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Real0ne -> RE: The gift of rising CO2 just keeps on giving (9/14/2017 12:24:13 AM)
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ORIGINAL: MasterJaguar01
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ORIGINAL: DesideriScuri
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ORIGINAL: MasterJaguar01
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ORIGINAL: Real0ne
[sm=champ.gif]
Bingo!
Yahtze!
You got it, plants dont get their nutrients from air, every farmer on the planet knows you have to either replenish the soil or rotate crops in a manner that self replenishes.
Thats why Phds get a Phd so they can show us how fucking stupid they are with their half asses analysis in support of the latest Zio Jiz.
Bingo!
Yahtze!
You TOTALLY misunderstand the issue.
Where plants get their nutrients from is COMPLETELY irrelevant. The theory is: The increased photosynthesis, due to increased CO2, leads to more carbohydrates (e.g. glucose), and less nutrients that benefit humans.
You are COMPLETELY misunderstanding, confusing, and conflating nutrients that plants need for THEIR health with nutrients which plants produce which benefit OUR health.
See excerpt below:
But as the zooplankton experiment showed, greater volume and better quality might not go hand-in-hand. In fact, they might be inversely linked. As best scientists can tell, this is what happens: Rising CO2 revs up photosynthesis, the process that helps plants transform sunlight to food. This makes plants grow, but it also leads to them pack in more carbohydrates like glucose at the expense of other nutrients that we depend on, like protein, iron and zinc.
I don't think he missed the point. The greater photosynthesis rate doesn't mean that the uptake of minerals/nutrients from the soil is any different. Increasing the rate at which foliage or other plant matter grows without increasing nutrient uptake from the soil means the plant is going to have a lower density of those nutrients/minerals.
For instance, you have to limit the amount of foliage and fruiting on a grape vine to match it's ability to get nutrients from the soil, or you'll have a poor harvest.
This isn't rocket surgery.
He most definitely DID miss the point. The article mentions nothing about uptake from the soil.
Rather than my paraphrasing:
Rising CO2 revs up photosynthesis, the process that helps plants transform sunlight to food. This makes plants grow, but it also leads to them pack in more carbohydrates like glucose at the expense of other nutrients that we depend on, like protein, iron and zinc.
It's NOT a question of getting anything from the soil. (Hence the missed point)
as usual more bs completely inconclusive political study like the rest of climate bs being pedaled.
climate howlers forget there is much more to this than meets the eye, nutrient levels of plants can easily vary 20% from contry to country as a result of the soil they are grown in so whats the big trama LOL
V. How Mineral Nutrients Are Depleted in US Soils.
A. Crop Removal and Livestock Operations
The practice of removing part or all of the crops grown from the soil accelerates the loss
of nutrients from the soil. The cycling of nutrients from plant uptake and release is
interrupted by crop removal. This loss, if not corrected by fertilization, must be made up
by nutrient release from primary soil minerals and from soil organic matter.
Heavy tillage of soils adds oxygen which accelerates the decomposition of soil organic
matter and increases in the release of nutrient elements. In soils with high levels of
native soil humus, this "mining" of soil nutrients can occur over decades with little sign of
soil exhaustion. Eventually, the humus content drops low enough so that it cannot
supply enough nutrients to feed the crop. Nitrogen is usually the first element that is
affected by soil tilling. Since primary soil minerals are not reservoirs of nitrogen,
fertilization with nitrogen or rotation with nitrogen fixing crops (legumes) becomes
necessary early on to maintain production.
In livestock operations the cycling of nutrients in the soil is also interrupted. Meat and
dairy products are sold off-farm, so the organic material is not returned to the soil. In
some areas large feedlots have replaced on-farm operations. Typically in large feedlots
the manure is not returned to the farm. If the manure created is not returned to the farm,
the nutrients contained are lost.
B. Soil Erosion
Soil erosion is particularly devastating on older, more highly weathered soils in the
southeast U.S. since the supply of tiny nutrient-rich primary minerals is already limited.
Erosion removes the soil organic matter where much of the soil's nutrient reserve exists.
Soils that are low in organic matter, or have lost much of it through erosion exhausts the
soil's native nitrogen supply quickly compared to soils unaffected by erosion or low
organic matter. Erosion of soil organic matter not only causes nitrogen loss, but also
loss of other nutrients, including sulfur and boron.
Soil erosion is a problem on privately held lands and public lands alike. For decades,
overgrazing on public lands has resulted in soil erosion, which is severe in many areas.
This overgrazing plus erosion has reduced the incidence and tonnage of palatable
forage species available to livestock. Thus the yield of nutrients from those soils to
livestock via forage has been substantially reduced by erosion and overgrazing.
Standards for allowable levels of soil erosion were set by the Soil Conservation Service
at 3 - 5 tons/acre/year for most soils. Today, soil erosion in the U.S. is nearly twice that
level, although declining due to the implementation of protective measures.[15][15]
C. Increased Nutrient Demand by Higher Yielding Crops
Advances in plant breeding and management expertise have resulted in crops with far
higher yield potential. For example, corn yields of 50 bushels an acre were considered
quite good in the 1930's. Since the 1960's, corn yields over 200 bushels an acre are not
uncmmon on more productive soils. This greatly increased demand by the new crops
on the nutrient resources of most soils cannot be sufficiently met by natural release from
primary minerals and organic matter. Thus the deficiency of the rate of nutrients
released by soils for these super crops is induced by the high yield crops' greatly
increased demands on the soil.
Usually, the ability of a soil's primary minerals to supply enough phosphorus and
potassium becomes limited under high yield cropping because both elements are
required in relatively large amounts by plants. Thus, those elements are usually applied
as fertilizer salts in conventional farming systems, or as biomass or crushed rocks
containing these elements in certified organic systems. Almost all fertilization regimes
now require regular inputs of those elements due to the effects of high yield crops.
D. Depletion of Nutrient Bases Creates Soil Acidity
As cropping continues on mature soils, and as soils age in natural systems under
leaching conditions, the soils slowly become acidic. As basic nutrient elements like
potassium, calcium and magnesium are lost via leaching and crop removal, acidic
elements are created or released from clay minerals. There are other sources of acidity
in soils (nitrification of ammonium nitrogen), but the loss of nutrient bases, without
sufficient replacement by release from primary minerals, eventually leads to acid soils.
In almost all soils, the most abundant available nutrient element is calcium, followed by
magnesium. When soils become acid, and those elements are lost, the application of
crushed limestone is needed to neutralize the soil acidity, and replace the calcium and
magnesium. Federal subsidies to farmers for the application of lime to acid soils was
highly successful in the mid-twentieth century. The federal government has
discontinued those subsidies and not all farmers have continued adding lime frequently
enough to replace the calcium and magnesium removed by cropping and from acids
created by nitrogen fertilizers.
E. Development of Micronutrient Deficiencies through Long-Term Crop Removal
The long-term, heavy demands of high-yielding crops on the nutrient supply by soil
primary minerals and organic matters may show up as shortages of micronutrient
elements (iron, manganese, zinc, copper, boron, nickel, molybdenum, etc.). Many soils
are naturally low in available levels of one or more of these elements. But heavy crop
demands over time may increase the severity of the deficiency, and begin to exhaust the
soil's ability to supply sufficient quantities of other micronutrient elements. Such
deficiencies, if mild, often do not show visible symptoms in the plants. A slight yield
decline may or may not be noticed. Soil and plant tissue testing are needed to verify
these mild deficiencies. Many farmers do not perform these micronutrient tests on
plants and soils until the deficiencies become severe enough to be noticed.
If micronutrient deficiencies are identified, soluble sources of those nutrients must be
applied to the soil. Foliar applications of micronutrients[16][16] may provide temporary
relief, but must be repeated at regular intervals unless the soil deficiencies are
corrected. Additions of organic matter or humates (oxidized lignites) may provide
organic acids that help speed the release of micronutrient elements from primary
minerals, if the necessary primary minerals are present.
F. Western Alkaline Soils
Soils in the more arid regions of the western U.S. are irrigated to supply enough water to
grow crops and to leach out salts that may exist in high levels in the soil. In some areas
the irrigation water is high in salts so extra water must be applied to prevent salt buildup
and leach out the excess salts. When this happens, some nutrient elements are also
leached out with the water (nitrogen, potassium, boron, etc.). Those elements must
eventually be replaced if soil primary mineral release of these elements cannot keep up
with plant demand.
However, sodium, bicarbonates and the natural hardness (calcium + magnesium) of
much western irrigation water keeps the soil alkaline. That alkalinity, whether native or
induced through irrigation, greatly reduces the solubility of mineral elements like
phosporus, iron, manganese and zinc. Plants cannot absorb insoluble mineral
elements. This type of chemically induced "deficiency" is corrected by a variety of
strategies, including concentrating fertilizers in a band, foliar feeding micronutrients, soil
acidification, growing adapted varieties of crops, increasing organic matter contents
through biomass addition, and long rotations with forage crops. Again, sufficient
management expertise is needed, or access to such expertise must be utilized, to
maintain nutrient levels and balances.
G. Over-Fertilization with Some Nutrient Elements can Create Deficiencies in the
Supply of Other Nutrients.
Soils are complex systems, and this fact holds true when considering the plant
availability of mineral nutrient elements. Fertilization with highly soluble commercial
sources of nutrients has an effect on the plant availability of other nutrients. For
example, heavy fertilization with ammonium-N may reduce potassium availability. High
levels of ammonium-N or magnesium can reduce calcium availability. However, when
high amounts of macronutrients are applied, often micronutrient availability is adversely
affected. High applications of nitrate-N may reduce iron availability. Long term
phosphorus application will reduce zinc availability and, to a lesser extent, iron
availability.
Since most growers fertilize with macronutrients, and fewer test for or apply
micronutrients, this form of induced micronutrient deficiency can be a significant problem
in many soils.
H. Livestock Grazing on Public Lands
Public lands (Bureau of Land Management; Forest Service) have been leased by
ranchers for grazing by livestock for nearly a century. Although the deposition of
manure does return some mineral elements to the soils, the nutrients captured in the
weight gain the animals accrue is removed. Fertilization of these public lands by the US
Government and the lessors is not usually practiced. Thus this slow deficit in nutrient
balance has been continuing for a long time.
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