Browsing by Author "Delgado, Jorge A."

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    Assessment of nitrogen dynamics and cropping system sustainability in the Andean region of South America with a new tool available for computers and smartphones
    Delgado, Jorge A.; Alwang, Jeffrey R.; Escudero, Luis O.; Saavedra, Ana Karina; Monar, Carlos; Barrera, Victor H.; Botello, Rubén C. (2013)
    Implementation of best soil and water conservation practices will be key to addressing challenges we will confront in the 21st century. With challenges such as climate change and continued population growth, there is a need for tools that can help us quickly assess how to maintain sustainability of cropping systems, which will be essential for maximizing agricultural production, especially in fragile soils of the Andean region of South America. Nitrogen (N) inputs are key for agricultural production, but because N is so mobile, high efficiency in the management and use of N input is necessary to reduce risk of N losses to the environment while maximizing production. One of the key crops in this region is the potato (Solanum tuberosum L.) crop. This crop leaves a small amount of crop residue after harvest, which increases the potential for a high rate of erosion, especially in the steep soils where the crop is cultivated in this region. A new Nitrogen Index with a Sustainability Index has been calibrated and validated for this region. The tool is available in the English and Spanish languages and can be run in metric or English units. It can be run on desktop and laptop computers (using the software written in the programming language Java™), or on a smartphone that has the Android™ system (via the “app”). The tool is very user friendly and can be used by conservationists, field agronomists, technical personnel, and others. It was found that the tool can accurately assess nitrogen dynamics and evaluate the crop uptake for crops grown in this region, such as corn (Zea mays L.) and potato (P
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    Assessment of nitrogen dynamics and cropping system sustainability in the Andean segion of South America with a new tool available for computers and smartphones
    Delgado, Jorge A.; Alwang, Jeffrey R.; Escudero, Luis O.; Saavedra, Ana Karina; Monar, Carlos; Barrera, Victor H.; Botello, Rubén C. (2013)
    Implementation of best soil and water conservation practices will be key to addressing challenges we will confront in the 21st century. With challenges such as climate change and continued population growth, there is a need for tools that can help us quickly assess how to maintain sustainability of cropping systems, which will be essential for maximizing agricultural production, especially in fragile soils of the Andean region of South America.
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    Climate Change and Its Positive and Negative Impacts on Irrigated Corn Yields in a Region of Colorado (USA)
    Delgado, Jorge A.; D’Adamo, Robert E.; Villacis, Alexis H.; Halvorson, Ardell D.; Stewart, Catherine E.; Alwang, Jeffrey R.; Del Grosso, Stephen J.; Manter, Daniel K.; Floyd, Bradley A. (MDPI, 2024-08-09)
    The future of humanity depends on successfully adapting key cropping systems for food security, such as corn (Zea mays L.), to global climatic changes, including changing air temperatures. We monitored the effects of climate change on harvested yields using long-term research plots that were established in 2001 near Fort Collins, Colorado, and long-term average yields in the region (county). We found that the average temperature for the growing period of the irrigated corn (May to September) has increased at a rate of 0.023 °C yr−1, going from 16.5 °C in 1900 to 19.2 °C in 2019 (p < 0.001), but precipitation did not change (p = 0.897). Average minimum (p < 0.001) temperatures were positive predictors of yields. This response to temperature depended on N fertilizer rates, with the greatest response at intermediate fertilizer rates. Maximum (p < 0.05) temperatures and growing degree days (GDD; p < 0.01) were also positive predictors of yields. We propose that the yield increases with higher temperatures observed here are likely only applicable to irrigated corn and that irrigation is a good climate change mitigation and adaptation practice. However, since pan evaporation significantly increased from 1949 to 2019 (p < 0.001), the region’s dryland corn yields are expected to decrease in the future from heat and water stress associated with increasing temperatures and no increases in precipitation. This study shows that increases in GDD and the minimum temperatures that are contributing to a changing climate in the area are important parameters that are contributing to higher yields in irrigated systems in this region.
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    Conservation agriculture can help the South American Andean region achieve food security
    Barrera, Victor H.; Delgado, Jorge A.; Alwang, Jeffrey R. (2021-09-15)
    The Andean region of Ecuador is dominated by small-scale agriculture on steep slopes vulnerable to erosion, soil degradation, and subsequent productivity loss. Soil erosion rates exceed the average rate of soil formation by 9-286 times, making current agricultural practices in the region unsustainable, and threatening to increase food insecurity. The projected effects of a changing climate vary across the Andean region, with higher precipitation and erosion rates projected for some areas. However, even in areas where the precipitation rates are expected to be lower, the projected erosion rates will still be unsustainable. Research on conservation agriculture (CA) practices conducted from 2008 to 2017 in the highlands of Ecuador suggests that yields and cost savings ultimately make several CA production systems profitable compared to conventional practices. In the very short term, large gains did not emerge, and the best that could be said about CA is that it did not reduce productivity. Over the medium term, improvements in soil health (lower erosion) led to higher profitability that made the practices more profitable than conventional practices over the entire rotation. However, adoption of these alternatives by local producers, even in research areas, is low. Lack of public or private agricultural extension contributes to slow diffusion of new technology and best management practices in the region. There is a need to develop improved communication with local farmers to more effectively relay how CA protects the soil, mitigates degradation, and provides a means to achieve food security and avoid a humanitarian crisis.
  • Conservation practices are essential land management strategies for climate change mitigation and adaptation
    Delgado, Jorge A. (2013)
    Climate change and rising populations are placing higher demands and larger constraints on the world’s resources. This PowerPoint describes the impacts of these challenges on agriculture, as well as adaptive and mitigative agricultural practices. Practices which conserve soil and water include forest riparian buffers, cover cropping, and agroforestry. In exploring agriculture’s role in mitigating climate, the presentation examines the effect of nitrogen fertilization on N2O global atmospheric pressure. A nitrogen index is established as a valuable tool for evaluating the impact of agricultural practices on emissions.
  • Conservation practices for climate change adaptation.
    Delgado, Jorge A. (2013)
    Climate change and rising populations are placing higher demands and larger constraints on the world’s resources. This PowerPoint presents what these challenges mean for agriculture, and describes principles for soil and water conservation to confront these challenges, including forest riparian buffers, cover cropping, and agroforestry. Agriculture’s role in mitigating climate change is also explored, examining the effect of nitrogen fertilization on N2O global atmospheric pressure. A nitrogen index is established as a valuable tool for evaluating the impact of agricultural practices on emissions.
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    Estimating Economically Optimal Levels of Nitrogen Fertilizer in No-Tillage Continuous Corn
    Villacis, Alexis H.; Ramsey, A. Ford; Delgado, Jorge A.; Alwang, Jeffrey R. (2020-11)
    Stochastic plateau production functions provide improved fertilizer recommendations based on multi-year agronomic experiments where weather and other stochastic variables change over time. This research assesses the profitability of no-tillage corn production in northeastern Colorado and determines economically optimal nitrogen fertilizer rates. It also proposes an alternative parameterization of the linear response stochastic plateau model which provides a robustness check against traditional parameterizations. Results show the current use of nitrogen fertilizer in the area exceeds estimated economically optimal levels. This suggests that a reduction in nitrogen use could increase expected profits and simultaneously reduce environmental costs.
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    Evaluation of tillage systems, cover crops and rotations in the maize-bean production system in Alumbre-Ecuador
    Escudero, Luis O.; Barrera, Victor H.; Valverde, F.; Célleri, M.; Chamorro, F.; Arévalo, J.; Alwang, Jeffrey R.; Delgado, Jorge A.; Gallagher, R. (2014)
    The purpose of this poster is to describe research results for the SANREM project in Alumbre, Ecuador. Various conservation agriculture practices have been evaluated following more than four years of CA trials in the area. Parameters such as yield, soil physical and chemical properties, and overall economic benefits are presented.
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    Long-Term Effects of Nitrogen and Tillage on Yields and Nitrogen Use Efficiency in Irrigated Corn
    Delgado, Jorge A.; D’Adamo, Robert E.; Villacis, Alexis H.; Halvorson, Ardell D.; Stewart, Catherine E.; Floyd, Bradley A.; Del Grosso, Stephen J.; Manter, Daniel K.; Alwang, Jeffrey R. (MDPI, 2024-10-07)
    By tonnage, corn (Zea mays L.) is the #1 crop produced globally, and recent research has suggested that no-till (NT) systems can lead to reduced yields of this important crop. Additionally, there is a lack of long-term data about the effects of tillage and N management on cropping systems. Corn is the most nitrogen (N)-fertilized crop in the USA, and N losses to the environment contribute to significant impacts on air and water quality. We conducted long-term studies on conventional tillage (CT) and conservation tillage systems, such as strip tillage (ST) and NT, under different N rates. We found that immediately after conversion to NT, yields from NT were significantly lower than yields from CT (p < 0.1), but after five years of NT, the NT yields were 1.5% higher than the CT yields (p < 0.1). Initially, the NT yields were lower than the ST (p < 0.01), but after seven years of NT, the NT yields were comparable to ST grain yields. Although the total aboveground N uptake with NT immediately after conversion to NT was lower than with CT and ST, these differences were not significant in the long run. The nitrogen use efficiency (NUE) with NT increased over time. The present work highlights the importance of long-term research for determining the cumulative impacts of best management practices such as NT. We found that NT becomes a more viable practice after five or seven years of implementation, demonstrating the high importance of long-term research.
  • A new nitrogen index for assessment of nitrogen management of Andean mountain cropping systems of Ecuador
    Escudero, Luis O.; Delgado, Jorge A.; Monar, Carlos; Valverde, F.; Barrera, Victor H.; Alwang, Jeffrey R. (Soil Science, 2014)
    Corn (Zea mays L.) is important for food security in much of Ecuador. Small-scale farmers are using nitrogen (N) fertilizer without technical advice based on soil, crop, and climatologic data. The literature lacks studies where tools that can quickly assess management practices’ effects
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    A new nitrogen index to assess sustainability of cropping systems of Andean regions of South America
    Delgado, Jorge A.; Alwang, Jeffrey R.; Monar, Carlos; Escudero, Luis O.; Saavedra, Ana Karina; Barrera, Victor H.; Botello, Rubén C. (2012)
    Population growth, impacts from a changing climate, and other challenges highlight the need to conserve soil and water quality so that maximization of crop yields to feed the expanding world population can be achieved and sustained into future generations. The Andean regions of South America are predominantly risky landscapes that have high slopes susceptible to erosion, especially after harvesting crops that leave low amounts of crop residue such as potatoes, and/or removing the straw from grain systems following cultivation of these landscapes. Tools that can be used by technical personnel who work with local farmers on these agricultural systems are needed to enhance communication with farmers and local communities in Andean regions and increase conservation. A new Nitrogen Index available in the English and Spanish languages, in metric and English units, and with a Soil Sustainability Index, was developed and evaluated for these regions by comparing results from the tool with research data. This Index is being used as an educational tool at the Universidad Estatal de Bolìvar in Guaranda, Ecuador, and is helping its users assess the effects of management practices on the sustainability of cropping systems in their region. Preliminary results from evaluation of the new Nitrogen Index and its Soil Sustainability Index for these high-risk cropping system-landscape combinations of South America will be presented. These preliminary results suggest potential exists to use the tool to help assess effects of management practices on the sustainability of systems and on nitrogen use efficiencies in Andean regions of South America.
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    Nitrogen Index 4.4. User Manual
    Gagliardi, P. M.; Delgado, Jorge A.; Rau, E. J.; Fry, R.; Figueroa, U.; Gross, C.; Cueto-Wong, J.; Shaffer, M. J.; Kowalski, K.; Neer, D.; Sotomayor-Ramirez, D.; Alwang, Jeffrey R.; Monar, Carlos; Escudero, Luis O.; Saavedra Rivera, A. K. (USDA ARS, 2011)
    User manual for a web-based tool to help farmers make optimal decisions about nitrogen application in degraded and other lands.
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    Nitrogen Management Can Increase Potato Yields and Food Security for Climate Change Adaptation in the Andean Region
    Delgado, Jorge A.; Barrera, Victor H.; Alwang, Jeffrey R.; Cartagena, Yamil E.; Escudero, Luis O.; Neer, Donna; D'Adamo, Robert; Zapata, Angelica C. (Springer, 2023-04)
    The Andean region of Ecuador is being impacted by climate change, and improved best management practices for agriculture are needed to increase yields and food security. We conducted a study comparing different nitrogen (N) rates to determine the optimum N application rate for potato (Solanum tuberosum L.) systems in this region. We examined five application rates of N: 0, 100, 200, 300, and 400 kg N ha(- 1). The results suggest that an N application rate of 300 kg N ha(- 1) increased productivity and net income by 87% and 146%, respectively, compared to no application of N. We transferred these improved practices to farmers, and all farms increased their yields and net economic returns. The average yields and net economic returns for these farmers increased by 50% and 64%, respectively. Additional N use efficiency (NUE) studies are needed to continue increasing yields and economic returns for farmers in the Andean region.
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    Nutrient cycling and uptake in conservation agriculture production systems in the Andean region
    Stehouwer, R.; Webber, K.; Gallagher, R.; Alvarado, S.; Barrera, Victor H.; Delgado, Jorge A.; Alwang, Jeffrey R. (2014)
    Our project conducted multi-year cropping system experiments in two sub-watersheds in Ecuador: a pasture-potato system in the Illangama (3400 m), and a beans-maize system in the Alumbre (2000 m). All experiments included treatments involving tillage, crop residue management and fertilizer inputs. Here we report on yields, nutrient removal and uptake in these CAPS experiments.
  • Positive impacts in soil and water conservation in an Andean region of South America: Case scenarios from a US Agency for International Development multidisciplinary cooperative project
    Monar, Carlos; Saavedra, Ana Karina; Escudero, Luis O.; Delgado, Jorge A.; Alwang, Jeffrey R.; Barrera, Victor H.; Botello, Rubén C. (2013)
    The Andean region of South America faces many challenges to increasing agricultural productivity: shrinking farm sizes, poor soils, erratic rainfall, and very high erosion rates. This article summarizes the positive impacts of the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program’s (SANREM CRSP) promotion of conservation agriculture (CA) in the region. SANREM emphasizes thorough and holistic evaluation of the impacts of CA, and active participation of local farmers. Farmer field schools in the Illangama watershed in Ecuador proved an effective means of encouraging CA adoption by demonstrating its positive effects. Other positive impacts are listed, emphasizing the increases in yields and economically beneficial diversification. A need for new, bilingual tools to assess the impacts of CA is identified; the article presents the adaption of the Mexican Nitrogen index for Ecuador and Bolivia as a successful example of tool development. The strong international cooperation for this project has provided an illustration of the positive results of soil and water conservation practices that will assist in addressing the environmental challenges and constraints of the twenty-first century.
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    Potential for use nitrogen index for Ecuador and conservation practices for climate change and conservation of our biosphere
    Delgado, Jorge A. (2011)
    This resource is a presentation to the University Estatal de Bolivar on the use of nitrogen index to manage soil fertility and conserve resources in conservation agriculture systems in Ecuador and Bolivia.
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    Potential use of cover crops for soil and water conservation, nutrient management, and climate change adaptation across the tropics
    Delgado, Jorge A.; Barrera Mosquera, Victor H.; Alwang, Jeffrey R.; Villacis, Alexis H.; Cartagena Ayala, Yamil E.; Neer, Donna; Monar, Carlos; Escudero López, Luis O. (Elsevier, 2021-01-01)
    One of the greatest challenges in the 21st century is the question of how humanity will adapt to a changing climate to continue producing food at the production levels that will be necessary to feed an increasing global population while conserving soil and water resources. While there are political, social and economic factors that impact agricultural development, this paper will not be focusing on those factors, instead focusing on the potential use of cover crops as a nutrient management tool, a soil and water conservation practice, and a good approach to adapting to a changing climate. The potential of using cover crops for climate change adaptation and mitigation will be reviewed. Cover crops are a key tool that could contribute to increased yields, conservation of surface and groundwater quality, reduced erosion potential, sequestration of atmospheric carbon (C), and improved soil quality and health across the tropics. However, there are a lot of research gaps, and there is a need for additional research about the potential use of cover crops for soil, human, and animal health, as well as a need for an open-access data information system about research on cover crops in the tropics. While cover crops show a lot of promise, they are not a silver bullet, and in some circumstances, they can also contribute to reduced yields. We evaluated the use of cover crops and we ranked the different ways that cover crops can contribute to climate change adaptation, on a scale ranging from very low potential to contribute to climate change adaptation to very high potential. For example, cover crops have very high potential to reduce erosion generated by a changing climate in humid systems. On average, cover crops appear to be a good practice for climate change adaptation and mitigation across the tropics, and nutrient managers, agronomists, and soil and water conservation practitioners could add them to their management toolbox for different regions of the tropics. The 4 Rs of cover crops should be applied when using this tool (the right cover crop, the right timing of placement, the right timing of killing, and the right management).
  • Potential Use of Tillage, Crop Residue, and Nitrogen Management for Soil and Water Conservation, Higher Yields, and Increased Economic Returns in Cropping Systems of the Andes
    Delgado, Jorge A.; Barrera, Victor H.; Escudero, Luis O.; Cartagena, Yamil E.; Alwang, Jeffrey R.; Stehouwer, Richard C.; Arevalo, Juan C.; D'Adamo, Robert; Dominguez, Juan M.; Valverde, Franklin; Alvarado, Soraya P. (2018-07-22)
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    Prácticas de agricultura de conservación que promueven la productividad y sostenibilidad del sistema de producción papa-pastos en la microcuenca del rio Illagama, Ecuador
    Barrera, Victor H.; Delgado, Jorge A.; Alwang, Jeffrey R.; Escudero, Luis O.; Arevalo, Juan; Cartagena, Yamil E. (Arco Iris, Quito, Ecuador, 2020-11-11)