Building Soils for Better Crops, Third Edition

Summary and Sources



It is very difficult, if not impossible, to come up with a meaningful monetary value for the worth of organic matter in our soils. It positively affects so many different properties that taking them all into account and figuring out their dollar value is an enormous task. One study published in 2004 estimated the value of nitrogen contributions and the added water availability from increased organic matter. In 2008 dollars, their estimates for just those two aspects would amount to about $20 per acre per year for every extra percent of organic matter.


Soil organic matter is the key to building and maintaining healthy soils because it has such great positive influences on essentially all soil properties—helping to grow healthier plants. It also plays a critical role in the water, nitrogen, and carbon cycles. Organic matter consists mainly of the living organisms in the soil (“the living”), the fresh residue (“the dead”), and the very well decomposed (or burned) material (“the very dead”). Each of these types of organic matter plays an important role in maintaining healthy soils.


Allison, F.E. 1973. Soil Organic Matter and Its Role in Crop Production. Amsterdam: Scientific Publishing Co.

Brady, N.C., and R.R. Weil. 2008. The Nature and Properties of Soils, 14th ed. Upper Saddle River, NJ: Prentice Hall.

Follett, R.F., J.W.B. Stewart, and C.V. Cole, eds. 1987. Soil Fertility and Organic Matter as Critical Components of Production Systems. Special Publication No. 19. Madison, WI: Soil Science Society of America.

Lehmann, J., D.C. Kern, B. Glaser, and W.I. Woods, eds. 2003. Amazonian Dark Earths: Origin, Properties, ManagementDordrecht, Netherlands: Kluwer Academic Publishing.

Lehmann, J., and M. Rondon. 2006. Bio-char soil management on highly weathered soils in the humid tropics. In Biological Approaches to Sustainable Soil Systems, ed. N. Uphoff et al., pp. 517–530. Boca Raton, FL: CRC Press.

Lucas, R.E., J.B. Holtman, and J.L. Connor. 1977. Soil carbon dynamics and cropping practices. In Agriculture and Energyed. W. Lockeretz, pp. 333–451. New York: Academic Press. See this source for the Michigan study on the relationship between soil organic matter levels and crop-yield potential.

Manlay, R.J., C. Feller, and M.J. Swift. 2007. Historical evolution of soil organic matter concepts and their relationships with the fertility and sustainability of cropping systems. Agriculture, Ecosystems and Environment 119: 217–233.

Oshins, C., and L. Drinkwater. 1999. An Introduction to Soil Health. [A slide set available at the Northeast Region SARE website:][this slide set no longer available online]

Powers, R.F., and K. Van Cleve. 1991. Long-term ecological research in temperate and boreal forest ecosystems. Agronomy Journal 83: 11–24. This reference compares the relative amounts of carbon in soils with that in plants.

Stevenson, F.J. 1986. Cycles of Soil: Carbon, Nitrogen, Phosphorus, Sulfur, Micronutrients. New York: John Wiley & Sons. This reference compares the amount of carbon in soils with that in plants.

Strickling, E. 1975. Crop sequences and tillage in efficient crop production. Abstracts of the 1975 Northeast Branch American Society Agronomy Meetings, pp. 20–29. See this source for the Maryland experiment relating soil organic matter to corn yield.

Tate, R.L., III. 1987. Soil Organic Matter: Biological and Ecological Effects. New York: John Wiley & Sons.

Weil, R., and F. Magdoff. 2004. Significance of soil organic matter to soil quality and health. In Soil Organic Matter in Sustainable Agriculture, ed. F. Magdoff and R. Weil, pp. 1–43. Boca Raton, FL: CRC Press.

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