David Doll4 CommentsJune 30, 2019Horticulture, Soil

Cover crop research review: How can it help almonds?

Cynthia Crézé (1), Jeffrey Mitchell (1), Andreas Westphal (2), Danielle Lightle (3), David Doll (3), Mohammad Yaghmour (3), Neal Williams (4), Amanda Hodson(4), Houston Wilson (5), Kent Daane (6), Brad Hanson (1), Steven Haring (1), Cameron Zuber (3) & Amélie Gaudin (1) Department of Plant Sciences, University of California – Davis Department of Nematology, University of California – Riverside University of California Agriculture and Natural Resources – Cooperative Extension Department of Entomology and Nematology, University of California – Davis Department of Entomology, University of California – Riverside Department of Environmental Science, Policy and Management, University of California – Berkeley Although cover cropping is compatible with almond production and is often implemented in other orchard systems, this practice has never been widely implemented in California. The potential benefits are recognized by growers, especially their value for pollinator forage and soil health but operational concerns, lack of cost-benefit analyses and unclear best management practices have hampered wide adoption. As cover cropping can provide significant sustainability benefits, there is an urgent need to assess and develop feasible and beneficial cover crop systems for California almond production. Here is some insight gathered by a research team assessing the impacts of multiple cover crop management strategies on: 1) soil health, 2) water use and dynamics, 3) bee visitation and pollination, 4) weed and pest pressure (NOW) and 5) almond yields in four orchards across the Central Valley precipitation gradient. Cover crop research trial in almond: Project website: https://almondcovercrop.faculty.ucdavis.edu Design: Three commercial orchards in Corning (Tehama county, 2nd leaf), Merced (Merced county, 16th leaf) and Arvin (Kern county, 16th leaf). One experimental station: Kearney (Fresno county). Two cover crops: Soil Mix (2 legumes, 2 brassicas & 1 grass), Pollinator Mix (5 brassicas, Project Apis M – https://www.projectapism.org/pam-mustard-mix.html) Compared to resident vegetation & to bare soil. Cover

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Brand Hanson6 CommentsOctober 11, 2013Weeds

Goosegrasses in nut orchards

Cross-post from UCWeedScience In the past couple of years, I’ve gotten a lot of questions about goosegrass in orchard production systems, particularly about suspected glyphosate-resistant biotypes. From a California orchard standpoint, we have two main goosegrasses (Eleusine spp) to deal with; these are goosegrass (Eleusine indica) and threespike goosegrass (Eleusine tristachya).  These species are fairly similar but have quite different flowers (see the photo below).

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Franz Niederholzer3 CommentsDecember 21, 2012Horticulture, Insects, Weeds

What did I learn at the Almond Board’s annual conference?

The Almond Board of California’s annual conference is a chance to connect with others in the almond industry, listen to world class researchers talk about their work, and check out a huge almond-focused trade show all at one event. The 2012 meeting was last week (Dec 11-13).  Here is a quick review of some of the things I picked up from researchers and informed industry members at that meeting…

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David Doll0 commentsJanuary 12, 2010Weeds

Organic Weed Control in Almond Orchards

Weed control within organic blocks is more critical than in conventional blocks. Weedy orchards can compete for the high value organically certified nutrients, decreasing yields and/or increasing fertilizer input costs. Organic weed control methods are also not as effective and more costly than conventionally available materials. Therefore it is important for growers to use multiple strategies to reduce weeds to a level that is economically acceptable. This entry will focus on several methods available for organic almond production weed control. These methods may also be useful in conventional orchards that have multiple areas of herbicide resistant weeds. Mulches: Plastic or fabric mulches block light, preventing weed germination or growth. These materials are often placed in the row strip before planting. Upon planting, a hole is made at the planting location so that the tree can be planted. Placing the mulches post planting can also be done. These materials control most weeds effectively while they are still intact. Materials do degrade over time due to UV light and temperature. Weed seeds that land on top of the mulches can germinate and grow. These types of materials are expensive ($250-$300 treated acre) and post-use disposal can be problematic since they are currently are not able to be recycled. Organic mulches (straw, newspaper, wood chips) can be used for early season weed management, but often interfere with harvesting practices. Organic mulches are most effective when they are at least four inches thick. Use on non-bearing age trees may be feasible. Remember, these mulches MUST be organically certified to be used. Cultivation: This is the most widely used organic weed control method. Cultivation uproots and buries weeds. This tends to work better on smaller, shallow rooted weeds. Deep cultivation is not advisable since it can damage tree roots. Usually, a mix of a tractor

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David Doll0 commentsNovember 2, 2009Weeds

Fall survey for problematic weeds

Written by David Doll, UCCE Merced CountyMonitoring weeds in the fall provides the ability to evaluate the current year’s weed control program. By surveying the orchard for areas of weed species that escaped control, control practices can be adjusted to control these weeds in the following year. Fall monitoring also provides the ability to identify emerging winter species and allow for the selection of a pre-emergent herbicide to control spring weeds. (Note: Pre-emergent herbicides are usually applied at a later date – December-February). Surveying for weeds is relatively simple. After the first rains look for annual weeds in the tree rows to check the effectiveness of any previous pre-emergence herbicide applications. Check the ground cover in the row middles for any perennial seedlings. Record weed infestations and use a map to show areas of escaped weeds. With the emergence of herbicide resistant weeds in almond orchards (Hairy Fleabane, Pigweed, Horseweed, etc.) control of escaped weeds is critical to an affordable weed management program. For example, controlling glyphosate resistant fleabane with spot treatments of Rely/Gromoxone tank mix that has been found on 3 acres of the orchard block is more affordable than trying to control it over the entire 40 acre block. Only by monitoring can the areas infested by escaped weeds can be identified. It is important to use a different chemistry and address these escaped weeds BEFORE they become to big or go to seed. Below are some pictures of common weeds to help in identification:Figure 1: Bermudagrass (Cynodon dactylon). Vigorous spring- and winter-growing perennial. Frequently becomes a problem in mowed orchards. Very competitive for moisture and nutrients. Spot treat with postemergents. Figure 2: Dallisgrass (Paspalum dilatatum). Perennial commonly found in orchards. Seedlings in spring and summer. Tends to become dominant in mowed areas and standing water. Figure 3:

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