Effect of using Azolla (Azolla microphylla) in Combination with Nitrogen Fertilizer on Growth and Nutrient Content in Leaf of Oil Palm.

Abstract

The use of azolla as green manure corporated with chemical fertilizer was studied in new oil palm in October 2011 to September 2013 at Nongsuea district, Pathumthani province. Experimental design was Randomized Completely Block design with 4
replications and 5 treatments 1) nitrogen fertilizer application rate recommendation (1N) 2)
nitrogen fertilizer (recommendation rate) with azolla (1N + A) 3) nitrogen fertilizer 0.75 time of recommendation rate with azolla (0.75N + A) 4) nitrogen fertilizer 0.50 time of recommendation rate with azolla (0.50N + A) 5) nitrogen fertilizer 0.25 time of
recommendation rate with azolla (0.25N + A). At 28 months old of oil palm, results showed that the combination of nitrogen fertilizer at recommendation rate with azolla caused the fastest growth in oil palm. The number of frond was 18.17 per 6 months, leaf
area was 5.78 m2/plant, frond length was 327 cm2/plant and nitrogen content in leaf at
a level sufficient for the growth of plant was 2.68 %. However, the growth of plants was not significantly different from application of nitrogen fertilizer at recommendation rate treatment. The number of frond was 17.41 per 6 months, leaf area was 5.54 m2/plant, frond length was 316 cm2/plant and nitrogen content in leaf was 2.68 %. The combination of nitrogen fertilizer 0.50 and 0.25 of recommendation rate with azolla caused the oil palm grow slower than other treatments and was not different from the control group. The number of frond was 16.10 and 15.25 per 6 months and nitrogen content in leaf was not enough for the growth of plant was 2.50 and 2.29 %