Contribution of Nitrogen from Biofertilizer Inoculum to Young Oil Palm under Field Conditions

摘要

Continuous and excessive use of chemical fertilizers leads to deterioration of soil and environmental health especially under tropical dimates which could accelerate losses of nutrients in the soil through leaching and other processes. The use of plant growth-promoting rhizobacteria (PGPR) as a biofertilizer inoculant could potentially mitigate the problem. However, the effectiveness of microbial inoculants in the field is still questionable. The present study was conducted on young oil palms to compare the contribution of nitrogen (N) through N2 fixation from a PGPR biofertilizer with that from chemical fertilizer using the nitrogen-15 (15N) isotopic dilution method. The results indicated that inoculated young oil palm accumulated 63.4 percent N through the activities of biofertilizer microorganisms, similar to un-inoculated young oil palms which were fertilized totally by chemical fertilizer and accumulated 58.8 percent N. Therefore, biofertilizer inoculant can be potentially exploited for improving food crop productivity and environmental health.