Zinc Solutions for Cotton

Zinc Solutions for Cotton

Zinc Solutions for Cotton
Zinc (Zn) is essential for the normal
growth and reproduction of cotton
plants. Cotton is a moderately
sensitive crop to zinc deficiency and
when the supply of zinc to the plant is
inadequate, crop yields are significantly
reduced. Cotton is generally grown in
heavy clay soils with high pH, elevated
sodium and magnesium levels and low
initial zinc levels. Although, much zinc
has been applied to these fields, the
availability of this zinc may be reduced
due factors such as water logging and
elemental tie-up.
The Role of Zinc in the Plant
Zinc plays a key role in a wide range of
enzymes and proteins, controlling many
important biochemical pathways. These
are mainly concerned with;
••
Carbohydrate metabolism, both
in photosynthesis and in the
conversion of sugars to starch
••
Protein metabolism
••
Auxin (growth regulator) metabolism
••
Pollen formation
••
Maintenance of the integrity of
biological membranes
••
Resistance to infection by certain
pathogens.
Uptake, Movement & Removal
of Zinc
High yielding irrigated cotton crops
can take up about 260g Zn/ha. Of
this, 150g Zn/ha (13g Zn/bale) may
be removed in seed cotton and lint.
As seen in Figure 1, 70% of the zinc is
taken up during flowering. Zinc is able
to move from leaves and stems to the
lint, seed and boll walls with 60% being
removed in the seed.
Zinc is very immobile in the soil and
needs to be either mixed through the
root zone or sprayed onto the leaf to
supply plant available zinc. This can be
done through incorporation of surface
applied zinc, in-furrow injection or a
foliar spray.
Figure 1.
The pattern of nutrient uptake during the growth of an irrigated cotton crop
that yielded 2250 kg lint/ha in Narrabri, Australia.
Nutrient uptake (g/ha)
2500
2000
1500
1000
500
0
40 60 80 100 120 140 160 180
High Risk Zinc Deficient Situations
High risk soils:
••
Calcareous
••
Salt affected
••
pH > 7
••
Fields that have been laser levelled
••
High phosphorus status or
applications
••
Low organic matter and low zinc
soil fertility
Environmental conditions:
••
Waterlogged soils and crop
••
Cool, wet periods that reduce root
growth
••
Crops affected by herbicides which
reduce/ prune root growth
DAS
Zinc Deficiency Symptoms
Figures 2, 3 and 4 illustrate zinc
deficiency in cotton. The leaves can
show yellowing between the leaf veins,
leaves can appear bronzed and often
are cupped. Zinc deficient plants are
often shorter than unaffected plants,
indicating that growth has been
suppressed. Crops may grow out of
zinc deficiency, especially when cotton
is grown after long fallows, but yield,
maturity and fibre quality may be
affected.
Figure 2. Cupping of Cotton leaf
Figure 3. Cotton growth stunted from Zinc deficiency
Figure 4.Leaf cupping and bronzing from Zinc
deficiency
Fe
Mn
B
Zn
Cu
© Yara

Critical Zinc Concentrations in
the Soil and Plant
The critical value for Soil DTPA
Extraction (0-30 soil sample) is

Irrigated Cotton Crop Program
Pre-Plant Planting Emergence
1st Squares
1st Squares
1st Flowers
1st Flower
Peak Flower
Peak Flower
Bolls Open
Approximate
Day Degrees
Yara Liquids
Zn-SUL
Apply
20-60 L/ha and
incorporate into
soil
70 - 540 540 - 840 840 -1300 1300 - 1600
Yara Liquids
FLOWPHOS 13Z
Apply
100-200L/ha
Apply
30-40 L/ha
in-furrow
Yara Liquids
P-FOL Zinc
Apply a band spray 3-5 L/ha
YaraVita
ZINTRAC
Apply 300mL-1 L/ha
YaraVita
GLYTREL ZnP
Yara Liquids
K-FLOW 0-14-30
Yara Liquids
K-FLOW 4-0-12
Yara Liquids
N26
Yara Liquids
N-FOL 24+TE
Apply
400-500L/ha
in pre-irrigation
Apply 2-3 L/ha as required with
Glyphosate
Apply 1-2 applications of 10 L/ha
Apply 2-3 applications of
30 L/ha, starting 7-10 days after
first flower
Apply 500-600 L/ha in multiple applications
Apply 30-40 L/ha as required
While Yara Australia has taken all reasonable care in the preparation of this document, the information is a guide only. It is advised that potential users read the products Safety Data
Sheet prior to using the product, which is available on request from Yara Australia. There are no warranties, express or implied by operation of law or otherwise, including but not limited to
any warranty as to merchantability or fitness for any particular purpose.
www
1800 684 266 Yara_Australia au.sales@yara.com
www.yara.com.au