By Ashley Robinson
A shortage of nitrogen is the most common reason for a cabbage crop not reaching its full yield potential. However, applying too much nitrogen may cause more harm than good. It’s important to determine the optimal rate for production.
Researchers at the University of Georgia (UGA) and the University of Florida are working in collaboration to conduct trials investigating the optimal rates of nitrogen fertilizer to produce cabbage. According to Andre da Silva, UGA Cooperative Extension vegetable specialist, the recommendations for fertility programs in Florida and Georgia were developed in the 1980s.
“We were really in need of an update,” says da Silva. “Especially since new varieties have been introduced.”
According to da Silva, the study has taken place over the last four years and was tested in six different cabbage varieties.
“Two years of the project were conducted in Florida’s sandy soils, then we repeated the trials for another two years in Georgia’s loam sandy soil to compare,” da Silva said.
During the study, researchers looked at the effects of applying a total nitrogen fertilizer rate of 107, 225 and 280 pounds per acre. Current recommendations suggest applying between 150-200 pounds of nitrogen per acre. But after harvest, researchers found that applying 225 pounds of nitrogen per acre produced optimal yields.
According to da Silva, the results were the same for Florida and Georgia and in all six cabbage varieties. He also mentioned that there was no significant impact on yield between applying 225 pounds of nitrogen per acre and 280 pounds. However, he recommends growers apply 225 pounds per acre to maintain yields and increase profits.
Although 225 pounds of nitrogen per acre seems to be the magic number, applications may need to be adjusted depending on weather conditions.
“We found that in rainy years, we experienced a significant loss of nitrogen due to leaching. In this case, growers may need to bump up their fertility program,” da Silva said.