Pattern and process in crop species diversity and lime requirements models

Autores
Aramburu Merlos, Fernando
Año de publicación
2022
Idioma
inglés
Tipo de recurso
tesis doctoral
Estado
versión aceptada
Colaborador/a o director/a de tesis
Hijmans, Robert J. (director)
Descripción
Tesis para obtener el grado de Doctor of Philosophy in Horticulture and Agronomy, de la University of California Davis, 2022
Changes in crop species diversity can affect agroecosystem function. However, most crop diversity studies insufficiently account for the influence of scale on spatial crop diversity, and its relation to temporal diversity has not been explored. Moreover, crop diversity might be limited by environmental constraints and market demand for specific crops, which needs to be considered when assessing opportunities for diversification. This dissertation developed and applied new approaches to gaining a quantitative understanding of diversity patterns and processes, allowing for improved comparison between regions and countries. It includes an analysis of the scale dependency of crop species diversity and its relation with temporal diversity using high-resolution crop-specific land-cover data for the conterminous US. It also shows the magnitude of environmental and demand-side constraints to crop diversity globally. For that purpose, a theoretical framework of hierarchical levels of crop species diversity is presented, in which potential, attainable, and current diversity levels are compared to compute diversity gaps. We found that spatial diversity monotonically increases with the size of the observational unit, and the strongest association between spatial and temporal diversity is observed when measured in areas comparable to farm sizes. In larger areas, the association weakens because of the increasing diversity among farms. At the national level, the diversity among farms is usually higher than the diversity within them, which needs to be considered when inferring diversity effects with national-level data. v Environmental limits to crop diversity are higher in temperate and continental areas than in tropical and coastal regions. Crop diversity is also constrained by a high demand for a few crop species, which results in an attainable diversity that is much lower than the potential. Nevertheless, there are large gaps between current and attainable diversity levels in most croplands. These gaps are particularly large in the Americas, where croplands are dominated by a few major annual crops (maize, soybean, wheat) mostly grown on fields with a very low temporal diversity. In contrast, diversity gaps are relatively small in Europe and East Asia. Changes in food demand favoring minor crops could positively impact spatial and temporal crop species diversity by increasing the attainable diversity. But given current consumption patterns, the most effective strategy to increase crop diversity in areas with high diversity gaps might be to expand the area of a major crop adapted to that specific environment, but that is not widely planted. Securing adequate soil fertility is also critical for diversification, especially in the tropics, where low soil pH is one of the main limiting factors of potential crop diversity, and soil acidity remains a key management challenge for smallholder farmers. Liming can boost the productivity of acid soils, but the lime rate required to achieve this is unknown for many tropical regions where food production increases are urgently needed. Therefore, lime requirement models based on readily available soil data could be very useful in these places. However, the great variety of lime requirement models available in the literature introduces much uncertainty. We evaluated current lime requirement models for acid tropical soils and introduced a new model based on acidity saturation using data from four soil incubation studies and 31 soil types. Foundational models based on acidity or base saturation are reasonably accurate (r ≥ 0.9), but later attempts to vi improve these models were unsuccessful. The new model, in contrast, has more precision than all earlier models across a wide range of acid tropical soils from different regions. Moreover, lime requirement estimates largely depend on the target soil chemical property of the model. For instance, many more African soils would require liming based on base saturation models than acidity saturation models, regardless of the accuracy. The new acidity saturation model can effectively estimate the lime rate required to address aluminum toxicity. This model could be incorporated into more comprehensive models once lime rates needed for other acidity problems are well established.
EEA Balcarce
Fil: Aramburu Merlos, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.
Materia
Cultivos
Diversidad de Especies
Agrobiodiversidad
Análisis Espacial
Agroecología
Crops
Species Diversity
Agrobiodiversity
Spatial Analysis
Agroecology
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
INTA Digital (INTA)
Institución
Instituto Nacional de Tecnología Agropecuaria
OAI Identificador
oai:localhost:20.500.12123/12403

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network_name_str INTA Digital (INTA)
spelling Pattern and process in crop species diversity and lime requirements modelsAramburu Merlos, FernandoCultivosDiversidad de EspeciesAgrobiodiversidadAnálisis EspacialAgroecologíaCropsSpecies DiversityAgrobiodiversitySpatial AnalysisAgroecologyTesis para obtener el grado de Doctor of Philosophy in Horticulture and Agronomy, de la University of California Davis, 2022Changes in crop species diversity can affect agroecosystem function. However, most crop diversity studies insufficiently account for the influence of scale on spatial crop diversity, and its relation to temporal diversity has not been explored. Moreover, crop diversity might be limited by environmental constraints and market demand for specific crops, which needs to be considered when assessing opportunities for diversification. This dissertation developed and applied new approaches to gaining a quantitative understanding of diversity patterns and processes, allowing for improved comparison between regions and countries. It includes an analysis of the scale dependency of crop species diversity and its relation with temporal diversity using high-resolution crop-specific land-cover data for the conterminous US. It also shows the magnitude of environmental and demand-side constraints to crop diversity globally. For that purpose, a theoretical framework of hierarchical levels of crop species diversity is presented, in which potential, attainable, and current diversity levels are compared to compute diversity gaps. We found that spatial diversity monotonically increases with the size of the observational unit, and the strongest association between spatial and temporal diversity is observed when measured in areas comparable to farm sizes. In larger areas, the association weakens because of the increasing diversity among farms. At the national level, the diversity among farms is usually higher than the diversity within them, which needs to be considered when inferring diversity effects with national-level data. v Environmental limits to crop diversity are higher in temperate and continental areas than in tropical and coastal regions. Crop diversity is also constrained by a high demand for a few crop species, which results in an attainable diversity that is much lower than the potential. Nevertheless, there are large gaps between current and attainable diversity levels in most croplands. These gaps are particularly large in the Americas, where croplands are dominated by a few major annual crops (maize, soybean, wheat) mostly grown on fields with a very low temporal diversity. In contrast, diversity gaps are relatively small in Europe and East Asia. Changes in food demand favoring minor crops could positively impact spatial and temporal crop species diversity by increasing the attainable diversity. But given current consumption patterns, the most effective strategy to increase crop diversity in areas with high diversity gaps might be to expand the area of a major crop adapted to that specific environment, but that is not widely planted. Securing adequate soil fertility is also critical for diversification, especially in the tropics, where low soil pH is one of the main limiting factors of potential crop diversity, and soil acidity remains a key management challenge for smallholder farmers. Liming can boost the productivity of acid soils, but the lime rate required to achieve this is unknown for many tropical regions where food production increases are urgently needed. Therefore, lime requirement models based on readily available soil data could be very useful in these places. However, the great variety of lime requirement models available in the literature introduces much uncertainty. We evaluated current lime requirement models for acid tropical soils and introduced a new model based on acidity saturation using data from four soil incubation studies and 31 soil types. Foundational models based on acidity or base saturation are reasonably accurate (r ≥ 0.9), but later attempts to vi improve these models were unsuccessful. The new model, in contrast, has more precision than all earlier models across a wide range of acid tropical soils from different regions. Moreover, lime requirement estimates largely depend on the target soil chemical property of the model. For instance, many more African soils would require liming based on base saturation models than acidity saturation models, regardless of the accuracy. The new acidity saturation model can effectively estimate the lime rate required to address aluminum toxicity. This model could be incorporated into more comprehensive models once lime rates needed for other acidity problems are well established.EEA BalcarceFil: Aramburu Merlos, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.University of California at DavisHijmans, Robert J. (director)2022-07-26T21:02:22Z2022-07-26T21:02:22Z2022-07info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/acceptedVersionhttp://purl.org/coar/resource_type/c_db06info:ar-repo/semantics/tesisDoctoralapplication/pdfhttp://hdl.handle.net/20.500.12123/12403enginfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:INTA Digital (INTA)instname:Instituto Nacional de Tecnología Agropecuaria2025-09-04T09:49:28Zoai:localhost:20.500.12123/12403instacron:INTAInstitucionalhttp://repositorio.inta.gob.ar/Organismo científico-tecnológicoNo correspondehttp://repositorio.inta.gob.ar/oai/requesttripaldi.nicolas@inta.gob.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:l2025-09-04 09:49:28.489INTA Digital (INTA) - Instituto Nacional de Tecnología Agropecuariafalse
dc.title.none.fl_str_mv Pattern and process in crop species diversity and lime requirements models
title Pattern and process in crop species diversity and lime requirements models
spellingShingle Pattern and process in crop species diversity and lime requirements models
Aramburu Merlos, Fernando
Cultivos
Diversidad de Especies
Agrobiodiversidad
Análisis Espacial
Agroecología
Crops
Species Diversity
Agrobiodiversity
Spatial Analysis
Agroecology
title_short Pattern and process in crop species diversity and lime requirements models
title_full Pattern and process in crop species diversity and lime requirements models
title_fullStr Pattern and process in crop species diversity and lime requirements models
title_full_unstemmed Pattern and process in crop species diversity and lime requirements models
title_sort Pattern and process in crop species diversity and lime requirements models
dc.creator.none.fl_str_mv Aramburu Merlos, Fernando
author Aramburu Merlos, Fernando
author_facet Aramburu Merlos, Fernando
author_role author
dc.contributor.none.fl_str_mv Hijmans, Robert J. (director)
dc.subject.none.fl_str_mv Cultivos
Diversidad de Especies
Agrobiodiversidad
Análisis Espacial
Agroecología
Crops
Species Diversity
Agrobiodiversity
Spatial Analysis
Agroecology
topic Cultivos
Diversidad de Especies
Agrobiodiversidad
Análisis Espacial
Agroecología
Crops
Species Diversity
Agrobiodiversity
Spatial Analysis
Agroecology
dc.description.none.fl_txt_mv Tesis para obtener el grado de Doctor of Philosophy in Horticulture and Agronomy, de la University of California Davis, 2022
Changes in crop species diversity can affect agroecosystem function. However, most crop diversity studies insufficiently account for the influence of scale on spatial crop diversity, and its relation to temporal diversity has not been explored. Moreover, crop diversity might be limited by environmental constraints and market demand for specific crops, which needs to be considered when assessing opportunities for diversification. This dissertation developed and applied new approaches to gaining a quantitative understanding of diversity patterns and processes, allowing for improved comparison between regions and countries. It includes an analysis of the scale dependency of crop species diversity and its relation with temporal diversity using high-resolution crop-specific land-cover data for the conterminous US. It also shows the magnitude of environmental and demand-side constraints to crop diversity globally. For that purpose, a theoretical framework of hierarchical levels of crop species diversity is presented, in which potential, attainable, and current diversity levels are compared to compute diversity gaps. We found that spatial diversity monotonically increases with the size of the observational unit, and the strongest association between spatial and temporal diversity is observed when measured in areas comparable to farm sizes. In larger areas, the association weakens because of the increasing diversity among farms. At the national level, the diversity among farms is usually higher than the diversity within them, which needs to be considered when inferring diversity effects with national-level data. v Environmental limits to crop diversity are higher in temperate and continental areas than in tropical and coastal regions. Crop diversity is also constrained by a high demand for a few crop species, which results in an attainable diversity that is much lower than the potential. Nevertheless, there are large gaps between current and attainable diversity levels in most croplands. These gaps are particularly large in the Americas, where croplands are dominated by a few major annual crops (maize, soybean, wheat) mostly grown on fields with a very low temporal diversity. In contrast, diversity gaps are relatively small in Europe and East Asia. Changes in food demand favoring minor crops could positively impact spatial and temporal crop species diversity by increasing the attainable diversity. But given current consumption patterns, the most effective strategy to increase crop diversity in areas with high diversity gaps might be to expand the area of a major crop adapted to that specific environment, but that is not widely planted. Securing adequate soil fertility is also critical for diversification, especially in the tropics, where low soil pH is one of the main limiting factors of potential crop diversity, and soil acidity remains a key management challenge for smallholder farmers. Liming can boost the productivity of acid soils, but the lime rate required to achieve this is unknown for many tropical regions where food production increases are urgently needed. Therefore, lime requirement models based on readily available soil data could be very useful in these places. However, the great variety of lime requirement models available in the literature introduces much uncertainty. We evaluated current lime requirement models for acid tropical soils and introduced a new model based on acidity saturation using data from four soil incubation studies and 31 soil types. Foundational models based on acidity or base saturation are reasonably accurate (r ≥ 0.9), but later attempts to vi improve these models were unsuccessful. The new model, in contrast, has more precision than all earlier models across a wide range of acid tropical soils from different regions. Moreover, lime requirement estimates largely depend on the target soil chemical property of the model. For instance, many more African soils would require liming based on base saturation models than acidity saturation models, regardless of the accuracy. The new acidity saturation model can effectively estimate the lime rate required to address aluminum toxicity. This model could be incorporated into more comprehensive models once lime rates needed for other acidity problems are well established.
EEA Balcarce
Fil: Aramburu Merlos, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.
description Tesis para obtener el grado de Doctor of Philosophy in Horticulture and Agronomy, de la University of California Davis, 2022
publishDate 2022
dc.date.none.fl_str_mv 2022-07-26T21:02:22Z
2022-07-26T21:02:22Z
2022-07
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/acceptedVersion
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url http://hdl.handle.net/20.500.12123/12403
dc.language.none.fl_str_mv eng
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dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv University of California at Davis
publisher.none.fl_str_mv University of California at Davis
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