Nitrogen, Potassium, and Nitrate Concentrations of Lettuce Grown in a Substrate with KNO3-Enriched Zeolite
The research paper investigates the effects of potassium nitrate (KNO3)-enriched zeolite on the nitrogen (N), potassium (K), and nitrate (NO3-N) concentrations in lettuce (Lactuca sativa) grown in a controlled substrate environment. The research was conducted in a greenhouse using a completely randomized block design with three replications, testing various levels of enriched zeolite (20, 40, 80, and 160 g per pot) against a control group that received no zeolite.
The study found that the addition of KNO3-enriched zeolite significantly increased the concentrations of total N, total K, and NO3-N in the lettuce shoots. Specifically, the highest N concentration (33.6 g kg−1) was observed at the maximum zeolite dose, which was 22% greater than the control. However, the K concentration (36.7 g kg−1) was deemed low compared to the recommended levels for optimal lettuce growth.
The research also highlighted a critical finding regarding nitrate accumulation, noting that the maximum NO3-N concentration (3,798 mg kg−1) occurred at a zeolite dose of 138 g per plant, exceeding the European community's safe limit of 3,000 mg kg−1. To maintain safe nitrate levels for human consumption, the authors recommend a maximum application of 78 g of KNO3-enriched zeolite per plant.
The study concludes that while KNO3-enriched zeolite can effectively supply essential nutrients to lettuce, careful management of application rates is necessary to prevent excessive nitrate accumulation, which poses health risks.
This research paper is significant in the field of agricultural science, particularly in the study of nutrient management and plant growth in controlled environments. It contributes to ongoing discussions about sustainable agricultural practices by exploring the use of zeolite as a nutrient source, which can enhance nutrient efficiency and reduce environmental impacts associated with traditional fertilizers. The findings are particularly relevant for hydroponic and greenhouse growers who seek to optimize plant nutrition while ensuring food safety. By providing evidence-based recommendations for zeolite application, the article offers practical benefits to researchers, agronomists, and farmers aiming to improve crop quality and safety.
