Optimizing tomato mineral nutrition using biologically active compounds

This study examines the optimization of mineral nutrition for greenhouse tomato cultivated under low-volume technology through adjustments in nutrient solution composition and foliar applications of biologically active compounds. The investigations were conducted during extended production cycles. The experimental nutrient regimen involved modifications of macro- and mesoelement concentrations to enhance plant nutrient availability. The biologically active compounds included glutamic acid, aspartic acid, 4-chlorophenoxyacetic acid, kinetin and 2-diethylaminoethyl hexanoate. The optimization of nitrogen, potassium and calcium content in the experimental nutrient solution, combined with systematic application of bioactive compounds, activated the endogenous regulatory system and plant metabolism. This manifested in enhanced metabolic processes and improved growth and development parameters of tomato plants. Cultivation under the experimental nutrient regimen resulted in increased photosynthetic rate by 5 mg CO?/dm?/h compared to standard scheme and improved yield by 4.4 kg/m?. Experimental data demonstrate that application of the studied compaunds influenced the hormonal status of plants and stimulated metabolic processes: (a) photosynthetic rate increased by 20.0 mg CO?/dm?/h and (b) transpiration rate increased by 1 g/m?/h compared to untreated controls. Implementation of biologically active compounds in low-volume tomato production technology led to weekly plant height increase of 0.7-3.1 cm. Moreover, the average fruit weight increased by 7-24 g. Finally, total yield improved by 3.1-5.2 kg/m? per production cycle. The maximum treatment effects were achieved with foliar applications of 2-diethylaminoethyl hexanoate.