Preparing a new tract of land for planting is one of the challenges of the small grower, especially if the hobby farm you purchased hasn't been used for crops in many years. Vehicles, livestock, or just the natural qualities of the soil can compromise crop growth if you don't anticipate and remedy soil issues. The following can help you overcome compaction issues before you plant.
Compacted soil has many causes, but the result is always the same—hard soil that prevents plants from sending out deep roots. There are also other concerns beyond initial plant growth. Compacted soil doesn't absorb water well, so irrigation tends to run off and does your plants little good. The same goes for any fertilizers you apply to your crops. For healthy growth, you need loose, friable soil.
There are two types of compaction to understand on a hobby farm, surface and subsurface. Surface compaction is of smaller concern, since it is simple enough to till the top several inches of the soil before planting each crop in your rotation. Surface compaction can also be remedied by increasing the amounts of amendments, such as manure, that is added before planting.
Subsurface compaction is typically the result of heavy use, such as on former grazing land or plots with previous heavy machinery exposure, combined with heavier soils, such as clay, that are more naturally prone to compaction. This results in drainage issues below the usual till zone, so it can be easy to overlook this as the cause of poor crop performance.
Diagnosing and fixing subsurface compaction
Fortunately, there are tools and methods to diagnose and repair compaction. A soil penetrometer is a device that is inserted into the soil to judge compaction. It consists of a pressure-responsive spike topped by a pressure gauge, so you get an immediate readout on the depth and severity of the compaction.
If you find compaction, then there are deep tilling and soil fracturing methods that can help break it up and improve the soil drainage and permeability in your field. Which method is used will depend on the depth and extent of the compaction. For most smaller fields, a cultivator with deep-reaching spikes will be sufficient to break through a relatively thin layer of hardpan subsurface compaction. This may need to be repeated every few years, since regular tillage activities can cause this layer of compaction to reform.
For more help, talk to a penetrometer manufacturer like Certified Material Testing Products in your area.