Not sure if I’m posting on the correct garden thread. My apologies if I’m in the wrong class room!
Begin, Installment 5 on SOILS
MOBILITY OF NUTRIENTS (cont)
Plants absorb Nitrogen from a large volume of soil. If there are lots of plants in an area, they can compete.
He showed a drawing here of a couple of plants with their roots able to be seen in the soil. Below is my best attempt to indicate it with typing symbols
Plant above ground ___\l/___ ___\l/__
Root stems l l
Root system / l \ / l\
[ ] [ ]
Imagine a couple of spheres surrounding the root systems of each plan with the diameter shown (very) roughly by the above braces. The spheres would encompass the root systems up to the surface of the soil. In his picture, the spheres did not overlap, but if they had been closer together, they certainly would have, indicating competition for the resource.
[O dear. Just saw on the preview that my carefully crafted “drawing” got blown to bits. Not sure what to do about it. Basically think of the zone of nutrient uptake for mobile soils is a spherical area around the root system, and can enter into another plant’s uptake sphere if the plants are too close together.]
NITROGEN REQUIREMENT
* Crop to be grown
* Yield goal
* N requirement
* N needs = N requirement – Soil NO3-N
* Credits for subsurface and manure N
CROP UPTAKE OF IMMOBILE NUTRIENTS (P and K)
Another picture. See a plant with its root structure shown, as above. Instead of seeing a large sphere of resource available around the plant, with the IMMOBILE nutrients, there is only a small cylinder surrounding each root fiber providing the immobile nutrient. Absorption is from just a thin cylinder of soil around each root. Immobile nutrients can build up to adequate levels.
PHOSPHORUS REQUIREMENT
*Soil test P index (Mehlich 3 method)
* Percent sufficiency
* P requirement (P2O5 pounds per acre)
He showed a graph here which I am unable to duplicate plotting on the x axis the Soil Test P. The vertical axis shows the Relative Crop Yield (%)
As your soil test of P is low (bottom left on the graph) and the Relative crop yield increases, there is a rising curve as the soil test reaches high levels. What is interesting about this graph is that once you get adequate high levels of phosphorus, the yield levels off, and the line has flattened out at the top of the 100% yield. Once this has been reached, application of more phosphorus becomes excessive and nonproductive, and in fact can begin causing significant environmental problems.
Nutrient imbalance, too much N, are the causes of delayed crop maturity.
~ ~ ~ ~ ~
SOIL IS A LIVING BODY
Soil is a Fundamental Part of the Ecosystem
The living systems occurring above and below the ground surface are determined by the properties of the soil.
There was an intricate picture of “The Soil Food Web” shown.
It showed the relationship among plants, organic materials, bacteria, protozoa, nematodes, fungi, arthropods, birds, and animals. Each of these were assigned a trophic level. There are 5, the first of which is photosynthesis by the plants, with the higher life forms (birds and animals) being Trophic Level 5.
“Living systems above and below grounds are determined by the soil.”
Soil components consist of water, air spaces, bacteria, clay, sand, silt, fungae, clay-organic matter complex.
IMPROVING SOIL QUALITY
Adding organic material – can take a lot of work, but is worth it!
Minimize soil loss – Takes a long time to create 1” of soil. This is why cover crops are important.
Keep it natural – minimize adding chemicals as much as possible. He does not use a lot of chemical insecticides
Soil Organic Matter Benefits soil in many ways:
*Improves soil physical condition
* Increases water infiltration and holding capacity
* Improves soil tilth
* Decreases erosion losses
* Supplies plant nutrients
*Increases CEC [Texokie: ok, I don’t have a clue what CEC is…]
He showed a number of pix of how to incorporate organic matter. He also stated that one can bury plant residues, chop it into pieces. Use poultry litter / animal manure
He was saying that one CAN use fresh poultry litter. A person asked, “doesn’t poultry litter have to lay for a year or so? “ He said, “no, just be very reserved in using it – less than ½ “ and you’ll be ok.” He was saying he uses fresh litter to dress some of the plants in his flower beds. “Be very careful with hot manures on veggies. Do let them sit for several months – be conservative with the application of “hot” nutrients, but you can do it for veggies after a few months.
Leaf shredders- can put result into bags and use as organic matter or mulch at any time
Cover crops – (“green manure”) : retains nutrients, reduces erosion, fixes nitrogen, adds organic matter to the soil. He likes to plant peas because they fix N and his family enjoys the peas. When they are finished, he chops them and buries them. Their favorites are the English (Oregon) Snow Peas. Farmers will often plant clover.
Legumes fix N into the soil naturally. There is 78% N in the air, but plants can’t use it. It has to be “fixed.”
End of Installment 5 on SOIL
I treat the soil like it was alive, because it is.
If my soil is healthy, my plants turn out healthy.
/johnny
Well, there is an installment Volume 17, but this is a great little summary on soil. Help me remember to link it to Friday’s thread in case anyone missed it.
Thanks for the great job you are doing sharing your experiences in gardening class.
I use clover, hairy vetch, and rye for my main cover crops. When I’m done with my green beans, I work them into soil too. I also plant a few beans in with my corn patch.
Thank you for these weekly updates ~
Thanks for your efforts to write all that info. I have copied and saved all you have written from the beginning.