organiC Matter, soil PhysiCal Condition, nutrient availability
Because organic matter is lost from the soil through decay, washing, and leaching, and because large amounts are required every year for crop production, the necessity of maintaining the active organic-matter content of the soil, to say nothing of the desirability of increasing it on many depleted soils, is a difficult problem.
—a.F. gustafson, 1941
Increasing the quality of a soil—enhancing it as a
practices, in addition to those that directly impact soil
habitat for plant roots and beneficial organisms—takes
organic matter. Paying better attention to soil tilth and
a lot of thought and action over many years. Of course,
compaction is more important than ever, because of the
there are things that can be done right off—plant a cover
use of very heavy field machinery. Last, although good
crop this fall or just make a New Year’s resolution not to
organic matter management goes a long way toward
work soils that really aren’t ready in the spring (and then
providing good plant nutrition in an environmentally
stick with it). Other changes take more time. You need
sound way, good nutrient management involves addi-
to study carefully before drastically changing crop rota-
tional practices. In this chapter we’ll focus on issues of
tions, for example. How will the new crops be marketed,
organic matter management.
and are the necessary labor and machinery available?
All actions taken to improve soil health should
ORgANIc MATTER MANAgEMENT
contribute to one or more of the following: (a) growing
As we discussed in chapter 3, there are no generally
healthy plants, (b) stressing pests, and (c) increasing
accepted guidelines as to how much organic matter
beneficial organisms. First, various practices to build
should be in a particular soil. And it is difficult to be
up and maintain high levels of soil organic matter are
sure exactly why problems develop when organic matter
key. Second, developing and maintaining the best pos-
is depleted in an individual field. However, even in the
sible soil physical condition often require other types of
early 20th century, agricultural scientists proclaimed,
Photo by Jerry DeWitt
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Building SoilS for Better CropS: SuStainaBle Soil ManageMent