Cover crops and compost influence soil enzymes during 6 years of tillage-intensive, organic vegetable production

Soil enzymes are considered sensitive indicators of soil health but are not well understood in tillage-intensive vegetable systems. The activities of soil enzymes involved in nutrient cycling (β-glucosidase, β-glucosaminidase, alkaline phosphatase, dehydrogenase, aspartase, and L-asparaginase) were evaluated during 6 yr of commercial-scale production in five organic vegetable systems in Salinas, CA. The systems differed in yard-waste compost inputs (none or 15.2 Mg ha–1 yr–1), winter cover crop frequency (annually or every fourth year), and cover crop type (legume-rye, mustard, or rye). Large differences in cumulative organic matter input (7.4 to 136.8 Mg ha–1) from compost and cover crop shoots affected soil enzyme activities. With exception of aspartase, all enzyme activities were on average lowest without compost, intermediate with compost and infrequent cover cropping, and highest with compost and annual cover cropping. After 6 yr of vegetable production there was a positive relationship between microbial biomass and activities of all enzymes except aspartase. Despite lower inputs of cover crop shoot biomass from mustard compared with rye and the legume-rye, and differences in shoots residue quality, cover crop type had relatively little influence on enzyme activities. We conclude that soil enzyme activities were influenced primarily by annual cover cropping. These results and other attributes of soil health in this long-term study illustrate the importance of frequent cover cropping in tillage-intensive vegetable production. This raises questions about the sustainability of organic and conventional vegetable systems if cover crops are seldom used, and highlights the need for innovative strategies to increase cover cropping

It Cuts Both Ways: An Annelid Model System for the Study of Regeneration in the Laboratory and in the Classroom

The mechanisms supporting regeneration and successful recovery of function have fascinated scientists and the general public for quite some time, with the earliest description of regeneration occurring in the 8th century BC through the Greek mythological story of Prometheus. While most animals demonstrate the capacity for wound-healing, the ability to initiate a developmental process that leads to a partial or complete replacement of a lost structure varies widely among animal taxa. Variation also occurs within single species based on the nature and location of the wound and the developmental stage or age of the individual. Comparative studies of cellular and molecular changes that occur both during, and following, wound healing may point to conserved genomic pathways among animals of different regenerative capacity. Such insights could revolutionize studies within the field of regenerative medicine. In this review, we focus on several closely related species of Lumbriculus (Clitellata: Lumbriculidae), as we present a case for revisiting the use of an annelid model system for the study of regeneration. We hope that this review will provide a primer to Lumbriculus biology not only for regeneration researchers but also for STEM teachers and their students.Fil: Martinez Acosta, Veronica G.. University Of The Incarnate Word; Estados UnidosFil: Arellano Carbajal, Fausto. Universidad Autonoma de Queretaro.; MéxicoFil: Gillen, Kathy. Kenyon College; Estados UnidosFil: Tweeten, Kay A.. St. Catherine University; Estados UnidosFil: Zattara, Eduardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Indiana University; Estados Unidos. National Museum Of Natural History. Departamento de Zoología. Area de Invertebrados; Estados Unido

Dryland cropping systems influence the microbial biomass and enzyme activities in a semiarid sandy soil

Indicators of soil quality, such as microbial biomass C and N (MBC, MBN) and enzyme activities (EAs), involved in C, P, N, and S cycling, as affected by dryland cropping systems under conventional (ct) and no tillage (nt) practices were evaluated for 5 years. The soil is sandy loam with an average of 16.4% clay, 67.6% sand, and 0.65 g kg−1 OM at 0– 10 cm. The crops evaluated were rotations of grain sorghum (Sorghum bicolor L.) or forage sorghum (also called haygrazer), cotton (Gossypium hirsutum), and winter rye (Secale cereale): grain sorghum–cotton (Srg–Ct), cotton–winter rye– sorghum (Ct–Rye–Srg), and forage sorghum–winter rye (Srf– Rye). The tillage treatments did not affect soil MB and EAs of C cycling (i.e., β-glucosidase, β-glucosaminidase, α- galactosidase), P cycling (alkaline phosphatase, phosphodiesterase), and S cycling (arylsulfatase)—except for separation due to tillage for Srf–Rye and Ct–Rye–Srg observed in PCA plots when all EAs were evaluated together. After 3 years, rotations with a winter cover crop history (Ct–Rye–Srg and Srf–Rye) enhanced soil MBN (up to 63%) and EAs (21-37%) compared to Srg–Ct. After 5 years, Srg–Ct and Ct–Rye–Srg showed similar soil MBC, MBN, EAs, total carbon (TC), and organic carbon (OC). A comparison of Srg–Ct plots with nearby continuous cotton (Ct–Ct) research plots in the same soil revealed that it took 5 years to detect higher TC (12%), MBC (38%), and EAs (32–36%, depending on the enzyme) under Srg–Ct. The significant improvements in MB and EAs found, as affected by dryland cropping systems with a history of winter cover crops and/or higher biomass return crops than cotton, can represent changes in soil OM, nutrient cycling, and C sequestration for sandy soils in the semiarid Texas High Plains region. It is significant that these soil changes occurred despite summer crop failure (2003 and 2006) and lack of winter cover crops (2006) due to lack of precipitation in certain years

Microbiology of wind-eroded sediments: current knowledge and future research directions

Wind erosion is a threat to the sustainability and productivity of soils that takes place at local, regional, and global scales. Current estimates of the cost of wind erosion have not included the costs associated with the loss of soil biodiversity and reduced ecosystem functions. Microorganisms carried in dust are responsible for numerous critical ecosystem processes including biogeochemical cycling of nutrients, carbon storage, soil aggregation, and transformation of toxic compounds in the source soil. Currently, much of the information on microbial transport in dust has been collected at continental scales, with no comprehensive review regarding the microbial communities, particularly those associated with agricultural systems, redistributed by wind erosion processes at smaller scales including regional or field scales. Agricultural systems can contribute significantly to atmospheric dust loading and loss or redistribution of soil microorganisms are impacted in three interactive ways: (1) differential loss of certain microbial taxa depending on particle size and wind conditions, (2) through the destabilization of soil aggregates and reduction of available surfaces, and (3) through the reduction of organic matter and substrates for the remaining community. The purpose of this review is to provide an overview of dust sampling technologies, methods for microbial extraction from dust, and how abiotic, environmental, and management factors influence the dust microbiome within and among agroecosystems. The review also offers a perspective on important potential future research avenues with a focus on agroecosystems and the inclusion of the fungal component

Spatial simulation op Claviceps gigantea (fuentes, of the isla, ullstrup and rodríguez) in the STATE OF MEXICO

SE LOGRO DETERMINAR LA DISTRIBUCIÓN ESPACIAL EN EL TIEMPO DE claviceps gigantea EN MAÍZ MEDIANTE SIMULACIÓN ESPACIAL EN EL ESTADO DE MÉXICO.The cultivation of corn in Mexico is one of the most important highlighting the High Valleys of Mexico, in this region the main problem of cultivation are diseases, mainly those that cause ear rot which decreases yield and represents large economic losses. One of these diseases is caused by the fungus Claviceps gigantea which is commonly known as horsetooth. This disease can invade the whole cob, preventing the formation of grain. In recent years, climatic conditions have favored the proliferation of this fungus in farms cultivated with corn Zea mays L. The present work was carried out in plots of one hectare of five municipalities of the State of Mexico, with the natural incidence of the fungus during three growing cycles (2013-2015) using geostatistical techniques and performing the conditioned and unconditioned simulation process to predict the spatial behavior of the disease over time. The results show that the simulation techniques used to predict the behavior of Claviceps gigantea are an effective tool to prevent the infestations produced by this fungus. This type of study aims to help the development of integrated management programs

Modelización espacial de frankliniella occidentalis (thysanoptera: thripidae) en aguacate

SE LOGRÓ DETERMINAR LA DISTRIBUCIÓN ESPACIAL DE Frankliniella occidentalis MEDIANTE EL ANÁLISIS GEOESTADÍSTICO EN COATEPEC HARINAS, ESTADO DE MÉXICO.El cultivo de Aguacate (Lauraceae: Persea americana Mill.) es para México de gran importancia económica en cuanto a los sistemas de producción perenne. Esto se debe a que en los últimos años la comercialización de este fruto se ha incrementado notablemente a nivel nacional e internacional. En México, se cultivaron 168113,64 ha con un rendimiento promedio de 10,2 ton/ha en 2013, obteniendo una producción aproximada de 1467837,35 ton. Como cualquier otro frutal, el aguacate puede sufrir daños ocasionados por plagas (insectos, nematodos, ácaros entre otros) y enfermedades (causadas por hongos, bacterias y virus). A este respecto, uno de los insectos con mayor problemática es Frankliniella occidentalis, que provoca pérdidas significativas en el cultivo, al preferir alimentarse de tejidos tiernos como brotes foliares, florales, hojas jóvenes y frutos en desarrollo. Los daños más severos, económicamente hablando, son notorios a simple vista, ya que originan crestas o protuberancias sobre el pericarpio y estas lesiones son más evidentes conforme madura el fruto. El objetivo del presente trabajo fue modelizar la distribución espacial de F. occidentalis mediante técnicas geoestadísticas, así como obtener mapas de densidad por medio del krigeado. Los muestreos fueron llevados a cabo quincenalmente en tres parcelas comerciales de cuatro hectáreas cada una en el municipio de Coatepec Harinas, Estado de México usando el método de cuadrantes. Los resultados indicaron que la distribución espacial de las poblaciones de F. occidentalis presentó una distribución agregada en cada una de las fechas de muestreo. La validación cruzada de los valores de los semivariogramas obtenidos corroboraron dicha información, además de una dependencia espacial alta. Los mapas obtenidos permiten delimitar áreas infestadas y áreas libres de daños, lo que permitirá establecer medidas de control en puntos específicos de cada parcela para hacer un uso eficiente de los recursos plaguicidas

Understanding and Enhancing Soil Biological Health: The Solution for Reversing Soil Degradation

Our objective is to provide an optimistic strategy for reversing soil degradation by increasing public and private research efforts to understand the role of soil biology, particularly microbiology, on the health of our world’s soils. We begin by defining soil quality/soil health (which we consider to be interchangeable terms), characterizing healthy soil resources, and relating the significance of soil health to agroecosystems and their functions. We examine how soil biology influences soil health and how biological properties and processes contribute to sustainability of agriculture and ecosystem services. We continue by examining what can be done to manipulate soil biology to: (i) increase nutrient availability for production of high yielding, high quality crops; (ii) protect crops from pests, pathogens, weeds; and (iii) manage other factors limiting production, provision of ecosystem services, and resilience to stresses like droughts. Next we look to the future by asking what needs to be known about soil biology that is not currently recognized or fully understood and how these needs could be addressed using emerging research tools. We conclude, based on our perceptions of how new knowledge regarding soil biology will help make agriculture more sustainable and productive, by recommending research emphases that should receive first priority through enhanced public and private research in order to reverse the trajectory toward global soil degradation

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks