To Stop Nitrogen Overdose in Soilless Tomato Crop: A Way to Promote Fruit Quality without Affecting Fruit Yield

Abstract

Precision horticulture is fundamental to ensure high quality production with a minimalenvironmental footprint. It offers the possibility to manage climatic and fertilization inputs closerto the plant needs. In practice, there is a tendency to over‐fertilize, as nitrogen limitation candecrease photosynthesis and consequently fruit yield, but also because nutrient recycling does notlead to any substantial costs increase, thus ignoring the influence of nitrogen input on the balancebetween growth and metabolism. Nitrogen recommendation for tomato greenhouse production onrockwool is 16mM, even it is well established that only 50% of nitrogen amount is really absorbedby plants. This study compares the usual practice (16 mM) to a nitrogen supply to meet plant’sneeds (5 mM). We analyzed plant growth and development, yield, leaf photosynthetic activity andfruit quality (sugars, acids, vitamin C,) over the entire crop period (December to October).Over‐fertilization favoured the accumulation of nitrogen in leaves and stem but yield, leafphotosynthetic activity and plant architecture were not significantly improved. In addition, itdecreased the quality of the tomatoes as the sugar:acid ratio decreased dramatically in the pericarp,whereas the locular gel composition remained similar. A reduction of the nitrogen supply is onesolution to improve tomato quality without any reduction of yield in greenhouse. These data haveto be incorporated in tomato fertigation management to define a new standard based on overallquality of tomato fruit and low environmental footprint.