Orchard Management Weed Management 
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The definition of what plants are 'weeds' can vary between orchards and regions. Plants are often defined as weeds in fruit orchards if they
It is important that weeds are managed in the orchard to minimise competition with tree growth and crop development. Critical timing for weed management Weed management toolsThe goal of any weed management program should be to minimise weed competition during critical periods of tree growth and crop development. In the orchard a properly maintained weed free zone (or herbicide strip) of about 1-2 meters from trees is important.
Figure 1: Well managed weed free zone in an intensive 'Packham' block. The main tools that growers can use when managing weeds include good orchard hygiene, mulching, cultivation, herbicide application and competition through establishment of a permanent sod. Often these tools are combined into an integrated weed control program. HygieneGood hygiene practices should aim to restrict the intorduction of weeds into an orchard and their spread between blocks. This may require the restriction of machinery/labour movement across blocks particularly if in highly weed infested sites and the regular cleaning of machinery and equipment. Preventing seed set in weeds is also important. Weeds should also be controlled in non-cropped areas of the property. MulchingMulching helps to retain moisture, minimise weeds and improve biological activity in the soil. Inorganic and organic materials may be used for mulching. The mulch must be applied thickly enough to suppress the growth of weeds and germination of their seeds. A layer 2–3 cm deep should be adequate but will depend upon the density of the material being used. Various methods can be used to accumulate mulch under a tree row. These include;
Thick layers of mulch may increase frost risk during early spring as it acts as an insulating layer and can prevent heat being stored in the soil. See here for further information
Figure 2: Thick layer of mulch under Abate Fetel trees in France. CultivationCultivation destroys or buries weeds and is often considered an inexpensive control measure. However it can adversely affect soil structure and tree root growth and can spread weeds vegetatively. HerbicidesThere are many different forms of herbicides that can be used to control weeds. It is important that weeds are correctly identified to ensure herbicides are correctly targeted. Growers should seek local advice about herbicide options. Permanent SodPermanent sods are used to suppress weed growth through competition. Permanent sods need to be able to establish effectively to be able to outcompete weeds. This requires elimination of weeds prior to planting of the chosen sod mix. The permanent sod also needs to remain healthy and regular slashing is an important tool for controlling weeds within the sod. Critical timing for weed managementPre plantingManaging weeds before the planting of a pear block will help reduce the competitive pressure of weeds during young tree establishment. It is particularly important to control perennial weeds as these are harder to manage in established blocks than in open ground. They will also compete with any cover crops or permanent sod sown. Planting of a green manure crop or permanent sod before planting can help reduce weed pressure and provides other benefits to soil structure and organic matter. It is important before planting a cover crop or sod that weeds are eliminated through either cultivation or herbicide application. New orchardsIt is critical for newly planted trees to achieve maximum growth in the first 2-3 seasons. Good weed management is essential to ensure that trees are not competing with weeds for nutrients and moisture that may stunt growth. Young trees are not as capable of competing with weeds for light, water and nutrients as root systems are small and canopy cover is low. If weeds are not managed adequately it may delay growth and production. A weed free zone of 1-2m from trees is ideal. Within the tree row mulches, herbicides or short pasture cover can help suppress weeds. Any herbicide applications need to be carefully considered as they may damage young trees. Established orchardsWeed control in established orchards is still important, even though established trees can more effectively compete with weeds. It particularly important that the tree is not robbed of moisture or nutrients during the critical periods for tree growth and crop development including ;
During dry seasons it is particularly important that weeds are controlled in the orchard to conserve soil moisture. Weeds also may need to be eliminated to minimise the frost risk in an orchard in early spring, as they can prevent heat being stored in the soil.
Figure 3: Weeds will be competing for water and nutrients at flowering in this orchard. Further informationThese Australian and international sites may be useful for growers. However they are intended as an information source only. Any specific chemical or other control recommendations may be outdated or irrelevant for Australian conditions and growers should seek local advice. Please note: By electing to visit sites linking from this page you will be leaving the intensivepear.com website. Australian ResourcesWeed management
International ResourcesWeed management
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