Naked Science Forum
Life Sciences => The Environment => Topic started by: thedoc on 14/08/2012 23:11:28
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Less than 5% of the nitrogen added to crops to feed animals ends up as meat in our mouths. The rest is wasted and enters the environment with potentially devastating effects. Here Robinson Fulweiler looks at practical ways to bring the nitrogen bigfoot down a shoe-size or two...
Read the article (http://www.thenakedscientists.com/HTML/articles/article/bigfoot-the-nitrogen-problem/) then tell us what you think...
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Interesting.
Livestock is relatively inefficient compared to vegetable diets as one has to grow the grain crops first which is then fed to the livestock, with perhaps a 10% efficiency. However, often livestock can be foraged in marginal, non irrigated land that would otherwise not be put into agricultural use. So, while the conversion efficiency may be poor, we may not be competing for a few blades of grass scattered between sage brush.
Animal manure is often used with organic gardening. But, it is a good point that the nitrogen burden, especially with respect to our rivers and oceans is not insignificant.
Different plants can be good or poor with nitrogen fixing. Clovers and legumes can be some of the best, and may be good to plant with other crops, or for crop rotation. Apparently much of the nitrogen fixation is due to varieties of Rhizobia (http://en.wikipedia.org/wiki/Rhizobia) bacteria. I was reading about hemp production earlier which I believe suggested inoculating the hemp seeds with a subspecies, Bradyrhizobium (http://en.wikipedia.org/wiki/Bradyrhizobium) bacteria before planting. I presume different plants will either function well, or poorly with the bacteria. It still releases ammonias into the soil, but perhaps less would leach into the streams and rivers.
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Plants that host Rhizobacteria in their root nodules are well placed to capture the nitrogen straight into their circulation, and into the soil. This should produce less runoff than spraying fertiliser on the soil.
http://en.wikipedia.org/wiki/Nitrogen_fixation#Root_nodule_symbioses
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I did try to plant a row of mixed peas and corn this year. For some reason, that row of mixed peas and corn, neither seemed to do well, which puzzles me greatly. I think I'll have to do some more experiments next year to verify, as well as mixing clover and corn.
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Eating homegrown and organic as well as cutting meat out of your diet will certainly improve your N footprint, but another consideration is how much overall protein you consume. Most Americans eat WAY more protein than their body can metabolize. I believe a 150 lb person can use around 50-60 g protein per day.
About the N-fixing plants: Keep in mind that legumes and other plant with symbioses for fixing atmospheric N use that N to build more tissues, especially those high protein seeds we love. In a natural environment, the tissues would die and the nutrients would make their way into the soil. In the case of crops, such as peas and soybeans, farmers and agriculturalists not only remove the fruit, but all aboveground biomass. When this happens, almost all of the N is removed from the system and therefore will not benefit the soil. There are, of course, N fixers that live in the soil. This might be one way to bypass fertilizers.
The Galloway paper cited in the above paper is very helpful for anyone looking for further reading about the N cascade.
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More information on the N-cycle (in theNetherlands, Europe and worldwide can be found at http://themasites.pbl.nl/balansvandeleefomgeving/2012/integraal-stikstof/trend-stikstofintensiteit-nederlandse-economie%2c-eu-en-wereld.
A very informative infographic on the N-cycle and the loss due to manure: http://www.pbl.nl/infographic/de-mest-blijft-achter
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Presumably, grass-fed beef requires less fertiliser than corn-fed beef, and so should be cheaper.
Why then do they advertise beef as being "grain-fed"?
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Presumably, grass-fed beef requires less fertiliser than corn-fed beef, and so should be cheaper.
Why then do they advertise beef as being "grain-fed"?
In the USA, Marbled Fat (http://en.wikipedia.org/wiki/Marbled_meat) is popular. [:-\] It is beyond me why, as many people also wish to get low fat cuts. However, the fat likely adds both to the flavor, as well as the tenderness of the beef.
I assume that "range fed" beef is done with minimal fertilizer on marginal land. However, it is common to at least fertilize hay fields.
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Seems to me that one of the worst wastes of fertilizer is on lawns. People just want it to be green. Nitrogen and phosphorous is going into the environment for no good reason. Personally, I think lawn fertilizers and most of the other lawn chemicals ought to be outlawed.