Effects of field application of anaerobic sorghum digester sludge on sorghum growth, nitrogen uptake and sludge decomposition /
Land disposal of sludge produced as a by-product of methane generated from sorghum stover could be beneficial or potentially hazardous to the environment, depending on the sludge/soil characteristics and interactions, as well as application rates and frequency. A f ield study was conducted in which...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742470961&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Land disposal of sludge produced as a by-product of methane generated from sorghum stover could be beneficial or potentially hazardous to the environment, depending on the sludge/soil characteristics and interactions, as well as application rates and frequency. A f ield study was conducted in which anaerobic sorghum digester sludge was applied to ascertain growth response from sorghum (Sorghum bicolor L. Moench), measure sludge inorganic N release and uptake and the rate of sludge decomposition. Rates of 30 and 90 Mg sludge ha-1 (dry weight basis) were applied and compared to 45, 90, and 135 kg N ha-I (as NH4NO3) on a Weswood silt loam near College Station, Texas. Two months after the initial application, plant emergence was significantly lower in the sludge treatments, particularly at the 90 Mg rate. No significant difference in plant emergence was detected in the second cropping season. Plant growth during the first year, as measured by sorghum height and weight, was significantly less in the sludge treatments, particularly with 30 Mg ha-1, which was lower than the control in many instances. During the second year, however, dry plant weights were equal or significantly higher for the sludge compared to the fertilized treatments. Grain production with 90 Mg sludge ha-1 was statistically similar to yields receiving the higher fertilizer rates. These results indicated that after an initial period of immobilization, sufficient inorganic N was mineralized to equal that provided by inorganic fertilizers. Results from soil analyses over the two year period indicated that much of the applied fertilizer and sludge N was taken up by the crop. Accumulation and downward movement of nitrate was detected, particularly at the 90 Mg sludge ha-1 rate. Sufficient movement for ground water contamination was not found in this study. Sludge decay data indicated essentially complete decomposition after approximately 4.5 years. A significant decrease in the CIN ratio of sludge samples over time was also shown. |
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| Item Description: | Vita. "Major Subject: Soil Science". |
| Physical Description: | xiii, 148 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |