Soil Compaction and Root Growth: A Review

Abstract Adverse effects of soil compaction on crop production have been recognized for many years. The objectives of this report were to briefly review the early literature, review the contributions of Dr. Howard M. Taylor (1924–1991) and co‐workers, examine the current status of soil compaction and root growth research, and identify research needs related to soil compaction and root growth. Early in his career, Dr. Taylor and co‐workers established relationships among soil strength, soil water content, and seedling emergence and root growth. These studies showed that root growth and distribution were altered to the point that water and nutrient uptake, and, hence, plant growth and yield, were reduced when soil strength reached critical levels due to natural or induced compaction. That research formed the basis for our current knowledge concerning the effects of compaction on root growth and the alleviation of compaction through soil and tillage management. Usually, not all parts of a root system are equally exposed to compaction under field conditions. Hence, because of compensatory growth by unimpeded parts of the system, only the distribution and not the total length of roots may be altered. Even if compaction limits root growth, weather events sometimes enhance or diminish the effect of root limitation on crop growth. To reduce risks in dry years and to use applied nutrients efficiently, managing soils through the use of tillage and related practices and growing of deep‐rooted crops in rotations will help avoid or alleviate compaction, thus improving root distribution and increasing rooting depth.