1. Efficient Management of Micronutrients in Rice
K. V. Rao
Principal Scientist (Soil Science)
Directorate of Rice Research

2. Fertilizer nutrient consumption and balance in Indian Agriculture
Year
Fertilizer consumption (M. tons) N
P2O5
K2O
Total
1951 -
0.065
1999
11.6
4.8
1.7
18.1
2020
20.74
6.77
2.06
29.07
Crop uptake (M. tons)
11.87
5.27
20.32
37.46
Deficit
+8.9
+1.5
-18.3
-8.3

3. Zone wise consumption ratio of nutrients (NPK) 2007-2008
P2O5
K2O
Total (kg/ha)
North
17.5
3.9 1
161.5
East
4.1
1.6
103.5
West
5.1
2.6
82.5
South
2.8
1.4
154.9
All India
5.5
2.1
117 3

4. Emerging Nutrient Deficiencies

5. Critical limits and extent of deficiency in Indian soils
Nutr-ient
Critical limits (ppm)
Extent of def. (% samples) S 10 41 Zn
0.6 49 Fe
4.5 12 Cu
0.2 3 Mn
2.5
4.4 B
0.5 32

6. Deficiency of Boron in Indian soils
State/soil
% Deficiency
Bihar
39.0
West Bengal
68.0
Karnataka
32.0 UP
24.5 MP
22.5 TN
21.0
Punjab
13.0
Gujarat
2.0
Haryana
1.5
India
33.0
Red & laterites
37-68

7. Deficiency of Sulfur in different states
Bihar
28.0
Rajasthan
23.0
Kerala
33.0
Karnataka
34.0 HP
43.0
Orissa
51.0 UP
62.0 MP
40.0 TN
36.0
Punjab
26.0
Gujarat
38.0
Haryana
35.0
India
41.0

9. Soil/water resources and rice production
Rice production demand by ~ 125 Mt
Rice is cultivated in > 44 M. ha of variety (15) of soils; and
consume > 50% of irrigation water; 38-40% of fertilizers; and
17-18% of pesticides
About 8M.ha of rice soils are deficient in Zn, and is most
preferred crop in salt affected soils (> 8M.ha)
About 15 M ha of rice soils are acidic associated with Fe
or Al toxicity, depletion of bases (Ca, K, Mg), P fixation and
likely deficiency of B, Si
Blanket fertilizer management over large domains
Stagnation/ deceleration in productivity growth, and changing
pest and disease intensity
Major nutrient problems observed in rice are –
Deficiency N, P, Zn, Fe, S, K, Mn, Ca, B, Si and
Toxicity Fe, H2S, Al, B, As, Se 9

10. Zn deficiency in rice
It is widely spread in calcareous, clayey-neutral, saline-sodic,
coarse-textured, highly weathered and leached soils in
Bihar, Karnataka, AP, Punjab, Haryana, UP, Tamil Nadu,
orissa, Maharashtra, and Madhya Pradesh,
Uneven plant growth in patches and stunted, earliness, low
spike let no. and yield.
Brown to dusty brown spots on younger leaves in red soils,
yellowing of leaves /midrib bleaching in black soils
appearing at 2–4 WAT.

11. ZINC MANAGEMENT
Regular application of OM (FYM, PM, BG slurry, 5-10 t /ha helps mitigate deficiencies of all micronutrients
Drain the fields frequently with good quality irrigation water
Normal soils- Apply kg Zn /ha for every 3 seasons
preferably in rabi season in soils with < ppm Zn in
sandy and clay soils, respectively
Sodic soils / Brackish ground water kg Zn / ha initially
followed by 5-10 kg Zn in the later years or 50% gypsum + 10 t
GM + 22 kg Zn once in 2-3 years
Seed treatment or root dipping in 2.0% ZnO suspension in
moderate Zn deficient soils
Mid season correction -Spraying 0.5% ZnSO4 thrice at weekly
intervals between 3-6 WAT
Grow Zn efficient and tolerant varieties- Vikas, Rasi, Hybrids etc

12. Response of crops to zinc fertilization in India
No. of
Expts.
Range of response t ha-1
Av. Resp.
t ha-1
Individual expt.
Mean of expt.
Wheat
2447
0.42
Rice
1652
0.54
Maize
280
0.47
Sorghum 83
0.36
Soybean 12
Onion 3
5.13
Potato 45
3.0
Sugarcane 6
3.8
Source: M.V. Singh (1997, 1999a), AICRP Micronutrients , IISS, Bhopal

13. Effect of zinc and gypsum application on yield of rice in sodic soils(t/ha)
ZnSO4 (kg/ha)
Gypsum levels (t/ha)
Mean
2.5
5.0
10.0
0.13
0.98
2.14
2.65
1.48 10
0.49
1.87
3.06
3.77
2.30 20
0.58
2.00
3.14
3.85
2.39 30
0.68
1.75
2.99
3.92
2.34 40
1.05
2.02
3.29
3.89
2.56
0.59
1.72
2.93
3.62 -
LSD (0.05)
Gypsum 0.36; ZnSO4 0.28 13

14. Fe deficient upland rice
Iron Deficiency in rice
Fe deficient upland rice
Interveinal chlorosis of emerging leaves,
whole leaves becoming chlorotic and turns very pale. Plants become stunted with narrow leaves.
Fe deficiency is serious constraint to rice in uplands in neutral, alkaline and calcareous soils, in coarse textured low organic matter soils, in alkaline and calcareous low lands, and under excessive concentrations of Mn, Cu, Zn, Al and nitrates in root zone.

15. Management of Fe deficiency
Sources-
Ferrous sulphate ( %Fe), Fe-EDTA (9-12%Fe), Fe-
EDDHA (10% Fe), besides organic manures (FYM 0.15%
Fe), poultry and piggery manure (0.16% Fe), sewage
sludge are used as sources for correcting Fe chlorosis.
Seed treatment with 2% FeSO4.7H2O solution/slurry.
Foliar sprays (2-3) of 1-2% FeSO4.7H2O/FeNH4SO4 (pH
5.2) solution or of chelates at weekly interval at
early stage of deficiency are successful.
Combination of green manure (GM) or organic manures
with foliar spray of un-neutralized 1%FeSO4.7H20
/FeNH4SO4 (pH 5.2) solution

16. Sulfur Nutrition in Rice
Rice field showing S deficiency symptoms
Chlorosis of young leaves and necrosis of tips
Soils with low organic matter status,
highly weathered ,containing large
amounts of Fe oxides, sandy soils are
deficient in S supply.
About 3-5 kg S is removed by rice per ton
of grain. Apply kg/ha S through
gypsum, phospho-gypsum, ammonium
sulphate, elemental S etc.,
Reduced plant height and tillering

17. Boron deficiency in rice
B deficiency occurs in highly weathered, acid upland, coarse
textured sandy soils, acid soils derived from igneous rocks, and
in soils of high organic matter and calcareousness
B availability is reduced under moisture stress and dry
conditions
B deficiency symptoms usually appear first on young leaves.
Reduced plant height and the tips of emerging leaves are white
and rolled
Rice plants fail to produce panicles if they are affected by B
deficiency at the panicle formation stage

18. Management of Boron deficiency
Borax, granubor & boric acid are efficient sources
Basal soil application of B (1-2 Kg B / ha) is superior to foliar
sprays. Soil application has residual effect for 1-2 seasons
For hidden deficiency spray 0. 2% boric acid or borax at pre
flowering or flower head formation stages
AICRIP results show increased grain number (25-45), filled spike
lets and significant increase in grain yield by 4-8% of cultures
IET 20979, IET and IET
Influence of Boron application on rice yield (g/sq.m) (11 locations, AICRIP, 2009)

19. Manganese deficiency in rice wheat system
Manganese deficiency in rice is sporadic and increasing in wheat in Punjab in R-W
system (after 7-10 years) in highly permeable alkaline soils low in OM
Also in highly degraded, acid sulfate and acid upland soils, and alkaline / calcareous
soils with low OM and reducible Mn
Symptoms on rice are pale grayish green interveinal chlorosis from tip to base of
young leaves with necrotic brown spots developing later.
Management
Soil application kg/ha (less economical)
Foliar spray % MnSO4 solution (5-15 kg Mn /ha) at tillering stage in
about 200 L water per ha.
Durum wheat more susceptible than aestivum wheat.
Apply farmyard manure or straw incorporation
Chelates are less effective because Fe and Cu displace Mn.

20. Residual response (kg/ha) to secondary and micro- nutrient applied in rice under RWCS
Site S Zn B Mn Cu
Ranchi 48 -
Modipuram
1350
960
580
600
Kanpur
511
286
R.S. Pura
191
183 57
277
Pantnagar
505
471
Ludhiana
167 90 96 36
119
Average
462
313
382
231
173
PDCSR and IPNI Research, Modipuram

21. Approved micronutrient fertilizers under FCO
Materials
Element/Forms
Content (%)
Zinc sulphate. Zn
21.0
Manganese Sulphate* Mn
30.5
Ammonium Molybdate Mo
52.0
Borax (For soil application) B
10.5
Solubor (Foliar spray)
19.0
Copper Sulphate* Cu
24.0
Ferrous sulfate
Ferrous & Ferric
19.0 & 0.50
Zinc Sulphate mono-hydrate
33.0
Zinc Phosphate Zn3(PO4)2.4H2O
Zn + P
19.5
Chelated Zn (EDTA form)
12.0
Chelated Fe (EDTA form) Fe
Boronated super phosphate
B+P2O5
0.18B +16.0
Zincated urea
Zn+N
2.0 Zn N
*S % in ZnSO4.7H2O-15%, MnSO4.4H2O -17%, CuSO4.5H2O-13%, FeSO4.7H2O-19%

22. Iron toxicity in rice
Tiny brown spots from tips to leaf base of older leaves, reddish
brown, purplish bronzing, yellow orange discoloration
Commonly observed at maximum tillering / heading stage
Reduces yields by12-100%.
Reported in Orissa (42%), West Bengal, Chattisgarh, Jharkhand,
Kerala, NE and NW hills, HP, Karnataka, North costal AP, in acid
and acid sulfate soils rich in reducible iron, light textured,
moderate to high SOM, and low CEC.

23. Management of Fe toxicity
Plant rice tolerant varieties (e.g., Mahsuri, Phalguna,
MTU 1010, IET 20550).
Seed treatment (DSR) with Ca 50–100%
seed wt.
Delaying planting until peak in Fe2+ concentration has
passed (> 10–20 DAF)
Intermittent irrigation and midseason drainage at
mid-tillering stage (25–30 DAT/DAS),
Balanced use of fertilizers (NPK or NPK + lime),
additional K, P, and Mg fertilizers.

24. Sulfide toxicity Symptoms Management
S toxicity occurs in degraded, low active Fe status, poorly drained
organic soils, acid- sulfate soils.
Deficiency of K and unbalanced crop nutrient status, excessive
application of urban or industrial sewage aggravate sulfide toxicity
Symptoms
Reduced nutrient uptake due to decreased root respiration
Interveinal chlorosis of emerging leaves, coarse, sparse, and
blackened roots,
Toxicity occurs at >0.07 mg H2S per L in soil solution
Management
Midseason drainage at mid tillering stage (25–30 DAT/DAS),
Avoiding flooding and maintain moist conditions for 7–10 days
Apply K, P, lime and Mg fertilizers, and Fe (salts, oxides) to
immobilize H2S .
Avoid large quantities of organic matter application
Dry plough field after harvest to oxidize S and Fe

25. Aluminium toxicity Symptoms Occurrence
Orange-yellow interveinal chlorosis of younger leaves
Poor growth stunted plants
Yellow to white mottling of interveins, followed by leaf tip death and leaf margin scorch
Necrosis of chlorotic areas occurs if Al toxicity is severe
Occurrence
Al toxicity is major constraint in acid upland soils of pH <5.2 with large exchangeable Al content in NEH, Jharkhand, WB, Assam,
Acid sulfate soils when grown as upland crop few weeks before flooding

26. Al toxicity management
Planting tolerant cultivars which accumulate less Al and absorb Ca and P efficiently e.g. IR43,CO37 and Basmati 370
Liming of soil with CaCO3 preferably dolomite lime to supply 2-4 t/ha to neutralize soil acidity and replace exchangeable Al.
Correct sub soil acidity by leaching soluble source of Ca like gypsum / phosphogypsum / SSP / lime
Incorporate 1 t/ha of reactive rock phosphate to supply P
Planting Al-tolerant cultivars such as IR43, CO 37, and Basmati 370 which complex soluble Al by root exhudates and accumulate P, Mg and Ca
Soil mulching and / or green manuring / organic manuring prevents water loss and phytotoxicity

27. Boron toxicity
Occurs in arid and semi arid regions, high in temperature, in volcanic soils
Use of B-rich groundwater, sewage and municipal wastes or borax
Critical toxicity limits of B in soils - > 4 mg/ kg (0.05N HCl) or > 5 mg B per kg (hot-water soluble B) or > 2 mg B per L in irrigation water.
Symptoms
Plants show brownish leaf tips and dark brown elliptical spots on leaves
Management
Deep plowing during off season and leaching, use of surface water with low B content or dilution, Growing tolerant varieties like IR42, IR46, IR48, IR54,

28. Management of Si deficiency
Rice absorbs ~100 kg Si per ton of grain.
Si-deficient plants are susceptible to lodging with soft, droopy
leaves and culms, Lower leaves with yellow / brown necrotic,
Critical concentration for Si - 40 mg Si per kg soil (1 M Na acetate
4.0 pH)
Si deficiency occurs in old and strongly weathered, leached acid
soils, and due to removal of rice straw , excessive use of N.
Si deficiency is not yet common in intensive irrigated rice systems
of tropical Asia.
Management of Si deficiency
Recycling rice straw (5–6% Si), and rice husks (10%), applying rice
hull ash and balanced nutrient use of NPK
Apply granular silicate fertilizers for rapid correction- Ca silicate:
120–200 kg/ha; K silicate: 40–60 kg/ha
Apply basic t/ha once in two years, or fly ash (23% Si)
use is beneficial
Foliar spray with sodium silicate improve Si nutrition

29. Efficient genotypes for nutrient stress situation
Low N
Swarna, Sarjoo-52, Bejhary, Pranava, Salivahana
Low P
Rasi, RPA 5929, MTU 2400, Vikramarya
Low Zn
CSR 10, Sarjoo-52, Vikas, IR-30864
Fe toxicity
Mahsuri, Phalguna, Dhanrasi

30. Thank You 30

31. Low nutrient use efficiency in rice
30-40 P
15-20 K
40-50 Zn
2-5 Fe
1-2 S
20-25

32. Distribution of Sulphur Deficiency (240 Districts)
A- 45% Districts having > 40% soil samples deficient in S
B- 40% Districts having 20-40% soil samples deficient in S
C- 15% Districts having < 20% soil samples deficient in S

33. AVAILABILITY INDICES FOR MICRONUTRIENTS
Critical level (ppm) Range
Mean B
Hot water soluble
0.7 Cu
Mehilch No.1
DTPA + CaCl2 (pH 7.3)
AB-DTPA (pH 7.6)
0.1-10
3.0
0.8
1.8 Fe
4.0 Mn
0.03 M H3PO4
4-8
0-20
7.0
1.4 10 Mo
(NH4)2C2O4 (pH 3.3) - Zn
0.1N HCl
Mehlich No.1 5
1.1
1.5

34. Major management-related concerns in Agricultural Production
Increasing food demand >300 Mt. by 2025; Rice - >130 Mt
Low and imbalanced use of fertilizers and OM -negative balance, soil nutrient depletion, low NUE and declining soil quality
Blanket fertilizer management over large domains
Increasing area under water and management induced soil degradation
Stagnation/ deceleration in productivity growth in intensive rice crop systems
Changing pest and disease intensity and scenario
Nt related