causes a-biotic and increases biotic diseases in crops
nutrients prevent crops from diseases, if are available in
adequate quantity; otherwise, imbalanced use or deficiency
of nutrients causes a-biotic (non infectious) diseases and
also help to increase biotic (infectious) diseases, wherever
crops are sown timely or in case of off time sowing in
proper as well as improper way.
Therefore, growers must be
aware about presence of all nutrients in their crop fields,
or they must use balanced nutrients, otherwise, there is no
way to overcome losses.
The soil, which is an
important source of crop production, varies from place to
place, depending upon the effect of different soil forming
factors (Chart 1). If the soil supplies all the essential
nutrients in reasonable amounts and on soluble balance to
the crop plants.
It can be called fertile,
otherwise, may cause non infectious and help to increase
infectious diseases in crops, as low or high soil
temperature, moisture, light, gasses, acidity and alkalinity
(pH) causes not transmitting (un-spread-able) diseases in
The plants need 21 essential nutrient elements (Fig. 1)
including gasses and mineral elements, from the soil for
growth and development. These all basically are obtained
from air, water and soil.
About 95-99.5% of fresh plant tissue is made up of Carbon,
Hydrogen and Oxygen, only about 0.5-5% remain as ash after
fresh plant tissue is died and burned.
On a whole, all nutrients are important, but NPK are being
used in greater quantities and play important role. Much
more studies are carried out on status of NPK in Pakistan,
but still needs more analyses, whereas, only little work has
been carried out on other 13 nutritional elements, and there
is dire need to extend work on all needful aspects.
Our common growers are totally unaware to the major soil
fertility affecting factors like high temperature, leaching,
soil erosion and improper fertilizer application, whereas,
most of the growers are also not knowing that which factors
may affect fertilizers efficiency up to how much extent
efficiency affecting factors
fertilizer efficiency (%)
scenario, the soil tests and plant tissues analysis are used
to determine the status of various nutrients and to diagnose
nutrients deficiencies that may exist for sustained
productivity of agricultural crops.
The soil fertility
assessment may be defined as chemical or physical
measurement of the soil, but in the customary sense, it
refers to the laboratory analysis to assess the plant
available nutrient status and elemental toxicity of a soil.
A soil testing programme includes the analysis of electrical
conductivity, soil pH, organic matter, lime content and
soil fertility can be managed with the application of
fertilizers but farmer must aware of the nature and severity
of the nutrient problems in his field in order to arrive at
decision regarding the kind and dose of fertilizer to be
It is therefore very important to classify the soil
according to their fertility status as they tend to vary
from place to place due to various soil forming processes.
Only the soil analysis provides actual data for physico-chemical
and biological properties at various soil depths.
reports, Pakistan soils are very seriously and severely
deficient in different major and minor plant nutrients. 100%
of analyzed Pakistan soils found deficient in Nitrogen due
to very low organic matter, whereas, phosphorous and zinc
deficiency also observed higher to that of potassium, boron
and iron deficiency in the soils of Pakistan (Table 2).
Nutrient deficiencies in
Symptoms or a-biotic diseases of crops
occurring due to imbalanced nutrition
have no idea that which type of symptoms or a-biotic
(non-infectious or un-spread-able) diseases are occurred in
crop plants, in case of nutrient deficiencies or due to
imbalanced use of plant nutrients. They become worry and
mostly considering as virus problem to all the appeared
symptoms. No doubt, most of the diseases show similar
symptoms but this may also not be regretted that the signs
which are considered as infectious diseases may also be due
to deficiencies or non judicious use of fertilizers for
fulfillment of plant nutrient requirements. Therefore, the
most common and major symptoms are discussed here under
which are most possibly occurred due to nutritional
In case of
nitrogen deficiency, the leaves become small, turn in to
yellow color. Deficiency inhibits the cell division hence
vegetative growth retarded. It also causes lowering of
respiratory rate. Some fruits shed leaves and causing heavy
appeared dark green in color. Some times dead patches appear
on leaf petioles. Retarded growth and purplish discoloration
of foliage are most typical symptoms. The leaves of
deciduous trees become narrower, fruit become soft prior to
maturity. In apple, fruit drop is common, juice decrease in
fruit. Fruits and leaves fall early.
deficiency causes die back of young shoots and leaves.
Scorched appearance observed due to the tips of young leaves
take up. The leaf margins become dull yellow in color.
Appearance V- shaped chlorotic spots, rolling, cupping and
curling is common in deciduous fruits, major quality of
fruit and vegetables also affected.
green color or chlorosis occurs due to lack of sulfur.
Younger leaves affected more then older leaves because
element is immobile. Leaf margin and tips ruled in words and
rapid leaf fall, stunted chlorotic growth, thinner and woody
stems are sulfur deficiency symptoms.
growth, apical buds disintegrate and secrete gummy fluid,
blossom end rot in tomatoes and pepper, bitter pit in
apples, hindered seed formation, appearance of chlorotic
patches on leaf margin occurs. While calcium also retards
movements of carbohydrates.
deficiency leads to inter-veinal chlorosis. In vegetables,
Crimson Reddish or orange yellow color in cabbage, dead
spots on turnips, yellowing in foliage structure and
retardation in cell division occurs.
cells discolored, young leaves brittle, flowering suppress,
slow pollen tube growth, reduces stigmatic secretion and
corky core of apples, hard fruit of citrus, hollow stem of
cabbage and cauliflower. The deficiency appears first as
abnormal of apical growing points. The youngest leaves
misshapen and wrinkled and are often thicker and of brackish
blue green color. Deformed and curled leaves appear in
rapeseed and mustard plants. Root development is also
affected and found thickened with necrotic tips and appear
Due to lack
of chlorine there is burning of leaf tips or margins,
abscission of leaves and also result reduction in yield and
In fruits gum
pockets develops under bark, twigs die back in citrus, fruit
dropping before maturity, cupping in tomatoes, rolling of
leaves is most common. The leaf tips later become white and
leaves narrow and twisted. Depressed internodes length
results dwarf and bushy plant. The ears are jagged and
mostly empty at grain filling stage.
young leaves. Veins remain green but in new leaves yellowing
of inter-veinal areas are observed. Iron deficiency
seriously retarded growth and some time plant dies.
small and curled near shoots tips. Small yellow spots on
leaves and inter-veinal chlorosis also occurs.
become chlorotic first. Growth disturbed. Yellow spot
disease also appears on leaves. Whiptail in cauliflower and
gum deposition in lower leaf surface occurs in citrus.
deficiency show rosette formation and short internodes. Zinc
deficient pea plants produce seedless pods.
Improving nutrient deficiencies
deficiencies could be improved through integrated plant
nutrition management system (IPNMS).
IPNMS for improving
Judicious and balanced
use of chemical fertilizers
Introduction and use of
micronutrients and potash
Integrated use of
bioorganic and mineral sources of
Objectives of IPNMS
To maintain or enhance
soil productivity through a balanced use
of mineral fertilizers combined with
organic and biological sources of plant
To improve the stock of
plant nutrients in soil.
To improve the efficiency
of plant nutrients, thus limiting losses
to the environment.
Components of IPNMS
The Soil sources
13 essential nutrients
Mineral fertilizers and
Organic fertilizer sources
Farm Yard Manure
Fish pond effluent
Wastes of food processing
Plant growth stimulator
Plant growth promoting
The symptoms developed due to imbalanced
and improper use of fertilizers or because of
nutritional deficiencies, must not be considered as
virus infections or other widely transmittable
infectious diseases, as mostly publicized in
un-authenticated media reports, spreads rumors. And, in
view of continues increase in population, it is
important to enhance crop productivity by adopting
modern techniques as suited to different soils of the
area. A protocol assessment of soil fertility status is
to identify nutrient deficiencies and
other soil related problems in advance. Meanwhile, we
should check our soil in Soil Laboratory; we should
maintain soil fertility by adopting integrated plant
nutrition management system (IPNMS) and we should apply
mineral fertilizers, organic matter, bio-fertilizers and
compost, through improved techniques viz. fertigation,
foliar fertilization, composting, mulching etc,
according to suggestions of the Soil Scientistís.