Agriculture Reference
In-Depth Information
Amount of fertilizer in mature orchards.
As our organic orchard matures
and we develop organically rich soils and nitrogen-fixing alley and/or com-
panion crops, determining how much nitrogen fertilizer to apply becomes
much more complicated. We need to account for the nitrogen that is fixed in
the alley and companion crops and available to our fruit crops. We also need
to account for the estimated amount of nitrogen that becomes available to
plants each year as the soil organic matter decomposes.
The most effective strategies are to 1) carefully observe and document
tree growth and productivity each year, and 2) use annual foliar tissue ana-
lyses and compare them with your observations. Be consistent each year in
where you sample and from which varieties. Keep the samples for different
crops and varieties separate. Keep accurate records of alley crops, compan-
ion crops, and types and amounts of compost, fertilizers, mulches, and other
materials added to the orchard. At the end of each growing season, try to
determine how these practices affected your crops.
In the long term, we want to greatly reduce or eliminate the need for
off-farm nitrogen fertilizers. Our focus will be on building abundant supplies
of soil organic matter and developing an orchard floor management system
that helps provide or conserve nitrogen and make it available to our fruit
trees.
How and Where to Apply
Because we are covering many different crops, ranging from a few trees to
large commercial plantings, it is hard to make specific recommendations on
how to apply fertilizers. It is most important to make accurate applications.
For large orchards, dry, granular fertilizers and soil amendments are often
broadcast using cone spreaders mounted on the backs of tractors. Some
fertilizer spreader designs allow the product to be applied in narrow bands
along the tree rows. Smaller cone spreaders are available that work with
garden tractors and ATVs (all-terrain vehicles). For smaller orchards, hand-
held spreaders (belly grinders) can be used to broadcast fertilizers across
