Application of Controlled Release Fertilizers in Iceburg Lettuce to Reduce Fertilizer Consumption
Hsieh M. H., W. J. Jiang, and C. W. Lin
Iceburg lettuce is the second largest vegetable for export, with an average exceeding 10,000 tons per year in Taiwan. According to the results of previous studies, using a controlled release fertilizer can reduce the number of applications from three to one in a whole period of iceberg lettuce cultivation, which reduces the impacts of labor shortages. However, controlled release fertilizer will increase the soil EC and its price is higher than traditional fertilizer. To overcome these problems, we evaluated the effects on heading characteristics and soil fertility by reducing the application amount. Results showed that the soil EC value of a 50% application was significantly less than those of a full application and a traditional fertilizing treatment in winter cropping. Additionally, its average head weight was above 530 grams. In spring cropping, the soil EC values were similar for 50% and 80% applications of controlled release fertilizer, and a traditional fertilizing treatment. The average head weight was above 470 grams and no tip-burn occurred in the 50% application. This research has proven that the 50% application of controlled release fertilizers can maintain the average head weight, the standard traits of sphericity and tightness, and decreased the fertilizer consumption by at least 50%.
What is already known on this subject?
The previous research has proven that the application of the controlled release fertilizers increased yield as well as soil EC. However, the higher cost of the controlled release fertilizers is still the main issue.
What are the new findings?
This research has proven that the 50% application of controlled release fertilizers can maintain the average head weight, the standard traits of sphericity and tightness, and decreased the fertilizer consumption by at least 50%.
What is the expected impact on this field?
The impacts of the higher cost of controlled release fertilizers has been overcome by using a 50% application. The controlled release fertilizers use can be realized in iceberg lettuce cultivation for exportation and increase the competitiveness of the export vegetable industry.
Key words: Iceberg Lettuce, Controlled Release
Fertilizers, Reduce Fertilizer
Accepted for publication: June 25, 2015