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RISS 인기검색어
- 검색키워드
- 저자 : Douglas D. Malo (검색결과 4 건)
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South Dakota Soils: Their Genesis, Classification, and Management
더글러스 D. 말로,유진희,김시주,정덕영,Malo, Douglas D.,Ryu, Jin-Hee,Kim, Si-Joo,Chung, Doug-Young Institute of Agricultural Science 2010 Korean Journal of Agricultural Science Vol.37 No.3
South Dakota is an important agricultural state in the United States with annual cash receipts from agricultural products exceeding $9 billion dollars. This production is possible because of large areas of productive soils. This publication describes the general characteristics and qualities of the major soil groups recognized in South Dakota. The soil forming factors are briefly described, soil classification is introduced, and the genesis of typical Udalf and Ustoll soils are discussed. Soil management issues impacting the use of SD soils are considered. Long-term (>70 yrs) cultivation has significantly reduced surface soil organic carbon levels (>30% reduction) when compared to non-cultivated soil. Soil test phosphorus levels significantly increased in cultivated fields due to commercial P fertilization. The major long-term production problems for SD soils are conservation of soil moisture, organic matter and nitrogen losses, fertility management, and wind and water erosion control.
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더글러스 D. 말로(Douglas D. Malo),유진희(Jin-Hee Ryu),김시주(Si-Joo Kim),정덕영(Doug-Young Chung) 충남대학교 농업과학연구소 2010 농업과학연구 Vol.37 No.3
South Dakota is an important agricultural state in the United States with annual cash receipts from agricultural products exceeding $9 billion dollars. This production is possible because of large areas of productive soils. This publication describes the general characteristics and qualities of the major soil groups recognized in South Dakota. The soil forming factors are briefly described, soil classification is introduced, and the genesis of typical Udalf and Ustoll soils are discussed. Soil management issues impacting the use of SD soils are considered. Long-term (>70 yrs) cultivation has significantly reduced surface soil organic carbon levels (>30% reduction) when compared to non-cultivated soil. Soil test phosphorus levels significantly increased in cultivated fields due to commercial P fertilization. The major long-term production problems for SD soils are conservation of soil moisture, organic matter and nitrogen losses, fertility management, and wind and water erosion control.
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Influence of Drying Temperature and Duration on the Quantification of Particulate Organic Matter
Lee, Jin-Ho,Doolittle, James J.,Lee, Do-Kyoung,Malo, Douglas D. The Korean Society of Environmental Agriculture 2006 한국환경농학회지 Vol.25 No.4
Various drying conditions, temperatures (40 to $80^{\circ}C$) and durations (overnight to 72 hrs), for the particulate organic matter (POM) fraction after wet-sieving size fractionation have been applied for determination of POM contents in the weight loss-on-ignition method. In this study, we investigated the optimum drying condition for POM fraction in quantification of POM and/or mineral-associated organic matter (MOM; usually indirectly estimated). The influence of the drying conditions on quantifying POM was dependent upon soil properties, especially the amount of soil organic components. In relatively high organic soils (total carbon > 40 g/kg in this study), the POM values were significantly higher (overestimated) with drying at $55^{\circ}C$ than those values at $105^{\circ}C$, which were, for example, 173.2 and 137.3 mg/kg, respectively, in a soil studied. However, drying at $55^{\circ}C$ for longer than 48 hrs of periods produced consistent POM values even though the values were much higher than those at $105^{\circ}C$. Thus, indirect estimates of MOM (MOM = SOM-POM) also tended to be significantly impacted by the dry conditions. Therefore, we suggest POM fractions should be dried at $105^{\circ}C$ for 24 hrs as determining POM and MOM contents. If the POM traction is needed to be dried at a lower temperature (e.g. $55^{\circ}C$) with a specific reason, at least 48 hrs of drying period is necessary to obtain consistent POM values, and a moisture correction factor should be determined to adjust the values back to a $105^{\circ}C$ weight basis.
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Influence of Drying Temperature and Duration on the Quantification of Particulate Organic Matter
( Jin Ho Lee ),( James J. Doolittle ),( Do Kyoung Lee ),( Douglas D. Malo ) 한국환경농학회 2006 한국환경농학회지 Vol.25 No.4
Various drying conditions, temperatures (40 to 80℃) and durations (overnight to 72 hrs), for the particulate organic matter (POM) fraction after wet-sieving size fractionation have been applied for determination of POM contents in the weight loss-on-ignition method. In this study, we investigated the optimum drying condition for POM fraction in quantification of POM and/or mineral-associated organic matter (MOM; usually indirectly estimated). The influence of the drying conditions on quantifying POM was dependent upon soil properties, especially the amount of soil organic components. In relatively high organic soils (total carbon > 40g/㎏ in this study), the POM values were significantly higher (overestimated) with drying at 55℃ than those values at 105℃, which were, for example, 173.2 and 137.3㎎/㎏, respectively, in a soil studied. However, drying at 55℃ for longer than 48 hrs of periods produced consistent POM values even though the values were much higher than those at 105℃. Thus, indirect estimates of MOM (MOM = SOM-POM) also tended to be significantly impacted by the dry conditions. Therefore, we suggest POM fractions should be dried at 105℃ for 24 hrs as determining POM and MOM contents. If the POM fraction is needed to be dried at a lower temperature (e.g. 55℃) with a specific reason, at least 48 hrs of drying period is necessary to obtain consistent POM values, and a moisture correction factor should be determined to adjust the values back to a 105℃ weight basis.
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