This project showed that fall or spring planting was more effective than early summer for establishing grass ground cover between orchard rows. We evaluated a new ground cover option “Low-Grow mix”, a low growing, low maintenance mixture of four fescue seeds compared to OVN at 2 seeding rates and Dutch white clover. In 2012, six GC treatments were seeded early spring at Fowler Farms and utilized lower rates (16 and 22 lbs/acre) for both grass mixtures. There were no consistent benefits of using the new low maintenance mixture of fescue seeds (Low-Grow mix, either using the low or high rates) over two years of continuous observation. Evaluation of weed coverage (%), ground cover coverage (%), and ground cover height (inches) in year 2 and at the beginning of year 3 determined that the Low-Grow Mix is not yet a better replacement to the widely used OVN-Mix. The OVN-mix is still a good grass ground cover alternative and one of the cheapest options if planted early in the spring or late in the summer (August 15-Sept.15) in Northeastern apple fruit regions. Clover was easy to establish. But the disadvantages of using clover include 1) the invasion of clover in the tree rows, 2) herbicides are generally ineffective against clover, 3) clover flowers in the summer will be a problem when growers need to apply insecticides or carbaryl at petal fall for thinning which will affect pollinators.
This project supported the side-by-side demonstration and testing of new herbicide options in new, high density apple plantings compared to some old standard herbicides. No herbicide program in these plots gave season long control. But there were differences in the number of post-emergent herbicide applications required depending on the residual herbicide used in the spring. Irrigation definitely reduces the residual herbicide effect and requires more post-emergence treatments. To evaluate any negative impact of the use of glyphosate in these plantings, 2 treatments used glyphosate for post-emergent control with residual herbicides. No trunk damage was noted in glyphosate treated plots. We compared the resulting tree growth and determined the best treatment for weed control resulted in trunk size twice that in the weedy check. The weed species and growth cycles of the weed populations showed the untreated weedy check plots clearly had the greatest percent weed cover by perennial weeds, and the greatest number of perennial weed species after 2 seasons. A preliminary study of the resulting soil health measurements showed that a hardpan at 9 inches deep is common in orchards. This project showed that weed control is critical to tree growth and ultimate profitability of new plantings in the early years. Weed control impacts on how soon the orchard will reach a breakeven point using Net Present Value Analysis. Good weed control can improve profitability of a new high-density apple planting by $2105-2732 per acre over 2 seasons.
- Identify the pros and cons of various ground cover seeding options.
Identify strengths and weaknesses in side-by-side herbicide treatments.
Evaluate control of established perennials.
Evaluate herbicide treatments for trunk damage from glyphosate.
Evaluate changes in soil health.