Effects of Azospirillum inoculation on N2 fixation and growth of oil palm plantlets at nursery stage

• Main Authors: Ahmad Ghazali, Amir Hamzah, Shamsuddin, Zulkifli, Mohd Saud, Halimi, Ramlan, Mohd Fauzi, Mahmood, Maziah
• Format: Article
• Language: English
• Published: Malaysian Palm Oil Board 2001
• Online Access: http://psasir.upm.edu.my/id/eprint/22432/1/0000.pdf; http://psasir.upm.edu.my/id/eprint/22432/; http://jopr.mpob.gov.my/effects-of-azospirillum-inoculation-on-n2-fixation-and-growth-of-oil-palm-plantlets-at-nursery-stage/

Nitrogen fertilizer is the most expensive nutrient input in oil palm production, with an average total nitrogen fertilizer cost estimated at RM 470 mil­lion yr–1. The use of nitrogen fixing bacteria (e.g. Azospirillum spp.) as a biofertilizer and bioenhancer can reduce the production cost of this crop. A glasshouse experiment was undertaken to observe the effects of Azospirillum inoculation on N, fixation, plant growth and photosynthetic rate of the host plant. This experiment was conducted in undrained pots with 15N labelled Selangor series soil and each pot was planted with a two-month-old oil palm plantlet (MPOB clone, P149). Three treatments were applied: 1) control [+ killed inoculum (Sp7)], 2) Azospirillum brasilense (Sp7) inoc­u­la­tion and 3) A. lipoferum (CCM 3863) inoculation. This experiment was laid out in a ran­dom­ized com­plete block design with four repli­ca­tions and har­vested four months after plant­ing. Two weeks before har­vest, the first fully expanded leaf from each seedling was analysed for light and CO2 response using a closed sys­tem of portable infrared gas analyser. At har­vest, the plantlets were sep­a­rated into tops and roots, dried, weighed and ground for total nitro­gen and 15N analyses. Results showed that Azospirillum inoc­u­la­tion contributed up to 40% of the total nitro­gen require­ment of the oil palm plantlets, stim­u­lated top and root growth by 30% and 60%, respec­tively and increased the host pho­to­syn­thetic rates com­pared to the con­trol. Azospirillum (Sp7 and CCM 3863) is a poten­tial biofertilizer and bioenhancer for sustain­able oil palm plant­let cul­ti­va­tion and saves cost on nitro­gen fertilizer.