Native Plants to Arid Areas: A Genetic Reservoir for Drought-Tolerant Crops

Droughts are common in arid areas. These cause important losses in crop production, while the increasing population demands more food and goods. Cultivars able to produce under drought conditions are required to avoid or reduce production losses. Plants have evolved different mechanisms to face drought, and many genes have been already discovered in model and cultivated plants that are involved in this trait. Some of these genes have been successfully transformed into cultivated plants for drought tolerance. Plants native to arid lands may possess variants of drought tolerance mechanisms as compared to mesophytic or model plants. Also, different drought-related genes can be revealed. Studies using high-throughput and bioinformatic tools may allow to discover new genes and give new insights on the mechanisms involved in drought tolerance. However, still scarce studies in plants native to arid lands show that there are many drought-related genes that have not been already characterized and potentially they may be novel genes. These novel genes may be used to improve crops for drought tolerance. Therefore, more physiological, transcriptomic, proteomic, and metabolomic studies are needed on plants native to the deserts

Efecto de la cobertura del suelo sobre el crecimiento y productividad del zacate buffel (Cenchrus ciliaris L.) en suelos degradados de zonas áridas

The objective of this study was to evaluate the use of corn crop residues as mulch and its impact on soil moisture content and the establishment, development and productivity of buffel grass (Cenchrus ciliaris L). A randomized block design with three replications was used. The treatments were: sowing of 10 kg ha-1 of buffel grass seed (Bs); vegetation cover on soil with 10 t ha-1 of corn crop residues (Vc); Bs + Vc combination; and control (no grass sowing and no vegetation cover). The Bs + Vc treatment maintained a higher soil moisture content (P≤0.05), with 13.8 % vs 10.6 % of the control. Consequently, the number of grass plants m-2, buffel grass cover, plant height, chlorophyll index and dry biomass production had a tendency to respond better, with values of 518.5 plants m-2, 51.23 %, 31.8 cm, 162 and 167.8 g m-2, respectively, and they exhibited a tendency toward a statistically similar response as to this treatment when  applied  separately (Vc and Bs).  Photosynthesis (µmol s-2s-1), stomatal conductance, transpiration (mmol H2O m-2 s-1), and water use efficiency were not affected by any of the treatments in this study, their response being equivalent to that of the control.El objetivo de este estudio fue evaluar el uso de residuos de cosecha de maíz como cobertura vegetal y su impacto en el contenido de humedad del suelo y el establecimiento, desarrollo y productividad del pasto buffel (Cenchrus ciliaris L). Se usó un diseño de bloques al azar con tres repeticiones. Los tratamientos fueron: siembra de 10 kg ha-1 de semilla de pasto buffel (Sp); cobertura vegetal en suelo con 10 t ha-1 de residuos de cosecha de maíz (Cv); combinación Sp + Cv; y testigo (sin siembra de pasto y sin cobertura vegetal). El tratamiento Sp + Cv mantuvo un mayor contenido de humedad en el suelo (P≤0.05), con 13.8 % contra 10.6 % del testigo. En consecuencia, el número de plantas de pasto m-2, cobertura de pasto buffel, altura de la planta, índice de clorofila y producción de biomasa seca, tuvieron una tendencia de mejor respuesta, con valores de 518.5 plantas m-2, 51.23 %, 31.8 cm, 162 y 167.8 g m-2, respectivamente, con una tendencia de respuesta estadísticamente similar este tratamiento al aplicarse de manera separada (Cv y Sp). La fotosíntesis (µmol s-2s-1), conductancia estomática, transpiración (mmol H2O m-2 s-1) y uso eficiente del agua, no fueron afectadas por ninguno de los tratamientos de este estudio, con respuesta equivalente a la del testigo

Management Practices and Bioproductivity in Grassland of Dry Areas

In Mexico, the grassland represents 40.1% of the total area of the country and it is a source of feed for livestock, although suffers different degrees of degradation due to lack of management and adverse climatic conditions. The problem of the grasslands is complex since it involves diverse type’s soils, presence of invasive plants, low success in the establishment of grasses or replanting, high fluctuation in the rainfall distribution, as well as the low capacity of the soil to retain moisture. Among these constraints, the limited availability of soil moisture in arid conditions, makes these areas more fragile to the degradation of the environment which results in low productivity of the grassland. In this chapter, major ecological limitations of the grassland and techniques which improve the soils moisture retention capacity of the grassland especially in moisture deficit areas will be discussed

Feasibility of the adoption of soil erosion mitigation technology on farmland and pastures in northern Mexico

Objective: Identify the socioeconomic factors that determine the adoption of mitigation technologies of soil erosion in the Nazas-Aguanaval watershade at Durango State, Mexico. Design/methodology/approach: During 2018, 61 semi-structured surveys were applied to farmers in the region. The variables associated with the adoption disposition a binomial Logit regression of maximum likelihood was used. Results: Perception of the soil erosion problem, location of the watershade or agriculture productive unit, and economic activity were the most influential variables in the model. The main variable that conditions the disposition to improve the soil is the perception of soil erosion in the farm, with a marginal effect of 45.03 %. Limitations on study/implications: The results of this survey could be applicable to the study area only. Findings/conclusions: It is necessary to promote and increase the perception, understanding and acceptance of soil erosion mitigation technologies through training.Objective: To identify the socioeconomic factors which determine the adoption of soil erosion mitigation technologies in the Nazas-Aguanaval watershed region in the state of Durango, Mexico. Design/methodology/approach: During 2018, 61 semi-structured surveys were applied to farmers in the region. The variables associated with the willingness to adopt or not were analyzed with a maximum likelihood binomial Logit regression model. Results: Perception of the soil erosion problem, location of the watershed or agricultural unit, and economic activity were the most influential variables in the model. The main variable that conditions the willingness to adopt technologies to improve the soil is the perception of soil erosion in production areas, with a marginal effect of 45.03%. Limitations on study/implications: The results of this survey may only be applicable to the study area. Findings/conclusions: Training is necessary to promote and increase the perception, understanding and acceptance of soil erosion mitigation technologie

Water Harvesting and Soil Water Retention Practices for Forage Production in Degraded Areas in Arid Lands of Mexico

The area under arid conditions in Mexico is greater than 50%. This area faces a high risk due to environmental effects. The soil degradation in arid, semi‐arid, and dry sub‐humid areas is of multi‐causal nature, among which climatic and anthropogenic factors stand out. At least, three distinct elements with different effects may be considered: recurrent droughts in short periods, long‐term climate fluctuations, and degradation of soils by human activities. These threaten the productivity and sustainability of ecosystems and agro‐ecosystems. Thus, it is needed to maintain a constant exploration of new and more appropriate technologies that promote the efficient use of natural resources, in a framework of greater sustainability. Many of these technologies are focused toward better management of water and soil resources in production systems. Water management is oriented with rainwater harvesting, efficient irrigation systems, as well as soil moisture retention techniques, and the use of plant species tolerant to water stress. Planting of native species and using soil improvers of edaphic moisture retention can enhance reclamation (recovery) of degraded soils. The aim of this chapter is to show and discuss some experimental results using the above technologies applied to rangelands with degraded soils in dry lands

Impacto del uso del rodillo aireador para la siembra de pasto en el proceso hidrológico de una cuenca con lluvia natural y en condiciones de lluvia simulada

La investigación se realizó en la Región Hidrológica 36 (ríos Nazas-Aguanaval), zona árida del norte de México. En 2017, parte de la cuenca fue alterada durante el establecimiento de pasto buffel (Cenchrus ciliaris L.) con rodillo aireador (RA). El objetivo de esta investigación fue proponer un marco metodológico para integrar y analizar la información experimental de una cuenca de zonas áridas. El impacto del RA se cuantificó mediante el uso de simulador de lluvia in situ en el área de la cuenca. Los resultados indican que el empleo de RA provoca un retraso en el inicio del escurrimiento. De igual manera, la producción de escurrimiento fue menor en la parcela donde se utilizó el RA, con una producción media de 0.000004 m3s-1, mientras que la producción media de escurrimiento en las parcelas bajo condiciones naturales (testigo) fue de 0.000016 m3s-1. Además, la producción de sedimentos en la parcela con paso de RA fue significativamente mayor en la producción de sedimentos, con un valor medio de 833 mgl-1; en tanto que en la parcela experimental bajo condiciones naturales, la producción media de sedimentos fue de 470 mgl-1. Se infiere que las microdepresiones causadas por el RA capturaron el agua de lluvia ejerciendo una mayor retención del líquido en el suelo, lo cual redujo la escorrentía y aumentó la infiltración de agua en la cuenca. Los hallazgos muestran que, debido al tamaño, la cuenca (158.87 ha) es muy sensible a los cambios en los regímenes de precipitación y la cubierta vegetal

Características morfométricas y calidad de gel en sábila ("Aloe barbadensis" M.) aplicando algaenzimas y composta

The study was conducted in 2011-2012 and aimed to evaluate the effect of different sources and doses of fertilizers on leaf growth and quality on aloe vera gel, the latter as a product of high demand in the market. A random split plot block design with three replications was used. The main plots were algae extract (algaenzims) doses (0, 7 and 14 L ha-1) and subplots compost doses (0.5 and 10 t ha-1). The measured variables were: plant height, width, length and thickness of leaf; while in juice and gel, pH, °Brix, total solids, settleable solids in methanol, proteins, carbohydrates, gel content and macro (P, K, Ca, Mg and Na) were measured. Plant height and leaf length were significantly higher (p= 0.05) by applying 14 L ha-1 of algaenzims. Gel content, sugar and settleable solids in methanol were significantly higher, 273 days after the first application of the biofertilizer (DDPAB) (December), 273-393 DDPAB (December-April) and 273 DDPAB (December), respectively. The content of P and Mg were significantly reduced, 273 DDPAB (December) by applying 10 t ha-1 of compost, then the content of these elements is recovered. The carbohydrate and protein content increased significantly at 273 DDPAB (December), which is critical to identify the cutoff date of aloe leaf.El estudio se llevó a cabo en 2011 y 2012 y tuvo como objetivo evaluar el efecto de diferentes fuentes y dosis de fertilizantes en el crecimiento de la hoja de sábila y la calidad del gel, este último como el producto de mayor demanda en el mercado. Se usó un diseño de bloques al azar en parcelas divididas con tres repeticiones. Las parcelas grandes fueron las dosis de algaenzimas (0, 7 y 14 L ha-1) y las parcelas chicas las dosis de composta (0.5 y 10 t ha-1). Las variables que se midieron fueron: la altura de planta, ancho, largo y grosor de hoja; en tanto que en el jugo y gel, se midió el pH, °Brix, sólidos totales, sólidos precipitables en metanol, proteínas, carbohidratos, contenido de gel y macroelementos (P, K, Ca, Mg y Na). La altura de planta y largo de la hoja, fueron significativamente mayores (p= 0.05) al aplicar 14 L ha-1 de algaenzimas. Los contenidos de gel, azúcares y sólidos precipitables en metanol, fueron significativamente mayores, 273 días después de la primera aplicación de los biofertilizantes (DDPAB) (diciembre), 273-393 DDPAB (diciembre-abril) y 273 DDPAB (diciembre), respectivamente. El contenido de P y Mg se redujeron significativamente, 273 DDPAB (diciembre) al aplicar 10 t ha-1 de composta, después se recupera el contenido de estos elementos. El contenido de carbohidratos y proteínas se incrementaron significativamente a los 273 DDPAB (diciembre), lo cual es determinante para identificar la fecha de corte de hoja de sábila

Plant disease epidemiology: A quantitative approach on phytopathology = Epidemiología agrícola: Un enfoque cuantitativo de la fitopatología

A new technological approach in crop production is required in order to increase a sustainable food production, it keeping the agroecosystem balance. A new approach to do agriculture needs taking advantage of the inter and multidisciplinary participation of different specialities in emergent areas, such as, System Theory, Biotechnology, Environment Impact, Geographical Information Systems, Sustainable Agriculture, Expert Systems, and Plant Disease Epidemiology. Epidemic triangle host-pathogen-environment has been recognized as an integrated factor in plant disease epidemiology, which, currently is a useful phytopathological tool to quantify the diseases prevent the damage caused by plant pathogens. Important surveys about Comparative Epidemiology were conducted as a result of development in plant disease epidemiology in order to achieve better strategies in plant disease management.La producción sostenida de cultivos requiere de un nuevo enfoque tecnológico, tal que, permita incrementar la producción de alimentos sin alterar sustancialmente el agroecosistema. Este nuevo enfoque de hacer agricultura debe estar basado en la participación inter y multidisciplinaria de diferentes espcialidades en áreas emergentes, como: Teoría de Sistemas, Biotecnología, Impacto Ambiental, Sistemas de Información Geográfica, Agricultura Sustentable, Sistemas Expertos y la propia Epidemiología Agrícola. El triángulo epidémico patógeno-hospedante-ambiente se ha reconocido como la enfermedad en forma integrada, a través de la Epidemiología Agrícola, la cual es actualmente una base importante para el análisis temporal y espacial de las epidemias, así como para el diseño de sistemas de predicción para prevenir el impacto nocivo de las enfermedades. En los últimos años, se han hecho importantes contribuciones en estudios de Epidemiología Comparada, lo cual ha contribuido al diseño de mejores estrategias en el campo de enfermedades en la agricultura

Hydrogel, biocompost and its effect on photosynthetic activity and production of forage maize (Zea mays L.) plants

The increase in the incidence and intensity of drought caused by climate change is a critical factor in agricultural production in some regions of the world. Dry lands are often severely affected by water shortages caused by low rainfall. This study evaluated the effect of compost and hydrogel used to retain soil moisture on photosynthetic activity and forage corn production. The experiment was designed as a randomized block with a split plot design; the main plots were the hydrogel application rates (0, 12.5 and 25 k.ha-1), and the subplots were the compost application rates (0 and 20 t ha-1). Photosynthetic activity increased by 20.2-28.0% when the hydrogel was applied at rates of 12.5 and 25 kg ha-1, respectively, compared with the control. As a result, the production of fresh forage increased from 19.5 t ha-1 in the control to 77.6 and 81.6 t ha-1 when the hydrogel was applied at rates of 12.5 and 25 kg ha-1, respectively. A similar effect was observed for dry matter production. The compost had a weakly effect on photosynthetic activity

Growth, Physiology, and Productivity of <i>Bouteloua gracilis</i> and <i>Cenchrus ciliaris</i> Using Moisture Retainers under Different Planting Methods

The extensive raising of livestock on grasslands is a relevant economic activity in northern Mexico. These are regions of high climatic uncertainty and have extreme weather events, which requires the exploration of technological innovation to mitigate the negative impacts on these agroecosystems. The aim of this study was to evaluate two grass species using two planting methods and two types of soil moisture retainers and to determine their response based on growth and some physiological and productive attributes. A randomized complete block design (RCBD) was used in a split–split plot arrangement with six replications. The main plots were planted with two grass species: Bouteloua gracilis and Cenchrus ciliaris; the subplots were differentiated by two grass planting methods: seeding and seedling transplanting; the sub-subplots were differentiated by the soil moisture retainers used: (1) application on the soil of 10 t ha−1 of corn harvest residue (CHR) as organic cover on the soil surface, (2) application of hydrogel at 20 kg ha−1 mixed in the soil rhizosphere because it must be in contact with the root and soil due to its chemical composition, and (3) control, no application of any type of input. The seedling transplant method with the application of CHR significantly increased (p C. ciliaris showed a higher photosynthetic rate and, therefore, higher forage productivity than B. gracilis. The hydrogel only showed a moisture retention effect in the soil during the first 20 days after the transplant or sowing of the grass seed; after this period, there was no longer any effect as a water retainer in the soil. The soil cover with CHR was confirmed as a good moisture retainer with greater productivity of rangeland forage in degraded soils in arid areas