Long-term effects of sod competition on peach yield

Excessive vegetative growth in peach (Prunus persica) causes canopy shading that reduces fruit bud initiation in the canopy interior and increases pruning costs and time. Sod competition can reduce pruning but may also reduce yield. The objective of the present study was to measure the effects of increased sod competition [2- vs. 8-ft-wide vegetation-free areas (VFA)] on yield and quality of irrigated peach. Total pruning weight was reduced by sod competition in the first 4 of 7 cropping years. Subsequent years indicated no effect on vegetative growth due to sod competition. Annual increase in trunk cross-sectional area was reduced by sod competition in the first year of cropping and unaffected in subsequent years. Canopy development was reduced by sod competition in the first 2 years of cropping, which increased photosynthetically active radiation transmission through the canopy and increased fruit red color in the first year. The width of the VFA did not alter the relationship between total fruit number and total yield in any year; however, the total number of fruit per tree was reduced in all years and total yield was reduced in 6 of 7 years. Results suggest that dormant season pruning was removing a higher percentage of the crop bearing wood from the 2-ft VFA compared with the 8-ft VFA treatment, resulting in reduced yield per unit of dormant pruning. This indicates that pruning practices must be modified to leave more bearing wood in mature trees to maintain yield potential when sod competition is used to control vegetative growth.