Circulation Culture of Tomato for Efficient Nutrient Uptake and High Yield in Tropical Greenhouses

The rate of nutrient uptake and resultant yields  of tomato (Lycopersicon esculentum Mill), grown in protected culture at different rates and methods of water and  fertilizer applications were tested in a tropical environment.  The experiment was conducted  in a naturally ventilated glasshouse under hot and humid conditions where the mean daytime  temperature and evapo-transpiration rate (ET) in the greenhouse were 29±3.7°C and  65.6±4.7 mm/day, respectively. The standard irrigation method (T1) was subjected to  changes by adjusting supply volume to 150 % of ET (T2 and T4) and doubling the standard  volume together with drainage collection and re-circulation (T3). Standard soluble  inorganic fertilizer dosage (in T1 and T2) was adjusted to T3 by doubling the dosage of  essential plant nutrients, except N and Ca from the early fruit development (12 weeks after  planting). Inorganic fertilizer dosage was completely replaced with phospho-compost and  foliar application of plant extracts (T4). Plant and medium samples were tested for N, P and  K compositions.  Electrical conductivity and pH drifts in media and  leacheate were also  determined. Results revealed the necessity of excess irrigation from the flower initiation  stage of tomato preferably in the form of circulation culture. Significantly high N and P  nutrition together with adequate K improved the fruit growth and yield. Overall yields were  below the recorded averages due to hot, humid and overcast conditions. Further  improvements are needed for K nutrition in the circulation culture of soluble fertilizers and  for N nutrition in phospho-compost supplemented plant nutrient supply.

Tropical Agricultural Research Vol. 23 (3): 204-217 (2012)

DOI: http://dx.doi.org/10.4038/tar.v23i3.4658