Oxygation enhanced pineapple yield and quality

Oxygation, understood as the use of aerated irrigation water with sub-surface drip irrigation, has been documented to benefit growth of a range of crops, particularly on heavier soils. For this research, this technology was applied to pineapple (Ananas comosus) on a loamy sand at Yeppoon, Australia. Two treatments, irrigation with and without oxygation (12% air by volume of water), were evaluated in a replicated randomised block layout. For each of seven replicates, two sampling areas each of 4 m linear row length were established. The crop was planted on the 24 October 2007, and oxygation treatment commenced 90 days after transplanting (DAT), and continued until harvest. Total amount of irrigation water applied to the oxygation and control plot was 1.09 and 1.24 ML/ha respectively, because mixing air replace the water volume during irrigation, hence reduced water emission from oxygation plots by 12% compared to the control over the same irigation period. Most crop water demand (19.63 ML/ha) was supplied by rainfall. The first season crop fruit was harvested from January 2009. Total fruit yield of the sampling area for the oxygation treatment was 17% higher than that of the control, however, the industry yield, which accounted for only the marketable component of the yield, was higher only by 4.24% for the oxygation compared to the control. Such higher yield in the oxygation in the sampling area was attributed to larger average fruit size in the oxygation compared to the control (1493 vs 1279 g/fruit). Fruit total soluble solids were only slightly higher (0.16 °brix units) than that of irrigated control fruit. The first season crop occurred during a period of good rainfall, and the small yield difference between rainfed and irrigated treatments suggests that soil water was not a major limiting factor during growth of this crop. The crop is currently ratooning and we expect greater effects of oxygation on the next harvest, as lower rainfall amounts are already occuring. We conclude that oxygation can improve both yield and quality of pineapple at the field scale operation, the extent determined by the amount of irrigation required by the crop.