Influence of Various Rates of Ca(NO3)2 Fertilizer and Soil Management on Young Apple Trees

Abstract

Abstract Calcium nitrate applied annually at rates ranging from 22.5 g actual N per tree (0.5 N, one-half the recommended rate) to 363 g/tree (8 N) and adjusted according to tree age did not influence the growth of 4 apple (Malus domestica Borkh) cultivars (‘Golden Delicious’, ‘Triple Red Delicious’, ‘Red Yorking’, and ‘Stayman 201’) on EM 7a rootstock. There was a significant soil management (herbicide, clean cultivation, or mowed sod) × rate interaction; trees in mowed sod responded to additional N with growth and leaf N levels comparable to the vegetation-free management systems at 4 times (4 N) the recommended rate (45 g N/tree/year age). Soil management and rate of fertilization influenced leaf N levels but not leaf Ca. Leaf N and Ca differed significantly among the 4 cultivars. Cumulative yield after 4 growing seasons was influenced by tree size and soil management, but not rate of fertilization. Soil pH was significantly higher under sod than under cultivated or herbicide strip culture. Soil Ca levels were not affected in the 0 to 30 cm profile. Residual soil NO3-N did not accumulate in the surface 30 cm for any of the management systems except at the highest rate (8 N) under the cultivated and herbicide systems. Data for residual NO3-N in the 0 to 120 cm soil profile indicated that the tree demand and leaching potential for NO3-N was met at the 0.5 N rate when competition was eliminated and between the 2 N and 4 N level in mowed sod.