Agriculture Reference
In-Depth Information
While the recycling is commendable and the materials are generally
available in large quantities at low cost, beware! Such mulches have
been found to be contaminated with pesticides from roadside and home
herbicide and pesticide applications. Determining whether a municipal
source of mulch or compost is pesticide-free may be impossible.
If you choose to incorporate uncomposted woody materials into your soil,
add nitrogen at the same time. For every cubic yard of bark, hardwood saw-
dust, or hardwood wood chips, add 4 to 5 pounds of actual nitrogen the first
year and half that amount the following year. For straw and softwood saw-
dust or chips, apply 2 to 2.5 pounds of nitrogen the first year and half that
amount the following year. In this case, if you were adding one cubic yard
of hardwood sawdust and wanted to provide the nitrogen in the form of dry,
composted cattle manure (approximately 0.5 percent nitrogen), you would
need to add about 800 pounds of manure. Leaving uncomposted woody ma-
terials on the soil surface as mulches usually does not deplete soil nitrogen,
and supplemental nitrogen often does not need to be applied.
Adding uncomposted woody materials as a soil amendment can require
large quantities of the amendment and nitrogen fertilizer. Time is another
factor. If you incorporate uncomposted woody materials into the soil, it is
best to wait at least one full year (preferably two or more) before planting
trees, even when you apply extra nitrogen. From these standpoints, amending
soil with sawdust and similar materials is seldom feasible except for the
smallest orchards.
Green Manure Crops
An effective way to add organic matter to the soils of orchards large and
small is to grow one or more green manure crops and cultivate them into the
