SOMETHING THAT SOLD ME ON WOOD CHIPS.
Wood Chips in Vegetable Production
Brian Caldwell
A major problem in vegetable production is maintaining high soil quality in the face of
typical practices that work against it. Vegetable growing involves intensive tillage,
cultivation, exposure of almost
bare soil to the sun and rain for long periods, and heavy
traffic from people and equipment. All of these tend to destroy soil organic matter and
soil structure while increasing soil compaction. This reduces yield over the long run
because it creates a poor environment for root growth and function; also the soil
biological community is adversely affected. Soils with poor quality cannot retain
sufficient nutrients and moisture.We can address this problem in several well
known ways. These include. Adding compost, manure , mulches, and other organic residues
Reducing the intensity and frequency of tillage
Growing cover crops, especially legume sods
Restricting wheel and human traffic to specific areas of the field, such as grass
aisles or drive lanes. In addition to these common methods, it appears that there is another
adding wood chips to the soil. From 1951 to1965, a remarkable experiment was carried out on a Soil
Conservation Service research farm in Marcellus, NY. The project is written up in a 1971
Cornell bulletin called, “Soil Management for Vegetable Production on Honeoye
Soil with Special Reference to the Use of Hardwood Chips” by G. R. Free. This 15
year study used a 5 year vegetable rotation of sweet corn, beans, tomatoes, cabbage, and peas.
It compared 14 different treatments, including several in which 10 tons per acre moist
weight (7 tons dry weight) of wood chips were added each year. Other treatments looked
at using overwintered ryegrass or bromegrass cover crops, and more extensive rotations
in which legume sod hay crops were substituted for the beans and tomatoes. The hay
crops were harvested and removed, not simply plowed under. Crops were fertilized with
chemical fertilizers and (as seems likely) probably sprayed for pests and weeds. Crops
were also cultivated for weed control.
Some results were apparent within a few years and continued for the duration of the
project. Yields of most crops were improved with the addition of wood chips and best
when the chips were topdressed on the soil surface after the crops were planted instead of
being plowed under. Over the years, soil organic matter (SOM) and nitrogen increased in
the chip amended plots, while they dropped in the chipless plots without cover crops.
Including yearly grass cover crops allowed SOM and soil nitrogen to stay at about an
even level over the 15 years
