EFFECTS OF ALLEY SWARD WIDTH, IRRIGATION AND NITROGEN-FERTILIZER ON GROWTH AND YIELD OF COXS ORANGE PIPPIN APPLE-TREES

From 1972 to 1988 an experiment was conducted which investigated the effects of four soil management treatments in combination with two rates of fertiliser application, on the growth and components of yield of Cox's Orange Pippin/MM 106 trees. By four years after planting, trees receiving irrigation and those in uncultivated soil maintained completely bare by herbicide had substantially greater girths than trees growing in narrow and wide bare soil strips between grassed alleys. This effect persisted throughout the life of the orchard, although after 16 years the girths of trees receiving irrigation were much greater than those of trees growing in bare soil. Increasing fertiliser application rate from 63 to 189 kg N ha−1 had either negligible or inconsistent effects on tree growth, fruit yield and size. The cumulative yield of fruit over 12 cropping years was much greater for trees growing in bare soil and for those receiving irrigation than for those growing in the narrow bare‐soil strip system. The increase in tree girth and yield caused by irrigation and bare soil, particularly in dry years, together with the lack of response to the larger rate of fertiliser application, suggests than water was more of a limiting factor than nitrogen supply for this orchard. Irrigation offers an alternative method of management to herbicide for increasing tree growth and fruit yield. Copyright © 1990 John Wiley & Sons, Ltd