Testing Combined Multiple Sustainable Production Methods in Asparagus for Symbiosis between Irrigation, Biofumigation, Advanced Cultivars, and Soil Amendments

2013 Annual Report for FNC12-849

Project Type: Farmer/Rancher
Funds awarded in 2012: $7,500.00
Projected End Date: 12/31/2013
Region: North Central
State: Michigan
Project Coordinator:

Testing Combined Multiple Sustainable Production Methods in Asparagus for Symbiosis between Irrigation, Biofumigation, Advanced Cultivars, and Soil Amendments

Summary

Michigan Asparagus Fumigation Alternative

Several acres of sandy loam (Spinks complex) vegetable ground in Oceana County, MI were used for this trial. This is where Michigan’s commercial asparagus production is centered so most suitable ground has been planted at least once into asparagus. Productive life of fields has dropped from over twenty years to around twelve in the past several decades because of replant issues. Much of this reduction is thought to be the result of accumulating root pathogens in the soil.

Recently soil fumigation has been viewed as the best method to deal with this pathogen load but the fiscal and environmental costs of this treatment are significant. The ground in this trial had been rotated out of asparagus for 5 years into other vegetable and cover crops without fumigation. This trial attempts to negate soil pathogens using multiple weaker methods to help discover successful alternatives to fumigation.

In the fall of 2011 rye had been planted and was disked out on March 25, 2012 with small plant size but with good ground coverage. The trial area was divided into six large rectangular plots in an alternating plot design. Total field size was two acres consisting of eleven 1/3 mile long rows with 4 foot row spacing between asparagus rows.

Objectives/Performance Targets

Spring Mustard Cover Crop

Mustard cover crops are thought to have significant value as biofumigants. For this trial specialized Mighty Mustard was planted in early spring to help clean the soil of weed-seeds and fungus without requiring another year for the asparagus preparation cycle.
An early cover cropping of Pacific Gold “Mighty Mustard” was hand broadcast at 18 lbs. per acre on March 31 into the three experimental plots and the entire field was cultipacked to ensure good soil seed contact.

Mustard was disked under after a month before it went to seed as recommended by the cover crop supplier. Mustard germination rates and soil moisture were good, as was soil moisture but an uncharacteristically warm, dry snap reduced biomass accumulation because of early initiation of the reproductive phase. All plots were disked the beginning of May to incorporate mustard and kill weed seedlings. Two weeks were given in May before planting of crowns to let biomass decompose as per recommendation of cover crop company after mustard disking.

Compost in furrow, high quality crowns, buried trickle tape.

24,000 hi-bred New Jersey Supreme asparagus crowns from Nourse Farms were planted at the common commercial density, 12,000 per acre. This newer high yielding variety has shown good adaptability to Michigan conditions but has exhibited some susceptibility to root rots in replant situations. Crowns exhibited no sign of root rot at planting time.

These crowns were planted the third week of May in two-foot deep furrows created with a double moldboard plow. In-row crown spacing was 8” so the roots of neighboring plants were in contact. MAP fertilizer was applied at the standard local rate, 60 lbs. acre, in furrow to ensure adequate available Phosphorus. At the same time five apple boxes of “Dairy Doo” compost were applied in furrow in half the plots with an application rate of two tons per acre.

13 mil Netafim Typhoon tape, 18” emitter spacing at .24 gph, was installed in the three experimental plots at the bottom of the furrow. Water usage rates were 30 gpm per acre with 15 hours required for an acre/inch of irrigation. These costs per acre were slightly higher than anticipated but part of this cost overrun was due to the complexity of system required with small scientific plots. Total cost per acre was around $500 per acre if applied to simple production fields as opposed to the hard walled tubing ($.15 per/ft.) which runs over $1600/a. Converting from 4 foot to 5 foot row spacing would also lower irrigation cost.

The Netafim Typhoon tubing was more prone to kink at installation versus thick walled tube and it burst in several spots with the initial water surge. This required slight repairs and the addition of inexpensive pressure limiters at the main header to limit PSI to 20 lbs.

Summer Growth and Development

Since we planted our crowns several months after local farmers traditionally do there was no risk of spring frost but the plants lost both long spring days to photosynthesize and the opportunity to establish well-developed root systems before summer heat and water competition from weeds occurred.

There was significant drought stress in Oceana County in 2012; typically new asparagus isn’t irrigated but this season even the control treatment plants required several manual waterings with yard sprinklers to avoid total stand loss. This may have impacted trial results but was deemed necessary and the amount of labor saved not moving hoses in the trickle plots was a significant unforeseen benefit. The experimental treatment received half a dozen moderate applications of water by September to avoid water stress altogether.

Competition from weeds became intense by July despite spring cover cropping to eliminate winter annuals, multiple cultivations, and selective herbicide application. This pressure was due to high weed seed populations blown in from a neighboring access road for grasses and Pigweed’s ability to establish and thrive in hot conditions. By late July hand weeding was required for the entire field at significant cost and some stunting of asparagus became apparent.

Chemigation and Monitoring.

As planned Ridomil Gold fungicide was injected into the trickle irrigated plots mid-summer at 1 pint/acre. No apparent Phytophthora or Fusarium problems were observed in the field but long time-frames are required to take down healthy, larger asparagus plants.

Moisture monitoring was checked weekly with four Diviner 2000 tubes but familiarity with rough Evapotranspiration rates from the soil and plants would be adequate to cue irrigation. Pests: Rust, Purple Spot, Asparagus beetle, cut worm, Armyworm, were checked by a local crop scout and farm staff and treated for with IPM thresholds.

Accomplishments/Milestones

This trial accomplished several things: the field was successfully established in experimental/control treatments in 2012. Disease and insects were kept under control but more attention will be given in future freshly planted fields on controlling weeds in mid summer. Most of the herbicides commonly used in asparagus aren’t regarded as safe for new plantings, so tight weed control full season with the selective herbicides available and cultivations is necessary. Establishment of a fern canopy to shade out weed competition early in the season is a very important aspect of traditional planting times that we missed in this trial.

Impacts and Contributions/Outcomes

Evolving Production Methods

Several components of this trial were good in theory but should be adapted to become more practical in the field. Examples of this include:

Spring Mighty Mustard planted for a longer window at lower density with a no till drill to lower seed costs and increase plant biomass. Follow this with another generation of mustard or a forage radish for the fall to increase total biofumigation impact, to increase soil Organic Matter levels, and to lower weed pressure.

Planting is moved back to March or moved back to early winter; if enough straw mulch for coverage of each furrow to minimize winter injury was available. This would allow plants to establish canopy quickly in the spring and make use of long day lengths.

Utilize more injection of fertilizers and labeled chemicals to the root zone to maximize the investment return from trickle and decrease N loss.

Results of 2012

Crowns set decently in the spring, but summer weed pressure in July may have suppressed asparagus growth in August. The data taken from late summer reflects this trend, although it’s possible some of this numerical decrease is from sampling error.

By October fern number and heights became higher in the experimental plots, but the treatment difference doesn’t look statistically significant yet. Spring harvest yield and fern measurements in 2013 may continue this trend if plant health truly is better in the experimental plots.

Collaborators:

Verne Huntley

Equipment Operator
Larry Byl Asparagus Farm
PO Box 130
Shelby, MI 49455
Benjamin Byl

benbyl@gmail.com
Grower
1259 W Shelby Rd
Shelby, MI 49455
Office Phone: 2313011285
Larry Byl

larrybyl@gmail.com
grower
PO Box 130
Shelby, MI 49455
Office Phone: 2318612103