Thursday, May 7, 2009
ISSUES WITH PHOSPHATE FERTILIZERS
Phosphate is an essential macro nutrient and is a critical component of adenosine triphosphate, (ATP) the energy molecule which drives most biological processes. It is also found in DNA and RNA. Phosphate enhances the fundamental processes of photosynthesis, nitrogen fixation, root growth, flowering and fruiting. Phosphate deficient plants will usually be stunted, thin stemmed; but the foliage will often be dark and even purple in some plants. Phosphorous is very mobile in the plant, therefore older leaves show deficiencies first.
Most soils are low in phosphate. To make matters worst, less than 0.01% of the total soil phosphorous is available to plants. Phosphorous binds easily to calcium, iron and aluminum. As a result, it does not readily leach, but for the same reason, it is not readily available for plant uptake. Even when phosphorous is added in the form of an inorganic fertilizer, it will rapidly become insoluble.
The dilemma is that calcium is also essential to plants. It is often added to soils in the form of lime rock, dolomite or gypsum, not only to replenish soils low in calcium but to also raise pH in soils made acidic by nitrates. Calcium carbonate will dissolve and calcium ions will latch on the phosphate ions, becoming a nearly insoluble compound.
In the last decades, growers have progressively added more phosphate to their fertilizer mix to counter this problem. However, even the little leaching that occurs creates enormous environmental problems. Some vegetable growers are taking a different approach. They apply a small amount of phosphate at time of planting in the furrow (starter fertilizer); then at four to six true leaves, they foliar spray (usually a mixture of potassium phosphate) on a weekly basis thereafter, (based on tissue samples). I use 3-18-18 high grade liquid fertilizer which is designed for this very reason. It is composed of food grade materials, meaning the same high quality products used in the food industry.
Most soils are low in phosphate. To make matters worst, less than 0.01% of the total soil phosphorous is available to plants. Phosphorous binds easily to calcium, iron and aluminum. As a result, it does not readily leach, but for the same reason, it is not readily available for plant uptake. Even when phosphorous is added in the form of an inorganic fertilizer, it will rapidly become insoluble.
The dilemma is that calcium is also essential to plants. It is often added to soils in the form of lime rock, dolomite or gypsum, not only to replenish soils low in calcium but to also raise pH in soils made acidic by nitrates. Calcium carbonate will dissolve and calcium ions will latch on the phosphate ions, becoming a nearly insoluble compound.
In the last decades, growers have progressively added more phosphate to their fertilizer mix to counter this problem. However, even the little leaching that occurs creates enormous environmental problems. Some vegetable growers are taking a different approach. They apply a small amount of phosphate at time of planting in the furrow (starter fertilizer); then at four to six true leaves, they foliar spray (usually a mixture of potassium phosphate) on a weekly basis thereafter, (based on tissue samples). I use 3-18-18 high grade liquid fertilizer which is designed for this very reason. It is composed of food grade materials, meaning the same high quality products used in the food industry.
Labels: 3-18-18, fertilizer, gardening, Lawn Care, leaching, liquid fertilizer, macro nutrients, phosphate
Monday, March 2, 2009
SEAWEED EXTRACT TO INCREASE PLANT GROWTH
Seaweed extracts contain a number of natural plant growth hormones (i.e. cytokinins, auxins) as well as other plant biostimulants (e.g. betaines, polyamines, oligosaccharides), which can improve plant resistances and tolerances to environmental, disease and insect stresses. For example, Polyamines influence the mechanism that controls pollination and the formation of fruits. Their presence in optimal quantities is the determining factor in the number of fruits and their development. Seaweed extracts are also rich in vitamins and micro nutrients and like humates hold ground moisture.
So does applying seaweed extract to plants increase growth, yield and resistance to disease?
Interestingly, there is an ongoing debate as to its effectiveness. For example, in a well presented article, Dr. Linda Chalker-Scott, Washington State University Puyallup Research Station debunks its effectiveness and calls it a myth*.
On the other hand T. Butler and A.H. Hunt in a research paper presented at the ISHA 2006 International Symposium on Horticultural Plants in Urban and Peri-Urban Life examined golf course turf grass subject to plant stress, due to high traffic levels and short grass mowing. Their research showed that seaweed extract in this instance reduced the nutrient inputs, increased tissue NPK levels, grass growth, color and stress tolerance.
What is one to believe?
Based on my personal experience, certain sea weed extracts can greatly increase plant fruit yields when the plant is under stress. In a twenty five acre cucumber trial over three plantings, 3 days apart, the yields from those fields where in excess of 30% greater than the plantings prior and after; and were the highest of the season. From a scientific stand point, one could argue that this was not a correct trial because the control plots were not planted at the same time and in the same fields. Furthermore, environmental conditions prior and after these plantings could have affected the yields of the rest of the plantings. In fact the entire season was subject to heavy rain fall due to two back to back tropical depressions which hovered over Florida for more than three weeks. Plants were definitely stressed from a lack of sun light and excess water.
I performed a multiple regression analysis taking in consideration solar radiation, precipitation, wind, hours of sunlight, plant stands and fertilizer regimen. With a high coefficient and statistical confidence, the sea weed extract was clearly the greatest contributor to the yield increase. Is this definitive proof that it works? I would say it’s more anecdotal experience.
It has been my experience that when plants are healthy due to the right soil and environmental conditions most additives will not significantly improve growth or yield. However, when plants are stressed, (heat, cold, wind, too much or not enough water, nutrients, etc.), these growth enhancers do make a difference.
So does applying seaweed extract to plants increase growth, yield and resistance to disease?
Interestingly, there is an ongoing debate as to its effectiveness. For example, in a well presented article, Dr. Linda Chalker-Scott, Washington State University Puyallup Research Station debunks its effectiveness and calls it a myth*.
On the other hand T. Butler and A.H. Hunt in a research paper presented at the ISHA 2006 International Symposium on Horticultural Plants in Urban and Peri-Urban Life examined golf course turf grass subject to plant stress, due to high traffic levels and short grass mowing. Their research showed that seaweed extract in this instance reduced the nutrient inputs, increased tissue NPK levels, grass growth, color and stress tolerance.
What is one to believe?
Based on my personal experience, certain sea weed extracts can greatly increase plant fruit yields when the plant is under stress. In a twenty five acre cucumber trial over three plantings, 3 days apart, the yields from those fields where in excess of 30% greater than the plantings prior and after; and were the highest of the season. From a scientific stand point, one could argue that this was not a correct trial because the control plots were not planted at the same time and in the same fields. Furthermore, environmental conditions prior and after these plantings could have affected the yields of the rest of the plantings. In fact the entire season was subject to heavy rain fall due to two back to back tropical depressions which hovered over Florida for more than three weeks. Plants were definitely stressed from a lack of sun light and excess water.
I performed a multiple regression analysis taking in consideration solar radiation, precipitation, wind, hours of sunlight, plant stands and fertilizer regimen. With a high coefficient and statistical confidence, the sea weed extract was clearly the greatest contributor to the yield increase. Is this definitive proof that it works? I would say it’s more anecdotal experience.
It has been my experience that when plants are healthy due to the right soil and environmental conditions most additives will not significantly improve growth or yield. However, when plants are stressed, (heat, cold, wind, too much or not enough water, nutrients, etc.), these growth enhancers do make a difference.
Labels: fertilizer, gardening, Lawn Care, organic, plant nutrition, seaweed extract, soil amendment
Friday, February 6, 2009
DOLOMITE VERSUS BORREPLEX CA (Calcium Lignosulfate)
Calcium is critical to plant health and the building of strong cell walls. Calcium also regulates intake of other nutrients. Gardeners and farmers seek inexpensive source of calcium and historically have applied lime rock (calcium carbonate), dolomite or gypsum. Aside from the fact that overtime, the use of these products will increase the pH of the soil, how effective is dolomite, for example, as a source of calcium for the plant compared to BorrePlex Ca?
If you are not familiar with BorrePlex CA, it is a blend of wood sugars and modified calcium lignosulfate. I take the liberty of using the trade name because there is only one manufacturer of this product approved for agricultural use in the US. This is not ment to be a plug for the manufacturer. It is an organic labeled product (OMRI) which is a byproduct of the pulp industry. Lignin which compromises 30% of all plant mass is the back bone of BorrePlex Ca. More on that later.
Without getting too technical, the solubility of calcium carbonate (Ca CO3) is dependent on the soil pH and partial pressure of CO2. Assuming the we focus on pH only, the following molar solubility table will provide some answers.
pH Mol
2 170
4 1.7
6 0.02
8 0.0011
At a soil pH of 7, solubility of calcium carbonate is around o.oo5. This means that if one ton of dolomite (2,000 lbs) is applied per acre, at best only 2.17 lbs of soluble calcium (Ca++) is available to plants, (assuming 100% water saturation). 2000 lbs x 0.005 = 10 lbs x 0.217 (21.7% molar concentration of Ca++ in CaMg(CO3)2 = 2.17 lbs.
This of course assumes that:
1) Particle size of the dolomite is extremely small to interact with water.
2) The dolomite is 100% pure.
3) The dolomite is immersed in water at all times in order to dissolves.
4) There is no precipitation of the calcium with phosphates or any other chemical reactions which may tie up calcium.
The reality is that none of these caveats apply. Particle size vary considerably depending on the source, dolomite is rarely pure, 100% moisture also implies water logging of roots which ultimately kills the plant. lastly, calcium will bind to other atoms or molecules such as phosphate.
In a perfect environment, assuming that the phosphate is already tied up in the soil and will not react with additional calcium input, a realistic 10% soil moisture, and extremely fine powder of 100% pure dolomite, at best 0.217 lbs of Ca++ is available to plants (based on soil moisture). Note that the rate of solubility of calcium is also dependent on the rate of absorption by the plant and the rate at which it binds to other atoms or molecules.
Compare this with the use of Calcium Lignosulfate, an organic source of calcium and sulfur. The recommended rate of 8.5 lbs of BorrePlex Ca, with a 5% concentration of calcium will provide 0.425 lbs in a complexed form which the plant can readily absorbed.
Assuming dolomite is purchased at $26/ton, and one ton is applied per acre, the cost per acre of Ca++ potentially available to plants = $119.81 ($26/0.217 lbs).
The cost per acre of Ca++ from BorrePlex Ca = $51.24 ($21.78 for 8.5 lbs/0.425 lbs), more than half the cost of dolomite.
Borreplex Ca offers a lot more:
1) It is an OMRI approved source of calcium.
2) Its lignin backbone is highly charged, as a result, it complexes (binds) nutrients which would otherwise be tied in the soil particles.
3) It also contains wood surgars which feed and therefore increase microbial populations including rhizo bacteria which fixate nitrogen to roots.
4) It also binds bacteria to root zone causing auxin response by plants, thereby increasing yield.
Bottom line: Studies after studies on a wide range of crops through out the world have shown that Calcium Lignosulfate increases yield from 10% to 30% depending on quantities applied.
One of the best products available for growers interested in higher yields and healthier plants.
If you are not familiar with BorrePlex CA, it is a blend of wood sugars and modified calcium lignosulfate. I take the liberty of using the trade name because there is only one manufacturer of this product approved for agricultural use in the US. This is not ment to be a plug for the manufacturer. It is an organic labeled product (OMRI) which is a byproduct of the pulp industry. Lignin which compromises 30% of all plant mass is the back bone of BorrePlex Ca. More on that later.
Without getting too technical, the solubility of calcium carbonate (Ca CO3) is dependent on the soil pH and partial pressure of CO2. Assuming the we focus on pH only, the following molar solubility table will provide some answers.
pH Mol
2 170
4 1.7
6 0.02
8 0.0011
At a soil pH of 7, solubility of calcium carbonate is around o.oo5. This means that if one ton of dolomite (2,000 lbs) is applied per acre, at best only 2.17 lbs of soluble calcium (Ca++) is available to plants, (assuming 100% water saturation). 2000 lbs x 0.005 = 10 lbs x 0.217 (21.7% molar concentration of Ca++ in CaMg(CO3)2 = 2.17 lbs.
This of course assumes that:
1) Particle size of the dolomite is extremely small to interact with water.
2) The dolomite is 100% pure.
3) The dolomite is immersed in water at all times in order to dissolves.
4) There is no precipitation of the calcium with phosphates or any other chemical reactions which may tie up calcium.
The reality is that none of these caveats apply. Particle size vary considerably depending on the source, dolomite is rarely pure, 100% moisture also implies water logging of roots which ultimately kills the plant. lastly, calcium will bind to other atoms or molecules such as phosphate.
In a perfect environment, assuming that the phosphate is already tied up in the soil and will not react with additional calcium input, a realistic 10% soil moisture, and extremely fine powder of 100% pure dolomite, at best 0.217 lbs of Ca++ is available to plants (based on soil moisture). Note that the rate of solubility of calcium is also dependent on the rate of absorption by the plant and the rate at which it binds to other atoms or molecules.
Compare this with the use of Calcium Lignosulfate, an organic source of calcium and sulfur. The recommended rate of 8.5 lbs of BorrePlex Ca, with a 5% concentration of calcium will provide 0.425 lbs in a complexed form which the plant can readily absorbed.
Assuming dolomite is purchased at $26/ton, and one ton is applied per acre, the cost per acre of Ca++ potentially available to plants = $119.81 ($26/0.217 lbs).
The cost per acre of Ca++ from BorrePlex Ca = $51.24 ($21.78 for 8.5 lbs/0.425 lbs), more than half the cost of dolomite.
Borreplex Ca offers a lot more:
1) It is an OMRI approved source of calcium.
2) Its lignin backbone is highly charged, as a result, it complexes (binds) nutrients which would otherwise be tied in the soil particles.
3) It also contains wood surgars which feed and therefore increase microbial populations including rhizo bacteria which fixate nitrogen to roots.
4) It also binds bacteria to root zone causing auxin response by plants, thereby increasing yield.
Bottom line: Studies after studies on a wide range of crops through out the world have shown that Calcium Lignosulfate increases yield from 10% to 30% depending on quantities applied.
One of the best products available for growers interested in higher yields and healthier plants.
Labels: farming, fertilizer, gardening, Lawn Care, plant food, plant nutrition
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