Nutrient stress in acid soils of the Cinzana Station, Mali /
Research was conducted to define soil chemical properties associated with poor early growth of sorghum (Sorghum bicolor) in Paleustalfs of Cinzana. Greenhouse studies indicated that P deficiency and Al toxicity were limiting sorghum growth in these soils. Soil amendment tested for two seasons limit...
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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=741965151&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Research was conducted to define soil chemical properties associated with poor early growth of sorghum (Sorghum bicolor) in Paleustalfs of Cinzana. Greenhouse studies indicated that P deficiency and Al toxicity were limiting sorghum growth in these soils. Soil amendment tested for two seasons limited symptoms of poor early growth to few treatments in 1990. However, symptoms were displayed in 1991 at every combination of amendments. Amendments significantly improved soil pH (5.1 to 7.8), Bray-1 P (7.1 to 48. 5 mg kg-1), exchangeable Al (0.48 to 0 cmol(+) kg-1), and ECEC (1.30 to 3.10 cmol(+) kg- ,). However, the facts that dying seedlings had deficient concentrations of P (<2 g kg-1 shoot) and toxic Al concentrations (>900 mg Al kg-1 shoot) suggest that these elements may be associated with reduced sorghum growth.Phosphorus sorption was strongly correlated with percent clay (r = 0.86**), organic matter (r = 0.87**), surface area (r = 0.84**), ECEC (r = 0.85**), and total and poorly crystalline Fe and Al oxides (r = 0.90**, 0.81 0.75 and 0.73**, respectively). Soils of Cinzana sorbod from 37 to 98 mg P kg-1. Phosphorus sorption data and Bray-1 P content of fertilized soils suggested that P sorption was not a major factor. Phosphorus concentration in soil solution was significantly higher in 1991 when seedlings failed to grow (0.003 vs. 0.005 mM P). The ionic strengthof the soil solution was significantly increased in 1991 (0.0026 to 0.0030).The ionic strength and osmotic potential of the soil solution were furthersignificantly increased as the soil dried and evaporative concentration of the soil solution took place. Yet, the increase in osmotic potential (Wo = 0.008 to Vo = 0.009 MPa) were below critical values for reduced sorghum growth (Wo = 0.27 MPa). Sandy soils of the Cinzana toposequence had deficient P concentrations and high Al concentrations . However, timing of soil sampling did not allow measurements of soil conditions during critical periods of seedling growth and symptom development. |
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| Item Description: | Vita. "Major Subject: Soil Science". |
| Physical Description: | xvii, 166 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |