Field trials to evaluate the benefits of biofumigation as part of a potato cropping system in the Northeast

2007 Annual Report for FNE06-575

Project Type: Farmer
Funds awarded in 2006: $8,079.00
Projected End Date: 12/31/2007
Region: Northeast
State: Pennsylvania
Project Leader:

Field trials to evaluate the benefits of biofumigation as part of a potato cropping system in the Northeast



Potato growers in the Northeast and the Northwest U.S. contend with similar potato disease and insect pressures. However, the climate and soils between these two regions are very different. Green manures are being researched and used as "bio-fumigants" in potato crop rotations in the Pacific Northwest. Information and research as to how these green manures, specifically mustard, can be used as part of a potato cropping system in the Northeast was not obtainable. Research and field trials are needed to evaluate the potential of successfully using mustard as a bio-fumigant under Mid-Atlantic climate, weather and soil conditions.

The objective of this 2006 SARE Grant is to begin the process of evaluating mustard in a potato-oats rotation, its potential to improve potato quality while significantly reducing pesticide requirements and improving soil tilth. The study of mustard as part of a potato rotation is projected to take several years as there needs to be an assessment of various cultural practices associated with growing mustard in the Northeast. The cultural practice to be evaluated in the 2006 field trial is to determine the nutrient and fertilization needs of the mustard and the mustards overall effects on nematodes and other soil pathogens.

Farm Profile

Glenn R. Hetherington Farms is a 500+ potato, small grain and hay operation near Ringtown, Pennsylvania. Glenn Hetherington began farming full-time in 1978 and is the owner and operator of the farm. The approximately 130 acres of potatoes are varieties grown for their chipping qualities and are all contracted to WISE Foods Inc. for the manufacture of potato chips. The potatoes are harvested in September and October and are stored until February into April when they are delivered to the plant in Berwick, PA.. Oats and timothy/alfalfa hay are used as rotational crops. There are about 130 acres of oats (underseeded with hay) and 120 acres in hay. Approximately 60 acres are enrolled in the CREP program. There are implemented conservation plans on all the farm’s acreage.

Since the SARE Grant was approved, two center pivot irrigation systems have been installed one on each of the farms where the field trials are being conducted. One system was installed on the "home" farm and the other on the "homestead" farm. Irrigation of the potatoes in the past has been done by using a solid set hand-moved overhead sprinkler system. This type irrigation system is inefficient as it is too slow to provide adequate moisture in a timely fashion to the potato acreage and it is extremely labor intensive (unable to find people to do this). The center pivot is a more efficient irrigation system, resulting in less water runoff, reduced erosion, and diminished nutrient leaching.

In order to justify the cost of a center pivot system, it is likely that the present crop rotation will change to a two year potato/oats rotation under the pivots. The oats would no longer be underseeded with hay. This more intensive rotation will probably require more pesticides to control overwintering insects, diseases and nematodes. The planting of mustard as a natural bio-fumigant following the harvest of the oats is expected to significantly reduce pesticide requirements and improve soil tilth.

The study of mustard as part of a potato rotation is projected to take several years as there needs to be an assessment of various cultural practices associated with growing mustard in the Northeast. The cultural practice to be evaluated in the 2006 field trial is to determine the nutrient and fertilization needs of the mustard and the mustards overall effects on soil tilth, nematodes and other soil pathogens.


Fall 2006 – Penn State pathologists and Extension agent George Perry took soil samples from each area of each field using GPS equipment so sampling could be repeated following the test.

Project Activities

Three fields were specifically selected for this project:

Home farm-G2W: – 8 acres, average field, (Calvin soil)
Home farm-G13N – 8 acres, tested and confirmed to have root lesion nematodes* (Calvin soil)
Homestead farm: S4B – 7 acres, potatoes in ’05 crop year had pink rot** (Leek Kill soil)

* Root lesion nematodes vector with vertillicium wilt (known to be present in this soil) and cause ‘early die’ in potatoes.
** Pink rot organism lives in soil for several years and will infect ’07 potato crop if late season moisture is high.

All three fields were planted to oats in crop year 2006. Half of each field was underseeded with a 75% timothy/25% alfalfa mix at oat planting, the other half of the field was not underseeded. The oats were harvested August 5 to 9 2006. The oat straw was baled between August 8 to 15. The half of each field that was not underseeded with the hay mix was sprayed Roundup to kill the volunteer oats and weeds on August 25th. During the 8 days from August 26 until September 2nd, it rained 4.3 inches. Due to the wet field conditions it was not possible to plant the mustard until September 11th. On September 8th, half of each field was resprayed with Roundup to kill additional volunteer oats that had sprouted due to significant heavy rainfall.

On September 11, 2006, "Caliente 119" (variety) mustard was planted in the half of each field that had been killed with Roundup. Planting was done using a rented John Deere no-till drill at a seeding rate of 16 Ibs/acre.

On September 15, 2006, fertilizer was applied to the portion of each field planted to mustard using a spinner spreader. The area of the field planted to mustard was divided in two sections so that two different rates of nitrogen could be applied. The nitrogen rates were 60 Ibs nitrogen/acre and 120 Ibs nitrogen/acre. This resulted in each of the 3 experimental fields having the following sections:

1) Mustard; 60 lb nitrogen/acre
2) Mustard; 120 lb nitrogen/acre
3) Mixed Hay with Mocap (applied in 2007)
4) Mixed Hay (alfalfa/timothy)

On November 29, 2006, the mustard in all fields was roto-chopped.

On November 30, 2006, all chopped mustard was disked using a heavy disk.

In crop year 2007, each field will be moldboard plowed and planted to chipping potatoes. One-half of the sections containing the hay mix will have Mocap applied prior to planting, the other half will not receive an application.

Penn State plant pathologists and Extension agent George Perry took soil samples from each section of each field using a GPS unit so that future sampling can be repeated in the same areas.


No-till planting of the mustard is successful. Similar to the planting in 2005, the mustard seed germinated very will using the no-till drill into the oats stubble.

The literature says that mustard should grow 3-4 feet tall to produce adequate biomass in order to be effective. The mustard this year grew only 6" (60 lb N/acre) to 12" (120 lb N/acre). The delayed planting (9/11/06) date due the need to bale the oats straw, kill the volunteer oats and extremely wet and cloudy weather was probably too late for allowing for the necessary growth. In general, we had a very cold, wet, sunless September, October, and November. In 2005, the mustard was planted earlier (August) but was not fertilized and an extremely dry August and September resulted in mustard growth much the same or less than 2006.

The seeding rate of 16 lb/acre may be too high. If the plant stand were less dense it may be possible that the mustard plants would have grown taller with less competition.
It appears that mustard does require fertilization in order to achieve the necessary growth. The mustard receiving 120 lb N/acre grew to 12 inches, while the mustard receiving 60 IbsN/acre only reached a height of 6 inches. The presence of the additional nitrogen was not noticeable until the plants reached about 4", then the ones receiving the additional nitrogen grew at a faster rate of speed. This was probably due to the plant roots becoming established and the plants were then able to uptake the additional available nitrogen.
Disking the mustard does not result in even distribution of the biomass throughout the working soil depth (at least 8" for potatoes) in my type of soil. It may be necessary to plow the mustard into the soil to adequately distribute the biomass. This raises several concerns: it would be an additional tillage practice (requiring additional time and fuel = money), what are the effects on soil compaction, it would create a highly erodible soil situation, and it may not be acceptable in a conservation plan.


The 2006 growing season contained the most weather extremes of any year that I experienced in my 30 years of farming. Twelve inches of rain fell between June 23rd and June 27th – twice as much as I have ever experienced before during that short time period. Water oozed out of most fields for 5 to 7 days, turning plants yellow. Starting on August 26th, 4.3 inches of rain fell during the next 8 days. The period between those two rain events was extremely dry and we ran the center pivot systems three cycles each. September, October, and November were cloudy, cold, and wet. These weather extremes may have effected the growth of the mustard making solid conclusions difficult. It may be difficult to draw any defining conclusions generated from production or quality data generated in the 2006 growing season due to weather related quality problems. For example, the quality of my potato crop is so poor (internal brown spot and brown center) that it may seriously affect their salability for chips due to these extreme weather conditions.


Preliminary results show that it will require a significant amount of additional nitrogen fertilizer to grow the mustard. The cost of nitrogen fertilizer has more than doubled during the past two years.


It appears that in order achieve adequate growth of the mustard in our climate it will be necessary to plant it earlier – perhaps too early to fit into a rotation with the oats. The next experiment should entail planting the mustard immediately after the oat/straw harvest instead of waiting for the volunteer oats to germinate and killing them with the Roundup. A post-plant selective herbicide to control volunteer oats would be used if necessary.

The mustard appears to require the addition of nitrogen fertilizer in order to promote adequate growth (120 lb N/acre).

Another trial using a reduced seeding rate from the one used in this trial (16 Ibs./acre) is suggested. The plants germinated very thick in the rows and it is thought that if the plants had less competition from each other and more room the plants might have grown taller.

One of the positive conclusions that can be reached is that the mustard can be successfully no-tilled into the oats stubble. Potato production requires a considerable amount of tillage in the rotation. The literature on the use of mustard recommends the soil be tilled and that a good seedbed should be established in order for the mustard to germinate successfully. Adding yet another tillage operation to the soil was not desirable and using no-till methods were explored. Apparently, using a no-till drill to plant the mustard is something unique to what has been done and it works!

There is a concern that heavy disking alone does not adequately mix the mustard biomass into the working soil depth. If moldboard plowing would be necessary in a two year rotation (potato/oats-mustard), the entire farm would be bare over the winter. This is unacceptable from a conservation and a soil erosion standpoint. A suitable cover crop has yet to be found that can be planted in the fields where potatoes have been harvested. Stone picking after harvest is not completed prior to November 10th and this is too late for most traditional cover crops to become established. Soil compaction with the additional soil tillage operations and equipment passes over the field should also be considered.

Another possibility to consider would be to remain on a three year rotation (maintain the year of hay). The hay provides additional root mass and organic material that provides much needed organic matter to the soil. The benefits of the addition of the hay organic matter may outweigh the benefits provided by the mustard. The mustard could be planted in fields where disease and insect pressure is the greatest. If the mustard biomass is effective in reducing disease and insect pressure, it is worthwhile to pursue a way to use it in a potato rotation.

Objectives/Performance Targets


Impacts and Contributions/Outcomes


George Perry
Techincal Advisor
1202 Ag Center Dr.
Pottsville, PA 17901
Office Phone: 5706224225