Texas Peach Handbook

Chapter 8: Peach Orchard Floor Management

Chapter 8 PeachOrchardFloorManagement W eed competition is a leading cause for failure of young peach orchards. Up to 90 percent of the tree roots are in the top 2 feet of soil, and weeds growing in the root area of the tree are in direct competition with the tree for water and nutrients. In young orchards, uncontrolled weed height also results in competition for sunlight. Peach trees are poor competitors, and the grower’s ability to manage competing vegetation has a tremendous impact on the success of the orchard. Growers should avoid the temptation of mowing only the row centers, or aisles, and ignoring weed growth down the tree row underneath the trees.While it is much easier to mow than to deal with weeds under the trees, vegetation from trunk to drip line is the most important to control. Growers face the challenge of needing to remove weed competition but at the same time to ensure that valuable and irreplaceable topsoil is not lost. The recommended method of managing the orchard floor is to develop a weed-free strip under the tree row with a permanent sod strip between rows. Mechanical tillage of the entire orchard floor was the standard of the past but is rapidly losing favor because of root pruning and erosion. Sod middles in properly contoured rows can stop or at least greatly reduce erosion, but they should be mown frequently to reduce insect and disease pressure. Sod middles also provide good footing for the movement of orchard equipment after a rain,which can be important in harvesting or making timely fungicide applications. 75 Tillage Tillage has long been used to control weeds in orchards and is still used in many production regions today. Yet tillage, especially deep tillage, results in the loss of many shallow feeder roots. The concept is that tillage essentially turns the tilled 2 to 4 inches of topsoil into mulch and forces the root system to develop below the tillage depth. In very deep sandy soils where air penetrates deep into the soil profile, this approach may be workable; but in heavy soils,tillage can seriously reduce the vigor of mature, bearing trees. Roots are important not Poor weed control is the main reason new orchards fail. 76 Chapter 8 only for water and nutrient uptake but also as vessels of carbohydrate storage and as regulator of growth and reproductive physiology. One more reason why tillage is no longer recommended is that it results in soil erosion. Soils take thousands of years to create and should be considered an important, irreplaceable resource. It has been documented that a deeply tilled orchard can lose as much as 2 feet of soil in a single high rainfall season. These are catastrophic events that can render a site useless for future production. Further, it is a misconception that tillage is the environmentally friendly approach to weed control. The environmental impact of burning fossil fuels many times Optimal floor management consists of a weed-free strip under the trees and tightly mown aisles. In addition to pruning vital root tissue, tillage can promote the loss of valuable topsoil through erosion. 77 Orchard Floor Management a season could arguably be the most unsustainable option available to fruit growers. Access issues arise too. It is a fact of life that commercial peach production requires a grower to make timely, sometimes critical fungicide applications to control fruit and foliage diseases. When an orchard is tilled and a high rainfall event occurs, the orchard floor may be impassible for equipment for a time. A delay of several days before a tractor and sprayer can enter the orchard may prove disastrous and result in high fruit loss to fungal or bacterial diseases. Repeatedly driving up and down a tilled row can also develop what is known as a plow pan, a compacted zone that restricts the penetration of roots into the soil. Finally, repeated tillage negatively impacts soil structure and can reduce root growth and water holding capacity. Mulch Peach growers may consider the use of organic mulch to manage weeds. To be effective, mulch should be applied at least 6 inches deep. In our hot southern climate organic matter dissipates quickly in or on the soil, so applications will indeed need to be made annually to be an effective means of managing competing vegetation. Straw, spoiled hay, and leaf litter are all appropriate materials for this purpose...