The effect of phosphorus and sulphur fertilization on the growth and distribution of dry matter, nitrogen, phosphorus, and sulphur in Townsville stylo (Stylosanthes humilis)

Abstract

The effects of phosphorus and sulphur applications on the growth of Townsville slylo (Stylosanthes humilis) and the redistribution of dry matter, nitrogen, phosphorus, and sulphur in various parts of the plant were examined in a glasshouse experiment. Large yield responses lo phosphorus and sulphur, and a highly significant interaction were obtained. Phosphorus and sulphur deficiency caused a 3-week delay in flowering. The rapid decline in nutrient concentrations both before and after flowering is discussed in relation to the use of critical values. Townsville stylo shows a very marked ability to translocate nutrients to the seed. Adequately fertilized plants contained only 0.02% phosphorus and 0.10% sulphur in the mature leaf, while the seeds contained 0.36% phosphorus and 0.36% sulphur. This is discussed in relation to animal nutrition during the dry season.