The same is true for on-farm reservoirs. “You reduce the carbon released because water isn’t being pumped from such a great depth. You won’t build an on-farm reservoir to gain carbon credits. But that’s possibly something you could gain revenue from in the form of an offset program.”

The good news: lowering your carbon footprint typically “runs parallel with increasing economic profit. That’s really good news whether you’re a producer or an environmentalist.”

Nalley and Michael Popp, a fellow agricultural economist at the university, co-authored a study (with much help from graduate student Brandon McFadden) that “took a good Extension budget … and carbon foot-printed it. This is on conventional rice on silt loams in east Arkansas.

“To flood rice takes 30.66 gallons, on average, of diesel fuel per acre. Well, with a carbon equivalent of 7.01 — which means if you burn 1 gallon of diesel fuel, you’ll release 7.01 pounds of carbon in the atmosphere — just by flooding alone, you release 214 pounds of carbon into the atmosphere per acre of rice. When you account for nitrous oxide, per acre of rice we’re releasing, roughly, 757 pounds of carbon.”

What if an on-farm reservoir is being used?

“Everything is the same, except we reduce (carbon output) to approximately 667 pounds. You’d save about 81 pounds of carbon per acre.

“Again, you won’t build a reservoir to save carbon. But if the government sets up a carbon offset program, this could be a nice supplemental income. You won’t get rich off it but, more importantly, you could say the industry as a whole is moving forward to reduce its carbon footprint.”

During their research, Nalley and Popp carbon footprinted rice varieties in Arkansas County. Compiling the amount of carbon released when growing one acre of a certain variety is “a function of how susceptible (the varieties) are to blast and sheath blight. We calculated the carbon equivalent of having to go out and spray.”

Also part of the calculation “is how much fertilizer and water is needed for each variety.” The figures obtained were for conventionally-planted rice.

If a carbon offset program was introduced — and carbon traded at $40 per ton — “you could get a rough payment of approximately $1.60 per acre for using a 50 percent on-farm reservoir (versus) using all wells.

“Agriculture is one of the few industries where you actually sequester carbon in the ground. We take CO2 out of the atmosphere and put it in the ground. Most other industries can’t do that.”

As for the net footprint for each variety, Nalley showed a chart illustrating net sequesterers and net emitters of carbon.

Each county and farm will be different, Nalley reminded. “But what this means is if there is a carbon offset program, you could potentially get payments for CL151, 723 and 729. That’s because up to the farm gate, you’re taking more carbon in than you’re releasing. This says carbon could be our friend and get us some money. But I should add this (calculation) doesn’t take methane emissions into account, which are very important.

“So, here are carbon footprints for diesel, fungicide, pesticide, fertilizer, nitrous oxide and emissions. Hybrids fare well in emissions because they don’t require as much fertilizer and typically yield more per acre. Hybrids are net sequesterers because, on average, they have a high biomass and high harvest index.”