Some effects of no cultivation on the yield and growth of citrus trees

Abstract

A factorial field experiment is described in which cultural, irrigation, and nitrogen treatments were tested on citrus trees of different stocks and scions. The sod treatment quickly caused decreases in growth of the trees and the yield and quality of the fruit produced. The plots where bare soil was maintained have given large healthy trees with high yields of good-quality fruit, in spite of an observed deterioration of soil structure in these plots. Nitrogen treatments improved the yield and health of the trees in the sod treatments but have had no effect on the other cultural treatments. Root distribution, soil fertility, and leaf analysis studies, undertaken to try to explain the reasons for the yield differences noted, are described and it is concluded that nitrogen effects could explain all differences recorded to date.