Nutrient accumulation and residue decomposition of switchgrass (Panicum virgatum L. cv. Alamo /
Alamo Switchgrass (Panicum virgatum L. cv Alamo) is a native warm-season (C₄) grass that has the potential to be used as a biofuel crop in the US. Since continuous use of switchgrass may deplete soil fertility, leaving plant parts with high mineral and low fiber concentration in the field is a str...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Summary: | Alamo Switchgrass (Panicum virgatum L. cv Alamo) is a native warm-season (C₄) grass that has the potential to be used as a biofuel crop in the US. Since continuous use of switchgrass may deplete soil fertility, leaving plant parts with high mineral and low fiber concentration in the field is a strategy that may decrease the impact of continuous cropping. The objectives of this study were to examine the patted of nutrient partitioning in switchgrass over time and to determine the C and N mineralization patterns of switchgrass in soil. Switchgrass was harvested biweekly from June to October in 1998. At each harvest the plant was separated into six parts (top leaves, top stems, middle leaves, middle stems, bottom leaves, and bottom stems) for mineral and fiber analysis. Plant material from three harvests (18 June, 12 August, and 8 October) was used in an incubation study to determine the patterns of C and N mineralization from switchgrass in soil. Sorghum (Sorghum bicolor L. cv Grassl) was used for companion. The results indicated that nutrient partitioning in switchgrass and sorghum was not as evident as in former reported studies. Thus, the harvest strategy of leaving plant parts high in nutrient concentration in the field could be validated. In the incubation study, only 50% of C added as switchgrass was mineralized as CO₂ after 100 days of incubation, indicating that switchgrass may be a good crop for sequestering C from the air into the soil. A first-order decay function best described the pattern of cumulative C mineralization. Sorghum had a higher mean decay rate than switchgrass. As the plant matured, structural fiber components became the dominating factors ceding cumulative C mineralized on day 100, surpassing all other favors. A similar relationship was found with sorghum. Nitrogen immobilization was observed in all switchgrass treatments, and N mineralization occurred in only three plant part treatments of sorghum. According to this observation, additional N fertilizer may be necessary for crop growth if switchgrass plant parts are left in the field during harvest. |
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| Item Description: | Vita. "Major subject: Agronomy". |
| Physical Description: | xii, 113 leaves : illustrations ; 28 cm. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references (leaves 92-98). |