The Effect of Lime and of Certain Fertilizer Constituents on the Yield and Composition of the Herbage from Pasture Plats at Beltsville, Maryland 1

The field in which thi~ experiment is located had previously one application of manure, but the rate and date are not known. In the spring of ~ 928 nitrate of soda w~s applied to a corn crop at the rate of approximately ~ oo pounds per acre. The area used for the experiment is divided into 25 plats ~ 2 feet wide and 96 feet long, exclusive of the end borders. The arrangement and treatment of the plats is shown in Fig. ~. Before the plats were seeded all but ~, ~3, and 25 were treated with ground limestone at the rate of 4 tons per acre. The fertilizers are applied annually at the following rates per acre: N, 24 pounds; P, 54 pounds of P~O~; and K, 5o pounds of K~O. These amounts are applied in the spring as nitrate of soda, superphosphate, and muriate of potash, except that the first application was made shortly before the grasses were seeded in the fall of ~928 and differed from the subsequent ones in that sulfate of potash was used instead of the chloride and that the nitrate of soda was applied half in the fall of ~928 and half in the sprng of ~929. No other fertilizers were put on in ~929 and the spring treatments began in ~93o. The fertilizer treatments extend across all of the plats in such a way as to divide them into eight equal sub-plats, each ~ 2 feet wide and ~ 7.75 feet long. A border ~ 5 inches wide (one-half of the lawn mower width) is cut off each side and there remains about ~/3ooth of an acre from which the samples are harvested._ The grasses were sown in October, ~928, and the legumes the following spring. The samples were obtained by mowing the plats with a lawn mower as often as the growth reached a height of about 3 inches. From the harvest thus obtained two samples of about 2 pounds each were taken. If there was not enough material for two samples, the entire harvest was used for the sample. All of the samples were dried in a ventilated room which was kept at 35° to 45°C. This usually required about 4 days. The dried samples were then stored in a rodentproof and well-ventilated loft. One sample was used for the determination of total moisture. The sample for the chemical analysis was ground through a ~-mm screen in a Wiley laboratory mill and mixed in a 5-pound MacLellan batch mixer. Two pint fruit jars (glass topped) were filled with the mixed sample. One jar served an emergency reserve supply. As far as possible, all of the portions of the sample for use in making the analyses were weighed out at one sitting and either placed in the appropriate vessels or stored in