Integrated Fruit Production
Lynn Long
Revised November 25, 2008

Integrated Fruit Production, or IFP, is a production system well known to tree fruit growers in Europe and is being adopted by orchardists in the Pacific Northwest, especially in The Dalles and Hood River areas. The program gives priority to environmental and human health safety in the production of high-quality tree fruits.
IFP is more than just integrated pest management with a new name. It takes into consideration all aspects of tree fruit production, not just pest control. For example, in an IFP program, guidelines are established to assure that only prime orchard sites are chosen for tree fruit production, soil is prepared properly for planting, trees are appropriately fertilized, “soft” pesticides are given preference over broad-spectrum chemicals, and fruit is harvested in the proper manner and time and stored to maintain the highest quality possible.
Part of a good IFP program is proper groundcover management. Once again, European scientists and orchardists have taken the lead in determining proper management techniques for orchard cover crops in an IFP system. They use several techniques to reduce soil erosion and limit the use of residual herbicides and yet maintain high-quality fruit production.
In mature European orchards, it is common to find a solid cover crop growing up to the trunk. It is important that young trees, up to the fourth leaf, become established with a weed-free zone around the trunk. However, European scientists believe that fruit size and quality are not reduced by a solid cover crop if it is mowed regularly to reduce competition for water, nutrients, and light. Although mouse damage is a potential problem, mowing the cover just before winter reduces or eliminates this concern.
Herbicide strips, when present, are small, constituting no more than 20% of the total orchard floor. Some IFP orchardists establish herbicide strips with glyphosate in early spring. Because of the extended activity of residual herbicides, they are limited in their use or totally eliminated from the system. Strips vary in width depending on tree size but are always small. For dwarf trees, strips are typically 3 ft wide. Two applications of glyphosate keep weeds away until late spring. After that, weeds are allowed to compete with the tree for nitrogen and, therefore, encourage better color on apples. In a well-maintained orchard, summer weeds are naturally suppressed by the trees’ shade. Occasionally, a postharvest application of glyphosate at half rate is made in the fall.
Research by Swiss scientists suggests the best treatment for fruit quality is a weed-free program only in early summer. Weeds are sprayed in mid-April with glyphosate. By midsummer to late summer, weeds begin to return. Weeds present in fall and winter help to reduce erosion and minimize nitrogen leaching. When weeds are killed the following spring, the nitrogen is released back into the soil for the tree’s use. In order to reduce the potential for herbicide resistance, a rotation or a mixture with another herbicide family is advised at some point during the year.
Swiss scientists also looked at the weed control potential of different mulches. At the research farm in Guttengin, where annual precipitation is 32 inches, fruit quality and quantity were best when a fabric row cover was placed under the trees. Tarp edges were buried 2 inches in the ground to hold it in place. Scientists found plastic provided higher temperatures, more moisture, and better nitrification than other products. However, in Wadenswil, Switzerland, with annual precipitation of 48 inches, results were negative: roots were asphyxiated because too much water was held in the soil around the tree.
Research at the OSU Mid-Columbia Research and Extension Center in Hood River has found that woven fabric ground covers installed under cherry trees significantly reduced the need for herbicides and improved horticultural attributes. Fifth-leaf Regina trees on Gisela 6 rootstock had greater vigor, branching, and canopy spread, and higher foliar nitrogen content compared to trees growing without row cover. In addition, water usage was reduced by 30% while yields were increased by 48% with no difference in fruit quality (Roberto Núñez-Elisea, personal communication). These benefits rapidly help pay for the cost of the material and installation. 
In areas where tree fruit production is limited by irrigation needs, such as Australia, growers often apply straw mulch around their trees. Applications of 4 to 6 inches of wheat straw are made in the spring in the herbicide strip area. The straw reduces weed growth, reduces water needs by 20%, and adds organic material to the soil as it decomposes. One application can last several years. Rodent control must be actively pursued with this system to prevent tree damage. When using any of these mulches, it is important to reduce irrigation levels to prevent root asphyxiation.
In a recent study conducted by OSU scientists in The Dalles, comparing straw mulch with black and white woven fabric ground covers in a cherry orchard, there was a trend in yield increase over 3 yr with straw mulch and fabric covers relative to no cover, but not to the level of statistical significance. In addition, straw mulch, black fabric and white fabric cover increased the percentage of marketable fruit in some years. In this same study, straw mulch reduced annual water use by 4.6 and 15.8% over a period of 2 yr (Yin, 2007). 

Yin, Xinhua (2007). Alternative nutrient, water, and floor management strategies. In 2008 NW Cherry Research Review, Washington Tree Fruit Research Commission.
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