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Browsing by Author "Jintaridth, Bunjirtluk"

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  • 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
    Jintaridth, Bunjirtluk (2008)
    This presentation was compiled as a class project presented at the Graduate seminar in the Soils department at the University of Missouri-Columbia. It sets forth the importance of monitoring soil quality and reducing soil degradation and erosion in the global context. The presentation also describes the basics of good soil quality and how these may be quantified.
  • 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.
  • 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.