Considering that water is extremely important in agricultural production, but with restricted availability in some Brazilian regions, this research sought to identify the water limit for the rootstocks: Cleóptra tangerine (Citrus reshni hort. Ex Tan), Volkamer lime (Citrus Volkameriano Pasquale), Citrandarin ‘indio’ (TSK X TRENG 256), Santa Cruz Rangpur lime (Citrus × limonia) and Sunki Tropical tangerine (Citrus sunki HORT. EX TAN) grafted orange ‘Pera’ (Citrus sinensis), obtained by two methods: the traditional method of determining the permanent wilting point described by SHANTZ & BRIGGS (1912) recovery of plants with saturated environment and by irrigating recovery method. The experimental design used was in a completely randomized design with four replications totaling 20 experimental plots. It was verified that the rootstocks Cravo Santa Cruz lemon and Volkamerian lemon were the most resistant in initial conditions of water restriction, evaluated by the method of BRIGGS & SHANTZ (1912), with recording of humidity of 0.0488 and 0.0489 respectively. Under more severe conditions of water restriction, determined by the irrigation method, Volkamerian lemon presented the highest resistance, with a humidity of 0.0371.

Foliar fertilization is an interesting strategy for nutrition with micronutrients in perennial plants; among the micronutrients, zinc (Zn) deficiency is the most frequent in cocoa trees (Theobroma cacao L.). The present study aimed to evaluate the efficiency of Zn sources through foliar application for the cocoa crop. The experiment was carried out in a randomized block design, with 10 treatments and four replicates. Treatments were: foliar fertilizations containing 1 g L-1 of Zn using two inorganic sources (chloride and sulfate), in the presence or absence of additives (urea and sucrose); two organic sources (Zn-EDTA, and from chloride and sulfate); soil fertilization with 8 mg dm-3 of Zn, and a control (without addition of Zn). Foliar fertilizations with Zn were monthly applied for five months, and the experiment was conducted for 210 days. The results were subjected to analyses of variance and contrast. Zn fertilization, regardless of the form of application, increased Zn contents and accumulations in the leaves. Zn fertilization in the soil, at planting, led to a recovery rate by the plant similar to the mean value caused by foliar fertilizations. ZnCl2 caused higher Zn contents and accumulations in the leaves and was more efficient than sulfate and EDTA; addition of urea to the ZnSO4 solution increased Zn accumulation in the leaves, whereas addition of sucrose to the ZnCl2 solution reduced Zn content in the leaves.

HIDRODINÂMICA EM SOLOS TÍPICOS DOS TABULEIROS COSTEIROS NO RECÔNCAVO DA BAHIA     MARIA MAGALI MOTA DOS SANTOS1; FRANCISCO ADRIANO DE CARVALHO PEREIRA2; LUCIANO DA SILVA SOUZA3; EMANUELA BARBOSA SANTOS4; FELIPE GOMES FREDERICO DA SILVEIRA5   1Bolsista (FAPESB) do Programa de Pós-graduação em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, 710, Centro, 44.380-000, Cruz das Almas, Bahia, Brasil. magali_motta10@yahoo.com.br 2Professor Titular do Centro de Ciências Agrárias Ambientais e Biológica, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, 710, Centro, 44.380-000, Cruz das Almas, Bahia, Brasil. fadriano@ufrb.edu.br  3Professor adjunto do Centro de Ciências Agrárias, Ambientais e Biológicas da Universidade Federal do Recôncavo da Bahia. lsouza@ufrb.edu.br  4Pós-graduanda do Programa Ciência do Solo, Universidade Federal do Ceará, Avenida da Universidade, 2853, Benfica, CEP 60020-181, Fortaleza, Ceará. emanuela_bs@hotmail.com 5Professor Substituto do Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, 710, Centro, 44.380-000, Cruz das Almas, Bahia, Brasil. felipegomes87@hotmail.com     1 RESUMO   O gerenciamento eficiente dos recursos hídricos, assim como o manejo adequado da irrigação e drenagem em uma área produtiva, requer conhecimento das características hidrodinâmicas do solo e das propriedades que quantificam a condução de água ao longo do perfil. Com a finalidade de avaliar a condutividade hidráulica em função da umidade em um Argissolo Amarelo em zona de tabuleiros costeiros, foi instalado uma chapa galvanizada de 3 m de diâmetro e 0,80 m de profundidade, onde foram inseridas dez sondas de TDR a cada 0,1 m de profundidade e 0,50 m de distância, avaliando-se a umidade do solo e drenagem interna do perfil por 131 dias. Demonstrou-se a aplicação do método, obtendo-se a condutividade hidráulica não-saturada para nove profundidades. A faixa de umidade obtida variou de 0,3932 a 0,0837 cm³ cm-³. O método do perfil instantâneo demonstrou adequada aplicação para os solos estudados, demonstrando a influência da camada coesa de origem pedogenética sobre o movimento de água no perfil do solo. Palavras-chave: camada coesa, drenagem, umidade do solo     SANTOS, M. M. M.; PEREIRA, F. A. C.; SOUZA, L. S.; SANTOS, E. B.; SILVEIRA, F. G. F. HYDRODYNAMICS IN TYPICAL COASTAL TRAIL SOIL IN RECÔNCAVO  BAHIANO     2 ABSTRACT   The efficient management of water resources, as well as the adequate management of irrigation and drainage in a productive area, requires knowledge of the hydrodynamic characteristics of the soil and soil properties that quantify the conduction of water along the profile. In order to evaluate the hydraulic conductivity as a function of humidity in Ultisol in the Coastal Table land zone, a galvanized plate was installed with 3 m in diameter and 0.80 m depth, wherein ten TDR probes were installed at each 0.1 m of depth, evaluating the soil moisture and internal profile drainage for 131 days. The application of the method was demonstrated, obtaining unsaturated hydraulic conductivity for nine depths. Moisture content ranged from 0.3932 to 0.0837 cm³ cm-³. The instantaneous profile method showed adequate application to the soils of the Coastal Table land, demonstrating that the movement of water in the soil profile is influenced by the cohesive layer of pedogenic origin.   Keywords: cohesive layer, drainage, soil moisture

Occurrence of more frequent events of prolonged periods of low rainfall (drought) in worldwide cacao (Theobroma cacao L.) production zones has not only compromised productivity of small farmers but also crop survival. This study aimed to evaluate how and to what extent cacao tree mortality in dry years is related with variations in soil and physiographic features. The rate of mortality of cacao trees cultivated under an agroforestry system was evaluated over three periods (1994-1995, 2009-2013, and 2015-2019) on 36 plots of a farm in Bahia, Brazil, which has a wide diversity of soils and is established in a region with a subhumid to dry climate. Correlation analyses (single and multiple), cluster analysis, and Tukey tests were performed. The explanatory variables studied were the attributes of two soil layers (physical, mineralogical, and chemical), the diagnostic horizon, and the physiographic attributes (slope, terrain orientation in relation to the sun, and crop shading). The edaphic attributes most related to cacao tree mortality were physical (granulometry, porosity, and density) and mineralogical (Ki), mainly in the subsurface layer. The lowest mortality was observed in Oxisols and on slopes facing south and east. It was possible to establish recommend limits of the most suitable edaphic attributes to ensure greater survival of cacao trees cultivated in regions subject to recurrent water deficit similar to the conditions of this study. These findings can be used to guide farmers on how to mitigate the effect of drought. INTRODUCTIONIncrease in the frequency of drought events in the cacao (Theobroma cacao L.) production regions of the world has Abbreviations: BD, bulk density; BS, base saturation; CEC, cation exchange capacity; Ki, SiO 2 /Al 2 O 3 molar ratio; Kr, SiO 2 /(Fe 2 O 3 +Al 2 O 3 ) molar ratio; PCA, principal components analysis; PDP, percentage of dead plants; P rem , remaining P; S-value, sum of basic cations; Sl, terrain slope; SLAI, shading leaf area index; SORS, slope orientation in relation to the sun; TOC, total organic carbon; TP, total porosity.

The market of citrus fruits for fresh consumption is greatly influenced by the external aspect of the fruit, which needs to meet certain quality requirements. Therefore, this study aimed to evaluate fruit characteristics and leaf concentrations of nutrients, associating them with soil available water, for combinations of 'Pêra' orange with five different rootstocks, in two planting systems [conventional seedlings and direct seeding (DS) of rootstocks] in soil without subsoiling, in two sampling periods (wet and dry) of leaves and fruits. The attributes evaluated in the fruits were as follows: fruit length (FL), fruit diameter (FD) (cm), fruit weight (FW), juice yield, total soluble solids (TSS, in ºBrix), titratable acidity (TA, in g de citric acid mL −1 ), and ratio (TSS/TA). For nutritional evaluation of the plant, the contents of N, P, K, Ca, Mg, Fe, Cu, Mn, and Zn were determined in the leaves. The fruits produced in the rainy period showed better physical and chemical characteristics. Higher average ratios were found in 'Volkameriano' lemon, 'Índio' citrandarin and 'Cravo Santa Cruz' lemon. The planting system via DS led to higher values of FW, FD and FL. Leaf analysis indicated deficiency of N and Mn, excess of K and Fe; and P, Ca, Mg, Cu and Zn within the adequate range. The intensity of water stress, found in the dry period, increased the leaf concentrations of K, Ca, Mg and Cu. The preservation of the root system, promoted by DS, led to higher contents of N, Ca, Cu and Mn.