Multiple interactions between population increase-as driving force- and pressure factors can cause damage to human-nature interactions. In this paper, we aim to identify, understand, and assess those interactions that exert effects on environment quality. The assessments of multiple interactions will allow selecting management actions to reduce negative effects, such as the loss of vegetation cover, on the environment. However, multiple interactions hinder the understanding of such complex systems. The relevance of this study is related to the support of the systems thinking approach to achieve two objectives: (1) to build a conceptual framework that facilitates the construction of a network aimed at representing the multiple interactions; (2) to build a closed system for the sake of developing a sustainable environmental management system. Thus, the performance of the implemented management actions is assessed through the feedback loop of the closed system. The proposed conceptual framework and the closed system were applied to the state of Morelos, Mexico. We highlight the following results: the systems thinking approach facilitated the construction of a conceptual framework to build understandable causal network; a set of environmental pathways were derived from the causal network and then combined to define and assess a global environmental state. Environmental pathways are composed of relationships between population increase and pressure variables that exert effects on the environment quality; the feedback loop facilitated the performance analysis of implemented management actions related to natural protected areas. The current results suggest further research to apply this study to diverse systems where multiple interactions between drivers and pressure factors damage human-nature interactions, thus exerting effects on the environmental state.

In two contrasting agricultural ecohabitats (agrohabitats) in the avocado production area in the municipality of Cuernavaca, Morelos, an analysis of nutrimental status, soil fertility and water quality was conducted to measure soil fertility levels and to determine the nutrimental state of the trees. The "Hass" variety avocado groves studied had an average age of 8 years; the first grove was planted in an acrisol soil (1700 to 1900 meters above mean sea level [mamsl]); the second, in an andosol soil (1200 to 1700 mamsl). In each agrohabitat, tests were performed to determine the soil's physical and chemical characteristics. The physical and chemical characteristics of the soils of this zone differ as do the nutrimental states of the avocado trees in the two agrohabitats. The trees showed excessive concentration of Ca, Fe, S, Z and Mg. The indices of Deviation from Optimal Percentage (DOP) in the two agrohabitats showed different nutrimental requirements; nevertheless, they were low and very near to zero, 14.218 and 13.350 respectively. The water used for the agricultural irrigation was low in salinity and sodium content and thus may be used for the agricultural irrigation without restrictions.

The philodendron is a plant with a high sales price; however, in Mexico there is not enough plant material available for the producers of this ornamental. Therefore, the objective of this research was to establish an in vitro aseptic culture of philodendron; for this, the effect of fungicides and bactericides applied from the transplantation of mother plants to the production and harvest of explants (axillary shoots) for in vitro establishment was evaluated. Two experiments were carried out using MS (MURASHIGE; SKOOG, 1962) culture medium; in the second, silver nanoparticles (AgNPs) were added to the culture medium. Both experiments were established in a completely randomized experimental design. It was observed that with the joint action of the sanitizing products in the treatment of mother plants and in the disinfection process, as well as the addition of AgNPs to the culture medium, it was possible to establish an aseptic culture of philodendron. Results show that 2 g L -1 of Agry-Gent Plus 5000 ® plus 2 g L -1 of Prozycar ® in the treatment of mother plants was the one generated the highest percentage of aseptic explants (25.71%) in the first in vitro establishment, while, in the second experiment, the same products plus the addition of AgNPs to the culture medium for seven days generated 100% aseptic explants. The contaminants identified were yeasts, Aspergillus sp. and Penicillium sp.

El estudio se realizó en la localidad de Filo de Caballos, municipio de Leonardo Bravo, Guerrero, México, durante noviembre de 2011 a octubre de 2012 en un huerto de aguacate Hass, de 5 años de edad. El objetivo fue evaluar tratamientos de nutrición química y orgánica en árboles de aguacate; los abonos usados fueron: estiércol bovino 50 kg árbol (estiercol); 200-100-200 kg ha-1 de N-P-K (edáfico) y 30-10-15 kg ha-1 de Ca-Mg-B (foliar). Se encontró que en brotes florales, el tratamiento estiércol + edáfico + foliar (41 brotes/rama) fue mejor que los tratamientos estiércol + edáf ico (19 brotes/rama), foliar (9 brotes/rama) y el testigo (21 brotes/rama). Además, con17frutos,eltratamientoestiércol+edáfico+foliarsuperó de manera significativa a los tratamientos de Edáfico + foliar (6 frutos), foliar (1 fruto) y al testigo (3 frutos). El tratamiento de estiércol + foliar tuvo la mayor longitud (16 cm) del brote principal, superando a los tratamientos de estiércol + edáfico (7 cm) y foliar (9 cm). El tratamiento edáfico + foliar (75 cm2) presentó mayor área foliar que el testigo (65 cm2) y tuvo el mayor peso de fruto con 2.62 kg 10 frutos, el cual fue significativamente mayor que el testigo (1.51 kg 10 frutos).

This paper proposes a hybrid method integrating case-based reasoning (CBR) and analytic hierarchy process (AHP) methods to reinforce the sustainable performance of an environmental management system. The CBR–AHP method aims to support the decision-making process to select environmental management actions (EMAs) aimed at reducing risky trends of the environmental state of a region. The CBR methods takes advantage of a set of situation–solution pairs called cases, which are stored in a memory and then retrieved as candidates to solve new problems. Situations in this work are represented by a set of risky trends of key environmental pathways (KEPs) related to CO2 emissions, air quality, loss of vegetation cover, water availability, and solid waste, the combination of which damage the environmental state quality of a region. Meanwhile, solutions are represented by a set of EMAs. Similar situations to a given current situation are retrieved from the memory of cases, and then their solutions are combined through an adaptation mechanism, until the solution of the current problem is obtained. The AHP method is used to assign weights to environmental variables and to alternative solutions represented by EMAs. We used risky trends derived from real data related to the environmental states of a Mexican region to test the proposed CBR–AHP hybrid method. The results obtained provided insights into the potential of the CBR–AHP hybrid method to support the decision-making process to select EMAs aimed at reducing risky trends of current environmental states.