During the summer of 2004, the Cornell University Cooperative Extension staff in Washington County worked in partnership with three Washington County agricultural businessmen Jim Stannard, a vegetable farmer, and two commercial compost makers, Robert Wilmot, who makes a paper based compost and Kevin Booth, who makes a manure based compost. The project received funding from the Northeast Region SARE (Sustainable Agriculture Research and Education Program) Partnership grant program. The project looked into the possibility of integrating compost into an intensive plasticulture production system for vegetables for the purposes of enhancing weed control and incorporating organic matter and compared the performance of the two different compost materials.
According to the 2002 Census of Agriculture, Washington County, New York has 700 acres of fresh market vegetables, managed by dozens of growers. Most of this production is on sandy and gravelly soils that are low in organic matter. Vegetable growers in this county who use plastic mulch usually combine this tool with a raised bed that is fitted with trickle irrigation tubing to supply water and fertilizer when needed. High value crops, including melons, peppers, tomatoes, squash, broccoli and cabbage, among others, are grown in this manner.
Plastic mulch offers many benefits, including soil moisture retention, weed control and an increase in soil temperature allowing for earlier crop establishment. Weed control is often accomplished by applying a pre-plant, pre-emergent herbicide throughout the field. This practice makes it difficult to increase soil organic matter by incorporating a living mulch. Increasing soil organic matter on sandy and gravelly soils in an economical manner while also providing reasonable weed control between the plastic mulched rows is the primary question that this trial attempted to answer.
Washington County also has a growing number of compost suppliers, mostly dairy farms composting manure as a waste management system. This manure-based compost has been well accepted by local vegetable growers is primarily a dairy manure-based material with wood chips, horse and other livestock bedding used as bulking agents. It is composted in a turned-windrow system. It has a moderate nutrient content for compost and is typically less than 30% organic matter.
The second most prevalent compost type is derived from municipal and/or industrial waste. The Hudson River bounds Washington County on the west. Historically this river supplied power to dozens of paper mills; currently only five mills exist in the county, but these mills still have an excess amount of manufacturing by-product that needs to be disposed of safely. In an effort to produce a superior product, compost producers have been incorporating this paper waste into municipal yard waste. CTI-Agricycle Compost is made from yard waste and paper fiber residuals discarded after making paper. It is composted in a turned-windrow system. It has a low nutrient and high clay content. New York State Department of Environmental Conservation has approved it for use on fresh market vegetable crops. The problem with this material is acceptance – vegetable growers are reluctant to experiment with this material despite the fact that the low fertility may actually be beneficial to many production systems. This material also has virtually no risk of weed seed contamination. Concerns expressed by vegetable farmers are the perceived threats of salt and/or heavy metal accumulation. The product also tends to be heavier than manure based compost; this might affect ease of application.
The objectives of the project were twofold:
Can compost applied as mulch between rows of plastic adequately suppress weed growth without the use of herbicides and what would be the effect on crop production?
Will different types of compost have an effect on crop production and weed control in the plasticulture system?
This project examined the effects of manure based compost and paper sludge based compost in an intensive plasticulture production system of a high value, direct market crop, in this case melons.
This project examined the effects of two different types of compost on melon production. Jim Stannard fit the field as he normally does for cantaloupes, which were chosen as our study crop due to their high value and tight harvest window. All melons were grown in an intensive plasticulture system. This was defined as raised beds, machine laid plastic and trickle irrigation with a soluble 20-20-20 delivered throughout the season.
On June 9th, Athena seedlings (Cucumis melo) were transplanted into the field. Athena was the grower’s choice. It is a widely accepted and commonly grown melon. It is medium-sized (an average of 4 lb.), well-netted and sutureless. It is oval-round in shape with a slight taper at the stem end. Ripe melons seldom crack and have a tough rind. This variety has been shown to have a good shelf life, and features a thick, sweet orange flesh. Most importantly, Athena is resistant to fusarium races 0, 1, & 2 and powdery mildew.
Four treatments were tested:
Treatment One was a control of no herbicide and no compost between the plastic beds.
Treatment Two had post-emergent herbicide applied and no compost. The herbicide was to be applied when weeds were ~ 8” tall.
Treatment Three had no herbicide and a three-inch layer of manure-based-compost between plastic beds.
Treatment Four received no herbicide and a three-inch layer of paper fiber-based compost between plastic beds.
There were three replicates of all treatments. Plots were 20 feet long with 5 feet of an unplanted buffer between plots. Cantaloupes were planted in the middle row of the three rows.
Our second question involved the performance of two different composts. For the trial we examined paper-based and manure-based compost. Cow manure based composts have been well accepted by local vegetable farmers who use the material in seed starting mixes, as well as a way to increase soil organic matter and fertility primarily in non-plasticulture systems. The analysis of the manure based compost showed 15.2% OM and .56% total nitrogen. These values are somewhat lower than normally expected from a manure based compost, but are probably due to high mineral content of starting materials, which are sawdust from cow stalls, manure, and sand. This compost was ~4 months old. The physical properties of the material made it very easy to work with and it was well screened.
Paper based composts are more recently available to food producers as NYS DEC works to approve these materials. Most growers assume that the advantage to using a manure based compost is increased nitrogen, but the total nitrogen available from the paper based compost was .95% and organic matter was 33.9%, higher than the manure based compost. This compost was ~ 7 months old and the starting materials were paper sludge and yard waste. The paper-based compost had not been screened so was difficult to use. It has excellent water retention properties and was quite moist when applied which also made hand application more challenging.
In addition to cantaloupe yield and quality, measurements were taken on the types and quantity of weeds. Crop vigor was observed. Tissue samples were taken from each plot to monitor the nutrient status of the crop in each treatment. Soil moisture levels were visually monitored. The trial was evaluated three times a week during harvest and pest problems were recorded.
The control and herbicide plots set fruit and ripened earlier than both compost trials by 5-7 days. The average individual fruit weight was significantly greater for melons grown with paper compost between the alleys with manure based compost yield close behind. The greatest overall yield came from the manure based compost treatment.
An extremely wet summer encouraged disease and weed pressure. By July 6th, both the control and the post-emergent herbicide treatments had over 75% of the between row test area covered with weeds while only one of the compost replications reached that level of weed pressure a month later. On August 5th, all of the control reps were at 100% weed pressure and the weeds were very mature. None of the treatments received any hand weeding and the herbicide treatment had an application failure. By August 13th, the compost treatments had reached at least 80% weed infestation and at that point most of the weed seeds had germinated. It seemed that weed species were consistent throughout the trial – most of the weeds had germinated below the mulch. Weeds were primarily annuals, including ragweed, lambsquarters, pigweed and a few examples of velvetleaf. Perennials represented approximately 20% of the weed pressure and included grass, bedstraw, clover and a small population of nutsedge.
Because of the high moisture during the entire season, we can only comment that only on a very few occasions did we see wilting in the field in certain areas that were not in our trial. We never saw any plants in any of our treatments wilt.
The heavy weed population and high moisture resulted in a major disease problem. Alternaria spp. were isolated, but we believe that the most profound vine loss was caused by Angular Leaf Spot and powdery mildew (despite the resistance that Athena has to powdery mildew). Unfortunately, the greenhouse where these seedlings were started had a major fungal problem and many of the seedlings were infected prior to transplanting. Despite alternate sprays with Quadris and Bravo and occasional sprays of Oxidate, by August 5th all of the Control and Herbicide reps had experienced 100% infection, while the compost treatments were between 5 and 35% infection and no vine death. On August 23rd, over 95% of the vines had died on all of the control plots (including the ineffective herbicide reps). 40% of the vines had died on the manure based compost and just over 60% of the vines were dead on the paper based compost. 93% of the compost treatment vines were infected.
Yield on all plots was discouraged by disease pressure and weed pressure.
Leaf analysis results showed some difference in the plants grown with compost between rows. Paper based compost may have resulted in higher levels of Molybdenum, Boron and Magnesium with lower Manganese levels; Manure based compost showed slightly higher levels of Sodium, Boron and Magnesium. Leaf edges on both compost treatments were chlorotic in mid-August.
In summary, it seems that using compost in a plasticulture vegetable production system may result in slightly delayed yield, but weed control is enhanced at the beginning of the season. Although we still can only presume about the effects of compost when compared to an appropriately timed herbicide spray and a pre-emergent herbicide application.
Overall yield was respectable, but comparison is difficult due to vine death from disease. The fact that the compost treatments did not succumb to the same disease pressure is noteworthy. Perhaps early season weed control helped maintain good air movement in the compost treatments and reduced infection caused by soil splashing. There have also been many studies suggesting the presence of a disease suppressive characteristic in compost.
This project did not clearly illustrate a difference between the two different types of compost. It also did not give us a good comparison between herbicide treated alleys and compost treated alleys due to the failure of the herbicide and the high disease pressure.
This research trial did point out one clear thing. Compost plays a role in the suppression of weeds during the first part of the season and then later in the season plays some role in the suppression of disease. These two relatively unremarkable factors may have enough of an additive effect that growers will see the benefit to incorporating compost into their vegetable production systems.
This project illustrated the benefits of compost clearly to the 10 growers that attended our field meeting. One grower has been trying to modify a large manure spreader to accommodate compost distribution in vegetable fields.
Compost producers may be encouraged by our findings. Kevin Booth, the manure based compost maker, supplies many local growers with his product. He made a point to have photos of our trial along with results posted at his booth at the Washington County Fair.
This study works well with our ongoing investigation into biodegradable mulches. The waste disposal problem of traditional black plastic mulch has become a real challenge, so this topic continues to be an important area of research for our growers. Washington County vegetable farmers have grown on paper, photo-degradable, and bio-degradable mulch products.
In summary, it seems that using compost in a plasticulture vegetable production system may result in slightly delayed yield, but weed control is enhanced. Overall yield was respectable, but comparison is difficult due to vine death from disease. The fact that the compost treatments did not succumb to the same disease pressure is noteworthy. Perhaps early season weed control helped maintain good air movement in the compost treatments and reduced infection caused by soil splashing.
Education & Outreach Activities and Participation Summary
In early August we held a twilight meeting that looked at the progress of the trial. At that point the harvest had just barely begun, but 10 growers were able to look at weed pressure and very obvious disease control in the compost plots. A poster illustrating this project will be on display this winter at the Empire Expo, a vegetable growers meeting held in Syracuse in February, 2006. An article about this project was included in the AgDigest that is distributed to 150 farmers in Washington County.
This project is important because it investigates the value of a local product – compost, to a local industry – vegetable farming. It is our hope that the municipal/industrial compost will prove to be beneficial to those vegetable crops in high fertility soils while still helping to control weeds and add organic matter. This material will not replace manure based compost, but rather offer vegetable farmers an alternative.
The possibility that yield could be encouraged, herbicide use could be reduced and a bit of disease suppression would result from incorporating compost into an intensive plasticulture system is encouraging for farmers attempting to raise soil organic matter.
Areas needing additional study
One question that was brought up due to the rather inconclusive data from out experiment: Is it possible that the delay in disease incidence seen in the compost treated replications have something to do with Inducing resistance to fungal diseases? Our initial thought was that the lower incidence of disease in the compost treatments had more to do with reducing soil splashing than it did with resistance induction. However it has been shown that compost does inhibit disease induction or otherwise discourage the activity of soil-borne fungi as well as foliar fungi.
Additionally, we have no real data about the effect the compost had on the long term soil health of those plots that were covered with both the manure based compost and the paper based compost. It would be important to test the soil health in fields that utilize this production strategy for several years at a time.