Fertilizer Effects on Botanical and Chemical Composition of White Clover‐Dallisgrass Associations Grown on Sumter Clay 1

THROUGH use of fertilizers and proper seeding, excellent white clover-Dallisgrass pastures can be established on Sumter clay in the Black Belt of Alabama. However, after a few years of production, the white clover population tends to disappear. In general, the persistence of clovers in mixtures with grasses is known to be influenced by many factors that can be classified as climatic, cultural and biological in nature. Information available on magnitude of the effect of specific factors in each category is insufficient to permit definite recommendations to be made. Blaser and Brady (I) have reported results indicating that nitrogen and potash fertilization definitely affected the botanical composition of Ladino clover and non-legume associations. They found that potassium stimulated the growth of Ladino clover, but it did not directly affect the productivity of the non-leguminous plants in the association. Nitrogen fertilizers increased the growth of grasses and decreased the growth of leguminous plants. As the growth of grasses was increased, the amount of potassium removed by the grasses was increased. Hence, the concurrent and/or after effect of nitrogen reducing the leguminous associate was attributed to competition for potassium. In earlier studies Rich and Odland (6) reported that a reduction in potash fertilization lowered the proportion of legumes in grass-legume hay. However, Brown (2) reported that potash added to either superphosphate or superphosphate and limestone did not greatly affect the amount of white clover in a clover-grass sod. Robinson and Sprague (7) found that high rates of nitrogen fertilization without irrigation greatly decreased the stand of clover in white clover-Kentucky bluegrass sod. On plots clipped to 2 inches the clover was practically eliminated, but with more severe clipping treatments, considerable amounts of clover were maintained even with