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Post by seedywen on Jun 17, 2011 15:32:31 GMT -5
I used to say, that mowing the lawn was against my religion That was before I bought this 4 hectares in the West Coast rainforest. The lawns that still exist behind the house and a little under the orchard are now viewed as 'moats' keeping the forest and especially the Himalayan blackberries from laying seige to the 'castle' called home. Sure the goats and cows range the 2 acres of meadows(used to range the forest as well, however daunting predation by bears and cougars has in recent years, got them living behind an electric fence) and dozens of chickens/ducks/rabbits graze the lawn. Still that noisy gas-guzzling creature is brought out periodically each growing season, to add easily digested clippings to various other mulching projects!
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Post by steev on Jun 17, 2011 21:39:16 GMT -5
paquebot, if you've got grass that can fix nitrogen, I'd like some of that! Any grass I've ever heard of can only take carbon dioxide from the atmosphere, and must get its nitrogen from the soil, which gets it from nitrogen-fixing legumes, lightning, nitrogenous wastes of critters, or nitrogen compounds released by rotting plants (which got it from the aforementioned sources). This is why lawns are commonly wasteful, because unless there is an input of fertilizer (particularly nitrogen) the removal of clippings from the lawn tends to outstrip the natural input of nitrogen, leading to declining vigor of the lawn. Even legumes don't fix nitrogen directly from the air, but with the aid of nitrogen-fixing bacteria, which actually do the job, living symbiotically with the legumes.
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Post by Joseph Lofthouse on Jun 17, 2011 22:10:35 GMT -5
paquebot, if you've got grass that can fix nitrogen, I'd like some of that! ... This is why lawns are commonly wasteful, because unless there is an input of fertilizer (particularly nitrogen) the removal of clippings from the lawn tends to outstrip the natural input of nitrogen, In the usa I'd expect lawn clippings to be a decent source of nitrogen for a garden because of the huge amounts of Nitrogen based fertilizers that are dumped on lawns.
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Post by steev on Jun 17, 2011 23:49:45 GMT -5
Grass will indeed grow on some of the poorest soils, but the important word there is "on", not "from". Many plants will grow on substrates that provide little or no nutrients, if you bring in what they need often enough. You can grow tomatoes on gravel, if you supply enough water and fertilizers. It's just hydroponics with a support substrate.
Once, I installed a lawn and had ~10 rolls of sod left, so I figured I'd take care of them, in case I found a client who needed a little patching work. My driveway was full, so I unrolled them down my cement front steps, tucking them into the angles well. It was fun for a few weeks, all I had to do was keep it from drying out. If I'd wanted to sprinkle on some fertilizer and clip it once in a while, I suppose I could have maintained it indefinately, but the novelty wore off. It did cause a few double-takes from passers-by.
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Post by paquebot on Jun 18, 2011 0:47:54 GMT -5
Fresh or immature grass clippings are rated at a minimum 1% nitrogen. That percentage is the standard minimum for that green item but I've seen figures as high as 2.4%. That's no different than most other green materials. Apple leaves are minimum 1% nitrogen and the trees are not doused with fertilizer and that's after they've fallen. Alfalfa hay is about 2½% and also without a lot of fertilizer. Lettuce may be 3.5% while purslane may be 4.5%. None of those "fix" nitrogen in the soil but the nitrogen that they take from the air is able to be captured by composting. Grass happens to be the one of the cheapest and most readily available source of nitrogen and, like all other living plants, developed with the ability to extract nitrogen from the air from the moment of plants first existence on this planet. It needed no help from Man then, hasn't forgotten how since.
Martin
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Post by steev on Jun 18, 2011 1:35:05 GMT -5
Human flesh is higher in nitrogen than grass; does that mean humans can extract nitrogen from air for constructing proteins, or do humans get their nitrogenous needs filled by compounds manufactured by other organisms? The percentage of nitrogen in any organism is only reflective of its use for nitrogen and the availability of nitrogen to it. Grasses can suffer from nitrogen deficiency; does that imply that at some times, the atmosphere contains less nitrogen, or that some places have less nitrogen in the atmosphere? i think an attempt to grow grass in an artificial medium containing all necessary nutrients for the growth of grass, except nitrogen, will produce dead grass, regardless of its being allowed free access to the atmosphere.
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Post by 12540dumont on Jun 18, 2011 10:47:57 GMT -5
Lucky, how lucky I feel sometimes. Glad to be alive.
Glad that I can do what I love to do, farm. Read intelligent lively conversation. Feel bone tired at the end of the day. Fall asleep and give up everything to John of Dreams. Wake up to another day.
Feel the sun on my face. Attack another field of weeds. Plant another field of dreams. Eat a good supper. Make love.
Lucky, how lucky I feel sometimes.
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Post by paquebot on Jun 19, 2011 2:11:58 GMT -5
I will repeat. Grasses and all other living plants do not need artificial nitrogen to survive. Nor does the percentage of nitrogen in grass decrease with each cutting. Grass, like most other green plantlife, is able to extract nitrogen from the soil and which comes only from the atmosphere. Nitrogen enters the soil, is taken up by the roots, and stored in the leaves and stems. With few exceptions, that's the only way that nitrogen is naturally available. Unlike phosphate and potassium, nitrogen is seldom available in a form which may be mined as a solid. With few exceptions, the atmosphere is the only source of nitrogen even when derived from plants. And when not captured somewhere in the cycle, that's exactly where it returns to.
That answers the question about grass planted in a medium devoid of nitrogen but exposed to another medium containing nearly 80% nitrogen.
Martin
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Post by steev on Jun 19, 2011 23:37:41 GMT -5
Hi, there, WI LO M.
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Post by paquebot on Jun 21, 2011 0:01:15 GMT -5
Since it's difficult to explain something so simple that a 6th grader can understand, pictures usually do it quite well. The nitrogen cycle is one that has often been done in that manner. The picture on this site depicts how all plants obtain atmospheric nitrogen quite well without a diarrhea of words: en.wikipedia.org/wiki/Nitrogen_cycleMartin
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Post by steev on Jun 21, 2011 1:25:15 GMT -5
That's pretty much what I said, all right. Glad you understand it, now.
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