Growth ofStylosanthesspp. as spaced plants at eight sites in Rhodesia

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Abstract
As part of a programme to test the suitability of Stylosanthes spp. for Rhodesian conditions, plants of seven strains covering three species of this genus were grown at eight sites in Rhodesia. The seven strains were 5. guya‐nensis (erect, intermediate and fine‐stem), S. humilis (early, mid‐season and late‐mid‐season) and S. fruticosa. The eight sites ranged in altitude from 1 160 to 1 860 m and in average annual rainfall from 670 to 1 010 mm. Soil types ranged from clay to loamy sand. The seedlings were germinated in a glasshouse and were transplanted in early to mid‐December. At harvest in mid‐May selected plants were separated into leaf, stem and inflorescence before all were dried and weighed. The species flowered in the order S. fruticosa, S. humilis and S. guyanensis but the mid‐season cultivar of S. humilis generally flowered before the reputedly early strain. The fine‐stem form of S. guyanensis did not flower at the three highest sites. The percentage of plants surviving to harvest was inversely related to the clay content of the soil. For the surviving plants, there was a marked interaction on mean plant mass between site and strain. This interaction was largely the result of the differing reaction of the strains to extremely favourable or unfavourable sites but there were anomalies which could not be explained in terms of obvious soil or climatic differences. S. guyanensis strains produced the heaviest plants at all sites. S. humilis tended to have a lower proportion of leaf, and a higher proportion of inflorescence, than the perennial species. Analysis of the plants of one strain from all sites indicated possible deficiencies of phosphorus, calcium and sulphur.