Definition - What does Macropore mean?
Macropores are large pores (or small holes) in the soil that helps aerate the soil and allow moisture to drain. They occur between the various aggregates that comprise the soil. As a general rule, macropores are larger than 0.88 millimeters (0.035 inches) in diameter.
Soil structure is paramount for gardening, and soils lacking in macropores cannot drain adequately or grow crops.
MaximumYield explains Macropore
Soil may be comprised of many different aggregates of clay, sand, or loam. Macropores are the large pores through which water and roots are able to move.
Without macropores, soil wouldn’t be porous and water would never be able to leach through. Roots would have no space to grow to feed and stabilize a plant. Seeds would not be able to germinate without pores in which to produce a shoot.
Soil drains at a rate proportionate to the composition of macropores. Heavy soils like clay are low in macropores while light soils comprised mainly of sand have more and larger macropores. Organic matter can be worked into the soil to increase the number of macropores and “lighten” the soil.
There are also farming practices that can improve soil structure. This includes growing a cover crop, conservation crop rotation, and prescribed grazing. Improved residue and tillage management practices can improve soil structure and the presence of macropores.