vol. 4 no. 1 indian micro fertilizers imma manufacturers ... news apr-jun for net.pdf · pune- 411...

Apr - Jun 2011Vol. 4 No. 1

IMMANEWS

Indian Micro FertilizersManufacturers Association

Rs. 10/-

Saline Soils under Sugarcane in Maharashtra

Lateritic Acidic Soils ofKokan, Maharashtra

Iron Deficiency in Paddy Manganese Deficiencyin Wheat

Indian Micro – Fertilizers Manufacturers Association

Our Presidents85 – 87 Late Dr. T.B. Mirchandani86 – 91 Dr. S. S. Ranade91 – 97 Dr. G.P. Shetty97 – 01 Dr. S.S. Ranade01 – 05 Dr. Jimmy Mirchandani05 – 09 Mr. D.P. Chavan09 Mr. Kanak N. Sarkar

from the editor's desk

IMMA NEWS VOL. : 4 NO. : 1 Apr-Jun 2011Editor : Pramod SawantPrinted and Published by Pramod Sawant on behalf of Indian Micro Fertilizers Manufacturers Association, Pune- 411 037 E-mail- [email protected]

Printed at Prakash OffsetShop No. 10-14 & 21-22, ParvatiTowers, Pune - 411 009

Published at Indian Micro Fertilizers Manufacturers Association201, 2nd Floor, Shrikrishna Apartments, 39/A, Gultekadi,Market Yard Road, Opp. Apsara,Pune 411 037.

Invitation for Technical Data

We are publishing 'IMMA News' Bulletin every quarter with Technical Data on Fertilizers in general and Micronutrient Fertilizers in particular. We do forward the same as an complimentary to the Agriculture Scientists & officers, all over India.

We request all the readers to please send us Technical matter to be published in our 'IMMA News', which will assist the extension officers to disseminate your ideas to farmers, to increase crop yields.

Apr - Jun 2011IMMA News

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Farmer getting ready for paddy cultivation

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CONTENTS Page

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3. IDENTIFICATION AND AMELIORATION OF MICRO-

NUTRIENT IN RICE-WHEAT CROPPING SYSTEM

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Green Manuring in relation to the soil fertility and soil

health

Rajan Bhatt

Problem Soil Management in Agriculture

Rajan Bhatt

Rajan Bhatt:.

By implementing National Food Security Mission (NFSM) we as a country are putting more thrust to harvest higher yields of cereals, legumes and oilseeds from an unit area.Cultivation of HYVs for years together with fertilizer supplementation and irrigation, has brought down the Soil Productivity Index (SPI) substantially. Now efforts need to be taken up jointly by the farmers, industry and the scientific fraternity to meet newer challenges in Food Security arising with the changing scenario.Dr. Rajan Bhatt, Associate Professor of Soil Sciences from KVK, Kapurthala has addressed this issue in his articles on Green Manuring in relation to Soil Fertility and Soil Health, Problem Soil Management and Identification & amelioration of Micronutrient Deficiencies in Rice-Wheat cropping system.

Introduction

Owing to the constant production of crops from the soil, the latter is being depleted gradually of its nitrogenous and other nutrients. An ordinary crop takes about 25 lb of nitrogen from an acre. It is, therefore, necessary to replenish the soil with the elements, which are removed by the crops year after year.

Organic matter is the life of the soil because it contains all the essential elements required for plant growth. It also serves as food for soil bacteria. Decomposed organic matter, known as humus, improves the soil tilth and helps the plant to grow. Well-stored farmyard manure is most important of all organic manures, but it is not available in sufficient quantity. Farmyard manure, if not properly stored, loses its nutrient-supplying value to a great extent.

Therefore, in order to conserve farmyard manure and town refuse properly, two schemes were taken in hand by the Agricultural Department during the Second Five Year Plan (1956-61). But the answer to this problem is green manuring in which no such losses are there.

Green Manuring

Farmyard manure and compost are not available in sufficient quantities to the farmers to meet their full requirements. Artificial fertilizers are also in short supply. Owing to the intensely hot summers, the available humus in the soil is burnt up quickly. A periodical application of organic matter is, therefore, essential to replenish the loss of humus, which is necessary for keeping the soil in good condition by enhancing the supply of nitrogen and by promoting the growth of microorganisms. A leguminous crop producing 8 to 25 tonnes of green matter per hectare will add about 60 to 90 kg of nitrogen when ploughed under. This amount would equal an application of three to ten tonnes of farmyard manure on the basis of organic matter and it's nitrogen contribution. The green manure crops also exercise a protective action against erosion and leaching of the various nutrients into the deep soil layers.

Green-manuring is, thus, a very useful soil-improving practice for building up soil fertility. First, it increases the soil fertility by the direct addition of nitrogen to the soil.

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Second, it improves the soil texture by the addition of humus or organic matter, which is essential for making the soil more productive. The addition of organic matter improves both heavy and sandy soils, as it has a binding effect on the loose particles of the sandy soils and makes the hard and heavy soils porous. Thus, it also increases the water-holding capacity of the soil. Besides, the conditions for increasing the number of useful bacteria in the soil are also improved.

Kind of green manuring

The practice of green manuring is performed in different ways according to suitable soil and climatic conditions of a particular area. Broadly the practice of green manuring in India can be divided into two types

1. Green manuring in situ: In this system, green manure crops are grown and buried in the same field, which is to be green manured, either as pure crop or an intercrop withy the main crop. The former system is followed in the northern India while latter is common in the central and eastern India.

2. Green leaf manuring: Green leaf manuring refers to turning into the soil green leaves and tender green twigs collected from shrubs and trees grown on bunds, wastelands and nearby forest areas. This system is generally followed in the central India.

The crop generally used for green manuring is dhaincha (Sesbania aculeata) though the cultivation of sun-hemp and guara is also in vogue. The crops commonly used for green manuring in our country are the following:

Sunnhemp (crotolaraia juncea), Dhaincha (Sesbania aculeate), senji (Melilotus parviflora), Cowpea (Vigna catjang), berseem (Trifolium alexandrinum) etc. Sunhemp is the most outstanding green manure crop and is well suited in almost all parts of the country and fits in well with the sugarcane, potato, garden crops and the second season paddy in southern India and with irrigated wheat in the north. Dhaincha is also an outstanding green manure crop. It does well in the waterlogged and alkaline soil for it's reclamation programme. Green-manuring is in common use in irrigated lands, lands, but its popularity in barani land is hindered by the lack of irrigational facilities.

The Extension of Green-Manuring Scheme came into

IMMA News Apr - Jun 2011

Green Manuring in relation to the soil fertility and soil health

Rajan Bhatt

Assistant professor (SS), Krishi Vighyan Kendra, P.A.U. Ludhiana, Punjab

operation in the Punjab with effect from April 1, 1961. It aims at popularizing the use of green manure in the State. The Government encourages the adoption of this practice by the farmers by granting subsidies on seeds of green-manuring crops. The Irrigation Department also grants remission of water-rate, if crops are buried for green-manuring before 15th of September.

The total area under the green-manuring crops in the district, during the past few years, has been as under:

Table: 1 Area under green manuring crops with time.

(Source: Town Compost-cum-Field Manure Officer, Punjab, Chandigarh)

Techniques of green manuring in the field: The maximum benefit from the green manure crop cannot be obtained without knowing the

When it should be grown.

When it should be buried into the soil.

How much time should be given between the

burying of the green manure crop and the sowing of

the next crop.

Time of sowing of the green manure crop Normally the green manure crop should be grown immediately after the monsoon rains. As far as cultivation practice involved, no special care is needed in the preparation of the seedbed. Soil must have sufficient moisture for the quick germination and rapid early growth. Phosphatic fertilizers, if applied, should be evenly broadcast. Usually the seed of the green manure crop is broadcast preferably with higher seed rate.

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Stage of burying of the green manure crop: From the results of the several experiments, it is

Stage at which sun hemp was buried made a significant effect on the wheat yield. However basic principle is in green manuring crops, should aim at maximum succulent green matter at buring.

Time interval between burial of green manure crop and the sowing of the next crop:The time interval should be allowed for complete decomposition of the turned in green manure crop before planning of the next crop and that time should depend upon the following factors:

1. Weather conditions

2. Nature of the buried green material

In areas receiving rainfall >50 inches humid conditions favors decomposition. If the green manure crop is succulent, then there is no harm in transplanting the paddy immediately after turning in the green manure crop. However, in case of the woody, then sufficient time should be allowed for it's proper decomposition before planting the paddy. e.g. when succulent green manure crop of around 8 weeks was buried then paddy can be planted without having any adverse effect on the yield. But when dhaincha become woody (12 weeks), it was necessary to bury it about 4 to 8 weeks first for it's decomposition before planting paddy. In areas receiving 25 to 50 inches rainfall, green manure crop required about 6 to 8 weeks to decompose. It is only because of lesser moisture conditions.

When green manure crop was intercropped in between

observed that best results of the green manuring are obtained if it is buried at the flowering stage. Majority of the crops take about 6 to 8 weeks to reach at the flowering stage from sowing


Area under green-manuring crops (ha)

Year

1955-56

1960-61

1965-66

1967-68

716

7785

13254

26096

the rows of the main crops like paddy, cotton, sugarcane etc. then it is buried in the succulent stage for it's rapid decomposition.

Plants suitable for green manuring in the field or In situAn ideal green manure crop should possess the following desired characteristics, as listed by Dr. R. R. Agarwal (1965) are as follows

1. It should be a legume with good nodular growth

habit indicative of rapid nitrogen fixation under even

unfavorable soil conditions.

2. It should have little water requirements for it's own

growth and should be capable of making a good

stand on poor and exhausted soils.

3. It should have a deep root system, which can be open

the sub-soil and tap lower regions for plant nutrients.

4. The plant should be of a leafy habit capable of

producing heavy tender growth early in its life cycle.

5. It should contain large quantities of non-fibrous

tissues of rapid decomposability containing fair

percent of moisture and nitrogen.

Advantages of the Green manuringFollowing are the some of the advantages of the green manuring

1. It add organic matter to the soil. This stimulates the

activity of the soil microorganisms.

2. The green manuring crops return to the upper soil

plant nutrients taken up by the crop from deeper

layers.

3. It improves the structure of the soil.

4. It facilitates the penetration of the rain water into the

surface of the soil, thus decreasing the runoff and

thus erosion.

5. The green manuring crops hold plant nutrients that

would otherwise be lost by leaching.

6. When leguminous plants, like sun hemp and

dhaincha are used as green manure crops, they add

nitrogen to the soil for the succeeding crop.

7. It increases the availability of certain plant nutrients

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like phosphorus (P2O5), calcium, potassium, magnesium and iron.

Disadvantages of the green manuringEvery coin has got a head and a tail and it is the case with the green manuring. Some disadvantages are also associated with green manuring. When the proper technique of green manuring is not followed or when weather conditions become unfavorable, the following disadvantages are likely to become evident/happen.

1. Under rainfed conditions, it is feared that proper

decomposition of the green manure crop and

satisfactory germination of the succeeding crop may

not take place if sufficient rainfall is not received after

burying the green manure crop. This particularly

applies to the wheat regions of the India.

2. Since green manuring for rabi season (Wheat)

means the loss for the kharif crop, the practice of

green manuring may not be always economical. This

applies to the regions where irrigation facilities are

available for raising kharif crop along with easy

availability of fertilizers.

3. In case the main advantage of the green manuring is

to be derived from addition of nitrogen, however

sometimes the cost of growing green manure crops

may be more than the cost of commercial nitrogen

fertilizers.

4. An increase of diseases, insects and nematodes is

possible.

5. A risk is involved in obtaining a satisfactory stand

and growth of the green manure crops, if sufficient

rainfall is not available.


Problem Soil Management in Agriculture:Availability of plant nutrients to crops has a strong bearing on physic-chemical nature of soils. In has a vast area under acid soils as well as sodic soils. Productivity of such soils can be restored through well established ameliorative techniques. Use of lime or liming materials in acid soils and that of gypsum/ phosphogypsum in sodic soils has been advocated by Soil Scientists for correction of soil pH and improving physic-chemical nature of these soils. It is intended to support and popularize use of these abundantly available ameliorants in NFSM districts with large area covered by such soils.Management of acid soils:

Acid soils occupy vast area in high rainfall, mountains and coastal regions of india. The soils are highly leached, have poor fertility and water-holding capacity. Acid soils are deficient in phosphorus, calcium, magnesium and molybdenum. Severe acidity often causes iron and aluminum toxicity to crops. Acid soils are low in organic carbon, water retention and prone to run-off induced erosion. These constraints lead to sub optimal productivity of crops raised in acid soils.

Distribution and extent of acid soils in NFSM States:

Acid soils are widely spread in eastern, north eastern and peninsular region. Table1 depicts statewise area affected by soil acidity. Total area under acid soils in NFSM states is estimated to be 66 m ha, major part of which falls in targeted districts. However, area with soil pH < 5.5 is only 15.6 m ha and needs to be treated on priority.

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Amelioration of acid soils:Liming of acid soils has been advocated by soil scientists. However the lime requirement based on laboratory tests is usually too high for most of the farmers to afford. Besides, high transport cost of large quantity of lime and inadequate storage facilities at consumption sites have discouraged large scale use of the ameliorant. Now, it has been established that band placement/ incorporation of lime @ 1/10 of lime requirement along with recommended level of fertilizers every year is economical, practicable and effective.

Commonly available liming materials:Carbonates, oxides and hydroxides of calcium and magnesium are referred to as agricultural lime. Liming materials such as calcite, dolomite are naturally occurring ameliorants. Although, they are available in abundance, their use may not always be cost-effective. Industrial by products such as basic slag (steel industry), lime sludge from paper mills, etc are rich and relatively cheap sources of calcium. Liming materials available in different states are depicted in table 2. The material should have at least 25% calcium oxide and be ground to less than 80 mesh size.

Dose, schedule and method of application: The ground material conforming to BIS specifications (80 mesh size) should be broadcast/ applied in furrows at the rate of 10% of Lime Requirement (LR), (usually 2-4 q/ha) at the time of planting of an upland crop preceding rice. It may also be applied to rice crop during puddling (2-4 q/ha) if the soil is highly acidic (soil pH < 5.5).


Problem Soil Management in Agriculture:Rajan Bhatt

Assistant professor (SS), Krishi Vighyan Kendra, P.A.U. Ludhiana, Punjab

StatesAndhra PradeshAssamBiharChhattisgarhJharkhandKarnatakaKeralaM.PMaharashtraOrissaTamil NaduWest BengalTotal

pH <5.5-2.330.046.451.00.063.011.120.210.260.565.615.6

Total0.404.662.3610.846.773.313.7611.724.548.674.854.7666.64

pH 5.5-6.50.402.332.324.395.773.250.7510.604.338.414.291.2051.04

Table: 1. Extent of acid soils in NFSM States (m ha)

Acid soil region/statesAssamJharkhandKeralaMaharashtraOrissaWest BengalOthers

Quantity available(mt)

1514

0.20.20.33.0

Liming materialLimestoneBasic slagLime shellsLimePaper mill sludgeBasic slag, paper mill sludgeBasic slag

Table 2. liming materials available in NFSM statesin India

The quantity of lime equivalent to 10% of Lime Requirement (LR) is usually about 2-4 q/ha depending on soil type and pH. However, soil should be tested for LR by nearby Soil Testing Laboratory and the dose should be decided accordingly. Generalized LR is depicted in table 3.

Crop response to liming and economics:Yield advantage attributable to liming in case of pigeon pea grown in acidic soil of Jharkhand has been 34% under farmer's practice and 105% under 100% NPK application. Corresponding figures for Orissa are 44% and 92%. Productivity gain in wheat grown on acid soils of West Bengal has been 52% under farmers practice and 86% under 100% NPK application. Rice crop grown in submerged acid soils may witness moderate yield advantage which could be increased significantly provided recommended dose of NPK is applied. Thus, liming improves crop response to fertilizers applied to the crop. Productivity of wheat, cowpea, black gram, pigeonpea in States like Assam, Jharkhand, Orissa, West Bengal and Kerala with 50% NPK plus lime have been equal to or more than with 100% NPK application.

Management of moderately sodic soils:Salt affected soils cover more than 7 m ha area, most of which occurs in indogenetic plane in the states of Punjab, Haryana, Uttar Pradesh, Bihar and parts of Rajasthan. Arid tracts of Gujarat and Rajasthan and semi-arid tracts of Gujarat, Madhya Pradesh, Maharashtra, Karnataka and Andhra Pradesh also have large area affected by salinity/alkalinity. Crops grown on saline soils suffer on account of high osmotic stress whereas nutritional disorders, toxicities and poor soil physical conditions reduce crop productivity in alkali soils. Soils with pH >8 and exchangeable sodium more than 12-15% need to be treated with suitable ameliorant.

Distribution and extent of salt affected soils in NFSM states:

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Table 4. Depicts area affected by salinity and alkalinity in NFSM-wheat States. The area includes saline soils which can be reclaimed through leaching with good quality water. However a major area cropped to wheat has moderately alkaline pH which adversely affects nutrient use efficiency and wheat productivity. In order to achieve targeted wheat production, it is necessary that exchangeable sodium and subsequently soil pH are reduced to optimum levels through appropriate interventions.

Amelioration of alkali soils:Amelioration of alkali soils involves replacement of exchangeable sodium from soil exchange complex and leaching out of soluble salts from root zone. This is accomplished through application of chemical ameliorants (which furnish calcium for replacement of sodium from the exchange complex of the soil.) followed by leaching.

Soil of affected area should be tested for gypsum requirement (GR). However, generalized GR based on soil type and degree of sodicity is depicted in table 5. Agricultural grade gypsum or phosphogypsum should be incorporated into soil @75% of GR at least 15-30 days before planting of kharif crop. The treated field should be kept submerged with good quality water for facilitating reaction and subsequent leaching of by-product salts. Treated field should be planted to rice during kharif season followed by wheat during rabi.

Fields with marginally alkaline pH can support a wheat crop even without treatment. However, the productivity of the crop and nutrient use efficiency will improve significantly if soil is treated with gypsum or phosphogypsum at moderate (1-1.5 t/ha) rates either in kharif season or before planting irrigated wheat crop.


Table 3. Generalized lime requirement (t/ha)

Sand and Loamy SandSandy Loam LoamSilt LoamClay Loam

Targeted soil pH change

From 4.5 to 5.50.61.11.72.63.4

From 5.5 to 6.50.91.52.23.24.3

Soil Texture

StatesBiharGujaratHaryanaPunjabMadhya PradeshMaharashtraRajasthanUttar PradeshTotal

Area(000,ha)85164955548024212711389585234

Table 4: Area of salt affected soils in NFSM-Wheat states

Chemical ameliorants:Amendments used for chemical amelioration are either soluble calcium salts like gypsum, phosphogypsum or acid formers like pyrites, sulphuric acid, aluminium sulphate, sulphur etc. however, gypsum and phosphogypsum are easily available and are most economical ameliorants. Thus they have been included for financial assistance under NFSM programme for wheat crop.

Crop response and economics:

Soils with high alkalinity can be used to grow highly tolerant crops such as paddy. Productivity of even tolerant crops grown in such soils remains suboptimal. Reclamation of sodic soils requires fairly high quantity of gypsum (5-15 t/ha). Districts selected under NFSM-Wheat, however, exhibit respectable wheat yield levels

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and soil pH ranging from 7.5 to 8.5 thereby suggesting existence of moderate alkalinity. Application of gypsum to such soils at moderate rates (1-1.5 t/ha) is bound to improve nutrient use efficiency and crop productivity. Although yield gains attributable to gypsum application depend on many factors (existing level of sodicity, soil type, quality of irrigation water, nutrient management practices followed etc.) yield advantage of about 20% in each crop of rice-wheat sequence due to gypsum application has been observed in field studies. This amounts to additional yield of about 500-600 kg/ha of each crop. The additional annual monetary gain is therefore Rs. 9,000 to 10,000 in the very first year. The advantage will continue for 4-5 years with progressive decline in magnitude which can be reversed by repeating the treatment. Thus cumulative monetary gains are much higher compared to the cost of gypsum (Rs. 2000 to 3000 ha) incurred. Benefit: cost ratio will remain greater than 3:0. Fields being irrigated with poor quality (high residual sodium carbonate) irrigation water should be treated with moderate doses of gypsum annually for guarding against likely sodification of the soil. Underground irrigation waters in parts of Haryana, Uttar Pradesh, Rajasthan, Gujarat and Madhya Pradesh have been observed to be sodic. Their regular use for irrigation in many cases has caused soil degradation.


Initial exchangeable sodium (%)Soil type

Table 5: Generalized gypsum requirement (t/ha) for reclamation of sodic soils

LoamClay Loamclay

150.500.75

1.0

201.52.0

2.75

25203.35

4.5

303.04.5

60

405.07.0

9.5

506.510

13.0

Plants require about sixteen nutrients for normal growth and to complete their life cycle. They are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulphur, calcium, magnesium, boron, molybdenum, chlorine, zinc, copper, iron and manganese. Among them carbon, hydrogen and oxygen are absorbed by plants from air and water, while all other nutrients are absorbed by plants from soil. Nitrogen, phosphorus and potassium are required by plants in large amounts, therefore they are referred as major nutrients. Sulphur, calcium and magnesium are refereed as secondary nutrients. The remaining (boron, molybdenum, chlorine, zinc, copper, iron and manganese) nutrients are referred as micro nutrients. They are micro in the sense that they are required by plants in very small amounts in comparison to major nutrients, but not in the sense of their minor importance in plant life. Although they are present in minute quantities in soil, but they are as important for plants as the macro nutrients are. Their deficiency in plants may leads to reduction in crop yields to greater extent.

Intensive cropping (cropping intensity 188%) coupled with the use high analysis macro nutrient fertilizers over the last few decades has resulted in the deficiency of several essential micro nutrients in Punjab soils. According to the recent reports about 25, 10, 3 and 2 per cent soils of the state are deficient in available zinc, iron, manganese and copper. Among these essential micro nutrients the deficiency of zinc, iron and manganese has been seen on different crops in Punjab. Deficiency of zinc in widespread and is encountered under varying soils and crop situations, while the deficiency of iron and manganese is location and crop specific. Rice-wheat is the major cropping system in Punjab, and is very exhaustive in nature. Therefore, the micro nutrients deficiencies which affect these crops are d i s c u s s e d below.

SOILS PRONE TO MICRO NUTRIENT DEFICIENCIES

Zinc: Zinc deficiency is generally encountered in fields with coarse textured soils, low organic matter, high pH,

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high calcium carbonate. Use of irrigation water containing high amounts of bicarbonates and excessive use of phosphatic fertilizers can also leads to zinc deficiency in soils. The soils of floodplain areas and recently leveled soils are also prone to zinc deficiency. Soils testing less than 0.6 kg zinc/kg soil are rated as zinc deficient soils.

Iron: Iron deficiency is common in soils with coarse texture, low organic matter, high pH, high calcium carbonate content. Soils testing less than 4.5 mg iron/ kg soil are rated as iron deficient soils. Iron deficiency is conspicuous in rice grown on sandy soils which are unable to pond water for longer period due to very high permeability.

Manganese: Manganese deficiency is common in soils with coarse texture, low organic matter, high pH. Sandy soils under rice-wheat cropping sequence for last 6-7 years show manganese deficiency. Owing to flooding conditions developed during rice season, a part of manganese gets leached to the lower soil layers. As a consequence of that, the content of available manganese in the surface layer of soil reaches a level that is inadequate to meet the manganese requirement of wheat crop following rice. Soils testing less than 3.5 mg manganese/kg soil

V I S U A L D E F I C E C Y S Y M P T O M S A N D AMELIORATION


IDENTIFICATION AND AMELIORATION OF MICRO-NUTRIENTS IN RICE-WHEAT CROPPING SYSTEM

Rajan BhattAssistant professor (SS), Krishi Vighyan Kendra, P.A.U. Ludhiana, Punjab

Fig.1. Zinc deficiency symptoms in Rice

RICE: Zinc deficiency symptoms:Zinc deficiency in rice plants first appears on lower (old) leaves at about two-three weeks after transplanting the crop. Deficiency appears as light yellowish brown spots scattered in the interveinal areas imparting pale yellowish-brown color to the affected leaves. With the passage of time these spots enlarge, join together and become reddish brown or rusty in color. Under acute zinc deficient conditions, the plants give rusty look (Fig. 1). The affected leaves finally dry up and fall or float on water. The growth of plants under deficient situations is reduced and they give bushy appearance. Tillers fail to develop panicles and results in reduction in grain yield. Under acute deficient conditions, earing and maturity are delayed.

Amelioration: Zinc deficiency can be corrected by applying 25 kg zinc sulphate heptahydrate (21% Zn) or 16 kg zinc sulphate monohydrate (33% Zn) per acre by broadcast method at the time of crop transplanting.

Iron deficiency symptoms: I r o n d e f i c i e n c y symptoms are exhibited as interveinal chlorosis of the younger or newly emerging leaves. Soon after, the veins also lose green color and whole leaf turns yellow in color. Under acute iron deficient conditions, there is a bleaching of the affected leaves and the newly emerging leaves also look white or bleached (Fig. 2).

Amelioration: Iron deficiency can be ameliorated by foliar application of 1.0% ferrous sulphate solution, 2-3 times at weekly interval.

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WHEAT: Manganese deficiency symptoms:In wheat deficiency of manganese may appear at two stages i.e. at initial growth stage just after the first irrigation to crop and later at ear emergence stage. Manganese deficiency symptoms during the early growth stage of wheat appears immediately after first irrigation to crop. Deficiency symptoms are manifested as interveinal chlorosis on the middle leaves, with light grayish yellow to pinkish brown or buff colored specks of variable size confined largely to 2/3 lower portion of the leaf. With the passage of time, these spots enlarge and join together to form streaks or band in between the veins which remain green (Fig. 3). In case of acute manganese deficiency, whole plant may become dry and crop gives a burning look. At head emergence stage, these symptoms appear prominently on the flag leaf. Wheat crop in such deficient situations also experience a great difficulty at the time of ear emergence. The emerged ears remained week and deformed.

Amelioration: Manganese deficiency can be corrected through foliar application of manganese sulphate solution. In manganese deficient soils, give one spray of 0.5% manganese sulphate solution (1.0 kg manganese sulphate in 200 liters of water) 2-4 days before first irrigation to the crop and three sprays thereafter, at weekly interval on sunny days. Do not apply manganese sulphate to soil as it is not profitable. Durum wheat varieties viz. PDW-274, PDW-291 and PDW-233 etc. are more prone to manganese deficiency; therefore these varieties should be avoided in deficient soils.


Fig 2 Iron deficiency in paddy

Fig.3 Manganese deficiency in wheat.

Zinc deficiency symptoms: The deficiency symptoms of zinc in wheat are observed at tillering stage on second/third leaf from the top of plant. Zinc deficiency is manifested as light yellowish white tissue between the mid-rib and margins in the middle or lower half of the affected leaf (Fig. 4). Minute reddish brown spots are seen in the affected area. With the passage of time, these spots join together and form reddish-brown lesions leading to the necrosis and drooping of the leaf.

Amelioration: As soon as the deficiency symptoms appears on the wheat crop, top dress 25 kg zinc sulphate

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heptahydrate (21% Zn) per acre. Under severe deficient situations, soil application may be supplemented by foliar application of 0.5% solution of zinc sulphate. The solution can be prepared by dissolving 1.0 kg zinc sulphate and 0.5 kg un-slaked lime in 200 liters of water. This solution is sufficient for spraying an acre of wheat crop. Two-three such sprays at 15 days interval are needed.

Since rice is more susceptible to zinc deficiency, it is desirable to apply zinc sulphate to rice in rice-wheat cropping system. Zinc sulphate applied to rice may suffice for the subsequent 3-4 crops owing to its residual effect and as such its repeat application may not be needed to every crop/year provided the required dose has been applied. However, if zinc sulphate has not been applied to rice and deficiency appears on wheat, the recommended dose of zinc sulphate should be applied.

Since by the time the deficiency symptoms of a micro nutrient deficiency appear on the plant, the crop may have undergone considerable damage in respect of its ultimate yield. It is therefore, desirable to test soils for their available micro nutrient status before sowing/transplanting a crop in order to ensure timely corrective measures.


Fig.4. Zinc deficiency symptoms in wheat

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