If I want to not only take a crop output but give back the energy I take and some more as regeneration I have to split my nitrogen fixing crops in 3 equal parts. 1 for food 1 to take back what I harvest as food 1 to give regenerative surplus
or do you think that the regenerative effect (leave better than found) would be reached already with the sum zero of the first 2 crops? hope I made myself clear, sometime could sound kinda brainy
Location: swampland virginia
posted 9 years ago
Not exactly clear on what you are saying. Nitrogen is only one thing you are taking from the soil and would tend to think it depends on your setup, soil, crops. Including persistent nitrogen fixers, carbon builders, mineral builders, etc. would be different than growing acres of mono-crops in rotation.
You can reduce the stuff you take from the soil by using perennials. Or you can maximize the give-backs by using compost toilets. Nitrogen is never a problem in a garden. Just mix 1 part urine with 10 parts water. Voila!
Anyway: Your takings are not that big. Think about it: Do you eat the leaves the stem and the roots of a broccoli? What do you eat when you're growing sugar peas? Most of that stuff you grow is composted, chop'n'dropped or otherwise fed back to the soil organisms. Sometimes you even grow stuff specific for the soil organisms: Cover crops.
Life that has a meaning wouldn't ask for its meaning. - Theodor W. Adorno
Instead of the third group being just nitrogen fixers, some should be dynamic accumulators - that is, plants that have a deep root system that allows them to access subsoil nutrients. Comfrey is a good example.
posted 9 years ago
I agree with kirk that something that accumulates more than just nitrogen is a good idea. Nitrogen is great an all, but it primarily helps leaf and stem growth not the production of root systems, fruiting/flowering or disease/drought resistance which is needed if you want to grow, say, tomatoes or the like. As he said comfrey is great, nettles work wonders on soil fertility as well.
I do understand what you are asking though. Say you plant fava beans with innoculant, when the beans are ripe and you mulch just the foliage and harvest the beans your net nitrogen gain/loss in the soil is near zero which is great for not degrading the soil, but not building it either. this would be your first category.
Since your net gain/loss is zero for your food crop the other two categories are pretty much one and the same in my mind. You don't have to "take back what I harvest as food" because you haven't taken anything at all. Variety is king, just as biodiversity helps regulate growing conditions in living plants the same goes for what you mulch. The wider variety of plants that you mulch on your garden the wider variety of nutrients will be available in the soil. Best of luck
Location: Amsterdam, the netherlands
posted 9 years ago
I think in temperate climates, when eating part and adding the rest of the plant back to the soil, you will probably not go back to zero in what you've taken out and put back into the soil.
For this equation i think it's also good to realize that the a very big part* of the biomass of the plant is not build from what it takes from the soil (nitrogen, phosphor, potassium, magnesium, spores and minerals and whatever more I dont know of), but from gasses in the air and energy from the sun (stored as carbons).
When we take just a fruit or root, put back the rest, and plant and mulch diversified we should still be building soil overall. I dont know how this works out in warmer climates with most biomass being in the living part of it, but in temperate climates it should.
* i dont remember the exact number but in emilia hazelips movie she claims its well over half of the biomas.
i hope this helps a bit too.
land and liberty at s.w.o.m.p. www. swompenglish.wordpress.com
posted 9 years ago
If you had trees, shrubs, vines, and plants that filled other niches, and you took only a fraction of the productivity (with leaves falling to the ground, and allowing branches to fall and decay), I think you would probably come out even. The root system has about as much biomass as the above ground parts.
If you plant short clover and let some other 'weeds' grow between the other plants and just let that be, you will probably be regenerating and building the fertility of the soil. (Of course, these are very general perceptions, it depends on your system's details.)
i try to plant a great deal of diverse nitrogen fixing plants all over the proeprty, and use some of the tops of some of the plants for food leaving the roots in the ground, or using some that are perennial such as lupines, clovers, baptisia, russian and autumn olive, etc..but I also add in manures both fresh (deer and rabbit ) and composted (cow)..that way I have a lot of nitrogen both growing and added..I sheet compost over most of my gardens as well...and use a lot of mulches
Bloom where you are planted.
Joop Corbin - swomp wrote: I think in temperate climates, when eating part and adding the rest of the plant back to the soil, you will probably not go back to zero in what you've taken out and put back into the soil.
For this equation i think it's also good to realize that the a very big part* of the biomass of the plant is not build from what it takes from the soil (nitrogen, phosphor, potassium, magnesium,
Nitrogen is not taken from the soil but from the air, so the stock is limitless (as oil, it is not a problem of stock but of extraction).
Remember that plants use up a lot of energy from the sun by photosynthesis. they also fix carbon from the air in a greatr quantity than the food you would normally get from most plants. Grow cover crops and return all biomass to the soil and it will "build up" meaning you will be putting back more than you took out. Think about how much energy a tree has stored in its wood. When the wood is burnt the energy is set free again... Cannot have too much Biomass.
Jen0454 wrote: Remember that plants use up a lot of energy from the sun by photosynthesis. they also fix carbon from the air in a greatr quantity than the food you would normally get from most plants. Grow cover crops and return all biomass to the soil and it will "build up" meaning you will be putting back more than you took out. Think about how much energy a tree has stored in its wood. When the wood is burnt the energy is set free again... Cannot have too much Biomass.
Disagree, that's what a bog is, too much biomass and a bad pH
Location: South Puget Sound, Salish Sea, Cascadia, North America
posted 9 years ago
I'd agree with the focus on organic matter as much as Nitrogen as being the yardstick for net gain/loss.
I'd reframe the question as "what proportion of potential primary production, returned to the soil is necessary to increase the quality and quantity of organic matter pools"
The answer is dependant on biome, (i.e. tropical forest vs. cold temprate grassland) And the degree to which your site is achieving its potential primary production. Different systems have different qualities and quanities of organic matter in different pools. When we modify the system (make a "forest" into a "grassland") we change the nature of the question (i.e. regenerate to what?)
Paul Cereghino- Stewardship Institute Maritime Temperate Coniferous Rainforest - Mild Wet Winter, Dry Summer
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