Joe Grant UC Cooperative Extension San Joaquin County. Janine Hasey UC Cooperative Extension Sutter, Yuba & Colusa Counties

Transcription

1 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

2 And. LOCAL SEED DEALERS!

3 Winter green manures Annual reseeding Perennials Warm season annuals

4 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?

5 May use water that trees need Winter: 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

6

7 Mixtures: Large seeded cereal grains (oat, barley) and N-fixing legumes (vetch, pea, bell bean) seeded each fall, cultivated or mowed in spring.

8 Single species cover crops Tyndel Triticale Lana Woolypod Vetch

9 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

10 Maximize biomass without compromising other goals Remove at early flowering for maximum N content Allow removal of excess soil moisture without depleting stored reserves

11 Biomass and N concentration 80-90% of N is in above-ground parts; 10-20% in roots Max. 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 recovery Incorporated: assume a 70% N recovery

12 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

13

14 Legumes Clovers: Subterranean Persian Rose Crimson clover Bur medics

15 Grasses: Zorro fescue Blando brome (soft chess) Mid-March, Davis, CA

16 Reseeding annual mixtures Blando brome / clover mix

17 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

18 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

19 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

20 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

21 Maximize N by maximizing biomass Range lbs N/ac Average ~90 lbs N/ac Mowing 50-75% N recovery ANR pub assumes 50%N subclover

22 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

23 Thank you!