Performance of Acacia Tortilis, Prosopis Juliflora and Casuarina Equisetifolia Provenances in Soils Low in Phosphorus

Abstract

Acacia tortilis, Prosopis juliflora and Casuarina equisetifolia provenances were screened to determine their potential for adaptability under P limiting conditions as a strategy to exploit genotypic differences in terms of utilization and uptake efficiencies. The experiment was conducted in the greenhouse at the Kenya Forestry Research Institute using soils taken from the field which are critically low in available phosphorus (P). The experimental treatments comprised of P application at 0 and 60 Kg P205/ha for 11 provenances of Acacia, 6 Prosopis and 4 Casuarina spp. Trait for adaptability to P deficiency was determined by measuring the growth performance, P uptake and utilization efficiencies at zero and moderate application of P. The results indicated considerable differences in the growth performance and Phosphorus use efficiency (PUE). Acacia provenances showed the highest PUE compared with Prosopis and Casuarina spp although “this was not reflected in the total dry matter yield. However, it was observed that P application resulted in an increase in shoot dry matter, height, root collar diameter and root dry matter in case of Casuarina. Similarly, the highest total P uptake was obtained in Casuarina and Prosopis spp. The results further indicated that P application probably contributed to the reduction in root, dry matter and root:shoot ratios of Acacia and Prosopis but not Casuarina spp.