The effect of lime and of certain fertilizer constituents on the yield and composition of the herbage from pasture plats at Beltsville, Maryland

The yield and composition data for the 1930 and 1931 pasture mixtures are presented in such a way as to show the effects of an initial application of 4 tons of limestone per acre in addition to annual applications of certain fertilizer elements on the yields and percentages of dry matter, crude protein, calcium, and phosphorus. Data for Kentucky bluegrass and white clover are presented to show the effects of annual applications of nitrogen, phosphorus, and potassium on the composition of these plants in pure stands. In general the yield is influenced to a greater extent than the composition. These results should be evaluated with due regard to the amount and distribution of rainfall in the different years. Lime applied in the fall of 1928 increased the average yield per acre in 1930 and 1931, respectively, as follows: Dry matter, 9.53% and 20.69%; protein, 14.66% and 22.5%; calcium, 34.61% and 53.99%; and phosphorus, 11.23% and 37.58%. In each case the percentage difference is calculated on the average of the unlimed plats. Among the several treatments nitrogen alone and potassium alone, both of which yielded well in the series of treatments without lime, gave either small or negative response to lime. In fact no other treatments gave smaller yields with than without lime. Treatments NP and PK, both of which yielded poorly in the unlimed series, gave the largest increases due to lime. The application of lime had little effect on the chemical composition except in the percentage of calcium which was 0.46 in the herbage of the unlimed and 0.56 in that of the limed plats in 1930, and in the same order 0.42 and 0.52 in 1931. The phosphorus content was unchanged by lime in 1930, but in 1931 there was 0.39% of phosphorus in the herbage from the unlimed plats and 0.46% in that from the limed plats. The effects on the chemical composition of the herbage of including nitrate of soda, superphosphate, or muriate of potash in the treatments of pure stands of Kentucky bluegrass are as follows: Applications of a nitrogen containing fertilizer increased the percentage of crude protein in the crop but apparently had a depressing effect on the calcium content of the herbage. The presence of superphosphate in the fertilizer increased both the phosphorus and calcium contents of the herbage.