Crop yields affect the amount of food produced in any nation. A number of studies have shown that simply adding a basic N-P-K fertilizer to a formerly-unfertilized field will more than double yields. In the developed world, using fertilizer is the norm. But in the developing world, much of the agricultural land does not use fertilizer at all. Sometimes the farmer uses a technique of leaving the land fallow for a time. Another approach is to use manure as a natural fertilizer. However, manure is not nearly as effective as N-P-K.
An important meta-study (a review of other studies) was published in Agronomy Journal, 2005, “The Contribution of Commercial Fertilizer Nutrients to Food Production”. [W. M. Stewart, et al., The Contribution of Commercial Fertilizer Nutrients to Food Production, Agronomy Journal, vol. 97, Jan-Feb, 2005, n. 1] The study is crucial to our analysis of contributing problems to world hunger. Yields for a wide range of staple crops are much higher in the developed world, than in the developing world, especially for subsistence farmers, who depend on successful crops for their very survival. The lack of fertilizer is a significant cause of low yields. To what extent? Let’s take a look.
“Food production for the expanding world population has required the development and application of new technology and an intensification of management to produce more food per unit of land. This new technology and intensified production often involve a greater need for commercial fertilizer nutrients to avoid nutrient depletion and ensure soil quality and crop productivity. The need for increased inputs correctly raises questions about associated risks. Potential risks are often widely publicized while the associated benefits of an abundant, affordable, and healthful food supply can be overlooked or understated.” (Ibid.)
In other words, we shouldn’t deny artificial commercial fertilizer to the developing world merely out of a concern for the environment. Organic food production may result in healthier food and lower impact on the environment, but the needs of the hungry outweigh those values. First, feed the world.
In the U.S., one study found that 46% of the wheat yield (1989 to 1998) is attributable to fertilizer (nutrient inputs). [Ibid, citing University of Missouri Sanborn Field study.] In other words, a fertilized field produces 85% more wheat than an unfertilized field (100/54 = 1.85). The same study found that 77% of the wheat yield was attributable to fertilizer from 1979 to 1988, representing an increase of over 4 times (100/23 = 4.35).
Another U.S. study found that 67% of the corn yield (1995 to 2000) is attributable to fertilizer. [Ibid, citing University of Illinois Morrow study.] In other words, yields triple with fertilizer, compared to without fertilizer (100/33 = 3.0). A U.K. study found that 76 to 82% of the wheat yield is due to nitrogen in the fertilizer. [Ibid, citing a Rothamsted, England study.] This translates to an increase in yield of more than 5 times (100/18 = 5.55).
Studies in Brazil and Peru found that new agricultural land had an even heavier dependency on fertilizer. From 80 to over 90% of crop yields, for several different staple crops (rice, soybean, cowpea, and corn), were attributed to fertilizer. [Ibid, citing Brazil (Cravo and Smyth, 1997) and Peru (Alegre et al., 1991).] This implies a 5- to 10-fold increase in yield (100/20 = 5 and 100/10 = 10).
The above-cited meta-study (Stewart 2005) concludes that commercial fertilizer is indispensable in order to feed the world:
“Taken together and recognizing the uncertainty discussed previously in such estimates, it seems that without commercial fertilizer N, P, and K, crop production in the USA would decline at least 50% over time.”
“The data from the long-term studies discussed in this paper represent 362 seasons of crop production…. These data all support the oft-cited generalization that at least 30 to 50% of crop yield is attributable to commercial fertilizer nutrient inputs, and that is probably a conservative estimate. Commercial fertilizers make up the majority of nutrient inputs necessary to sustain current crop yields, with available organic sources, native soil reserves, and biological N fixation supplying the remainder. Using these inputs efficiently and in concert is essential in today’s agriculture and will be even more important in years to come. To produce the nutritious food supply needed to meet the demands of a growing and more affluent world population, the appropriate and effective use of nutrients supplied from commercial fertilizers is imperative.”
The U.S. would lose half its crop yields without fertilizer; in other words, fertilizer in the U.S. doubles yield. The often-cited 30 to 50% generalization (percent of yield attributable to fertilizer) is “probably a conservative estimate”. In some cases, a much higher percent of yield is due to fertilizer.
Adding fertilizer to the unfertilized fields of developing nations can increase yields very substantially, producing more food from the same land, time, and labor.