This study was conducted to investigate the effects of controlled-release fertilizers and wick addition to the root-zone on plant growth and yield of medium-fruit sized tomato up to the 18(th) truss in long-term forcing culture. The set-up consisted of a box partitioned by a board into two halves, named box 1 and box 2. Box 1 contained 2.8 ℓ of growth medium (soil : bark : perlite : peat=2 : 2 : 1 : 1). Plant was grown in box 1 with a capillary wick, and at flowering of the 8(th) truss, the partition was removed and box 2 filled with 2.8 ℓ of the medium. There were two treatments, with or without capillary wick in box 2, namely, single wick (S) and double wicks (D). Plant height was greater in D than S in January, and the difference increased gradually thereafter. Flowering time of 18(th) truss in D was 10 days earlier and decapitated shoot weight was twice that of S. Fruit yield per plant was 8 kg in S and 9 kg in D with similar value of Brix and titratable acidity. There was no difference between S and D in dry root weight (7g/plant) or in xylem exudates (8ml/h), while in S in April plant growth was inferior, leaf color yellow greenish and fruit colour uneven towards the end of growth of plants. Xylem sap analysis showed that NO(3)-N was 10 me/ℓ in S and 6 me/ℓ in D. This concentration is weaker than that of Enshi standard nutrient solution generally used in hydroponics. These results suggest that application of controlled-release fertilizers and wick addition to box 2 with root-zone extended was effective for plant growth performance and fruit yield.
combination of fertilizer
medium-fruit sized tomato