an introduCtion
The purchase of plant food is an important matter, but the use of a [fertilizer] is not a cure-all, nor will it prove an adequate substitute for proper soil handling.
—J.l. hills, C.h. Jones, and C. Cutler, 1908
Of the eighteen elements needed by plants, only
soil fertility management, they also cause widespread
three—nitrogen (N), phosphorus (P), and potassium
environmental problems. Poor soil and crop manage-
(K)—are commonly deficient in soils. Deficiencies of other
ment; overuse of fertilizers; misuse of manures, sewage
nutrients, such as magnesium (Mg), sulfur (S), zinc (Zn),
sludges (biosolids), and composts; and high animal
boron (B), and manganese (Mn), certainly occur, but they
numbers on limited land area have contributed to sur-
are not as widespread. Deficiencies of sulfur, magne-
face and groundwater pollution in many regions of the
sium, and some micronutrients may be more common
U.S. Because both N and P are used in large quantities
in regions with highly weathered minerals, such as the
and their overuse has potential environmental implica-
southeastern states, or those with high rainfall, such as
tions, we’ll discuss them together in chapter 19. Other
portions of the Pacific Northwest. On higher-pH calcare-
nutrients, cation exchange, soil acidity (low pH) and
ous soils, especially in drier regions, keep an eye out for
liming, and arid and semiarid region problems with
deficiencies of iron, zinc, copper, and manganese. In con-
sodium, alkalinity (high pH), and excess salts are cov-
trast, in locations with relatively young soil that contains
ered in chapter 20.
minerals that haven’t been weathered much by nature—
such as glaciated areas with moderate to low rainfall like
THE bOTTOM lINE: NUTRIENTS AND PlANT HEAlTH,
the Dakotas—K deficiencies are less common.
PESTS, PROFITS, AND THE ENVIRONMENT
Environmental concerns have resulted in more
Management practices are all related. The key is to
emphasis on better management of N and P over the
visualize them all as whole-farm management, lead-
past few decades. While these nutrients are critical to
ing you to the goals of better crop growth and better
Photo by Dennis Nolan
203
Building SoilS for Better CropS: SuStainaBle Soil ManageMent