- Fruits: berries (strawberries)
- Crop Production: nurseries
There is growing interest in using mustard as a cover crop preceding strawberries to help control nematodes, weeds, and soil-borne diseases. Varieties of two species of mustard (Sinapis alba and Brassica juncea) have been identified as producing chemical compounds known as glucosinolates that have been shown to reduce fungus and nematodes populations when mowed and incorporated into the soil. This process is known as biofumigation. These cover crops not only have the potential for controlling pests and pathogens, but also fill the role of traditional cover crops by reducing erosion, scavenging nutrients, and increasing soil organic matter.
Organic strawberry production requires reliable control for soil-borne pests and diseases. The land base limitations and pick-your-own marketing logistics on our farm, Little Lake Orchard, demand that some strawberry ground will be on a relatively short rotation. The short time between strawberry plantings will require near constant intensive cover cropping to replenish organic matter, nutrient levels, and reduce or eliminate residual fungus and nematode populations. This is where the biofumigant mustards fit in. If successful, these mustards will allow us to grow organic strawberries for many years into the future, as well as provide other organic growers with valuable information for their own pest management programs.
Project objectives from proposal:
Six varieties of mustard will be trialed to test glucosinolate production for disease and nematode control, and biomass production for organic matter and nutrient cycling. The varieties will include: Kodiak (Brassica juncea), Pacific Gold (Brassica juncea), Ida Gold (Sinapis alba), Caliente 119 (S.alba and B. juncea blend), Caliente 199 (S.alba and B. juncea blend), and Nemat (Eruca sativa- also a Brassica, bred as a nematode trap crop). These varieties will be planted in the spring and allowed to grow for 60 days before incorporation. Strawberries will then be planted no sooner than 14 days later to allow the biofumigation process to run its course. Strawberries are typically planted May through July. Spring planting mustard cover crops and planting strawberries in July allow these biofumigant cover crops to fit into a strawberry rotation.
The project will take place on former hay ground that has never been planted to strawberries and had a cover crop of oats and peas planted August 17, 2014. Soil testing will be done at the beginning (April 2015) and at the end (July 2016) of the project to measure any differences in organic matter and nutrient levels on all 14 plots. Soil testing will be done by the UVM soil testing lab.
Six varieties of mustard will be trialed to test glucosinolate production for disease and nematode control, and biomass production for organic matter and nutrient cycling. The varieties and seeding rates are as follows: Kodiak (20#/ac.), Pacific Gold (20#/ac.), Ida Gold (25#/ac.), Caliente 119 (15#/ac.), Caliente 199 (15#/ac.), Nemat (10#/ac.). These varieties will be planted in the spring between April 15 and May 1, depending on the weather, and allowed to grow for 60 days before incorporation. The mustard will be planted with the UVM Extension Haybuster 107C no-till grain drill. This drill has a small seed box and is capable of planting seed at the recommended ¼”- ½” depth. The trial will be a 1 acre block divided into seven strips, one for each mustard variety plus a control strip. This will be repeated on another acre, producing a total of 12 mustard plots and two control plots. Immediately before incorporation, samples will be taken from each plot for yield (biomass) and samples will be sent out for glucosinolate testing. Yield and biomass sampling will be done with a 30”x9” sampling quadrant. Five subsamples will be taken per sample. Glucosinolates will be tested by Dr. Matt Morra at the University of Idaho, an expert on mustard cover crops and the only lab in the United States currently testing for glucosinolates. Incorporation will consist of mowing and immediately chisel plowing and discing the mustard in. This maceration of the plant tissue is what activates the glucosinolates to be converted into isothiocyanates.
Strawberries will then be planted no sooner than 14 days later to allow the biofumigation process to run its course. Both 1 acre plots will be planted to six varieties of strawberries. The varieties are: Wendy (early season), Cavendish (early mid-season), Jewel (midseason), Cabot (late mid-season), Valley Sunset (late season), and Record (late season). The strawberry planting will go perpendicular to mustard plots so every strawberry variety will be planted on every mustard plot. Each mustard variety will be planted twice to provide one replication. This systems approach is not only trialing mustard varieties, but also how mustard cover crops fit into a strawberry production system.
The newsletter sent out by the Champlain Valley Crops, Soil, and Pasture Team of the UVM Extension office in Middlebury reaches an estimated 1,080 farmers and agricultural professionals. Also, the Rutland Area Farm and Food Link (RAFFL) sends out a newsletter that reaches over 1000 farmers and agricultural professionals. An article will be written for these publications showing all the results, analysis, and discussion of the project. Results will include glucosinolate levels and biomass production for each of the six varieties of mustard, and strawberry yields for each variety on each mustard plot. Discussion will focus on the successful mustard varieties as well as talk about why other varieties may have been unsuccessful. This is one of the major goals since there is very little guidance on which biofumigant mustard varieties are adapted to Northeast conditions. Also, results and analysis will be presented at a grower meeting such as NOFA Vermont winter conference, Vermont Vegetable and Berry Association winter meeting, or other related venue.
April 2015: Take soil samples on each plot. Plant mustard plots.
June 2015: Take mustard yield measurements and send samples for glucosinolate testing.
July 2015: Plant strawberries.
August-September 2015: Manage strawberries normally, taking note of differences in disease and plant vigor across all mustard plots, and strawberry varieties.
May–July 2016: Harvest berries and measure yields in all six varieties across all mustard and control plots.
July 2016: Compile results and write newsletter article for distribution to over 2000 farmers.
Winter 2016-2017: Present results at one winter meeting to be determined in the future. Possibilities include NOFA Vermont Winter Conference, Vermont Vegetable and Berry Association winter meeting, or other related venue.