Joe Grant UC Cooperative Extension San Joaquin County Janine Hasey UC Cooperative Extension Sutter, Yuba & Colusa Counties Young Almond & Walnut Orchards Workshop, January 14, 2016
Joe Grant UC Cooperative Extension
San Joaquin County
Janine HaseyUC Cooperative Extension
Sutter, Yuba & Colusa Counties
Young Almond & Walnut Orchards Workshop, January 14, 2016
And …. LOCAL SEED DEALERS!
http://anrcatalog.ucanr.edu
Winter “green manures”
Annual reseeding
Perennials
Warm season annuals
↑Winter / spring access
↑Water penetration Root channels, Less surface crusting
Remove excess soil moisture in early spring Nitrogen addition or conservation
↓Runoff, erosion, off-site pesticide movement
Weed suppression
↓ Dust Beneficial insects, nematode suppression ?
May use water that trees needWinter: ≅ 2.7 acre-inches per ton of dry matter Reduces salt leaching
Spring/Summer: direct competition / increased orchard water demand
↑ Frost risk May interfere with NOW sanitation
and pruning Nematode & rodent considerations
Mixtures: Large seeded cereal grains (oat, barley) and N-fixing legumes (vetch, pea, bell bean) seeded each fall, cultivated or mowed in
spring.
Single species cover crops
‘Tyndel’ Triticale
‘Lana’ Woolypod
Vetch
Complete pruning operations first
Or seed alternate middles? Prep and plant after harvest
before leaf fall. Good seedbed is essential!
Width per: equipment, avoid root damage, invasion of strips by cover crop
Broadcast or drill Irrigate up if necessary
Maximize biomass without compromising other goals
Remove at early flowering for maximum N content
Allow removal of excess soil moisture without depleting stored reserves
Biomass and N concentration 80-90% of N is in above-ground parts; 10-20% in rootsMax. N contribution is at flowering (2-5%)
Whether the legume species is combined with a grass species
Different legume cover crop species contribute different amounts of fixed N
Whether it is mowed or tilled (incorporated) Mowing: assume a 50% N recoveryIncorporated: assume a 70% N recovery
Used published estimates
OR
Cut and weigh a representative sample, then:
If incorporated, multiply by N conversion factor
OR If mowed (or N conversion unknown), send to lab for N analysis
Legumes Clovers: Subterranean Persian Rose Crimson clover
Bur medics
Grasses: ‘Zorro’ fescue
‘Blando’ brome (soft chess)
Mid-March, Davis, CA
Reseeding annual mixtures
‘Blando’ brome / clover mix
Planted initially in fall
Managed during spring/early summer to allow plants to mature used in no-till orchards
Mowed late May to mid-June Clippings decompose on soil surface
Naturally reseed the following fall
Can reseed (persist) many years
Better fall and winter orchard access Suited to areas with more rainfall
No extra summer irrigation
Legumes fix nitrogen
Grasses – better water penetration Less runoff
Weed suppression
May need fall or winter irrigation to ensure good germination and growth if rains inadequate Need full coverage system for this
Mow (~1 inch) in late February/early March Reduce winter weed competition Also reduces risk of frost injury
Mow to remove in late May – mid-June after seed has matured
Difficult to grow with our weather patterns last 4 years
Need light irrigation in fall after planting if no rain
Need winter irrigation if no rainfall to continue growth
Don’t plant if no ability to irrigate in winter
Not recommended in drought with limited water
Maximize N by maximizing biomass
Range 31 - 250 lbs N/ac Average ~90 lbs N/ac
Mowing 50-75% N recovery ANR pub assumes 50%N
subclover
Increased gopher activity reported not observed in our trials
See publications in binder Species information (soils, nutrition, etc) Seeding rates, equipment, costs Land (seedbed) preparation
Supplemental N Band next to tree rows or through low volume
system Don’t broadcast to maximize N fixation
Thank you!