June 4, 2015

Large farms are good for the environment. True or False?

We often hear about the restructuring/purchasing of smaller farms to make larger ones in agriculture today. This could be with livestock or crop farms. How does the size of the farm affect our environment? Is bigger better or worse? As tomorrow is World Environment Day, and while this can be viewed as an event that discourages modern agriculture, we want to embrace our efforts to conserve our environment. Let’s look into it…

Production agriculture operations or farms have an impact on the environment by using the nation’s soil, water, or air. Larry Jacobson, professor in bioproducts & biosystems engineering department at the University of Minnesota and a BestFoodFacts.org expert looks at each of these factors separately.


Production agriculture uses soil as one of its main resources to produce food (plants directly and animals indirectly). Crops remove nutrients and they must be replaced to maintain a sustainable soil system. Also, some cropping practices (and maybe some animal grazing practices) may promote soil erosion through water or wind forces. So soil can be degraded by excessive nutrient removal (mining) and/or soil erosion.

Almost every farm, large or small, will maintain the soils nutrients by the addition of natural (cover crops), organic (animal manure), or chemical fertilizers otherwise it will not produce the crops planted. Similarly, soil conservation practices such as contour farming, wind breaks, and vegetative buffer strips are practiced or built on both large and smaller farms. Therefore, Jacobson believes the statement that large farms are bad for the environment as pertaining to impact on the nation’s soil is misguided.


Obviously, farms need lots of water, either if they raise crops or produce animal products. Larger farms may need to draw from either surface or ground water sources to irrigate crops or water livestock or poultry so they may locally impact the quantity of water more than smaller farms, but when expressed on a per unit of production (bushel of crop or lb of milk or meat) this would not be different than for small farms. So barring some very local situations, the perception that large farms are bad for water quantity is also misguided.

The situation for water quality is more complicated. Larger farm certainly have greater potential to negatively impact water quality no matter if they produce only crops. However, on the positive side, large farm often participate in more conservation programs that reduce erosion (runoff to surface waters). Large farms often have more modern and high-tech machinery that practice so-called precision farming (apply only the fertilizer and herbicide/pesticide needed by the crop / land). Small farms, because of smaller equipment and fields may leave existing vegetative buffers along fence rows and windbreaks that would restrict field runoff.

For animal operations, large farms (> 1000 animal units(AU)) are required by EPA regulations to have nutrient management plans (NMP) which forces them to apply their animal manure produced on these operations at agronomic rates based on nitrogen (N) or in some cases phosphorous (P) levels in the manure onto cropland. Depending on the state, some smaller livestock farms under 1000 AU are also required to develop and use NMP but most states these are not required for small farms (< 100 or 50 AU). Thus, although they again have potential to impact water quality, because of regulations and the large financial incentive to use this resource (animal manure) wisely, the perception that large farms (crop or animals) have a greater negative impact on water quality is again misguided.


Finally the issue of air quality. Because large CAFO’s concentrate animals in a single location they often produce large single source emissions of gases, odors, and particulates from the animal buildings and any associated manure storage / treatments systems. These can have local (odor), regional (acidification of vegetation and surface waters), and global (climate change) impacts. Most damaging of these are the local and regional impacts since the global (greenhouse gases – GHG) effects would be cumulative even for small farms.

Small livestock and poultry operation will also produce emissions but typically are sufficiently low that their impact is considerably less on the environment. Also, crop farms can impact air quality by the emissions of particulates or dust from fossil fuel sources such as tractors, irrigation engines, or through tillage practices. Mitigation technologies are being developed to reduce air emissions from animal operations and even crop farms, but these are expensive and typically need more developmental work before they become commonly used on farms. So when it comes to air quality issues, Jacobson believe the statement that large farms are bad for the environment is plausible.

So tomorrow, please share this post to show that agriculture is making on our environment. Farmers are the original environmentalists and want the best for our environment and our future!

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