Tuesday, 24 January 2012

What is Humic Acid(POTASSIUM HUMATE) ?

100% organic

It is an organic water-soluble humic substance, derived from lignite.  It is a good plant growth 
stimulant acting on soil and plants.  It improves soil physical property, ion exchange capacity, 
water holding capacity, drought tolerance ability;  protect plants from physical/soil stress and 
increase soil microorganisms, Biological activity.  This also prevents loss of nutrients from soil 
and act as a storehouse by keeping plant nutrients in soil.  It increases crop growth and yield, soil 
fertility status and reduces use of chemical fertilizers
The term "humus" dates back to the time of the Romans, when it was frequently used to designate the soil as a whole. It was later applied to the organic matter of soils and composts, or to different fractions of this organic matter; as well as, to complexes formed from a variety of natural organic substances. Humus compounds are complex natural organic compounds that are formed in soils from plant residues, by a process of "humification". Humus materials are complex aggregate of brown to dark colored amorphous substances, which have originated during the decomposition of plant and animal residues by microorganisms, under aerobic and anaerobic conditions, in soils, composts, peat bogs, and water basins. Chemically, humus consists of certain constituents of the original plant material resistant to further decomposition; of substances undergoing decomposition; of complexes resulting from decomposition, either by processes of hydrolysis or by oxidation and reduction; and of various compounds synthesized by microorganisms.
"Humic acid " is the commercial term often used to refer to the combined humic and fulvic acid content found in these naturally occurring deposits. Humic acid is known to be among the most bio-chemically active materials found in soil



Humic Acid's Role in Fertilization

Humic acid is technically not a fertilizer, although in some walks people do consider it that. Humic acid is an effective agent to use as a complement to synthetic or organic fertilizers. In many instances, regular humic acid use will reduce the need for fertilization due to the soil's and plant's ability to make better use of it. In some occurrences, fertilization can be eliminated entirely if sufficient organic material is present and the soil can become self sustaining through microbial processes and humus production.
Why Use Humic Acid?
Today, there is a recognized and increasing use of humic acids for their beneficial impact on the growth and cultivation of crops (vegetable & non-vegetable), citrus, turf, flowers, and particularly in organically-deficient soils. Humic acid is not a fertilizer as it does not directly provide nutrients to plants, but is a compliment to fertilizer. Benefits include:
  • Addition of organic matter to organically-deficient soils
  • Increase root vitality
  • Improved nutrient uptake
  • Increased chlorophyll synthesis
  • Better seed germination
  • Increased fertilizer retention
  • Stimulate beneficial microbial activity
  • Healthier plants and improved yields
  • How Does Humic Acid Improve Soil?

    When applied to clay soils, humic acid can help break up compacted soils, allowing for enhanced water penetration and better root zone growth and development. When applied to sandy soils, humic acid adds essential organic material necessary for water retention thus improving root growth and enhancing the sandy soil's ability to retain and not leach out vital plant nutrients.

    How Does Humic Acid Improve Plant Growth?

    As mentioned above, one way plant growth is improved is through the structural improvement of both clay and sandy soil allowing for better root growth development.
    Plant growth is also improved by the ability of the plant to uptake and receive more nutrients. Humic acid is especially beneficial in freeing up nutrients in the soil so that they are made available to the plant as needed. For instance if an aluminum molecule is binded with a phosphorus one, humic acid detaches them making the phosphorus available for the plant. Humic acid is also especially important because of its ability to chelate micronutrients increasing their bio-availability.

    How Does Humic Acid Effect Microbial Activity and What is its Role?

    The activities of beneficial soil microbes are crucial for the sustainability of any soil and plant growth. Humic acid stimulates microbial activity by providing the indigenous microbes with a carbon source for food, thus encouraging their growth and activity. Soil microbes are responsible for solubilizing vital nutrients such as phosphorus that can then be absorbed by the humic acid and in turn made available to the plant. Additionally, microbes are responsible for the continued development of humus in the soil as it continues to break down not fully decomposed organic matter. This in-situ production of humus continues to naturally add to the humic acid base and its benefits
    Foliar Spray: In ratios of 400 ml per acre at actively growing and reproductive stages
    source --Natural Environmental Systems and  NLCINDIA


Friday, 13 January 2012

Phosphonates as fertilizers

Phosphonates were first investigated as fertilizers in Germany and the U.S. during the 1930s and 40s. At that time, agricultural officials were concerned that war activities would disrupt vital shipments of rock phosphate for fertilizer production, so alternative sources of fertilizer phosphorus were explored (6). Results of studies conducted in both countries demonstrated that phosponates were not effective substitutes for phosphate fertilizer. Scientists found that yields of legumes and grasses treated with calcium phosphite were lower than phosphate-treated plants, and in most cases, lower than controls plants receiving no phosphorus. However, a second crop seeded into the same soils that were treated with calcium phosphite showed improved yields. The authors attributed the delayed phosphorus response to the conversion of phosphite to phosphate in the soil (9). Subsequent research revealed that phosphite could be converted to phosphate primarily by soil-borne bacteria, but that these bacteria would not use phosphite until most phosphate was depleted (1). Based on the results of these studies, phosphonate fertilizer was viewed as an inefficient and costly means of supplying phosphorus to plants and scientists eventually lost interest in this compound as a phosphorus fertilizer.
Despite previous research findings, phosphonate compounds are marketed by some companies as a source of phosphorus and potassium fertilizer. Preliminary results with turfgrasses growing in sand culture and treated with equal amounts of potassium phosphite and potassium phosphate have supported claims that potassium phosphite does not supply usable phosphorus to turfgrasses ( see fig below . Although potassium phosphite can be converted to phosphate in soil, turf managers should realize that this is an inefficient means of supplying phosphorus to plants when compared with phosphate fertilizer.
Figure --. Annual bluegrass treated with a nutrient
solution containing potassium phosphate as the source
of phosphorus (left); and the same nutrient solution
with potassium phosphite as the source of phosphorus
(right). Annual bluegrass treated with potassium
phosphite shows phosphorus deficiency symptoms
(stunted growth and a red tint to foliage) indicating
that this compound is not supplying usable
phosphorus to the plants.
Claims that phosphonates consistently enhance rooting are debatable and more evidence is needed to support these claims. A two-year study performed at North Carolina State University showed that bentgrass root mass was unaffected by phosphonate products (4). Certainly, more research using precise root measurement techniques is needed to determine if enhanced rooting due to phosphonates occurs under different environmental and management conditions. If enhanced rooting does occur, it could be due to product formulation, or from the suppression of minor root pathogens (Pythium spp.) due to fungitoxic action of the phosphonate product, leading to healthier and more extensive roots.

Literature cited

  1. Adams, F. and J.P. Conrad. 1953. Transition of phosphite to phosphate in soils. Soil Science 75:361-371.
  2. Anonymous. 2005. Greenbook turf and ornamental reference for plant protection products. Vance Communication Corp., New York, NY.
  3. Brown, S., S.T. Koike, O.E. Ochoa, F. Laemmlen, R.W. Michelmore. 2004. Insensitivity to the fungicide fosetyl-aluminum in California isolates of the lettuce downy mildew pathogen,Bremia lactucae. Plant Disease 88:502-508.
  4. Dorer, S.P. 1996. Nutritional effects of a fungicide combination on summer bentgrass decline. Master of Science Thesis, North Carolina State University, Raleigh, NC.
  5. Griffith, J.M., A.J. Davis, and B.R. Grant. 1992. Target sites of fungicides to control oomycetes. pp. 69-100. In: Target sites of fungicide action. W. Koller (ed.), CRC Press, Inc., Boca Raton, FL.

Monday, 9 January 2012

What’s in a name? Phosphonates as fungicides

Phosphonate fungicides have very good efficacy for Pythium diseases and other diseases caused by oomycete fungi when applied preventatively; but are thought to have poor efficacy when applied post-infection (after disease symptoms and signs are apparent) see picture above --Effects of reagent-grade potassium phosphite
(H3PO3) and potassium phosphate (H3PO4) on symptom
development of Pythium blight of creeping bentgrass.
Potassium phosphite has good efficacy against this
disease when applied preventatively.




Literature cited

  1. Adams, F. and J.P. Conrad. 1953. Transition of phosphite to phosphate in soils. Soil Science 75:361-371.
  2. Anonymous. 2005. Greenbook turf and ornamental reference for plant protection products. Vance Communication Corp., New York, NY.

The following article provides some good information about phosphorus acid fungicides.


This term “phosphorous acid” should not be confused with phosphoric acid or 
phosphorous (P), a fertilizer component. In fertilizers, P is normally found in the form of 
phosphoric acid (H3PO4), which readily disassociates to release hydrogen phosphate 
(HPO42) and dihydrogen phosphate (H2PO4-). Both of these ions may be taken up by 
the plant and are mobile once inside the plant. Phosphorous acid is H3PO3. A single 
letter difference in the name of a chemical compound can make a major difference in its 
properties. Phosphorous acid releases the phosphonate ion (HPO32-; also called 
phosphite) upon disassociation. Phosphonate is easily taken up and translocated inside the 
plant. Phosphorous acid does not get converted into phosphate, which is the primary 
source of P for plants.  

Because phosphorous acid and its derivatives do not get metabolized in plants, they are 
fairly stable and probably contribute little or nothing to P nutritional needs of the plants. 
Some researchers have investigated the ability of phosphorous acid to act as a nutrient 
source for plant growth and found that P-deficiency symptoms developed with 
phosphorous acid as a sole source of P. This means that although phosphorous acid can 
control diseases it is not a substitute for P fertilization. The inverse is also true: phosphate 
is an excellent source of P for plant growth, but is unable to control diseases other than 
improving the general health of the crop. So applying high amounts of P fertilizer will not 
work as a disease control measurer. 

Researchers have found that phosphorous acid fungicides are especially effective against 
Oomycete pathogens, such as Phytophthora, Phythium, and Downy mildews in a number 
of crops. Phosphorous acid has both a direct and indirect effect on these pathogens. It 
inhibits a particular process (oxidative phosphorylation). In addition, some evidence 
suggests that phosphorous acid has an indirect effect by stimulating the plants natural 
defense response against pathogen attack. This probably explains the much broader 
spectrum of activity observed in fungicide efficacy trials in small fruit crops in Michigan. 
We found, for instance, that ProPhyt had efficacy against Downy mildew, Phomopsis,



The phosponate ion is highly systemic and fairly stable in plants. The systemic activity 
allows them to be applied as foliar fungicides for prevention of Phytophthora and 
Phythium root rot

Since these fungicides are actually 
in salt form, care must be taken not to exceed a certain concentration as crop injury may 
result. In addition, if the concentration is too high, the pH may become so low and result in crop injury



Source: Michigan Fruit Crop
Advisory Team Alert, Vol. 20, No. 5, May 10, 2005


Phosphorus Compounds


Fundamental understanding of phosphorus behavior is a key to solving environmental problems of plant, animal and microbe nutrition, eutrophication, corrosion, and geochemistry. Researchers of such problems nearly always assume that phosphorus in natural systems occurs exclusively in the +5 oxidation state as orthophosphate, polyphosphates, organophosphates, and paniculate phosphates. This assumption has never been explicitly proven.
Phosphorus is unique among the major nutrients (carbon, oxygen, nitrogen, phosphorus) in that it is often assumed to lack a gaseous species for atmospheric transport. However, the recent work of Glindeman et al. (1996a, 1996b, 1996c, 1999) and Han et al. (2000, 2003) unambiguously confirmed that volatile phosphine gas (i.e., hydrogen phosphide or PH3) can be detected in the earth’s atmosphere at trace levels. Several sources of phosphine have been also identified by these authors. Unfortunately, perhaps because of the erroneous assumption that phosphorus is nonvolatile, study of total transport through this mechanism has received minimal attention, and all atmospheric phosphorus transport is assumed to be via phosphate dust.
Atmospheric transport of phosphorus is significant. Pierrou (1979) estimated that atmospheric fallout of phosphorus is in the range of 3.6-9.2 Tg (1 Tg = 10^sup 12^ g) P/yr for terrestrial ecosystems (6.3-12.8 Tg P/yr for the earth), and Graham and Duce (1979) attempted to quantify P flux from land to the atmosphere and estimated to be 4.3 Tg P/yr. If this phosphorus was uniformly dissolved in the world average annual rainfall of about 400 χ 103 km^sup 3^, it would suggest an average phosphate concentration of about 10 ppb in rainwater. The potential importance of atmospheric phosphorus loading to oligotrophic lakes was seemingly confirmed by Lewis et al. (1985), who quantified soluble phosphate in rainwater to remote mountain lakes and determined it accounted for 25% of the total annual phosphate flux to the watershed. Interestingly, this phosphate was not associated with dust or pollen. Atmosphere input of soluble P to the coastal ocean was estimated to be 12 10^sup 10^ mol P yr^sup -1^ (Benitez-Nelson, 2000). This is about 10% of dissolved inorganic phosphate from rivers (Duce, 1986; Delaney, 1998). The issue of atmospheric phosphate is discussed in later sections in light of the results of Glindeman et al. (2003).
The phosphate industry directly and indirectly produces many reduced phosphorus compounds. The United States is the largest producer and consumer of phosphate rock in the world. In 1997, the marketable production of phosphate rock in the United States was 32% of the world total production (United States, 45.9 million metric tons; world total, 143 million metric tons). In 2001, the marketable production and sale of phosphate rock decreased worldwide due to decreased demand for fertilizer (USGS, 2001), and the U.S. share of production dropped to 25%.

Sunday, 8 January 2012

Phosphorous Acid Fungicides and Phosphorus Nutrients


Phosphites and Phosphonites are alkali metal salts of phosphorous acid and sold as fungicide that control a number of crop diseases particularly those caused by Phytophthora spp. Fosetyl-Al the active ingredient in Aliette is an example of a fungicide in this class that is registered on several crops in Canada for the control of diseases caused by Phytophthora. There are several other different metals salts of phosphorous acid sold as fungicides in the US that are not available in Canada. Fosetyl-Al, was one of the first phosphorous acid type fungicides developed that can move both up and down in plants. Once inside the plant, it is broken down rapidly into phosphorous acid, which is stable but extremely soluble in water and toxic to many Phytophthora species.

Phosphorous acid type fungicides works in two ways. They act directly on the invading fungus to stop its growth and sporulation. They also act indirectly by stimulating the plant to activate their own defense system, thus helping to prevent future infections.
 Plants that have their defense system activated prior to invasion by a pathogen can defend themselves much more effectively.

There is no evidence that phosphorous acid type fungicides can be used directly by plants as a source of nutritional phosphorus. It is possible that when these products are applied to plant root systems or in the soil, soil microbes could convert these compounds to phosphate which would be available to the plant as a phosphorus nutrient. This is a slow process and the amount of phosphate produced would not be sufficient to satisfy the phosphorus requirements of plants. There is evidence however that phosphorous acid type fungicides may actually intensify the deleterious effects of phosphorus deficiency by 'tricking' deprived plant cells into sensing that they are phosphorus sufficient, when, in fact, their cellular phosphorus content is extremely low. Therefore, it is a good idea to make sure that the plants are not deficient in phosphorus prior to using a phosphorous acid type fungicide
In contrast to phosphites and phosphonites, the form of phosphorus plants take up as a nutrient is known as orthophosphate. Fertilizers containing phosphorus are water soluble and once they dissolve, orthophosphate is available for uptake by plants. Following application to the soil, orthophosphate is prone to fixation reactions after which it is no longer available to plants. At lower pH, it forms insoluble salts with aluminum and iron. At higher pH, it reacts with calcium. Either way, these forms are not available to plants, which is why limiting the exposure of phosphorus fertilizer to soil by banded application is a common practice.