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Sustainability is a key concept in economic and policy debates. Nevertheless, it is usually treated only in a qualitative way and has eluded quantitative analysis. Here, we propose a sustainability index based on the premise that sustainable systems do not lose or gain Fisher Information over time. We test this approach using time series data from the AmeriFlux network that measures ecosystem respiration, water and energy fluxes in order to elucidate two key sustainability features: ecosystem health and stability. A novel definition of ecosystem health is developed based on the concept of criticality, which implies that if a system's fluctuations are scale invariant then the system is in a balance between robustness and adaptability. We define ecosystem stability by taking an information theory approach that measures its entropy and Fisher information. Analysis of the Ameriflux consortium big data set of ecosystem respiration time series is contrasted with land condition data. In general we find a good agreement between the sustainability index and land condition data. However, we acknowledge that the results are a preliminary test of the approach and further verification will require a multi-signal analysis. For example, high values of the sustainability index for some croplands are counter-intuitive and we interpret these results as ecosystems maintained in artificial health due to continuous human-induced inflows of matter and energy in the form of soil nutrients and control of competition, pests and disease.

Entre las zeolitas, la clinoptilolita y la mordenita se distinguen por su utilidad en la agricultura, debido a que al entrar en contacto con el amonio del medio lo retienen en su estructura interna y externa, funcionando entonces como un fertilizante nitrogenado de lenta liberación. Se estudió el efecto de la zeolita Z CU (clinoptilolita y mordenita) en la producción de biomasa vegetal y el ambiente químico del suelo, empleando la avena como cultivo indicador. Se evaluaron cinco concentraciones de Z CU en suelo (0, 5, 10, 20 y 30% peso base seca del suelo) y un tratamiento adicional preparado solo con Z CU. Las variables evaluadas fueron biomasa aérea y de raíces, pH y capacidad de intercambio catiónico (CIC), NH4+ sustrato y NO3-l lixiviado. La aplicación de Z CU tuvo un efecto positivo sobre la producción de la biomasa aérea y de raíces y modificó el ambiente químico edáfico en sus valores de pH y CIC. La aplicación de Z CU provocó una menor acumulación de NO3- lixiviado en relación a la cantidad de NH4+ en sustrato. Los resultados apoyan que la Z CU tiene capacidad para adsorber amonio y aminorar el proceso de nitrificación

The structure and tree diversity of traditional coffee agroecosystems was studied in a Popoluca community within the Biological Reserve of Los Tuxtlas, Veracruz, Mexico, along an altitudinal gradient from 450 to 1,000masl. The co...ffee agroecosystems were established in three physiognomic units: tropical semi-deciduous forest, tropical rain forest and deciduous forest. To understand the structure of the coffee agroecosystems, 30 plots of 400m2 were established. Sixty-four tree species and 23 herbs from 44 families were recorded. The most numerous families were Mimosaceae, Asteraceae, Faba...ceae and Myrtaceae. The coffee agroecosystems had four la...yers: herbs, shrubs, lower trees, and upper trees. The shrub layer was dominated by four varieties of Coffea arabica. The com...plementarity index indicated a high rate of replacement and confirmed the fundamental role of peasant's knowledge and management in the selection of species and the structure of the agroecosystem, but also in increasing and in some cases improving diversity without reaching the original diversity of the vegetation.

Arable soils tend to lose total organic carbon, thus contributing to the increase of CO 2 emissions into the atmosphere. This process has been occurring in large areas of Mexico cultivated with maize. Perennial species such as cactus ( Opuntia spp.) and agave are grown in Mexico and other parts of the world, which can contribute to the maintenance of total organic carbon in the soil (TOC). Within this context, a study was designed to compare the patterns of emissions of C–CO 2 and TOC in a highland of central Mexico. The selected management systems were the following: (1) maize monoculture with conventional tillage and fertilization, (2) maize associated with Vicia faba and manure addition, (3, 4) cactus without and with composted manure mulching, (5) soil in oak-pine forest, and (6) maize fields under 4 years of soil fallow and without weed control. Measurements of CO 2 flux pulses and volumetric moisture were performed every 15 days at 5 points of each plot. The soil in oak-pine forest showed stable C–CO 2 emissions throughout the year, while under maize fields, emissions were unstable with several respiration peaks. The soil in cactus crop showed a very close pattern of forest soil respiration. The annual patterns of soil respiration were in agreement with the results of TOC recently reported for the same plots where soil respiration was measured. Here we show, for the first time, that TOC in cactus approached the reference line of soil under forest (6 g 100 g −1 ), while in maize, we found a reduction greater than 50% of this value. Cactus crop represents an option in low-input maize for C–CO 2 -reduced emissions in agricultural zones with declining soil fertility.

The mining district of Molango in the Hidalgo State, Mexico, possesses one of the largest deposits of manganese (Mn) ore in the world. This research assessed the impacts of Mn mining activity on the environment, particularly the interactions among soil, plants, and arbuscular mycorrhiza (AM) at a location under the influence of an open Mn mine. Soils and plants from three sites (soil under maize, soil under native vegetation, and mine wastes with some vegetation) were analyzed. Available Mn in both soil types and mine wastes did not reach toxic levels. Samples of the two soil types were similar regarding physical, chemical, and biological properties; mine wastes were characterized by poor physical structure, nutrient deficiencies, and a decreased number of arbuscular mycorrhizal fungi (AMF) spores. Tissues of six plant species accumulated Mn at normal levels. AM was absent in the five plant species ( Ambrosia psilostachya , Chenopodium ambrosoides , Cynodon dactylon, Polygonum hydropiperoides, and Wigandia urens ) established in mine wastes, which was consistent with the significantly lower number of AMF spores compared with both soil types. A. psilostachya (native vegetation) and Zea mays showed mycorrhizal colonization in their root systems; in the former, AM significantly decreased Mn uptake. The following was concluded: (1) soils, mine wastes, and plant tissues did not accumulate Mn at toxic levels; (2) despite its poor physical structure and nutrient deficiencies, the mine waste site was colonized by at least five plant species; (3) plants growing in both soil types interacted with AMF; and (4) mycorrhizal colonization of A. psilostachya influenced low uptake of Mn by plant tissues.