Fescue sod suppresses young pecan tree growth

Abstract

Newly planted pecan (Carya illinoinensis Wangenh. C. Koch) trees were grown for 3 years in a tall fescue (Festuca arundinacea Shreb. cv. Kentucky 31) sod with vegetation-free circles 0, 0.91, 1.83, 3.66, or 7.32 m in diameter. Trees were irrigated to minimize growth differences associated with water competition from fescue. There were no differences among treatments in total shoot growth after 1 year, but trunk growth was increased by vegetation-free areas. During the second year, trees with a 0.91-m-wide vegetation-free area had twice as much shoot growth, and trunks were twice the size of those without a vegetation-free zone. The third year, trees with a 0.91-m-wide vegetation-free circle had 403% more new shoot growth, and trunks were 202% larger than those without a vegetation-free zone. Cumulative shoot growth was up to 559% greater with vegetation control. Tree growth was similar with a 1.83- or 3.66-m-wide vegetation-free circle, and trees in both treatments were larger than trees with 0- or 0.91-m-wide vegetation-free zones. Extending the vegetation-free zone to 7.32 m wide was not advantageous.