Growth response of Grevillea robusta A. Cunn. seedlings to phosphorus fertilization in acid soils from Kenya

Biotechnologie, Agronomie, Société et Environnement

关键词: grevillea-robusta;    fertilization;    phosphate-fertilizers;    phosphorus;    tracer-techniques;    plant-response;    growth;    acrisols;    andosols;    vesicular-arbuscular-mycorrhizae;    roots;    weight;    field-experimentation;    kenya;    africa;    africa-south-of-sahara;    biological-development;    east-africa;    elements;    experimentation;    fertilizers;    genetic-soil-types;    grevillea;    mycorrhizae;    nonmetals;    physiological-functions;    plant-anatomy;    plant-physiology;    plant-vegetative-organs;    proteaceae;    reproduction;    sexual-reproduction;    soil-types;    symbionts;   

DOI  :  

来源: DOAJ

【 摘 要 】

Three experiments were conducted to assess the response of Grevillea robusta to phosphorus fertilization using acid soils showing low P levels from Eastern (Gituamba-Andosols) and Western (Kakamega-Acrisols) Kenya. In the first experiment P was applied as Minjingu phosphate rock (MPR- 13/P) at 0, 52 and 77 kg P per ha into 5 kg of soil. In the second experiment 2 g vesicular arbuscular mycorrhizae (VAM) soil + root inoculum per 5 kg soil was included in addition to the same MPR rates using Kakamega soil only. In the third experiment, MPR and triple superphosphate (TSP) were added to 5 kg Kakamega soil at a rate of 25.8 mg P per kg soil, and 32P isotope dilution techniques were used to assess P uptake in the shoot harvested at 3 and 6 MAT (months after transplanting). Application of MPR to the Andosol reduced height and root collar diameter of G. robusta significantly (p < .05) as compared to the control. Significant increases (p < .05) in height and root collar diameter where P was added compared to control were recorded with the Acrisol. Soil interaction with P fertilizer rates was highly significant (p < .001) for both height and root collar diameter growth. The roots were not infected with VAM upon harvesting at 12 months. At 3 MAT the percentage P derived from the MPR and TSP was 3/ and 6/ respectively. P uptake decreased significantly (p < .05) between 3 and 6 months. The results indicated that addition of P fertilizer in the Acrisols was probably required at the early stages of G. robusta growth but further research and particularly root studies are required to ascertain the above observations.

【 授权许可】

Unknown