En los Valles Centrales de Oaxaca se localizan 118 unidades de producción, 30 % de la superficie de tomate en invernaderos del estado. Estas unidades de producción son heterogéneas en sus niveles de desempeño, rentabilidad y productividad. La teoría de la empresa basada en los recursos y en la ventaja comparativa propone que algunos recursos son estratégicos en las unidades de producción y permiten obtener ventajas comparativas y competitivas. Las unidades de producción carecen de organización; 30 % han sido abandonadas y 32 % de los invernaderos miden 2000 m2 y tienen 2.8 años en operación en promedio. El trabajo en estas unidades es familiar y sus integrantes tienen de 31 a 50 años de edad. Se concluye que para alcanzar la competitividad y aumentar el desempeño de las unidades de producción de tomate se deberá diseñar e implementar estrategias comerciales, financieras, organizativas, operacionales y ambientales.

Physalis ixocarpa (husk tomato) is traditionally cultivated in Mexico, and nowadays the yield is low. In this study, four cultivars of husk tomato were evaluated, under greenhouse and field conditions. It was carried out a split-plot experimental design in a 4x2 factorial arrangement. The large plot was the growth conditions and the small plot was the variety. The microclimate, soil and yield variables were recorded. In the field, the Integrated Photosynthetic Active Radiation (IPAR) was higher 12mol m-2 d-1 than in the greenhouse. The average temperature was slightly higher 1.18°C in the greenhouse and the average relative humidity was slightly higher 0.89% in the field. Plants grown in the greenhouse had lower negative values for the matric potential of the soil. Water consumption and water use efficiency were 10.31 and 53.43% higher in the greenhouse that in the field, respectively. The number of fruits and yield increased significantly in all varieties grown under greenhouse conditions.

The diversity of chilis in Oaxaca is one of the most extensive in Mexico. Growers select seeds in the traditional manner; information on its quality is unknown. The aim of this research was to compare the physical and physiological quality of seeds and seedlings of three native types to chili (Huacle, De agua and Pasilla) and of the commercial Green pepper as control. Fifteen variables were evaluated in seed and twelve in seedlings. The laboratory experiments were established under a completely randomized design. Means of the variables were compared using the Tukey test (α=0.05). Results showed that Pasilla chili had the highest values in seed size and weight, which was 1.44 g heavier than the control and 2.09 to 3.73 g higher than native types. Haucle chili and green pepper had a 90% germination rate, while chili De agua and Pasilla chili had germination rates of 51 and 38%, respectively. Huacle chili had the highest germination rate index (29.89) and seedling vigor index (992.25). The top highest values of number of normal seedlings were obtained in the control and Huacle chili seedlings (72 and 88%); also, the latter had the longest plumule (3.36 cm) and radicle (7.67 cm) values. Both Huacle and Pasilla chili seedlings had larger values in height, stem thickness, number of leaves, leaf area and slenderness index than De agua and Green pepper. Huacle chili had good physical and physiological quality similar to the seeds of the commercial Green pepper.

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Enzymes are proteins that catalyze chemical reactions in living systems, transforming specific substrates into the products needed in biological cycles and for many edaphic processes. Soil enzymatic activities have been proposed as soil quality indicators, due to their relation with soil biology. Although the long-term effects of organic and mineral fertilization on physical and chemical soil properties have been previously studied, little is known about their effects on microbial community structure, microbial biomass carbon, microbial activity and enzymatic activity. Some studies report that organic and mineral fertilizers can affect, be it positively or negatively, microbial biomass size as well as soil microbial activity. This work examines the effect of fertilization on the enzymatic activity of soil hydrolases. Keywords: hydrolases, mineral fertilizers, organic fertilizers, soilEnzimas hidrolíticas do solo e sua resposta à adubação: uma breve revisão ResumoEnzimas são proteínas que catalisam reações químicas em sistemas vivos, transformando substratos específicos para os produtos necessários em ciclos biológicos e para muitos processos edáficos. Atividades enzimáticas do solo têm sido propostos como indicadores de qualidade do solo, devido à sua relação com a biologia do solo. Embora os efeitos a longo prazo da adubação orgânica e mineral sobre as propriedades físicas e químicas do solo, foram previamente estudados, pouco se sabe sobre os seus efeitos sobre a estrutura microbiana, o carbono da biomassa microbiana, atividade microbiana e atividade enzimática. Alguns estudos relatam que os fertilizantes orgânicos e minerais pode afetar, seja ela positiva ou negativamente, o tamanho da biomassa microbiana, bem como a atividade microbiana do solo. Este trabalho examina o efeito da adubação sobre a actividade hidrolítica enzimática de solo.

<p><strong>Background: </strong><em>Agave potatorum</em> reproduces mainly through seeds is widely collected for the mezcal production, and there is currently a marked decrease in their wild populations. Therefore, to contribute to its sustainable use, it is important to characterize the morphology of its seeds and to know their germinative characteristics.</p><p><strong>Research question:</strong> Do the year and the collection site have an effect on the size, color, viability and germination capacity of <em>Agave potatorum</em> seeds?</p><p><strong>Species studied</strong>: <em>Agave potatorum</em> Zucc.</p><p><strong>Study site and period of research:</strong> Seeds of <em>Agave potatorum</em> were collected in Oaxaca, Mexico: Miahuatlán (MIAH), in 2014; Coixtlahuaca (COIX), in 2015; and Zaachila (ZAA), in 2015 and 2016.</p><p><strong>Methods:</strong> For the seeds, we analyzed four physical descriptors, five color coordinates, and nine germination variables. We used a completely randomized design with four replications (100 seeds). An analysis of variance, a comparison of means, and a linear correlation analysis were performed.</p><p><strong>Results:</strong> We found that the ZAA16 seeds showed the highest values (<em>P</em> &lt; 0.05) for weight and size, and for the luminosity coordinate (L*, 15.2). Color coordinate values revealed a black color of the seeds, which significantly diminished in luminosity with seeds age and varied with their origin. The coordinate L* was correlated significantly with the total dry weight of seedlings and seed volume.</p><p><strong>Conclusions:</strong> <em>Agave potatorum </em>seeds significantly changed their physical dimensions and germination capacity according to their origin. The luminosity of the black color of seeds decreased with seed age and was correlated with seed volume and seedling total dry weight.</p>

Although their control is based on chemical products, the infestations by ticks (Ixodes scapularis Say) are causing great losses and damages in the livestock production worldwide. In this study, the survival of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae, and Steinernema websteri in vegetal oil suspension at concentrations of 13 and 33% and their effectiveness to control ticks at concentrations of 50 ± 5 and 100 ± 10 nematodes in oil suspensions of Cymbopogon citratus, Pelargonium sp, Juniperus virginiana, Rosa sp, and Mentha piperita were evaluated in lab conditions. In field conditions, the lethal concentration (LC90) of S. websteri in oil suspensions of J. virginiana and C. citratus in dogs infested with ticks was evaluated. In the laboratory, it was found that an oil emulsion of C. citratus and J. virginiana at 13% maintained the survival of S. carpocapsae, H. bacteriophora, and S. websteri from 55 to 60% for a period of 96 hr. The combination of the S. websteri nematode with 50 or 100 nematodes in oil emulsions of J. virginiana at 33% presented a control effectiveness of 80 to100% in adult ticks 24 hr post-application. In field, the LC90 of 119 juveniles of S. websteri in oil emulsions of J. virginiana at 33% on domestic dogs presented an accumulated and a control effectiveness of 89% after 96 hr postapplication. The combined application of J. virginiana and S. websteri could be a good alternative for the control of ticks. It was observed that the time of contact and the type of vegetable oil were crucial factors to increase the effectiveness of control.

The industry of mezcal (Agave spp.) in Oaxaca, Mexico annually generates more than one hundred thousand tons of bagasse. With the aim of using this by-product as an alternative organic substrate, the physical, physicochemical and chemical properties of samples of A. angustifolia Haw bagasse were analyzed before and after composting. The analysis was carried out as a function of aging time, using 0, 90 and 180 days of aging. Before composting, all the physicochemical properties were different for each of the aging periods except for humidity and dry matter. During the composting process the temperature of the three materials was superior to 50 °C, and after 105 days mature compost, free of feces was obtained. The physicochemical and chemical properties of the three composts were different for each of the aging periods and most of them were not between the reference intervals, except in the C/N relation. This is in contrast to most of the other physical properties. Keywords: Biodegradation, organic fertilizer, organic substratum, reuse of residuesPropriedades do bagaço de Agave angustifolia Haw. antes e após a sua compostagem Resumo A indústria do agave (Agave spp.) em Oaxaca, México, gera anualmente mais de cem mil toneladas de bagaço. Com o alvo de utilizar este sub-produto como um substrato orgânico alternativo, foram analisadas as características físicas, físico-químicas e químicas de amostras de bagaço de A. angustifolia Haw antes e depois da compostagem. A análise foi realizada em função do tempo de maduração aos 0, 90 e 180 dias. Antes de compostagem, todas as propriedades físico-químicas foram diferentes para cada um dos três tempos de maturação, exceto enquanto à umidade e a massa seca. Durante o processo da compostagem, a temperatura dos três materiais foi superior a 50 °C, e a compostagem foi conseguida após 105 dias, livre de fezes. As propriedades físico-químicas e químicas das três compostagens foram diferentes para cada um dos tempos de maturação sendo que a maioria não situou-se dentro das faixas de referência, exceto para relação C/N. Isto está em contraste com a maioria das propriedades físicas. Palavras-chave:Biodegradação, adubo orgânico, substrato orgânico, reutilização de resíduos