A new species of the genus Cyclocephala Dejean, 1821 (Coleoptera: Melolonthidae) from Oaxaca, Mexico

Con base en material recolectado de ambos sexos, se describe una especie nueva de Melolonthidae, Dynastinae, Cyclocephalini: Cyclocephala mixteca sp. nov. La serie tipo fue capturada mediante trampas de luz negra en la comunidad de Santo Domingo Yanhuitlán, Oaxaca, México. Esta especie nueva es similar a Cyclocephala lunulata y representa la primera especie endémica para el estado de Oaxaca.Based on material collected of both sexes, a new species of Melolonthidae, Dynastinae, Cyclocephalini: Cyclocephala mixteca sp. nov. is described. Types were collected using black light traps in the community of Santo Domingo Yanhuitlán, Oaxaca, Mexico. This new species is similar to Cyclocephala lunulata and represents the first endemic species reported for the Oaxaca state

Review of agronomic research on the milpa, the traditional polyculture system of Mesoamerica

The milpa system is the basis of traditional agriculture in Mesoamerica. It is based on a polyculture of maize (Zea mays L.), bean (Phaseolus spp.) and squash (Cucurbita spp.) and is associated with a great diversity of crops and wild species. The milpa has great cultural and historical importance but can also be highly productive and provide sufficient and healthy diets for smallholder farmers. The milpa system is practiced less and less however, mainly due to socioeconomic changes, but also due to a lack of agronomic knowledge adapted to current conditions. To provide a starting point for new agronomic research, we reviewed the scientific literature to identify the current knowledge on milpa agronomy and determine research priorities to further improve the system. Given the wide diversity of conditions under which milpa is practiced, agronomic research is lacking, but indicates that improvements to the milpa can be made in all aspects of the milpa. 176 research articles on the milpa system were found in databases, of which 61 treated agronomic research. The main agronomic topics described in literature are crop variety, soil fertility management, weed management and productivity. Most research has focused only on maize and studies reporting on the associated crops are scarce. More research on all aspects of the milpa is needed to understand and improve the agronomy of the system under the changing conditions of modern agriculture. Reducing the workload associated with the milpa, as well as soil fertility and weed management can be identified as research priorities

Carbon-sensitive pedotransfer functions for plant available water

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute\u27s North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long-term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (θFC) and permanent wilting point (θPWP). New pedotransfer functions had predictions of θAWHC that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on θAWHC. For an increase in SOC of 10 g kg–1 (1%) in noncalcareous soils, an average increase in θAWHC of 3.0 mm 100 mm–1 soil (0.03 m3 m–3) on average across all soil texture classes was found. This SOC related increase in θAWHC is about double previous estimates. Calcareous soils had an increase in θAWHC of 1.2 mm 100 mm–1 soil associated with a 10 g kg–1 increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience

Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity

Jade: nueva variedad de avena para la producción de grano en siembras de temporal en México

The National Institute of Agricultural and Livestock Forestry Research, makes available to producers of oats from Mexico the variety ‘Jade’, which was obtained by its Genetic Improvement Program located in the Valley of Mexico Experimental Field (CEVAMEX). Jade was obtained through a simple cross between the line 815A-129-72-CI-648/SR-CPX and the Obsidiana variety, and its F1that was backcrossed to the variety, in the selection towards homozygosis the gravimetric methods were applied and massive families until obtaining the experimental line that was evaluated in 105 localities in 12 states of the republic in temporary conditions from 2008 to 2012. During this period in JADE there were readings of trace stem rust (TR) at 20 MR, type of resistance reaction that exceeded all the control varieties. Its average grain yield was 3681 kg ha-1in favorable environments, 2 302 kg ha-1in intermediate environments and 1382 kg ha-1in critical environments, surpassing the eleven control varieties in each condition. Based on its agronomic behavior and resistance to stem rust, with the Jade planting it can be substituted for the Menonita,Avemex, Papigochi, Chihuahua, Cuauhtemoc and Opalo varieties, which will increase on average 28% the productivity of oats in plantings of temporary. Due to the above, Jade will be part of the genetic mosaic of varieties that INIFAP recommends for rainfed sowing in Mexico.El Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias,pone a disposición de los productores de avena de México la variedad ‘Jade’, que fue obtenida por su Programa de Mejoramiento Genético ubicado en el Campo Experimental Valle de México (CEVAMEX).Jade se obtuvo a través de una cruza simple entre la línea 815A-129-72-CI-648/SR-CPX y la variedad Obsidiana,y su F1que se retrocruzó hacia la variedad,en la selección hacia homocigosis se aplicaron los métodos gravimétricosy familias masivas hasta obtener la línea experimental que se evaluó en 105 localidades en 12 estados de la república en condiciones de temporal de 2008 a 2012.Durante este periodo en JADEse registraron lecturas de roya del tallo de trazas(TR) a 20 MR,tipo de reacciónde resistencia que superóa todas las variedades testigo. Su rendimiento de grano promedio fue de 3681 kgha-1en ambientes favorables,2302 kg ha-1en ambientes intermedios y 1382 kg ha-1en ambientes críticos, superando a lasonce variedades testigos en cada condición. En base a su comportamiento agronómico y resistencia a roya del tallo, con la siembra de Jadese puede sustituir a las variedadesMenonita, Avemex, Papigochi, Chihuahua, Cuauhtémoc y Ópalo, lo que permitirá incrementar en promedio28% la productividad de avena en siembras de temporal. Por lo anterior, Jadeformará parte del mosaico genético de variedadesque INIFAP recomienda para siembra de temporal en Méxic

Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity.Foundation for Food and Agriculture ResearchOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

An evaluation of carbon indicators of soil health in long-term agricultural experiments

Soil organic carbon (SOC) is closely tied to soil health. However, additional biological indicators may also provide insight about C dynamics and microbial activity. We used SOC and the other C indicators (potential C mineralization, permanganate oxidizable C, water extractable organic C, and β-glucosidase enzyme activity) from the North American Project to Evaluate Soil Health Measurements to examine the continental-scale drivers of these indicators, the relationships among indicators, and the effects of soil health practices on indicator values. All indicators had greater values at cooler temperatures, and most were greater with increased precipitation and clay content. The indicators were strongly correlated with each other at the site-level, with the strongest relationship between SOC and permanganate oxidizable C. The indicator values responded positively to decreased tillage, inclusion of cover crops, application of organic nutrients, and retention of crop residue, but not the number of harvested crops in a rotation. The effect of decreased tillage on the C indicators was generally greater at sites with higher precipitation. The magnitude and direction of the response to soil health practices was consistent across indicators within a site but measuring at least two indicators would provide additional confidence of the effects of management, especially for tillage. All C indicators responded to management, an essential criterion for evaluating soil health. Balancing the cost, sensitivity, interpretability, and availability at commercial labs, a 24-hr potential C mineralization assay could deliver the most benefit to measure in conjunction with SOC.Samuel Roberts Noble FoundationOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]