The work aimed to evaluate the influence of potassium rates on the yield of yam (Dioscorea cayennensis) and determine your rate for the productivity of commercial tubers. The experiment was conducted at the Federal University of Paraíba, in Areia-PB, in the period from February to December 2010. The experimental design was randomized complete blocks with six treatments comprise the doses of 0; 50; 100; 150; 200 and 250 kg ha-1 of potassium, in four repetitions. Were evaluated the average mass of commercial tubers, productivity of commercial tubers, percentage of tubers classified as first, the leaf content of potassium in the leaves and the maximum rate of economic efficiency. The maximum average mass of commercial tubers was 2.60 kg, obtained at rate of 126 kg ha-1 of potassium. The rate of 189 kg ha-1 of potassium was responsible for maximum productivity commercial of 17.7 ha-1 t of tubers. The maximum percentage of tubers classified as first was 88%, achieved at a rate of 171 kg ha-1 of potassium. The maximum content of potassium in the leaves of yam was 22.3 g kg-1 obtained at a rate of 155 kg ha-1 of potassium. The maximum rate of economic efficiency of potassium for commercial productivity of tubers was de184 kg ha-1.

Ziziphus joazeiro es un árbol fructífero endémico del bioma Caatinga, situada en la región semi- árida del noreste brasileño. No obstante su amplia importancia económica y ecológica, las informaciones sobre la comunidad de insectos asociados a esa especie vegetal son insuficientes. Así, el objetivo de este trabajo fue realizar un levantamiento de los insectos asociados a las flores de Z. joazeiro y observar el horario donde ocurre el mayor número de visitas. El estudio fue realizado dentro del bosque de Z. joazeiro ubicado en el Campus de la “Universidade Federal Rural do Semi-Árido”, municipio de Mossoró, Estado de Rio Grande do Norte, Brasil. El muestreo fue efectuado durante el pico de floración entre los meses de noviembre y diciembre de 2010. Una vez por semana se observaron cuatro árboles de Z. joazeiro, al acaso, desde las 05:00 hasta las 17:00 horas. Cada árbol fue observado durante 15 minutos y los insectos capturados con red entomológica. Los insectos asociados a Z. joazeiro pertenecen al orden Hymenoptera, representados por las familias Apidae, Vespidae, Crabronidae y Leucospidae y, al orden Diptera, con las familias Syrphidae, Muscidae, Calliphoridae, Tabanidae, Dolichopodidae, Stratiomydae, Otitidae y Micropezidae. De todas las familias, Apidae, específicamente, Apis mellifera L., fue la que tuvo mayor frecuencia de visitas, con 48%, seguidas por Vespidae (31.4%) y Syrphidae (9%). En general, los insectos visitaron las flores de Z. joazeiro en mayor frecuencia durante el período matutino, con picos entre las 7:00 y 8:00 horas y entre las 11:00 y las 12:00 horas del día.

Rio Grande do Norte state despite having favorable conditions for growing garlic, currently depends on imports of this product to meet its domestic demand. Evaluation of cultivars from of other regions of Brazil was determined in order to verify the agronomic performance under the edaphoclimatic conditions of the Mossoró. region The study consisted of an experiment conducted in the city of Mossoro from June to November/ 2011. The experimental design was a randomized block design with four replications and eleven treatments, cultivars Amarante, Branco Mossoró, Caturra, Chinês Real, Chinês São Joaquim, Cateto Roxo, Gravatá, Gigante do Núcleo, Gigante Lavinia , Gigante Roxo and Hozan. Cultivars Branco Mossoró, Caturra, Cateto Roxo and Gravatá had a greater percentage of plants with bulb and larger diameter bulb, indicating adaptability conditions of Mossoró. Most total yield bulbs) was recorded by cultivar Branco Mossoró presented 65.22% and 11.53% distributed in bulb diameter grades 3 (32 to 37 mm) and 4 (37 to 42 mm), respectively.

Aiming at assessing the growth of sweet peppers (Ca psicum annum L.), submitted to different controlling strategies of weeds in the no-trillage and conventional planting systems, an experiment wa s carried out in UFERSA’s experimental orchard in Mossoró-RN. The split-plot scheme was used, which was distribu ted within the experimental design, in randomized block s with four replications. The planting systems (no- trillage and conventional) were assessed in the plots, and t hree weed handling strategies (soil covering with p olyethyl- ene film, with hoeing, and without hoeing) were ass essed in the subplots. Within each subplot, assessm ents were made on 0, 21, 42, 63, 84, 105, 126, and 147 d ays after transplanting (DAT) for the purpose of de termin- ing the following features of the sweet pepper: lea f area, leaf area index, dry mass of leaves, of ste m, of fruits, and the total dry mass per plant, leaf area ratio, leaf weight ratio as well as the rates of absolute and relative growth and of net assimilation. On the 30th and 90t h DAT, the weeds’ density was assessed in the treat ments without hoeing. It was found that the no-trillage s ystem displayed a decrease in the incidence of weed s as com- pared to the conventional planting system. The no-t rillage system decreased the incidence of weeds com pared to the conventional planting systems. The weed inte rference in treatments without hoeing reduced the g rowth of pepper in both systems and the no-trillage with hoeing system showed higher indices than the other manage- ment strategies of plants in both planting systems.

The evaluation of profitability of ‘Ponkan’ mandarin subjected to chemical thinning may constitute important information that allows the farmer to evaluate the feasibility of adopting the practice of management in his orchard. Thus, this study was developed with the aim to evaluate the profitability of the practice of chemical thinning in ‘Ponkan’ mandarin trees (Citrus reticulata Blanco). The work was carried out in 2009, 2010 and 2011 in an unirrigated orchard of ‘Ponkan’ mandarin, in the city of Perdões, the southern region of Minas Gerais, Brazil. Before the treatments, in October 2008, 80 plants we selected with abundant flowering on the entire canopy, so that all the mandarin trees could have production significant quantities of fruit. In half of the plants was not performed the chemical thinning and the other half was applied 600 mg L-1 of Ethephon, after the period of physiological fruit drop, in January 2009, January 2010 and January 2011, when these were at stage 25 to 30 mm in transverse diameter. At harvest, in June 2009, June 2010 and June 2011 were evaluated the production per plant (boxes of 22 kg) and estimated the productivity of plants subjected to the chemical thinning and plants that were not subjected to this practice. The profitability analysis was performed in a simplified manner considering the production costs of the orchard already deployed with the production stable. The practice of chemical thinning promoted superiority of 176% on the average profitability of 'Ponkan' mandarin trees.

In the last years, as interest in recycling and waste use has increased, many researchers have studied a wide range of potential substrates alternatives. Therefore, is possible that pulp mill sludge can be used as a substrate to seedlings production, while reducing costs. The aim was to evaluate the potential of using pulp mill sludge combined or not with cattle manure as an alternative substrate component for production of seedlings of yellow passion fruit. The experimental design was randomized blocks, in factorial 2 x 3 x 5 design, begin two cultivars (Yellow Maguary FB 100 and FB Master ® 200), three doses of N-P-K (0, 21.4 and 42.8 g plant-1) and five combinations of pulp mill sludge (PMS) and cattle manure (CM). Were used the following combinations: CM 100%, 25% PMS + 75% CM, 50% PMS + 50% CM, 75% PMS + 25% CM and PMS 100%, with four replicates. After 48 days were evaluated shoot and root length, number of leaves, stem diameter, shoot fresh and dry weight and root fresh and dry weight. Observed that increasing concentration of waste in the substrate caused significant damage to seedlings in both cultivars, probably due to nutrient imbalances, therefore is detrimental to the development of seedlings; the application of N-P-K, in the tested doses, is not sufficient to avoid adverse effects in the seedlings or to correct the balance nutritional of waste; and the cattle manure is the best option for the production of quality seedlings, in the conditions studied.

This research aimed to evaluate the tannins extracted content of Anadenanthera colubrina (Vell.) Brenan var. cebil (Gris..) Alts. bark in aqueous solution of sodium hydroxide, sodium sulfite and hydroxide + sulfite having as comparison the amount extracted in distilled. A total of 25 g of dry sawdust and 3% of chemicals were used with relationship to dry weight of sawdust. To compare the effect of water with one of the other used solutions it was found that the addition of sodium hydroxide, sodium sulfite or hydroxide + sulfite caused an increase in solid total contents (TST) of 60,17%, 28,45% and 60,17%, in condensed tannin contents (TTC) of 34,5%, 20,02% and 18,02% and of no-tannins of 117,34%, 47,3% and 146,6% and a reduction in the Stiasny’s index of 15,62%, 5,53% and 24,51%, respectively. Statistical analyzes showed that the sodium hydroxide solution extracted a larger amount from tannic substances when compared with the water, having the sodium sulfite and the hydroxide + sodium sulfite solutions presented middlemen results. The distilled water extracted a lower solid total content than other solutions, but the extract contained a greater Stiasny’s index than those obtained by other solutions.

This study evaluated the effect of different salt concentrations on growth, synthesis of organic solutes and ionic balance (Na+, Cl- and K+) of Jatropha curcas L. for 28 days. Seven treatments were established: 0, 15, 30, 45, 60, 75 and 90 mol m-3 NaCl in a completely randomized design with five replicates per treatment. The largest concentrations of NaCl the addition of the salt was made gradually to avoid osmotic shock. The number of leaves and leaf area were reduced in plants subjected to salinity from 30 to 45 mol m-3 NaCl, respectively. The production of fresh and dry matter were reduced from 60 mol.m-3 NaCl up to 36%. The concentration of soluble carbohydrates and total soluble proteins increased significantly only in plants exposed to 15 and 30 mol.m-3 and 30 mol.m-3 NaCl, respectively. The total phenol content increased in plants subjected to salinity from 30 mol.m-3 NaCl. The increase in the levels of total phenols, soluble carbohydrates and soluble proteins and the absence of reduced growth in seedlings subjected to 30 mol.m-3 NaCl indicates the activation of an efficient mechanisms of acclimatization of this stress magnitude. The levels of Na+ and Cl- increased in all parts of the plant were increased concentrations of salt in the nutrient solution. The high levels of Na+ and Cl- indicate the absence of extrusion mechanisms of these ions.

Cowpea [Vigna unguiculata (L) Walp] have great social and economic importance for the Para State. It grows well in areas with low precipitation and two crop cycles can be obtained annually. This study aimed to assess the effect of the residual fertilization from a previous culture (Sorghum bicolor L. Moench) and crop systems on cowpea yield and macronutrient concentration on leaves of three cowpea cultivars (BRS- Milênio, BRS-Urubuquara e BRS-Guariba). The study was conducted at the UFRA. The treatments were two crop systems (minimum tillage and conventional), four levels of potassium (50, 100, 200 e 300 kg de KCl ha-1 applied to a previous sorghum culture) and the three cowpea cultivars. Treatments were organized as a three (4 x 2 x 3) factor experiment on a randomized complete block design. The soil was a yellow latosol. In each ex- periment plot five plants were selected to determine shoot dry matter and foliar nutrient concentration. Grain yield was determined after harvesting all plants on the experiment plot. The residual KCl fertilization affected foliar nutrient content, but did not affect shoot dry mass or yield of grain. Yield was higher in the minimum tillage system. Highest yield (1590 kg ha-1) was recorded int the cv. ‘Guariba’ when 100 kg of KCl ha-1 had been used in the previous crop. The highest content of leaf N and K was found in cowpea under minimum till- age system. The amount of P and Mg were higher in the conventional system whereas the amount of Ca did not change.