Formulated Fertilizers Added to Soil-free Media for Tomato Seedlings Grown Under Salt Stress

An orthogonal experiment was conducted on soil-free media with differently formulated fertilizations for cultivating seedlings of Solanumon lycopersicum under salt stress. It aimed to develop an optimally formulated fertilizer that could maximize the resistance to salt stress for the tomato plantlets. The basic medium used in the lab experimentation was a mixture of peat/vermiculite/pearlite in a 3/1/1 ratio by mass. An organic fertilizer, a compounded 15/15/15 NPK fertilizer, or a calcium silicate fertilizer at varied rates was added to the medium. An artificial salinity was created by using a 100 mmol·L^-1 NaCl solution for the planting irrigation, as compared to control with tap water.The morphological and physiological responses of the tomato seedlings under the cultural conditions were observed and compared. The results indicated that the seedlings grown on Medium No.8, which contained NPK fertilizer 5.4 g·kg^-1, organic fertilizer 12.5 g·kg^-1, and calcium silicate fertilizer 0.54 g·kg^-1, showed a growth with high seedling index (1.199), root dry mass (1.00 g·plant^-1), above ground dry biomass (10.70 g·plant^-1), and chlorophyll a/b (1.065 mg·g^-1FW), while those grown on Medium No.4, which consisted of NPK fertilizer 2.70 g·kg^-1, organic fertilizer 6.75 g·kg^-1, and calcium silicate fertilizer 1.08 g·kg^-1, exhibited a relatively high plant height increasing rates and low electrolyte leakages. It appeared that the two combinations for the fertilization as tested might be potentially applicable for the seedling cultivation under salt stress.