Country roads often have axle load limits of 10 ton while large combines or grain carts, when fully loaded, can have axle loads up to 40 ton. Confining wheel traffic to specific traffic lanes in a field is an excellent way to manage compaction. Dry soils can be hard but this does not necessarily indicate that the soil is compacted. There are many visual symptoms of soil compaction that can be observed in the field-dark soil streaks, ponded water, accelerated runoff, increased power requirements, excess soil moisture, delayed crop emergence and poor crop growth, crop color, abnormal root development, and early plant water stress. CRP fields should have no compaction because of the lack of wheel traffic and tillage over a 10-year period.
Compaction can influence plant nutrition, pest problems and control as well as plant growth.
USDA scientists have developed new technology that modifies the traditional corn plant and results in cleaner water. When corn is used as feed for pigs and chickens, the amount of phosphorus in the animals' waste has now been cut in half. This is great news for those of us who want to reduce the amount of nutrients running into our waters. Excess phosphorus in manure has been identified as a serious pollutant in bodies of water from on both coasts. Rain and other runoff can carry phosphorus-containing soil to nearby lakes and streams.