Mark V. Yelanich

Fertilization Regimes Exceed Nutritional Requirements of Greenhouse crops

Abstract Nutrient solutions formulated for production of many vegetable and flower crops have been developed with a large margin of error to ensure crops are never deficient in any element. Such a nutritional approach results in low nutrient utilization efficiency and waste of nutrient. Over the past 10 years nutrient solution concentrations used in some commercial production have been reduced up to 50%. It is unknown to what extent uptake efficiencies can be improved by further reductions in nutrient concentration. This experiment compared nutrient uptake with nutrient delivery and found nutrient uptake to be less than 50% for most nutrients even though nutrient delivery concentration was significantly lower than typically recommended in vegetable and flower production. These results as well as experience on many other crops shows constant delivery of lower concentrations of nutrients produces acceptable crops and suggests that there maybe room for additional reductions to improve uptake efficiency.