Browsing by Author "Motavalli, Peter P."

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    Adapting to change: Changes in community perceptions and management of soil quality and soil organic matter
    Motavalli, Peter P. (2006)
    This presentation describes the development of the SANREM CRSP project, "Adapting to Change in the Andean Highlands: Practices and Strategies to Address Climate and Market Risks in Vulnerable Agro-Ecosystems", gives an overview of the planned research, and explains the project objectives.
  • Adapting to change: Changes in community perceptions and management of soil quality and soil organic matter
    Motavalli, Peter P. (2006)
    This presentation gives a definition of soil quality and explains the interactions of soil chemical, physical and biological properties that affect how a soil performs ecosystems functions. Soil organic matter and its relationship with sustainability is also explained, according to its functions. An overview, objectives, specific studies and proposed training of the research on soils within the SANREM CRSP project "Adapting to Change in the Andean region of Bolivia" are shown in detail.
  • Aplicación de abonos orgánicos e inorgánicos en el cultivo de la papa (Solanum tuberosum L.) en suelos del Altiplano central Boliviano
    Sipe, J.; Condori, B.; Gonzales, Miguel Angel; Motavalli, Peter P. (2008)
    El presente estudio se llevó a cabo, en comunidades del municipio de Umala (Vinto Coopani, Kellhuiri, San Juan Circa y San José), ubicada en la provincia Aroma del Altiplano central. El estudio se realizó con la aplicación de abonos orgánicos e inorgánicos al suelo, como alternativas para mejorar la fertilidad del suelo, en parcelas con cultivo de papa Waych´a. El ensayo se condujo bajo un diseño jerárquico factorial de BCA, con 4 repeticiones. Las variables evaluadas son las de suelo y cultivo, entre las de suelo se evaluaron a las propiedades químicas, físicas y biológicas, además con el fin de realizar la caracterización de los horizontes, se procedió a la apertura de calicatas en ambas zonas (alta y baja). No se encontró diferencias significativas en la emergencia. Se logro ver diferencias significativas en la altura de planta, observándose el valor mas alto en San Juan Circa (46.6 cm) y el mas bajo en Kellhuiri (38.1 cm). También se encontró diferencias estadísticas para Índice de Cosecha (IC), encontrándose el valor mas alto de IC en la comunidad Vinto Coopani y el más bajo en San Juan Circa. El cultivo de papa respondió de manera favorable a la aplicación de abonos orgánicos e inorgánicos, en la cual se encontró rendimientos de hasta 18 y 19 t/ha, comparado con el testigo absoluto que tiene los rendimientos mas bajos que van desde 7 a 11 t/ha. Aparentemente al combinar fertilizantes, se logran las mejores respuestas por el cultivo.
  • Assessing and managing soil quality for sustainable agricultural system
    Motavalli, Peter P.; Jintaridth, Bunjirtluk; Lehmann, Johannes; Goyne, Keith W.; Gilles, Jere L. (2008)
    Soil quality assessment is a process by which soil resources are evaluated on the basis of soil function. Soil organic matter (SOM) is one of the most widely knowledge indicators of soil quality(Gregorich et al., 1994). In general, SOC varies across landscapes, soil types and climatic zones. It is characterized by high levels of C in recalcitrant or humified forms and small changes in SOC resulting from changes in soil management are difficult to measure. An approach to evaluate the impact of agricultural management of SOM dynamics is to separate SOM into pools which will depend on differences in decomposition rates (Wander et al., 1994). In two-pool exponential decomposition models, the pool with the smallest size and most rapid turnover is termed labile and the larger pool with slow turnover is termed recalcitrant. The lability of SOM is defined as the ease and speed with which it is decomposed by microbes and depends on both chemical recalcitrance and physical protection from microbes. Changes in labile fractions of SOC provide an early indication of soil degradation or improvement in response to management practices (Islam and Weil,2000). In this research, soil samples will be collected from representative degraded and non- degraded soils at ongoing SANREM field sites, establish in-field and laboratory capacity to test soil quality, and develop analytical methodologies for the spectroscopic-based procedures. Collaboration with CGIAR system (i.e., ICRAF), USDA-ARS and USDA-NRCS are also important goals of this project due to the ongoing efforts and resources being invested at these institutions in developing low-cost methods for soil quality evaluation.
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    Assessing and managing soil quality for sustainable agricultural systems
    Motavalli, Peter P. (Blacksburg, VA: Office of International Research, Education, and Development, Virginia Tech, 2009)
    This brief presentation summarizes some of the major findings of the cross cutting research activity on soil quality including inexpensive and relatively quick methods for measuring soil quality and soil degradation. However, more appropriate methods need to need to be developed to measure changes in soil organic matter.
  • Assessing and managing soil quality for sustainable agricultural systems: SANREM CRSP Cross Cutting initiative
    Motavalli, Peter P.; Jintaridth, Bunjirtluk; Lehmann, Johannes; Goyne, Keith W.; Gilles, Jere L. (2008)
    A presentation about the SANREM CRSP Cross Cutting initiative in terms of assessing and managing soil quality for sustainable agricultural systems in the Altiplano of Peru and Bolivia.
  • Assessing soil quality for sustainable agricultural systems in tropical countries using spectroscopic methods
    Jintaridth, Bunjirtluk; Motavalli, Peter P.; Goyne, Keith W.; Kremer, R. J. (2008)
    Identifying and developing appropriate methods to quantify and assess changes in soil quality are essential for evaluating the extent of soil degradation and the effectiveness of improved management practices. The objective of this research, which will be conducted across a wide range of cropping systems and environments in Asia, Africa and South America, is to determine the efficacy of spectroscopic-based (i.e. near-infrared, mid-infrared, and visible range) analytical methods to evaluate soil organic matter fractions and soil quality in degraded and non-degraded soils. Initial activities of the project are to develop in-field and laboratory analytical methodologies for the spectroscopic-based procedures, conduct comparisons of use of those methodologies in different cropping systems and climates that have experienced soil degradation, and collect soil samples from representative degraded and non-degraded soils for additional characterization of their soil C and N fractions. Among the methodologies to be tested are diffuse reflectance infrared Fourier-transformed (DRIFT) mid-infrared spectroscopy, near-infrared spectroscopy (NIR), and use of the in-field potassium permanganate test. Additional assessment of the criteria used to evaluate the results from these tests will also be discussed.
  • Assessing soil quality for sustainable agricultural systems in tropical countries using spectroscopic methods
    Jintaridth, Bunjirtluk; Motavalli, Peter P.; Goyne, Keith W.; Kremer, R. J. (2008)
    Soil quality assessment is a process by which soil resources are evaluated on the basis of soil function. The need for an effective, low-cost method to evaluate soil quality is important in developing countries because soil degradation is a major impediment to sustainable crop growth. Soil organic matter (SOM) or soil organic C (SOC) is an important indicator of soil quality (Gregorich et al., 1994) because it affects many plant growth factors, including water-holding capacity and long-term nutrient availability. In general, SOC varies across landscapes, soil types and climatic zones and is characterized by both labile and recalcitrant or humified forms. There are many techniques that measure the size and turnover time of SOC pools to evaluate soil quality in the laboratory or the field to help guide sustainability of agricultural management practices. Among these methods are several spectroscopic procedures which are rapid and relatively low-cost. The KMnO4 method developed by Weil (2003) has been adapted for field use and measures a labile C fraction. Near infrared (NIR) spectroscopy has also been adapted for field use and could provide a rapid method to measure soil C fractions (Shepherd et al., 2007). Another technique which has been studied is the use of diffuse reflectance infrared Fourier-transformed (DRIFT) mid-infrared spectroscopy which can identify labile and recalcitrant C in soil (Ding et al., 2002). However, many of these techniques have not been assessed under a wide range of soil types and cropping systems.
  • Changes in soil organic C and N due to climate change and socioeconomic factors in potato-based cropping systems in the Bolivian Highlands
    Motavalli, Peter P.; Aguilera, Javier; Valdivia, Corinne; García, Magali; Jiménez, Elizabeth; Cusicanqui, Jorge; Miranda, R. (Madison, WI: American Society of Agronomy, 2007)
    Global climate change and changes in migration and market conditions in the Bolivian Highlands (Altiplano) have reduced the use of traditional cropping practices and increased the risk of crop failure and food insecurity. The objectives of this research were to survey indigenous farming communities in the northern Altiplano of Bolivia to determine the actual and perceived changes in cropping practices in potato-based cropping systems and to assess the effects of these changes on soil total organic carbon (C) and total nitrogen (N) levels and the availability and composition of soil amendments. Village-level surveys were conducted using questionnaires and participatory techniques in 2006-2007 in four communities that were selected to represent communities situated at relatively low and high altitudes in the region. Samples of soil amendments, primarily animal manures, were obtained from each community to determine the range of composition of the materials. In addition, soil samples were collected to a 20 cm depth from agricultural fields that represented different stages of the common agricultural rotation practiced in the region and that had different lengths of fallow periods. A hypothesis of this research is that climate change and socioeconomic factors have caused lower soil total organic C and total N levels due to increased intensity of land use and the amount and type of tillage, and a decrease in the length of the fallow period that was traditionally used to restore soil fertility. The results of the analysis of the soil amendments and soils will be compared to community perceptions of changes in soil quality and management and any differences among the communities will be discussed. The findings of this research will assist in determining if appropriate management practices need to be identified to improve soil organic matter in order to possibly mitigate negative effects of climate change in the area.
  • Cross-cutting activities: Soil quality and soil metagenomics
    Motavalli, Peter P.; Garrett, Karen A. (2008)
    This presentation reports on the work of the SANREM CRSP cross-cutting activities "Assessing and Managing Soil Quality for Sustainable Agricultural Systems" and "Soil Metagenomics to Construct Indicators of Soil Degradation." The introduction gives an overview of the extensiveness of soil degradation globally and defines soil quality. The objectives of the soil quality cross cutting activity are:
  • Differences in cropping systems and soil organic carbon due to climate change and socioeconomic factors in potato-based cropping systems in the Bolivian Highlands
    Motavalli, Peter P.; Cusicanqui, Jorge; Aguilera, Javier; Valdivia, Corinne; García, Magali; Jiménez, Elizabeth; Miranda, R. (2008)
    This presentation presents results of differences in cropping systems and soil organic carbon in the Bolivian Highlands, due to climate change and socioeconomic factors in potato-based cropping systems.
  • Differences in cropping systems and soil organic carbon due to climate change and socioeconomic factors in potato-based cropping systems in the Bolivian highlands
    Motavalli, Peter P.; Cusicanqui, Jorge; Aguilera, Javier; Valdivia, Corinne; García, Magali; Jiménez, Elizabeth; Miranda, R. (2008)
    This presentation discusses research performed in Bolivia on climate change in regard to soil degradation. Through interdisciplinary methods in soil science and social science, the researchers attempted to determine why and how much livelihoods have changed in the Bolivian highlands. Specifically, the researchers were interested in the climate and human interface and how this has been affected by reduced rainfall and climate change.
  • Do bacterial and fungal communities in soils of the Bolivian Altiplano change under shorter fallow periods?
    Gomez-Montano, L.; Jumpponen, A.; Gonzales, Miguel Angel; Cusicanqui, Jorge; Valdivia, Corinne; Motavalli, Peter P.; Herman, M.; Garrett, Karen A. (2013)
    Leaving fields fallow can improve soil fertility, but there is limited information on the effect of fallowing on soil microbiology. This article presents a study of soil fungal and bacterial properties in fallowed land in the Umala and Ancoriames municipalities of the Bolivian altiplano. The study tested the influence of fallowing, and of the presence of the native plant Thola, on fungal and bacterial populations. In Ancroaimes, fungal diversity increased with fallowing, while in Umala fungal diversity decreased with fallowing. Conversely, bacterial diversity with fallowing decreased in Ancoraimes and increased in Umala. The presence of Thola did not alter the level of diversity, but did result in higher populations of certain genera. Although these results demonstrate a variety of responses to fallowing, they establish its significance on bacterial and fungal populations
  • Efecto de aplicación de abonos orgánicos y químicos sobre la fertilidad del suelo en el cultivo de la papa (Solanum tuberosum) en el Altiplano Norte de la Paz
    Herrera, E. A.; Miranda, R.; Motavalli, Peter P.; Peñaranda, M. (2007)
    El trabajo de Enmiendas orgánicas se desarrolla en tres comunidades del municipio de Ancoraimes (Cohani, Chinchaya y Chojñapata), correspondiente a la provincia Omasuyos del departamento de La Paz. Los objetivos de la presente investigación son determinar la influencia de los abonos orgánicos y químicos en el desarrollo del cultivo de la papa y sus efectos sobre los suelos, para de esta manera proponer alternativas de manejo de materia orgánica. Para la presente investigación se utilizo estiércol de ganado vacuno y ovino, además de fertilizantes químicos como la urea y fosfato de amonio. Los resultados muestran que los diferentes tratamientos no son significativos en cuanto a la acumulación de humedad por parte del suelo, mientras que la densidad aparente del suelo bajo en los tratamientos donde se puso materia orgánica. En cuanto al desarrollo del cultivo se observan diferencias numéricas en cuanto a la altura de planta, mas no son estadísticamente significativas. En cuanto al rendimiento, se pudo observar que los tratamientos que contienen una mezcla de estiércol con fertilizantes químicos dieron los mejores resultados. A la fecha se siguen tomando datos de humedad del suelo y densidad aparente, asimismo falta la cosecha en la comunidad de Chojñapata, para realizar la evaluación de rendimiento. Según la percepción de los agricultores, el mejor tratamiento es la mezcla de estiércol de oveja con urea y fosfato de amonio, sin embargo estadísticamente no presentan diferencias significativas.
  • Effects of changes in fallow length on soil organic C due to climate change and socioeconomic factors in potato-based cropping systems in the Bolivian Highlands
    Motavalli, Peter P.; Aguilera, Javier; Jintaridth, Bunjirtluk; Valdivia, Corinne; Gonzales, Miguel Angel; Chambilla, Carola (2009)
    Fallowing land has an important role in soil fertility restoration in potato-based cropped systems in the semi-arid Bolivian Highlands (Altiplano) Region. However, climate change and changes in migration and market conditions have reduced the use of this traditional practice and possibly increased soil degradation. The objectives of this research were to assess the effects of cropping and length of fallow on soil total organic carbon (C) and labile soil C fractions among indigenous communities in the Central Altiplano. The study sites were four communities in the Central Altiplano that were selected to represent communities situated at relatively low and high altitudes in the region. Soil samples were collected to a 20 cm depth from agricultural fields that represented different stages of the common agricultural rotation practiced in the region and that had different fallow periods. Soils were analyzed for total organic C, water-soluble C, particulate organic matter C, and potassium permanganate reactive C. Humic acid from the samples was extracted and analyzed using diffuse reflectance infrared Fourier-transformed (DRIFT) mid-infrared spectroscopy. Results from the permanganate test showed that labile C increased with > 40 yrs fallow and varied among communities. The peak ratios measured by the DRIFT analysis also showed differences among the soil samples with different fallow histories. The findings of this research will assist in determining if appropriate management practices need to be developed to improve soil organic matter in the region.
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    Impacts of Cultivation and Fallow Length on Soil Carbon and Nitrogen Availability in the Bolivian Andean Highland Region
    Aguilera, Javier; Motavalli, Peter P.; Valdivia, Corinne; Gonzales, Miguel Angel (2013-11)
    Inclusion of periods of unmanaged or natural fallowing is an important soil management practice in the potato-based cropping systems of the resource-poor Andean highland region (Altiplano) of Bolivia. However, in recent years the area in fallow and the fallow length are being reduced due to greater land use intensity and competing land uses. The objectives of this study were to determine the effects of the length of cropping and fallowing periods on soil degradation or soil restoration, and to compare the potential soil carbon and nitrogen mineralization from a range of cropped and fallow lands at different elevations. Four representative indigenous communities of the semiarid central Altiplano were selected, 2 at a relatively high elevation and 2 at a relatively low elevation. Soil samples were collected in 2006 and 2007 from fields at the first, second, and third year of crop rotation and from fields with 1, 10, 20, 30, and 40 years of fallow and analyzed for several soil properties. In general, the upper elevations had significantly higher soil organic carbon, total nitrogen, inorganic nitrogen, soil test phosphorus and potassium, exchangeable calcium and magnesium, and cation exchange capacity than the lower elevations. Cropping significantly decreased total and active soil organic carbon and total, inorganic, and active soil nitrogen. Fallowing was observed to restore total and active soil organic carbon and total and active soil nitrogen more rapidly in the higher communities than in the lower communities; this difference was mainly attributed to differences in initial soil properties, climate, and land management in cropped fields with elevation. Further research may be needed to determine which factor has the most influence on soil degradation and soil fertility restoration in this environment in order to assist farmers to improve soil fertility.
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    Introduction to SANREM Cross Cutting Research Activities
    Moore, Keith M.; Motavalli, Peter P.; Christie, Maria Elisa; Garrett, Karen A.; Heatwole, Conrad D.; Mwangi, Esther (Office of International Research, Education and Development, Virginia Tech, 2009)
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    Management of organic and inorganic soil fertility inputs in indigenous agricultural communities in the Bolivian Highlands
    Aguilera, Javier; Miranda, R.; Motavalli, Peter P.; Tangara, E.; Herrera, E. A. (2008)
    The Bolivian highland plateau region (Altiplano) is a semi-arid region in the Andes Mountains that has a range in elevation of between 3600 and 4300 m above sea level. The region's climate is characterized by high diurnal temperature variations, frost risks, low and irregular precipitation and high risks of drought during the growing season (Garcia et al., 2007). Recent research has indicated that the Andes region will experience temperature increases of up to 6 degrees C by the end of the century (Bradley et al., 2006, IPCC, 2007). In addition, a consequence of global climate change has been and will be a higher incidence of extreme weather events (Haylock et al., 2006; Thibeault et al., 2008). These climate changes may increase the risk of crop failure and food insecurity of local indigenous communities in the region. Other economic and social changes in the region, such as urban migration, have also impacted agricultural practices in this region, which are primarily potato-based cropping systems and livestock rearing of cows, sheep and camelids (e.g., alpaca and lama) (Valdivia et al., 2001). Research in the Altiplano has indicated that one consequence of climatic and socioeconomic changes has been increased soil degradation (Swinton and Quiroz, 2004; Motavalli et al., 2008). An important component of soils that may assist in mitigating this soil degradation is soil organic matter (SOM) or soil total organic carbon (SOC). Increased soil organic matter generally improves soil quality and the long-term sustainability of agroecosystems (Gupta et al., 1994). Improvements in existing soil management practices or the introduction of alternative practices that increase SOM may be needed for increased production and for reducing the negative consequences of climate change.
  • Managing soil organic matter for sustainable agriculture and mitigation of the effects of climate change
    Motavalli, Peter P. (2007)
    A presentation that shows an overview of the definition of soil organic matter and its functions, major forms of Carbon in soil, the global carbon cycle, definition of carbon sequestration, soil organic matter and sustainability, reservoir of plant nutrients, management practices that decrease soil organic carbon, practices that increase soil organic matter, global carbon emission reductions and field trial results in the Bolivian Altiplano as part of the SANREM CRSP project practices.
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    Pyrosequencing to determine the influence of fallow period on soil microbial communities in the Bolivian Highlands
    Gomez, L.; Jumpponen, A.; Gonzales, Miguel Angel; Cusicanqui, Jorge; Valdivia, Corinne; Motavalli, Peter P.; Herman, M.; Garrett, Karen A. (2010)
    This poster addresses the shortened fallow periods in the Bolivian highlands, which result from the desire to increase short-term crop yields. Researchers conducted a study using 454-pyrosequencing techniques to characterize the response of the microbial community to the length of fallow period and the presence of plants, and the effect this response has on soil quality. The results of this study imply that the increase in fallow years was related to an increase in dominance in both fungal and bacterial communities.