is an important result to the sustainability of pro-duction. The current study has to evaluate the hydraulic performance of emitters under time exposure of drip-pers in the domestic sewage. With the performance evaluation system hydraulic prepared on a bench was car-ried out two experiments in a completely randomized design (CRD). In the first experiment, the treatments were three pressures (kPa) supplied to the system and in the second the treatments were made by operating time in interval of 60 h (composing seven intervals) with 28 drippers as repetitions. The system performance was evaluated for each treatment by the coefficient of distribution uniformity (CUD) and Christiansen's uni-formity coefficient (CUC). There was no statistical significance was set at a 5% for the different pressures, but there will be 1% for different times. When the CUD and CUC fell to 60 and 70 %, respectively, was cleaned with sodium hypochlorite. The system showed uniformity acceptable in the first 120 hours of operation with no need for cleaning. According to the coefficients evaluated this cleaning must occur before the 180 h, however, suggests that to maintain good uniformity this procedure should be done every 60 h.

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.