Synopsis Napiergrass, guineagrass, and paragrass responded strongly to annual applications of up to 800 pounds of nitrogen per acre. Protein content and protein yields increased up to the highest N level tested. Yields increased but quality of the forage decreased with length of harvest interval. Between 30,000 and 45,000 pounds of dry matter averaging about 9.5% protein were produced annually per acre.

No abstract

Synopsis Grass yields responded strongly to yearly applications of up to 400 pounds of K per acre and at a slower rate to even higher applications. With 800 pounds of K, exchangeable soil K content was maintained and two‐thirds of the applied K was recovered in the forage. At the 1600‐pound rate, recovery in the forage was reduced but exchangeable soil K content was increased. K content of the forage increased with rates and with yields.

No abstract

Heavily fertilized tropical grasses responded strongly to liming on two typical soils of the Humid Tropics. Liming increased the Ca and decreased the Mn content but did not affect the phosphorus or Mg content of the grasses. Surface applications of limestone were as effective as mixing limestone with the surface soil and one application was as effective as two applications at 2‐year intervals. Exchangeable Al and Mn content of the soils was sharply increased by fertilization alone but was decreased by liming. Base content at all depths sampled was decreased by fertilization alone but was increased by surface liming followed by heavy fertilization. Yields of grasses increased markedly with pH of the upper 6 inches to about 4.8, with bases to 8.0 me. per 100 g. of soil and with decreasing exchangeable Al to 2 me. per 100 g. of soil. Heavy fertilization of grasses over a 4‐year period without liming greatly depressed yields of subsequently planted tobacco and this effect was only partly compensated by reliming prior to planting the tobacco.