აზოტიანი სასუქის ფორმების გავლენა ურეაზის აქტივობაზე მანდარინის ფოთლებში

Abstract

Mandarin trees (cultivar unspecified) planted in 1969 received 6 fertilizer treatments viz. an unfertilized control, PK + CaO as a basal dressing, and a basal dressing plus N in 5 different forms. Urease activity in the leaves was determined before and after treatment. Urease activity increased on the second day after fertilizer application; it remained at that level for a further 2 days and then declined. A high level of urease activity was noted in leaves of trees fertilized with a urea-formaldehyde fertilizer (U-FF) and this was attributed to a uniform uptake of urea by the trees. It is suggested that in humid subtropical conditions a U-FF is the best N source for citrus trees.