Corn Yield as Affected by Lime Rate and Type on a Coastal Plain Soil
1979
Liebhardt, William C.
Ground limestone rates of 0, 2.24, and 8.96 metric tons/ha as calcite, dolomite or a mixture of the two were applied to a Kalmia s1 (Typic Hapludult) in 1970 and 1973. Soil pH was 5.7 at the low rate and 6.4 at the high rate in 1977. Corn (Zea mays L.) yield was significantly lower at pH 6.4 compared to pH 5.7. At pH 6.4 dolomite resulted in lower corn yields than did calcite or a mixture of the two. Yield of corn was negatively related to soil pH and higher soil Mg and positively with plant Mn. Extration of soil samples with the double acid extractant from 5 min to 48 hours showed that there was considerable non-exchangeable Ca and Mg at the high lime rate (pH 6.4), but little or none at the low rate (pH 5.7). The nonexchangeable Ca and Mg appear to be reaction products from dolomite. The ratio of nonexchangeable Mg/Ca is 4.48 on a meq basis which is unfavorable for plant growth and indicates why continued use of dolomite on sandy Coastal Plain soil with a low CEC results in a yield decrease.
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