Soil Health: What's Hemp Got To Do With It?

Our local agricultural industry has seen a lot of turbulence in the last few years. The legalization of marijuana caused both land lease rates and purchase prices to spike, and as I moved about the county in my ag consulting business, I heard story after story of farmers and ranchers losing their leases to someone willing to pay much more than someone raising a traditional product could afford. There were also lots of conflicts over water rights.

Then the hemp boom hit, and farmers and ranchers hoping for land prices to decline as marijuana declined were shocked to see competition for land become even more fierce. There are 8578 registered acres of hemp - total acreage is probably significantly more - and most of those acres were converted from hay and pasture land. With less land available for livestock and hay, and many leases lost, entire herds are being liquidated and sold out of state. From personal conversation, many of those herds are from cattle families that have ranched in the area for several generations.

Regardless of the future of hemp in our area, I don’t expect to see those herds return or the land put back into perennial crops. The orchard industry is struggling, and hay and livestock yield such a low return per acre that I fully expect the land to remain in annual crops or eventually be developed as urban growth boundaries expand.

I can’t blame anyone that chooses to grow hemp. After all, as one cattleman told me, he made more in one season of growing hemp than in 40 years of raising cattle. He hopes to be able to actually pay off his ranch due to hemp. Unfortunately, from a soil health standpoint, annual crops like hemp, as well as perennial crops treated as annuals (orchards and vineyards due to the amount of soil disturbance and bare soil throughout the year) are really destructive. I’m deeply disturbed by the amount of damage that has been done to the soil in the last two years. Very stable, healthy soils created by years of grazing and perennial grass stands have been deep ripped, plowed and disced - often repeatedly - and sometimes burned. Many of the fields have been laid bare for months; devastating when you consider that 80% of the soil carbon is lost within the first 10 days of the soil being disturbed or turned.

Assuming a conservative organic matter of 3% on the converted acres, and knowing that every 1% organic matter in the soil can result in an additional 25,000 gallons of water being stored, in the first 10 days of this soil being disturbed, Jackson County lost in the neighborhood of 514,680,000 gallons of water holding capacity. That means that over 500 million gallons of water that used to be held in our soils, is instead moving into streams and rivers and out of our ecosystem, and won’t be available in the summer when we need it most! Josephine County lost just shy of 260 million gallons of storage capacity!

Soil disturbance also destroys microbial communities, especially mycorrhizal fungi that are responsible for soil structure as well as moving carbon and nutrients between plants, which further disrupts nutrient cycling. When rain or irrigation or wind encounters bare soil, it causes erosion, moving soil into the air or into nearby waterways. The soil that erodes is the most valuable part - the organic matter. Bare soil is also a haven for weeds such as puncture vine, which I have seen in many of the hemp fields in our area.

On the other hand, perennial pasture or hay ground stores incredible amounts of carbon and can even act as a carbon sink. Mycorrhizal fungi and other soil inhabitants abound and thrive. Property managed grazing animals multiply this benefit (see chart below) and help create even healthier soil that stores carbon, cycles and hold nutrients, is resistant against erosion and also has superior water holding capacity.

Kelly Mulville soil quality management comparison.jpg

In the chart to the right, various management systems are compared in terms of soil quality (nitrogen, phosphorus, potassium and organic carbon). Organic is compared to no-till with low diversity of crops (think a rotation of corn and soybean), no-till with high diversity of crops (perhaps corn, soybean and wheat) but high synthetic fertilizer use, with no-till, high-diversity, no synthetics and the use of livestock to graze cover crops between “cash crops.” Note that when livestock are added, nitrogen in the system (not added synthetically!) is 140 times that of organic, and organic carbon is over 4.5 times as high! Property managed livestock play a critical role in soil health!!!

Locally produced, properly managed 100% grassfed lamb and beef provide huge environmental benefits. The perennial pastures cover an amazingly diverse and healthy soil while providing habitat for many insects, birds, animals and wildlife. They also maintain nice views (viewsheds) and contribute to Jackson County being an appealing place to live. They play an important role in nutrient and water cycling as well as water storage. As thousands of acres are converted to hemp, I keep asking, “do we really want to lose these benefits?”

As Kreg and I drive around and look at the bare soil, we are glad to walk our robust pastures full of happy animals. And we’re thankful for people like you, that make it possible to continue producing high quality protein in a way that is protecting and even improving the land on which we farm.