Contribution of arbuscular mycorrhiza inoculation on the growth and phosphorus nutrition of jatropha (Jatropha curcas) in degraded upland soils of Samar, Philippines

摘要

Pot culture experiments were conducted to evaluate the effects of arbuscular mycorrhiza (AM) inoculation and NPK fertilization on the growth and phosphorus nutrition of Jatropha curcas in degraded upland soils from Samar, Philippines. Treatment combination of AM inoculation x P application, and AM inoculation x levels of NPK fertilization were evaluated. Results showed that arbuscular mycorrhiza and phosphorus application enhanced the growth and yield of jatropha and increased P uptake compared to those treatments without AM or P application. Plants treated with 15kg NPK/ha + AM, 30kg NPK/ha+ AM and 60kg NPK/ha were taller and have higher dry matter yield compared to the non-fertilized, non inoculated control. The P concentration and uptake was higher in AM inoculated plants than those without AM even at higher NPK application rates. Analyses of the rhizosphere soil contained higher water soluble P and 0.1M HCL extractable P in AM inoculated pots indicating higher P availability due to AM inoculation and higher microbial activity as estimated by acid phosphatase levels in soils compared with that of the bulk soil or the uninoculated control.