This study was conducted to evaluate the yield, water use efficiency and physiologic characteristics of "Tommy Atkins" mango under partial rootzone drying. The experiment was carried out in an orchard of mango in the irrigated perimeter of Ceraíma, BA. Five treatments and six repetitions were used with one tree per experimental plot: 01-Full Irrigation, 100% of ETc, 02-100% of ETc with frequency of alternance (FA) of 15 days, 03-80% ETc with FA of 15 days, 04-60% of ETc with FA of 15 days, 05-40% ETc with FA of 15 days. The treatments were conductedfrom the beginning of flowering to the harvest of mango in an orchard irrigated by drip. There was no significant reduction in productivity of "Tommy Atkins" mango under PRD up to 40% of ETc and PRD with 40% ETc resulted in greater water use efficiency. There was no significant difference among the averages of photosynthetically active radiation, Qleaf; leaf temperature, Tl; internal CO2 concentration, Ci; transpiration, E; stomatal conductance, gs; photosynthesis, A; carboxylation efficiency, A/Ci; quantum efficiency of photosynthesis, A/Qleaf and instantaneous water use efficiency, A/E between full irrigation and PRD with different water depth. The increase in leaf temperature causes reduction in A/Qleaf and A/E, however, it increases the transpiration. Increased gs results in higher rates of E, A and A/Ci. The use of the PRD with 40% of ETc causes no interference in gas exchange, maintains the yield and increases water use efficiency in "Tommy Atkins" mango tree.

Water availability and substrate in the emergency and initial development of Bauhinia scandens L.

O cultivo de girassol (Helianthus annuus L.) se destaca por ser uma planta de ciclo curto, ter alto teor de óleo nos grãos, aonde o mesmo é utilizado para produção de biodiesel e alimentação humano, podendo também ser empregada para alimentação animal, assim como a silagem da planta e a torta proveniente da extração do óleo. Diante desses fatores, buscou-se avaliar o desempenho da cultura em diferentes condições no Sudoeste Baiano. O experimento foi realizado em condições de campo na área do Instituto Federal de Educação, Ciência e Tecnologia Baiano Campus Guanambi, avaliando-se o desempenho produtivo de 13 genótipos no semiárido baiano. O delineamento experimental foi em blocos casualizados com quatro repetições. O ciclo da cultura foi de 120 dias. Houve diferença estatística (p<0,05) para os caracteres produção de grãos, peso de 1000 aquênios, produção de matéria seca na floração, área foliar, altura de inserção do capítulo, diâmetro do capítulo e o rendimento de óleo, não havendo diferença apenas para os teores de N, P e K no florescimento. Os genótipos CF 101, BRS G43, HÉLIO 250 e SYN 045 foram os que apresentaram simultaneamente maior rendimento de grãos e de óleo. O genótipo CF 101 se destacou por possuir baixa estatura.

The main difficulty with propagating Urochloa humidicola Comum is the high percentage of seed dormancy. Thus, the objective of this study was to develop a treatment to overcome seed dormancy and promote seed germination of this species that can be applied at a large scale. This study was conducted in two stages. First, the following treatments were evaluated using one seed lot: control (without treatment), immersion in H2SO4 (98%, 36N) for 10 min, moistening the germination substrate with KNO3 (0.2%) and immersion in KNO3 at concentrations of 0%, 2%, 4%, 6%, and 8% for periods of 12, 24, 36, and 48 h, followed by drying in the shade. In the second stage, three seed lots were evaluated in all of the aforementioned treatments, except for those of immersion in 0% KNO3 and of all concentrations for 36 and 48 h. The seeds were evaluated for water content, germination, percentage of abnormal seedlings, dead and dormant seeds, first count, and average germination time. Immersion in the KNO3 solution was efficient in overcoming dormancy and promoting germination. To be used by companies, the immersion of seeds in a 4% KNO3 solution for 24 h was the most suitable treatment to overcome dormancy and promote the germination of U. humidicola Comum seeds.

Custard apple production (Annona squamosa L.) in the Brazilian Northeast occurs throughout the year. Its management involves pruning, irrigation, and proper nutrition. The objective of the present work was to verify the influence of different doses of nitrogen and the use of humic substances on soil chemical attributes and tree custard apple nutrition. The experiment was conducted in a commercial orchard in the municipality of Anagé, Southwest region of the state of Bahia, in a randomized block design in a 4 x 2 factorial scheme, four nitrogen doses (0, 284, 568 and 852 g per plant, urea) with and without the application of humic substances (Ks100), with 4 replicates. Soil chemical characteristics, macro and micronutrient contents were evaluated in the leaves of the custard apple tree. Nitrogen rates reduced soil pH and the availability of calcium, magnesium and boron. The application of humic substances increased the content of potassium in leaves. Under the conditions studied, high nitrogen doses influence soil fertility and the application of humic substances does not improve the absorption of most of the nutrients, except potassium, and it did not influence the chemical attributes of the soil.