FOOD TECHNOLOGY

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Monday December 11, 2017

Why use so much fertilizer?

Nitrogen, the chemical element that makes up 78 percent of the air you breath and the fertilizer element most heavily applied to Nebraska's corn and other crops, has become such an environmental problem that the government may soon tie farmers' government payments to the amount of nitrogen they can avoid using. Too much of the natural element washes off farmers' fields every year and ends up in stream beds and river deltas, according to experts, including a vast portion of the Gulf of Mexico at the mouth of the Mississippi. Once there, it in effect fertilizes the stream- and ocean-beds, causing miscropic animals and plants to over-produce and choke off other more beneficial species.

Although tying USDA benefits programs to fertilizer management raises numerous questions, one immediate question your shoppers may have is a basic one: If so much nitrogen washes away, why do farmers continue to use so much of it?

In a word: It's effective. Both here and around the world, the great success story of agricultural productivity that, according to National Review correspondent and director Kevin D. Williamson in his Feb. 22 article "Planet Nebraska" has made Nebraska agriculture not only the epitome of successful capitalism but the best hope to feed the world's hungry, has been driven in great part by the use of commercial fertilizer. The estimates for how much of crop production can be credited to nutrient inputs range from about 30 percent to as much as half for the major grains, according to soil scientist Mike Stewart and plant nutritionist Terry Roberts. Their most recent review of the scientific literature shows one-third of the increase in cereal production around the world and half of the increase in India’s grain production during the 1970s and 1980s was due to more and better use of fertilizer. Since the mid-1960s, from half to as much as 75 percent of the increased output of the farms in Asia's developing nations has been attributed to better use of fertilizer.

A study by Texas A&M University in 1990 modeled the production change that could be expected in the absence of commercial nitrogen-based fertilizer, using estimates by leading crop scientists from the major growing states. The results point the importance of fertilizer to maintaining supplies of the important grains.

How many fewer crops would we grow without fertilizer?

A quartet of European agronomy scientists put the value of fertilizer in even more stark terms in a 2008 review of the subject:

"Overall, we suggest that nitrogen fertilizer has supported approximately 27 percent of the world’s population over the past century, equivalent to around 4 billion people born...since 1908. ...We estimate, that by 2000, nitrogen fertilizers were responsible for feeding 44 percent of the world’s population. Our updated estimate for 2008 is 48 percent — so the lives of around half of humanity are made possible by Haber–Bosch nitrogen [the process that allows scientists to extract nitrogen from the air and use it as fertlizer]."

Although farmers fertilize because it improves their bottom line, it's not just a question of farm economics alone, as Williamson points out in his National Review article. "This is, for better and for worse, how it is supposed to work: Poor people get to eat, farmers get paid...." Indeed, as Stewart and Roberts point out, if the world will need 70 percent more food in 2050 than it grew in 2005, only one of three ways can make that happen: Produce more with land already in production, put vast amounts of new land into production, or do both. Putting more land into production will be a problem, they argue, because of issues like lack of infrastructure and technology, environmental concerns, politics and other opposition. That's one reason the number of humans supported per hectare of usable land has already increased from 1.9 to 4.3 persons between 1908 and 2008. As a result, the U.N.'s Food and Agriculture Organization has estimated that by 2050 an estimated 90 percent of the growth in crop production globally (and 80 percent in developing countries) will come from higher yields and increased cropping intensity, with only the remaining 10 percent (or 20) coming from land expansion.  It's apparent from history that increased use of fertilizer will come along with, or cause, those increases in food production per acre of land.

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