Submitted to: Trifolium Conference Abstract & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2000
Publication Date: N/A
Technical Abstract: The addition of lime to acidic soils increases both Soil Ca and pH. Therefore it is difficult to ascribe the effects of liming to either change in Ca or pH. Greenhouse and field experiments were initiated to determine the effects of independent changes in soil Ca and pH on the nodulation of white and red clover using a Gilpin series silt loam soil from New, WV. For greenhouse studies, soil was amended with CaSO4, CaCO3 or a mixture of the 2 Ca sources to increase soil Ca by 300 and 600 mg Ca kg -1 soil (dry weight). White clover seedlings were grown for 30 days in amended soils. There was a strong curvilinear relationship between the number of nodules per plant and soil pH. There was no relationship between soil Ca and nodules per plant. In 1995, field plots were fertilized with lime or different types of coal combustion by-products (CCB) to supply Ca. Plots were seeded to orchardgrass and tall fescue. In the early of 1998, plots were subdivided and drilled with either red or white clover. All treatments had received N, P and K fertilization. One treatment had received 4600 kg/ha of dolomitic limestone, another treatment received 8000 kg/ha of CCB gypsum (5 % Ca carbonate equivalent), and another treatment received both. The fourth treatment received no Ca containing amendments. When the clovers were planted, the soil in these four treatments had varying soil Ca and pH values. In May and August of 1998 and May of 1999, cores of soils 10 cm in diameter to a depth of 10 cm were removed from the clover rows. The primary roots of plants were washed free of soils and nodules counted. At all three sampling dates, number of nodules per primary root was associated with soil pH and not soil Ca.