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Comment by rmason | Hacker News Reader

Most of the nitrogen in our rivers and lakes causing problems isn't from farmers use of fertilizer. Farmers are in a low margin business and if they use too much nitrogen they make less money.

A lot of it used to be caused by manure runoff from large animal operations. But twenty or more years ago laws were changed and regulators focused their attention on correcting this problem. There are always exceptions but mostly this problem is fixed. Farmers have to file plans on which lands gets manure, complete with soil tests showing they're not overdoing it.

I helped farmers in the late nineties fill out these reports in my former career as an agronomist. Back then some larger farmers were either moving to composting or using the manure to power plants creating electricity.

So where is it coming from now? Lawn fertilizer! People over fertilizing their lawns.

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I held a similar view about fishermen and nets. Fishermen is a low margin business and nets are a massive investment, and loosing one would cost a lot of money. Look at any picture of fishermen or a fishing town and there is always a large number of nets being repaired. Repairing nets is almost an icon for the industry.

So why does there exist a massive waste problem from nets being dumped in the ocean? The answer lies in large scale fishing fleets which is an industry that is not a a low margin business. For them the cost of repairing or properly disposing nets is a cost compared to just dumping them into the ocean, and even if they get fined the cost would be less than the savings.

Small farmers are in a low margin business, and yes, if they use too much nitrogen they make less money. They would also get fined by local government, risk loosing farming rights and so on. Large scale farming and factory farming is not a low margin business, and sometimes the cost of violating regulations can be seen as the cheaper alternative. There is always the option to let a sub company go bankrupt, and route the profits away from the costs. Those are options not available to a small farm.

This is exactly right. The regulations are “scale discriminatory”. Written with the “help” of lobbyists paid for by big businesses that fully understand these economics. Classic regulatory capture.

So humanity's stupidest form of cultivation strikes again.

> Lawn fertilizer! People over fertilizing their lawns.

Lawn fertilizer!? I didn't even know that was a thing! Why would you fertilize a lawn. Won't that just make it grow faster and therefore require you to mow it more often?

The worst part is people clean off the lawn clippings, which would just decompose into nitrogen that the grass needs in the first place.

You seem to know what you’re talking about so I have a question. Is it possible that leaving fallen leaves on a lawn for a period of time can help to fertilize that lawn? I experimented with that on my lawn this past fall and while it’s too early to make any conclusions I wonder if there’s any prior art here?

Composted leaves will fertilize it somewhat, but if you just let leaves fall on your lawn, it tends to kill the lawn. I recommend raking into pile, and letting it sit for a year or so (fallen brown leaves compost rather slowly), then you can spread resulting compost. But, unless you have lots of trees, the amount of nitrogen in fallen leaves will be minimal (trees don’t like parting with valuable nutrients either).

Not an expert, just a gardener. Short answer: just letting leaves fall on your lawn for a period of time is unlikely to provide fertilization, in fact it may hurt your lawn, because the leaves will not break down fast enough and will instead cut off your lawn's access to air and sunlight.

Long answer: You need to break down the organic matter in the leaves through composting. To speed up composting you want the right proportions of both brown (carbon - your leaves) and green (nitrogen) matter, the right moisture levels, and access to oxygen, usually in a large pile to create the perfect environment for the microorganisms that break down the matter. Your leaves are a great base for your compost, I always use mine, but you will probably need to put a little sweat equity into it, as well as kitchen scraps, lawn cuttings, etc. to get the right proportion of greens.

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