RELATIONSHIP BETWEEN PLANT N, P, K, AND S NUTRITION, PROTEIN CONTENTS AND GRAIN QUALITY

1. PLANT NUTRITION AND CROP PRODUCTIVITY
SAID H. MARZOUK
RELATIOSHIP BETWEEN PLANT N, P, K, AND S NUTRITION, PROTEIN
CONTENTS AND GRAIN QUALITY
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2. NUTRIENT INTERACTIONS
 Interaction : In simpler terms interaction means influence / effect of one nutrient
upon the other nutrient(s)
 The availability of an ion is influenced/ or inhibited by the presence of other ions
in soil solution.
 It may positive or negative or no interaction
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3. TYPES OF NUTRIENT INTERACTIONS
 Synergistic effect : upon addition of two nutrients, a increase
in crop yield that is more than adding only one separately ,
the interaction is positive .
 Antagonistic effect: similarly, if adding the two nutrients
together produced less yield as compared to individual ones,
the interactions is negative.
 No interaction/ zero interaction : when there is no change,
there is no interaction.
 Different interactions among essential plant nutrients have
been reported. However, most interactions are complex.
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4. Forms of Interactions I. Interaction between the
nutrients .
II. Interactions between nutrients
and placement
III. Interaction between nutrient
placement and conservational
tillage
IV. Interaction between nutrients
and hybrid or variety .
A nutrient interacting
simultaneously with
more than one
nutrients.
This may induce
deficiencies,
toxicities, modified
growth responses,
and/or modified
nutrient composition
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5. Factors that influence interactions of nutrients
 Interaction of nutrients depend on soil type, physical
properties of soil, pH, temperatures and concentration of
participating nutrients.
 There is a highly controlled selectivity process involved in
uptake of nutrients by plants and that is the reason why the
plant does not contain the same ratio of nutrients inside the
plant as found in the soil.
 For example, alkaline soils normally contain higher
calcium levels than potassium but, when a plant growing
in this field is analyzed, it contains higher potassium level
than calcium.
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6. Synergism effects
 Many soil scientists, plant physiologists and plant
biochemists have tried to clarify the much complicated
relationships between nutrients.
 Some of these relationships are straight forward but, most
are not. A few examples from agricultural laboratory
research and field based experiments have shown us that
an:
 Optimum supply of nitrogen ensures optimum uptake of
potassium as well as phosphorus, magnesium, iron,
manganese and zinc from the soils.
 Optimal levels of copper and boron improve nitrogen
uptake by plant.
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7.  Optimal levels of molybdenum improve utilization of nitrogen as well as
increases uptake of phosphorus.
 Optimal levels of calcium and zinc improve uptake of phosphorus and
potassium.
 Optimal levels of sulphur increases the uptake of manganese and zinc.
 Optimal levels of manganese increases uptake of copper and P .
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8. Antagonism effects
 Excessive amounts of nitrogen reduce the uptake of
phosphorus, potassium, iron and almost all secondary and
micronutrients like calcium and magnesium iron,
manganese, zinc and copper.
 Excessive amounts of phosphorus reduces uptake of
cationic micronutrients like iron, manganese, zinc and
copper.
 Excessive amounts of potassium reduce uptake of
magnesium to a greater extent and calcium to a lesser
extent.
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9.  Excessive amounts of calcium reduces uptake of iron.
 Excessive Iron reduces zinc uptake.
 Excessive zinc reduces manganese uptake.
 The examples above show that the interrelationships
between nutrients in the plant system are quite
complicated and interdependent.
 More research is needed to be done on the molecular
levels to elucidate the actual relationships to specific
crops for better growth and yields.
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10.  Agronomists and plant nutritionists have long been aware
of the greatest competition that occurs between ions with
similar size, valency and ion charge.
 Calcium, magnesium and potassium ions are quite similar
in size and charge and hence, exchange sites cannot
distinguish the difference between the ions.
 Often times, they indiscriminately accept either ion
regardless of which ion is meant for that site.
 Generally, the binding strengths of potassium and
calcium are much stronger than magnesium and they
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11.  Applications of potassium fertilizers reduce a plant’s
ability to absorb magnesium.
 Similarly, very high rates of magnesium fertilizers will
indeed depress potassium absorption by plants, but this
antagonism is not nearly as strong as the inverse relation
of potassium on magnesium.
 Reiterating, calcium, magnesium, and potassium compete
with each other and the addition of any one of them will
reduce the uptake rate of the other two.
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12. Salinity and selectivity
 Today approximately 20% of the world’s cultivated land
and nearly half of all irrigated lands are salt-affected.
 The only element that affects sodium levels in the soil is
potassium.
 When sodium percentage is higher than potassium then
there is often trouble on the horizon from soil health and
crop productivity point of view.
 At higher levels of sodium, plants will preferentially take
up sodium in place of potassium.
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13.  Potassium deficiency inevitably leads to growth inhibition
because potassium plays a critical role in maintaining cell
turgor membrane potential and enzyme activities.
 Once sodium gets into the cytoplasm, it inhibits the
activities of many enzymes.
 As a domino effect, when sodium and potassium ratio is
excessive (ratio >10) then plant will not get enough
manganese.
 It isn’t that manganese is absent; it is just tied up and
hence, unavailable to the plant.
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14.  An important factor in the battle between sodium and
potassium ions is calcium.
 Increased calcium supply has a protective effect on plants
under sodium stress.
 Adequate levels of calcium assist in potassium/ sodium
selectivity.
 This beneficial effect of calcium is mediated through a
signaling pathway that regulates activity of potassium and
sodium transporters.
 Calcium may also directly suppress sodium import mediated
by nonselective cation channels.
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15. If become in excess Become deficit
Ca P
Ca and Mg K
Ca Mg if ratio is more than
K and NH4 Mg
N,K and Ca B
Fe and SO4 Mo
Cu, Mn, and NH4-N Mo
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16. If become in excess Become deficit
Cu, Fe and Mn Al
P Zn
N,P
,K Cu
Zn and Al Cu
P Mo
NO3-N Fe
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17. Mulder’s Chart,
Interactions of macro and micro nutrients 17

18. Table 1 .Effect of P and S levels on yield, P & S uptake and
use efficiencies of S.cane 18

19. 19

20. The effect of N level on nutrient uptake 20

21. The effects of S level on N,P,K and zn availability in maize
production 21

22. WHY WE NEED TO KNOW THE PLANT NUTRIENT INTERACTIONS ?
 Balanced supply of essential nutrients is one of the most important factors
in increasing crop yields.
 To know the effect of one nutrient upon the other.
 To minimize the antagonistic effects by applying -right quantity of
fertilizers at right time, in right place according to the crop needs.
 Better understanding of nutrient interactions may be useful in
understanding importance of balanced supply of nutrients and consequently
improvement in plant growth or yields.
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23. Grain quality  In ethanol production, for
example, the chemical
composition of grain, such as the
starch content, is important.
 In food and feed production,
properties like protein, oil and
carbohydrates are important.
 To consumers, properties like
Colour and flavour are important
 In the milling industry, the
health of the grain is the most
important factor
 For purpose of seed for planting,
a high germination percentage.
Grain quality is a term
that refers to the quality
of the grain.
However, quality
depends on what the
grain is used for.
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24.  Physical properties of seeds
quality include grain mass,
hardness, grain size and shape
and colour.
 Chemical characteristics of
grains include moisture
content, protein content, starch
content and fiber content.
Generally speaking the
quality of seed can be
divided further into three
main groups:
I. botanical (species
and cultivars).
II. Physical
III. chemical
characteristics
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25.  Composition
 Composition, e.g. protein, carbohydrate, lipids and
their breakdown products, qualitatively influences
product acceptability, by affecting texture and taste.
 Quality changes evolve slowly in stored grain and
more rapidly in milled or processed intermediary
products.
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26.  Odour, aroma
 Most grain types, when fresh, have a distinctive natural
odour or aroma.
 This is generally accepted as an indicator of good quality,
although some people prefer grain which smells 'old' or
even fermented.
 Certain cultivars of rice, for example, possess aromatic
qualities which are considered desirable by some
consumers.
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27. Proteins
 Are large biomolecules and macromolecules that are
comprised of one or more long chains of amino
acid residues.
 Proteins differ from one another primarily in their
sequence of amino acids, which is dictated by
the nucleotide sequence of their genes.
 Most proteins consist of linear polymers built from
series of up to 20 different L-α- amino acids.
 All proteinogenic amino acids possess common
structural features, including an α-carbon to which
an amino group, a carboxyl group, and a variable side
chain are bonded.
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28.  N and S are raw materials for protein synthesis.
 Others like Ca, P, Zn and Fe are involved in enzyme
synthesis, activation or as electron carriers while Mg, and
K are mostly involved in enzyme activation and
transportation of materials such as fructose and sucrose
from source to sink.
 It has been noted that crop quality is also greatly
influenced by the synergistic and antagonistic interactions
in various nutrients uptake and utilization.
 Therefore, balanced nutrition is noted to be of paramount
importance
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29. Nitrogen
 Nitrogen is very important macronutrient in protein
synthesizes
 According Leghari et al., 2016 nitrogen is an essential
constituent in Metabolic activities associated with
proteins.
 In rice plants, grain protein has been shown to increase
significantly with nitrogen fertilization.
 A study on the effect of N rates on maize grain quality
in Iran, showed highest crude protein content (8%) at
the higher N rate of 200 kg ha-1 as compared to lower
rates (50, 100, 150 kg N ha-1) (Bationo, 2004)
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30.  It was also reported that the protein content of oil seed
crops increases with the increase in the level of nitrogen
in the seed (Xue et al. 2019).
 According to Xue et al. (2019), nitrogen plays an
essential role in the synthesis of proteins that determine
the baking quality of grain crops like wheat.
 The major storage protein in the endosperm of the wheat
grain is known to be glutenin and gliadins (Mengel et al.,
2001).
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31.  Oversupplying of N especially with higher NH4–N: NO3-
N ratios, is reported to reduce calcium uptake .
 On the other hand, calcium is needed for synthesis of
strong cell walls (Capdevillea et al. 2005).
 A relationship in Ca uptake with increase in N amount
applied was reported from a study on N nutrition in
pepper in Israel in which a decrease of 50% for Ca uptake
when N was applied in excess (Bar-Tal et al. 2001).
 Increasing N application has also been reported to reduce
oil content in some legumes such as soybean and
groundnuts (Blumenthal et al., 2008)
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32. Potassium
 Potassium is an essential nutrient that is absorbed by
plants in larger amounts than any other nutrient except N
(Roy et al., 2006).
 Unlike N, P and most other nutrients, K is not
incorporated into structures of organic compounds; instead
potassium remains in ionic form (K+) in solution in the
cell and acts as an activator of many cellular enzymes
(Havlin et al., 2005).
 Potassium (K) is essential nutrients for all plants and is
involved in many vital plant functions such as plant
enzyme activation, water regulation, energy capture from
photosynthesis, N uptake and protein synthesis.
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33. Relationship between K and N in protein
 It was observed that the crop response to applied nitrogen fertilizers
decreases when the exchangeable potassium content of a soil is
below the optimal level.
 The “reading” of the genetic code in plant cells to produce proteins
and enzymes would be impossible without adequate potassium.
 Although, nitrogen is fundamental in production of proteins, plants
deficient in potassium will not produce proteins despite an
abundance of available nitrogen.
 Instead, incomplete protein such as amino acids, amides and nitrate
accumulate in the cell. This is because; the enzyme nitrate reductase
which catalyzes the formation of proteins is activated by potassium
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34. Relationship between S and N in protein synthases
 Sulfur is a structural component of some amino acids
(including cystein and methionine) and vitamins.
 Protein synthesis is affected when an insufficient level of
sulfur amino acids is available.
 Sulphur-containing amino acids represent a powerful part
of cell antioxidant system. Thus, they are essential in the
maintenance of normal cellular functions and health.
 In addition to their worthy antioxidant action, sulphur-
containing amino acids may offer a chelating site for
heavy metals.
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35.  Maximizing protein production and nitrogen fixation
requires an ample supply of sulfur.
 Amino acids end up as the backbone of all proteins, but in
different combinations. While nitrogen is a component of
all amino acids and proteins, sulfur is a component of
specific amino acids: methionine, cysteine and cystine.
 Sulphur deficiency has been reported to lead to
accumulation of NO3
- in vegetables which is dangerous as
these lead to fatal conditions such as methemoglobinemia
in infants and formation of cancer inducing nitrosamines
(Sylvia et al., 2005)
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36.  Increased rice grain quality (N content) by S containing
nitrogenous fertilizers, supernet (1.73% N) and
ammonium sulphate nitrate (1.66% N) as compared to
urea that produced 1.45% N was reported in India
(Chaturvedi et al., 2005)
 Also Sulphur application has been reported to increase the
quality characteristic such as pungent smell in onions
(Walker et al., 2008)
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37. Phosphorus
 P is an essential component of most organic compounds
in the plant including nucleic acids, proteins,
phospholipids, sugar phosphates, and enzymes.
 Research has determined that P improves crop quality in
a number of ways including:
 Reduced grain moisture content, increased sugar content,
increased protein content, and disease resistance in crops
such as wheat and maize (Havlin et all. 2005)
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38.  Magani (2009) reported an 8% increase in cowpea crude
protein with 37.5kg P ha-1 application compared with a
control in Nigeria.
 A 25% maximum protein content was reported from a
plot fertilized at a combination of 50 -75 kg NP ha-1 as
compared to other combinations of N (0, 25 and 50 kg ha-
1) and P (0, 50, 75 and 100 kg ha-1) in Pakistan (Malik et
al., 2003)
 Synergistic effect is one of the factors that increases crop
quality as far as N and P application are concerned.
 Application of 40Kg P ha-1 increased N and K
accumulation in the maize grain by 22.5% and 21.2%
respectively (Hussaini et al., 2008).
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39. Starch contents
 Starch is a primary insoluble polymeric carbohydrate
produced by higher plants and consists of amylose and
amylopectin as a major fraction.
 The enzymes responsible for synthesis of starch, starch
synthetase, is activated by potassium.
 Under inadequate potassium levels, the level of starch
declines, while soluble carbohydrates and nitrogen-based
compounds accumulate (Mae ,1997).
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40.  ZHANG et al., 2012 observed that low P rates (45
kg/hm2) resulted into low protein and amylose contents
compared to normal 90 kg/hm2 and high 135 kg/hm2 P-
rates with the maximum protein and amylose content
observed at high P rate.
 Phosphorus plays a major role in forming ester bonds and
as a result esterification of organic molecules.
 Due to these physiological relationships, the application
of phosphate fertilizers increases the P concentration in
potato tubers and also improved starch quality (Mengel et
al., 2001).
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41. Oil content in seed
 According to Dag et al., (2009), the oil content and
composition of the olive crop is highly influenced by
phosphorus nutrition of the plant.
 The influence of phosphorus in oil composition is
probably due to its fundamental roles in the biosynthesis
processes of the lipid molecules.
 It has also been reported that phosphorus increases the oil
content of sunflower seeds (Sadozai et al., 2014).
 Again the role of phosphorus in this aspect has been
attributed to the fact that phosphorous is involved in the
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42. Conclusions
 We have seen that plants are very demanding when uptake
of nutrients is concerned and they preferentially exclude
or absorb nutrients based on the concentration of nutrients
provided , with respect to soil and other factors.
 Therefore, any odd combination of nutrients is not going
to do the trick of providing all 17 nutrients in the
appropriate ratios required by the plant.
 Hence, the Use of BPN will ensures proper ratios of
essential nutrients and hence, enables the plant to
complete its life cycle in the precise period.
 The concept of BPN does not stop at administering NPK,
but also incorporates secondary and micronutrients.
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43. THANK YOU
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44. References
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
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