Several studies indicate that nitrogen fertilization is one of the main constraints in obtaining higher yields and better nut quality in pecan (Carya illinoensis [Wangenh] K. Koch). Therefore, the aim of this research was to evaluate a single and split application of nitrogen in ‘Western Schley’ variety pecan, as well as its effect on leaf nutrient concentration, yield and nut quality. A randomized complete block design with six replicates was established. N doses were 100, 150 and 200 kg∙ha^-1; the single application was made in March and the split one in March and June. The leaf concentration of total N, P, K⁺ , Ca²⁺, Mg²⁺, Fe²⁺, Mn²⁺, Zn²⁺ and Cu²⁺, yield (kg∙tree^-1), quality (nuts per kilogram and kernel percentage) and nitrogen use efficiency (NUE) were determined. Significant interaction between factors was detected for the Zn²⁺ concentration and the single applied dose of 200 kg∙ha^-1. With the single application of 100 kg∙ha^-1, the highest yield (44.60 kg∙tree^-1) and nuts per kilogram (194.83) values were recorded, where the kernel percentage remained constant. The maximum NUE was obtained with 100 kg∙ha^-1 applied in a single and split application (31.10 and 30.10 kg of nuts produced per kg of N applied, respectively). Increased yield and nut quality is the main objective in applying optimal N doses; however, ways of reducing the economic and environmental impact caused by its excessive application should also be sought.

Myrciaria dubia (Kunth) McVaugh is a fruit tree native to the Amazon with great potential due to its nutraceutical properties; thus, ex situ adaptation technologies should be developed. The objective of this study was to determine the evapotranspiration (ETc) and crop coefficient (Kc) of Myrciaria dubia for domestication and conservation on uplands. Two Myrciaria dubia plants of 2, 4, and 6 years old with similar morphological characteristics of height, number of branches (basal and terminal), and diameter (stem and canopy) were transplanted into drainage lysimeters. Residue of organic mulching composed of a native grass (Trachypogon plumosus) was applied once to one plant of each age category. The mean ETc values for 2-, 4-, and 6-year-old plants in the presence and absence of mulch were 2- and 2.7-mm∙day^-1, 3.2- and 3.9-mm∙day^-1, and 6.1- and 7.2-mm∙day^-1, respectively. The mean Kc values in the EI, EII, and EIII phenological stages with and without mulch were 0.4 and 0.6, 0.6 and 0.8, and 1.1 and 1.3, respectively. The ETc and Kc values for Myrciaria dubia plants with organic mulching can be used in irrigation planning for cultivation, domestication, conservation, and efficient use of water resources in tropical savannas of Roraima, Brazil.

Soursop fruit is highly appreciated for its organoleptic and medicinal characteristics and for its diversity in industrialization; however, there are no varieties generated in Mexico, even though it is believed that there is great diversity of this species in the country. This study aimed to assess the variability among soursop fruits grown in four municipalities of the Soconusco region, Chiapas, based on their physical and chemical characteristics, and to propose some materials for fresh consumption or industry use. Twentyeight trees propagated from seed and approximately 10 years of age were selected at each commercial orchard. Six fruits at physiological maturity were collected from each tree; then they were ripened and some quality characteristics, functional metabolites and antioxidant activity were evaluated. The population showed high variability (between 42 and 135 %) in fruit, pulp, seed and rachis weight, as well as in the chromaticity in pulp and peel, total soluble solids, total sugars and antioxidant activity. The formation of four groups was determined, where groups 1 and 2 (Tapachula and Huehuetán trees) had the fruits with the best productivity characteristics, namely greater weight and fruit size, while the fruits of groups 3 and 4 (Mazatán and Cacahoatán trees) were characterized by better flavor characteristics, a higher contribution of functional metabolites and greater antioxidant activity. Size, nutraceutical properties, peel chromaticity and brightness, sugars content and fruit acidity are important variables that helped to detect variability in soursop fruits.

Fertilization offers a way to counteract micronutrient deficiencies and achieve a higher mineral content in plants. The objective of this study was to evaluate the response to fertilization management in ‘Pinto Centauro’ beans, as well as its impact on yield, nutritional quality and profitability index. The study was conducted during the springsummer 2017 growing season in a rainfed ‘Pinto Centauro’ bean crop in the municipality of Cusihuiriachi, Chihuahua, Mexico. A randomized complete block experimental design was used with three fertilization management schemes: control FM1 (N, P and K, with 41, 46 and 22 kg∙ha^-1, respectively), fertilization FM2 (N, P, K, S and Zn, with 41, 46, 22, 12 and 1 kg∙ha^-1, respectively) and fertilization FM3 (N, P, K, S and Zn, with 45, 60, 22, 22 and 1.5 kg∙ha^-1, respectively). Yield, nutritional quality (physicochemical properties and mineral content) and profitability were evaluated. The results obtained were statistically significant. FM3 fertilization increased yield by 46.26 %. In terms of nutritional quality, the highest concentrations were 8.35 % protein, 74 % phosphorus, 16.3 % iron and 39.77 % zinc. The profitability index was higher (55 %) with the FM3 treatment, compared to the control. Fertilization improved bean productivity and quality under rainfed conditions, making it a viable and sustainable strategy in semi-arid bean producing regions in Mexico and the world.