Rates and Methods of Application of Nitrogen and Phosphorus for Commercial Field Production of Head Lettuce in Southcentral Alaska

摘要

Head lettuce (Lactuca sativa L.) is one of the majorud-- agricultural crops grown in Alaska. In 1992, its wholesaleud-- value was approximately $314,000, second only toud-- potatoes among Alaska’s commercially field grownud-- vegetables (Brown et al., 1992).ud-- The quality of head lettuce is as important as yield,ud-- as lettuce heads that do not meet minimum size andud-- weight standards are unmarketable. Head size andud-- weight are strongly influenced by management practices,ud-- dictating a high level of management for successfulud-- commercial production. Among manageableud-- cultural variables, rate of fertilizer application and theud-- method of fertilizer placement are two of the most critical.ud-- Despite the value of the head lettuce crop to Alaskaud-- vegetable growers and the importance of fertilizationud-- as a management practice, little research has been publishedud-- on rates of application and method of applyingud-- nitrogen and phosphorus to commercially grown headud-- lettuce.