Documenting Nutrient Deficiency and Accumulation Rate in Vegetables

Whenever crops are supplied with sub- or supra-optimal rates of macro and micronutrients, the impact on the yield can be drastic. The measurement of days needed to develop visual deficiency or toxicity symptoms indicates the sensitivity of the crop to a particular nutrient. Information generated in this on-going greenhouse project provides a unique and invaluable tool for technical personnel and growers to visually diagnose plant nutrition problems. Consequently, better nutrient management can increase the efficient use of fertilizer to increase the yield and quality of fruits and vegetables. The findings of this study provide the necessary information to develop guidelines for more precise nutrient management for these frequently overlooked crops. The entire study is conducted in the greenhouse by growing plants with a carefully controlled hydroponic system. The treatments are made with specially formulated nutrient solution using reagent grade chemicals and 18 megaohms purity water to eliminate any confounding errors. To date, we have documented and photographed nutrient deficiency symptoms as the symptoms appear for blueberry, coffee, cucumber, romaine lettuce, okra, eggplant, squash, and papaya at the vegetative stage.

The documentation of nutrient deficiency and toxicity symptoms for coffee, an important beverage plant consumed globally, was recently completed. With the world’s growing demand for coffee, there are initiatives to address the specific nutrient need for coffee production by small-sized farms. In coffee, unlike most species, the visual N deficiency symptoms developed first on the young leaves and not on older leaves. In blueberry, the mature leaves developed unique visual symptoms of blackened veins as a result of NH₃ toxicity under high alkalinity. There is special interest in the blueberry research since the acreage of this crop is rapidly expanding across North and South America. The results of the blueberry study have been presented at various regional conferences. On-going work involves studying the impact of macro and micronutrient at sub- and supra-optimal levels at fruiting stage for squash, eggplant, cucumber and okra. This work is a continuation of previous collaboration to document nutrient deficiency symptoms of the often overlooked vegetable and fruit crops. The photographs are added to the IPNI Deficiency Symptom collection.