ArticlesPosted by Apostolos Tue, December 02, 2014 11:39:46
Please NOTE: This article has been published in Farming Monthly (UK)
Achieving adequate calcium (Ca) levels in potato tubers has always been the aim in the industry and an unmet challenge. Dr Apostolos Papadopoulos, Director and founder of Crop Intellect Ltd, summarises and discusses research findings with an aim to increase knowledge and enlighten producers.
Increased Ca content in the tubers is associated with a reduction in economically important defects such as internal brown spot, soft rots and hollow heart. Dr Apostolos Papadopoulos, Director and founder of Crop Intellect Ltd, has worked extensively on understanding the complex mechanisms involved in the uptake of calcium in plants.
Amongst fruits and vegetable crops, several years of research have been dedicated to further the knowledge of calcium uptake by potatoes. Crop Intellect has submitted a patent on selected molecules discovered to be effective in increasing the uptake of Ca in plant tissue and are incorporated in the crop nutrition product TECAL. Crop Intellect also offers PotiZon which is a unique product only for the potato crop. The research findings of their work including other researchers are summarised here to increase knowledge and enlighten producers.
Ca is an important plant nutrient and essential for strengthening the plant cell wall for cell integrity as well as acting as a second messenger involved in many physiological functions and abiotic stress tolerance. External inputs containing Ca and plant genotype can affect the Ca levels in the potato plant. Several studies have demonstrated that applications of Ca in various forms including calcium nitrate and lime have the ability to increase the above ground Ca levels but this is not the case for the potato tubers. Ca like Sulfur, Boron and Copper are considered to be phloem immobile as they don’t re-translocate from older leaves to younger when these elements are in deficiency.
Transport of Ca is therefore believed to occur in the xylem tissue and it is not re-translocated via the phloem from the aerial shoot tubers and main roots. Water absorbed by the main roots bypasses the tubers which has significant implications for field applied Ca. Research studies where Ca was radiolabeled to trace its movement within the plant, showed that the main root doesn’t provide Ca to the tubers. It is only the roots on the stolon and tuber that are able to increase the Ca internally.
Furthermore, tuber tissue closer to the stolon had higher Ca levels compared to the opposite end of the tuber. Calcium available on the vicinity of the tuber i.e. to the periderm doesn’t contribute to the Ca in tuber tissue as it is not transported across the periderm. Ca in the periderm is manyfold greater than that in the internal tissue and levels fluctuate easier in the periderm with external Ca applications. However, no direct relation exists between periderm and internal calcium levels. It is likely that due to differences in water potential between tubers and foliage, tubers don’t compete for Ca in the transpiration stream. The water potential is nearly equal mostly in the evening although leaves always have a lower water potential which explains why only roots on the stolon and tuber are able to supply Ca to the tuber tissue.
Therefore, the form, placement and timing of Ca are important when intended to increase tuber Ca. A highly soluble form such as calcium nitrate will likely leach if not supplied at regular intervals in the soil and will not provide a constant supply to the tuber. A persistent form of Ca such as present in LimeX (lime) can supply adequate levels when incorporated in the soil near the tuber. Ca solubility will be limited by the soil moisture but adequate quantities provide a constant supply during the growing season.
It is wrongly believed that foliar Ca applications will improve tuber Ca content. There is also no evidence to suggest that foliar Ca applications will reduce the removal of Ca from the tubers to the foliage as this is not a common physiological process. The foliage will typically have significantly higher calcium content than the tuber when Ca in present in the soil. It is the management of the transpiration stream and the consistent supply of Ca in the vicinity of the tuber that is directly related to the potential of increasing Ca levels in the tuber tissue through the uptake by the stolon and tuber roots.
For more information and advice on how to improve growing potatoes and to increase Ca content in the tuber please contact Crop Intellect Ltd.
ArticlesPosted by Apostolos Mon, May 05, 2014 09:32:58
The phosphite truth!
been used by many producers as a fertiliser to provide phosphorous (P) to the
plants as it is an essential element required by most living organisms. Phosphites
can be made from phosphorous acid (H3PO3) containing one
less oxygen than phosphate. Many fertiliser formulations containing phosphate
such as monopotassium phosphate, super phosphate or others have as main source
phosphoric acid (H3PO4).
long been believed to have fungicidal effects and strong evidence exist to
demonstrate such effect but there is a lot of confusion as to how phosphites
work. Currently, phosphites are sold as fertilisers, biostimulants and
fungicides. These claims are to an extent all true. The fungicidal effect on
Oomycetes is widely accepted and several publications are available providing
evidence. However, the modes of action vary between studies and several
explanations are given under different methodologies. The most debate exists in
the supply of P to the plant as phosphite. Latest studies have confirmed that
phosphite provides very little P to be utilised by the plant causing deficiency
if this is the only supplied source. Plants cannot utilise phosphite directly,
so it has to be converted typically by soil microorganisms to phosphate before
it is used.
It is well known
that crop nutrition elements such as Mn, Cu, Al, Ca and Zn are associated with
fungicidal properties, with varying modes of action, either as fungistats,
direct suppression or by boosting the plant’s own defence mechanism. Literature
has also suggested that phosphate itself in certain forms has shown fungicidal properties.
Generally, this should not come as a surprise as a healthy plant would be able
to protect itself better than a plant with deficiencies. There are no much
evidence of direct comparisons between phosphate forms and phosphite. Work is
still required to quantify and compare such differences. Crop Intellect is
performing trials to provide insights in such direct comparisons and increase
the public knowledge. This comparison is also taking into account the existing evidence
of the effect of phosphate and phosphite on the plant’s rooting system. Several
phosphite forms are used as starter fertilisers to boost rooting with varying
difficulty with phosphites is the detection and quantification. The methods
available are typically lengthy, costly and complex, and not offered by many
laboratories. Crop Intellect has devised a method which has been adopted, and
uses photometric technics to quantify phosphites in liquid solutions. This
technique has been proven to provide a detailed analysis of the quantity of
phosphite present. During the development it became apparent that the stability
of phosphite is very critical. The issue is not during the formulation but
during spraying. When phosphites are bottled at their concentrate form they
degrade very slowly. But when they are added to water in a tank of a sprayer
they react very quickly turning into phosphate. This can be replicated in the
lab if tap water is used for dilutions or if the phosphite is mixed prior to
the analysis with other micronutrient or fungicide products. These reactions
occur rapidly and they cause oxidation of the phosphite turning it into
phosphate. This explains some of the claims made that phosphite provides
phosphate to the plant. Therefore, stabilising phosphites is vital in order to
obtain the benefits. Several companies provide evidence of stability by quick
methods in beakers which are meaningless since they don’t perform any analysis to
quantify the phosphite present and they are typically not sampling at the point
that the product finds the plant, which is sometime after it has been aerated
and agitated in the sprayer tank in the presence of other nutrition products.
But the question
as to how phosphites provide fungicidal benefits has not been answered yet.
Studies performed in very recent years provide evidence that phosphites are
fungistats and when used above certain levels are effective in petri dish
studies (in vivo). This clearly suggests that if phosphites are accumulated in
the plant tissue at these levels they will be effective to control certain
fungal attacks. A huge issue in such instance is that of phytotoxicity. Phosphites
can cause severe phytotoxicity in several plant species and this has been
reported widely. Such a limitation requires a good understanding of the
quantity to be accumulated in the plant tissue in order to effectively utilise
the fungicidal properties of phosphites. This is directly relating to knowing
how stable a product is to approximate the number of applications in order to
match the accumulation requirement to be effective. Another issue is the
allowable concentration of phosphite by the EU detectable in fresh produce as
MRL (maximum residue level) which is 2ppm for certain formulations. Multiple
applications will be required to increase the accumulation of phosphite which
may prove not viable from an economic sense.
studies with detailed analysis into plant proteomics before and after
applications of phosphite have proven that they stimulate the plant’s own
defence mechanism by regulating up or down specific proteins and those gene
clusters that relate directly to the defence mechanism of the plant. This is a
plausible explanation considering the evidence from several studies and experience
from field evidence supported by producers under varying circumstances. The
concentration of a stable phosphite is critical for its efficacy as typically
stimulants will not work at high concentrations or in fact low ones. Crop
Intellect has a patent pending method of stabilising phosphite at the form that
has had the most success. The analytical method developed has been vital to
understand the robustness of the phosphite. Therefore the levels of phosphite
used are minimal and known, applied at the appropriate level to stimulate the
immune system of the plants. A specific recommendation for different plant
species is given to ensure effectiveness, derived from greenhouse and field
studies. The product has been named Cropearnicus for its different view point
and it is embedded in a nutrient formulation containing many vital elements to
promote a healthy plant growth. The product is commercially available and
offered through a limited distribution network.
Questions such as
the ones following are common when phosphites are discussed with growers; do
producers know why they use phosphites; when, how and where phosphites should
be used; what are the benefits of using phosphites on a crop; are producers
buying an expensive and overrated phosphate! The answer in many such questions
is that growers are misinformed and biased by well marketed products rather
than evidence and proper instructions of use to achieve the benefits that
phosphites can offer.
Crop Intellect with any enquiries on this article and we will be happy to
provide details for your own benefit on using phosphites. We also offer the
analysis of phosphite as part of our services. Contact us at firstname.lastname@example.org or call 07500794140 / 01522 837268.
include: Crop Protection 2014, 56 (74-81), Crop Protection 2012, 32 (1-6), J.
of Proteomics 2013, 93 (207-223), New Ag International, Analytical Biochemistry
2011, 412 (74-78)
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ArticlesPosted by Apostolos Sat, February 08, 2014 13:10:49
Most of us assume that the largest portion of emissions
and energy use comes from other industries than agriculture. Globally, agriculture
is a significant contributor to greenhouse gas emissions. The Intergovernmental
Panel on Climate Change (IPCC) estimates that agriculture is directly
responsible for 13.5% of global greenhouse gas emissions (Figure 1), with a
further 17.4% coming from land use change (a staggering total of 30.9%). The
two biggest sources of greenhouse gases from agriculture are the release of nitrous
oxide from agricultural soils and methane from livestock and manures, each of
which represents more than 5% of total global greenhouse gas emissions. While
energy use in agriculture (for example, diesel for cultivation) is important,
its contribution to greenhouse gas emissions is much lower – less than 1.5% of
total emissions. For conventional cereal crops, nitrogen fertilisers are the
most important component of the carbon footprint (Figure 2). These emissions
from fertiliser are split into two parts, with emissions from fertiliser
manufacture and the emission of nitrous oxides from the soil of roughly equal
High-yielding crops are now constrained in many areas by restrictions
on nitrogen use introduced as part of the Nitrate Vulnerable Zone (NVZ)
legislation; future yield growth is, therefore, dependent on using nutrients
Crop Intellect’s research focuses on developing technologies to
improve efficiency of nutritional uptake. This combines both the increased
uptake by promoting growth and the reduction of inputs providing an increase in
yield and a reduction in input’s costs. Maintaining a healthy soil biology and
structure is vital to ensure optimal yield performance. A long term cultivation
and rotation plan is required for maximising efficiency in production and Crop
Intellect’s expertise in developing soil stability is available to the growers.
The figure below shows the portion of carbon footprint attributed
to fertiliser production and fertiliser-induced field emissions. These
contribute the most compared to other inputs. This is why our focus is on nutrient
uptake efficiency. It is also important to understand that nutrition on its own
is not able to increase yield more than what the crop can produce when not in a
deficiency. This is where our technologies are brought in, combined with nutrition
they promote a crop physiological change to increase the potential of the crop
to produce effectively and efficiently, directly making a positive contribution
in reducing the carbon footprint of agriculture.
References and Useful Links: http://archive.hgca.com/document.aspx?fn=load&media_id=8362&publicationId=9193