Developing a nitrogen application curve for spray chrysanthemums grown in hydroponic system and its practical use in NFT system

Spray chrysanthemums 'Talk' (autumn-nowering type) were grown in a hydropon ic system with N supply maintained at high levels. The plant growth, N upta ke, and cut flower quality were subsequently evaluated in relation to 3 dif ferent planting dates. Fresh plant weight and N uptake increased throughout the growing period but at a decreasing rate towards harvest. Shoot lengths and weights ranged fro m 92 similar to 112cm and 85 similar to 97g, respectively. Comparison revea led that the cut flowers were longer and heavier than a standard of best gr ade in the market. Based on N uptake and plant growth, a down-regulated N a pplication curve (NAC) was developed for producing economically marketable cut flowers. To produce a plant having two shoots of 70g, which is probably suitable for the market, 954 similar to 1142mg N fertilizer was computed t o be appropriate. Using the NAC, spray chrysanthemum 'Talk' was grown in Nutrient Film Techni que (NFT) system. Under 0.8 and 1.0 strengths of NAG, the mean shoot length s and weights were greater than or equal to 94.2 cm and greater than or equ al to 65.6g, respectively, yielding more than 64% of best grade cut flowers . At NAC 0.8 and 1.0 strengths, 90 similar to 100% N, 90 similar to 98% P a nd K of applied amounts were consumed, thus confirming an efficient uptake of these nutrients. Consequently, the nutrient application based on 0.8 sim ilar to 1.0 strengths of NAC could produce economically marketable autumn-f lowering spray chrysanthemums.