Orchard growers consider new crops to suppress weeds
primarily to provide food for pollinators, prevent soil erosion, retain nutrients in the soil or improve soil structure and or- ganic matter content may choose vari- eties and management practices to suit those purposes. But if themaingoal is tosuppressweeds, the key is the rapid development of high biomass cover crops to quickly fill the space between the rows and crowd out theweeds. “Select fast-growing, high biomass species like cereal rye,” Haring advised. “Timely cover crop planting supports in- creased cover crop biomass.” Cover crops are one of the weed sup- pression tools that could gain in promi- nenceas legal andhealth issues leadsome growers to take a second look at glypho- sate, themostwidelyusedbroad-spectrum herbicide inCalifornia orchards. “Some growers and end users are concerned about glyphosate,” said Brad Hanson, UCCooperative Extensionweed control specialist. “Wecancontrolweeds in orchardswithout glyphosate, but it’s going to costmore. Glyphosate is pretty cheap.” Some orchard growers are switching to weed control programs based on the her- bicide2,4-D, accordingtoHanson.But that material also faces some controversy and potential regulatory pressure.
Whilecover cropscantakeuppart of the slack in controlling weeds, high-biomass plants must be managed to fit with the overall orchard program. “Consider how high-biomass cover cropsmay interactwith irrigation, orchard sanitation or other orchard operations,” Haring said. For maximum weed suppression, the cover crop should be grown over a long season, frommid-October to mid-April. Haring found that waiting until after January sanitation did not give the cover crops enough time to grow. Even though rapiddevelopment of bio- mass isagoal, it isnot advisedtouse inputs to give cover crops a boost. “If your goal is to suppress weeds, I wouldn’t use a lot of inputs on my cover crop,”Haringsaid. “If youfertilizeyourcov- ercrop, you’regoingtogetaflushofweeds.” The annual cost for cover crops is around $50 for 50 pounds of seeds and an additional $20 an acre to seed. However, some pollinator mixes are available at no charge. “The (Project) Apis m. seed group has a ‘Seeds for Bees’ mix they send for free,” Haring said. ( Bo b J o hn s o n i s a r e p o r t e r i n Sacramento. He may be contacted at bjohn11135@gmail.com.)
ByBob Johnson As some herbicides come under scruti- ny, cover crops may give orchard growers another tool formanaging thebareground between rows. They can takeadvantageof that space, plus water and light, to grow cover crops that suppress weeds. But the choice of cover crop varieties, plantingdates andmanagement program should be chosen to suit the purpose of preventing weeds from taking over that bare ground. “Choose your cover crop species and management practices based on the
specific functions that are important for your own orchard system,” advised Steve Haring, a University of California, Davis, doctoral student in weed science. “Abundant cover crops limit bare ground and leave fewer resourcesavailable forun- wantedweeds.” Growers came to see and discuss the latest research at the Nickels Soil Lab Annual Field Day in Arbuckle. There, Haring suggested: “Have a specific man- agement goal for your cover crop and a plan tomeet that goal.” Growers looking to use cover crops
EPA ban draws farm critics American Farm Bureau Federation has urged the federal government to re- consider its decision to ban a crop-pro- tection material widely used on crops including tree fruits and nuts, vegetables and other produce. maker.Agroupconvenedby theCalifornia Department of Food and Agriculture and theDepartment of Pesticide Regulation is working to develop alternatives.
AFBF President Zippy Duval l ex- pressed concerns about the EPA action and said it “takes away an important tool tomanage pests.” “Farmers and ranchers care deeply about the quality of our crops. Nothing is more important than producing safe, nu- tritious food,”Duvall said. “So, wemust be guidedby themost reliabledeterminant of safety, which is science.” Chlorpyrifos has been widely used in U.S. agriculture since it was registered for use in the 1960s.
A pend i ng U. S . Env i ronmen t a l ProtectionAgency rulewill prohibit useof chlorpyrifosoncrops.Oncepublished, the regulationwould give farmers sixmonths to stop applying thematerial. California farmers have already been seekingalternatives tothebroad-spectrum pesticide. State sales ended in 2020, with limitedapplicationspermittedthroughthe end of that year, under a deal between the stateandDowAgroSciences, theproduct’s
www.afrikelp-usa.com
BETTER COLOR IN TABLE GRAPES WITH AFRIKELP
Percentage of fully colored berries in 2 table grape varieties at first harvest. Kern County, CA..
96.8%
0% 20% 40% 60% 80% 100%
81.0%
68.5%
47.5%
Flame Control
Flame Afrikelp
Alison Control
Alison Afrikelp
University of California, Kern county. Dr. Ashraf El-kereamy, 2018.
Control
Afrikelp
August 25, 2021 Ag Alert 9
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