The Environmental Upside of Modern Farming

New methods rooted in low-impact, precision techniques require less land, less energy and fewer chemicals than traditional agriculture

By Robert Paarlberg. Mr. Paarlberg is an associate in the Sustainability Science Program at the Harvard Kennedy School of Government. Excerpts:

"If you wanted to produce food at the lowest cost to the environment, what methods would you use? Would you select modern farming methods (large-scale, specialized, mechanized and increasingly digital), or would you opt for traditional farms that are small and low-tech? Environmentalists often prefer the latter, having seen the damage that modern farms can do.

But the sustainability of traditional American farming was mostly an illusion. Farm production in the U.S. has nearly tripled over the past 70 years, according to the U.S. Department of Agriculture, and trying to pull that off using the low-tech methods of the past—which delivered lower yields per acre—would have meant that more forests would have been lost, more fragile lands plowed and more natural habitats destroyed.

Modern farming is better because it uses low-impact, “precision” techniques that require less land, less energy and fewer chemicals for every bushel produced. The secret has been to incorporate tools that use sensors, information and communications technology, big data, and even machine learning to reduce farming’s dependence on material resources.

Traditional farming had already failed as a protector of the environment nearly a century ago—and scientific advances have long offered new ways to help the planet. In the 1930s, after low-yield cropping was extended onto the drought-prone Southern Plains, the soil blew away, creating the disastrous Dust Bowl. Cropland expansion could finally be halted in the 1950s, once scientists had developed higher-yielding hybrid seeds. In the 1970s, engineering advances allowed farmers to plant seeds in unplowed fields, which reduced erosion, conserved soil moisture, sequestered carbon and saved on diesel fuel.

New irrigation systems then began to replace wasteful flooding, while lasers leveled the fields to eliminate surface runoff. In the 1990s, farm tractors acquired GPS auto-steering, which ended wasteful gaps and overlaps in the field. This was followed by digital soil mapping, which could tell “smart” farm equipment to apply chemicals at variable rates tailored to each location’s differing soil characteristics. The spacing of seeds can also be varied with astonishing, sub-inch precision thanks to modern GPS equipment. And genetically engineered seeds now allow farmers to protect against weeds and insects with fewer chemical sprays.  

These innovations were more affordable for larger farms, so average farm size more than doubled, but when farm production surged in the late 20th century, the environment was better protected. Corn production in the U.S. increased fivefold between 1940 and 2010, but total acreage planted to raise corn actually declined by one-fifth"

"For every bushel of corn produced, water use and energy use also decreased. Since 1980, irrigation water use per bushel has fallen by 46%, energy use by 41% and greenhouse-gas emissions by 31%"

"total fertilizer use in U.S. farming peaked in 1981, and since then it has remained essentially flat, even as total crop production grew 44%. For pesticides, the total pounds applied to U.S. crops declined by 18% in absolute terms between 1980 and 2008, with insecticide use now more than 80% below its 1972 peak."

"each million pounds of milk produced in the U.S. today requires 90% less land compared with 1944—and 79% fewer animals. Fewer cows means not only less manure but also less methane belched into the atmosphere to threaten our climate."

"the climate burden of a single glass of milk in the U.S. today is two-thirds smaller than it was in 1950."