The asparagus stand of both experimental and control treatments is acceptable but large gains from the combined new grower practices has not yet shown substantial benefits. A high weed seed bank remained and caused substantial challenges during both growing seasons. Pre-plant fumigation would have likely controlled this problem to a large extent. May of 2014 will be the first real harvest of this plot and further data could be gleaned at that time however the offical data collection portion of this trial has come to a conclusion.
Soil fumigation has been recognized as a best grower practice in asparagus production to counteract the negatives of replanting asparagus several times in the same soil. Over the past several years due to environmental dangers of soil fumigation, it has become increasingly regulated so alternative practices have to be investigated. A number of these lower impact practices were combined for this trial to see if synergystic results occur.
The goal of this trial was to see if by including compost at planting, mustard cover cropping, buried trickle irrigation, and use of registered anti-fungal agents with modern asparagus varieties better plant health and ultimately higher yields and revenues would be achieved.
In the spring of 2011 an asparagus trial was initiated in west Michigan using New Jersey Supreme crowns in a sandy soil that had been in asparagus production five years before. The experimental plot was divided into two treatments with three large plots of each. Each plot was 1/10th of a mile long and multiple rows wide. Meter long sub plots of row were measured several times during each season to collect data. Ferns were collected and dried at the end of the season.
We had hoped to have an abbreviated harvest during 2013 but because of high competition from weeds during 2012 this was cancelled to allow the plants a longer growing season. Harvest would have allowed us the opportunity to apply another round of herbicides in May.
I had some differences between the control and the experimental treatments at the end of the 2013 growing season. Around Labor Day fern size was the same in both treatments but by early November a noticable difference had been established since there was no early killing frost this season. Dry fern weight was greater for the experimental treatment however Marestail density and biomass was as large as asparagus in many plots. (See Raw Data tables) This is even with multiple herbicide applications and periodic between-row mowing during the summer months.
Asparagus plants obviously faced strong competition from weed pressure. It was odd that the Marestail population was higher in the experimental treatment earlier in the season than in November.
- Graphs 2013
- Marestail with asparagus in early fall
- In row Marestail at the end of season.
- Raw Data from 2013
Impact of Results/Outcomes
The asparagus stand was still strong with no sign of root rot. This was a concern with using a NJ variety in a field that had previously been in New Jersey Giant asparagus. Foliar fungicide applications and other plant care, except for weed control, were all strong during the trial period leading to solid numbers when data gathering was carried out.
This was the first field on the farm with chemical injection and that process went well. Compost application in furrow was also surprisingly easy. I’ll be repeating those processes in future plantings.
Educational & Outreach Activities
Further details and public presentation will be taking place in Hart, MI at the Oceana County Asparagus Day in March 2014. The Michigan Asparagus Research Council is organizing this annual event.
Irrigation and cover cropping with mustards are increasingly popular practices with asparagus producers in Michigan but very little research data is available. Trying to get some practical data available is one of the main goals of this trial.
Cover cropping more heavily to reduce the amount of weed seeds would be a prudent decision as would changing the herbicide program to better cover Marestail. Having a clean growing area is more essential than most other factors in the field since weeds steal light from the crop, soil moisture, lower airflow, and ultimately lower yield. More attention should go into weed control for newly planted asparagus fields as older asparagus extension bulletins tended to stress.
Inclusion of liquid fertilizer would have been a sensible component to similar asparagus production system or trial. Since the buried trickle line is already in the system it would not add much work or cost.
Use of larger crowns would have been better. The late planting date in spring 2011 along with smaller crowns seemed to make it hard for the stand to catch up for future production. Winter-grown greenhouse plugs would have been another good option for the late spring planting in the experimental treatment with the compost and irrigation capability.