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An Improved Method for Determining the Fineness Value of Agricultural Limestone for Aquaculture
Author(s) -
Silapajarn Kom,
Boyd Claude E.,
Silapajarn Orawan
Publication year - 2004
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1577/a03-044.1
Subject(s) - alkalinity , fineness , zoology , particle size , mineralogy , particle (ecology) , chemistry , nuclear chemistry , metallurgy , materials science , biology , ecology , organic chemistry
The original method for determining the fineness of agricultural limestone was modified for the greater contribution of particles less than 0.25 mm in diameter that is found in the modern agricultural limestone used in aquaculture. Crusher‐run limestone was screened to give nine particle size separates. Systems containing 3.0 kg of soil (pH = 5.21) and 23.5 L of water (total alkalinity = 0.39 mg/L) were treated with 8.0 g of each separate, and total alkalinity and pH were monitored. After 70 d, total alkalinity equilibrated at 55 mg/L in systems treated with particles less than 0.106 mm. The total alkalinity in systems treated with other particle size separates were as follows: control, 0.52 mg/L; greater than 2.0 mm, 2.28 mg/L; 2.0–0.85 mm, 5.75 mg/L; 0.85–0.42 mm, 12.25 mg/L; 0.42–0.25 mm, 26.8 mg/L; 0.25–0.15 mm, 45.62 mg/L; and 0.15–0.106 mm, 49.30 mg/L. Water pH exceeded 7.36 after 2 weeks for systems treated with particles less than 0.25 mm. Wet soil samples (2.5 kg) of pH 5.04 were placed in trays and treated with 6.7 g of limestone of different particle size separates. After 1 week, pH was 6.9–7.1 in soil treated with particles less than 0.106 mm. By 10 weeks, a pH greater than 6.5 was attained in soils treated with particles less than 0.25 mm. The pH of soil treated with particles greater than 0.25 mm was similar to the control pH. Efficiency factors were assigned to particle size‐classes as follows: less than 0.106 mm, 100%; 0.25–0.106 mm, 86.7%; 0.42–0.25 mm, 49.06%; 0.85–0.42 mm, 22.4%; and greater than 0.85 mm, 7.3%. The sum of the products of the proportion of each particle size‐class and the corresponding efficiency factor gave the fineness value. Fineness values usually were smaller when determined by the new method instead of the old method.