Hybrid Mulching Effects on Vegetable Crop Productivity, Weed Dynamics and Soil Quality

Hybrid Mulching Effects on Vegetable Crop Productivity, Weed Dynamics and Soil Quality

Summary

It is critical that we reconsider the intensive tillage used in our current cropping systems. Ironically, as farmers work towards more sustainable cropping systems by reducing their reliance on herbicides, the frequency and intensity of tillage often increases and, consequently, soil quality declines. In northern agronomic zones, the surface residues in no-till systems result in cool spring soil temperatures resulting in poor crop emergence and generally unacceptable yields. The “hybrid-mulch” system described by Louis Lego offers a solution to the soil temperature problem by exploiting the thermal properties of black plastic-covered beds.

We propose systems comparison and associated “component” experiments to be conducted at the University of Maine Farms, and commercial farms. These experiments will investigate cash crop performance, selected soil quality parameters and weed seed bank dynamics over the three-year life of a hybrid-mulch system. A 3-year vegetable rotation will be grown in hybrid mulched perennial beds, in hybrid mulched annual beds, and in conventional spring-formed beds.

Objectives/Performance Targets

On-farm and Experiment station research will demonstrate and develop refinements to the hybrid mulch production system tailoring it to Maine and other northern growing conditions.

Three hundred farmers will observe the hybrid mulch cropping system. Thirty-five farmers will use the hybrid mulch system in at least one of their fields resulting in: decreased tillage, improvements in soil health, decreased weed competition, and increased economic returns.

Accomplishments/Milestones

Fifty mixed vegetable growers observed the hybrid annual beds established in the fall of 2003 during a twilight meeting held at Highmoor Farm in September of 2005. Additionally, 125 growers learned about the project at the Maine Small Fruit and Vegetable Growers Association winter meeting held in January of 2005.

Two experiments were established at Highmoor farm in the fall of 2004. One experiment to compare three crop rotations over a three-year period in hybrid mulched perennial beds (1, tomatoes-cucumbers-pumpkins; 2, pumpkins-cucumbers-tomatoes; 3, pumpkins-tomatoes-cucumbers). The second experiment (systems experiment) was to compare hybrid mulched perennial beds, hybrid mulched annual beds with the inter-row cover crop managed either by mowing or by herbicides, and conventional spring-formed beds. The beds were established in late October, 2004, much later than expected due to the frequent rains experienced during August and September. Fortunately, October and November were milder than usual allowing the inter-row cover crop to get partially established. Our team has some concerns about how well the system may work with such a late planting and will create additional research plots in the fall of 2005. Because of the difficulties due to the weather in the fall of 2004 no grower field plots were set-up.

The experimental plots established in 2004 were planted with cash crops in June of 2005. The crops were harvested and the data is currently under analysis. Initial evaluation of the yields in the rotational study appears to indicate little yield loss due to competition between the cash crop and the inter-row mulch. The inter-row area had been seeded with perennial rye, however, by the end of the 2005-growing season the living mulch is nearly 100% Dutch white clover. The inter-row area of the crop rotation study was easily managed by mowing the cover crop three times during the growing season prior to the time the vines of the cucurbit crops ran off the plastic filling the inter-row area. All of these beds were in excellent shape going into the 2005/2006 winter and will be planted again in 2006.

We had trouble in establishing the cash crops in the systems comparison experiment. Several plots exhibited stunted or reduced growth in both the experimental plots and guard rows. The plots with the poor growth were located on a section of field where there may have been herbicide carryover from the previous crop.

In the fall of 2005 on farm research plots were established at three grower locations, and University of Maine, Highmoor Farm and Roger’s Farm. Two other growers came forward saying that after seeing some of the initial experiments in perennial beds they had began using the system in 2003 and we will be working with these growers in the coming season.

In June of 2005, a M.S. graduate student began working with this project.

Impacts and Contributions/Outcomes

The growers we have communicated with regarding the project are very enthusiastic. However, the issue of time management of making planting beds in the fall is difficult to solve, particularly during wet falls. The two growers currently using beds multiple years are making the beds in the normal fashion in the spring and simply keeping the beds in place until the plastic becomes unusable. One of the growers has commented that tomatoes on second year plastic are easier to manage.

Collaborators: