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147 points rbanffy | 2 comments | | HN request time: 0s | source
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dizzant ◴[] No.42728125[source]
The comments here are focused on how much energy it would take to turn this into fuel. The real story here is decentralized fertilizer production, buried at the end of the article:

> this innovation could fundamentally reshape fertilizer manufacturing by providing a more sustainable, cost-effective alternative to centralized production

The high energy cost of Haber-Bosch, plus the additional cost of transportation from manufacturer to farmer could potentially be eliminated by distributed, passive fertilizer generators scattered around in the fields.

I'm no expert, but assuming sufficient local production, low concentration could potentially be overcome by continuous fertilization with irrigation throughout the growing season.

Let's find out. Some quick fiddling with a molarity calculator and an almanac:

-- 100 uM ammonia -> 1.7 mg / L ammonia

-- 82% nitrogen -> 1.4 mg / L nitrogen

-- My lawn needs around 1 lb / 1000 sq ft, or around 5 g / m2

-- So my lawn needs about 3500 L / m2 of fertilized irrigation total for the season

-- Ballpark farming irrigation is around 0.2 inches per day, or around 5L/m2

I would need to water my lawn about 700 days in the year, or more realistically up my irrigation rate by about a factor of 4, AND source all of the water from the fertilizer box.

I'm a little skeptical that I can allocate space for enough production and still have a lawn left to fertilize. The tech probably isn't ready for the big time on an industrial farm yet, but for research demo, this seems like a promising direction! Much more than concentrating it for fuel.

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trollbridge ◴[] No.42732368[source]
A somewhat passive fertiliser generator scattered around your fields is also known as a "cow" and a "chicken".
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1. SoftTalker ◴[] No.42734122[source]
Of course you can't have cows wandering through your corn or soybeans, they'll eat and/or crush it. But if you had fields that you could rotate between pasture and planted that could work.
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2. xenonite ◴[] No.42751556[source]
You don't need soy or corn if you have cows on grass instead: much less carbon dioxide and more nutritious.