Crop Related Knowledge Center

Appropriate crop nutrition requires intimate knowledge of the role of various nutrients for plants in general and also the specific nutrient requirements of individual crops.

• What is nutrition?
• DFPCL and Crop Nutrition
• Role of micronutrients
• Role of nutrition in Viticulture
• Role of nutrition in individual crops
• DFPCL Agrilab Services
• Collection and Preparation of Soil Samples for Analysis
• Potassium in plant physiology, its effect on yield & quality formation
• Agronomic aspects of Nitro phosphate based complex fertilisers
• The Indian Vegetable Seeds Industry
• Sulphur status of Maharashtra soils and crop responses to sulphur application

 

 

What is nutrition?

Plants need at least sixteen essential nutrient elements for proper growth and development. Some nutrients, referred to as primary nutrients are required in large quantities. These are Nitrogen, Phosphorus and Potassium. Other nutrients that required in small and very small quantities are referred as secondary nutrients (Ca, Mg and S) and micronturients (Fe, Mn, Zn, Cu, B, Mo and Cl) respectively.

Being essential plant nutrients, all these elements have certain specific roles to play in the plant and their presence in a certain critical concentration is a must for a plant to complete its life cycle. The roles of micronutrients are wide-ranging from very simple to highly complex and with few exceptions are fairly specific for each particular nutrient.

Even though micronutrients are required in very small quantities, the deficiency of any of these nutrients cannot be corrected by the addition of another nutrient. Deficiency of any of the micronutrients ultimately results in poor growth and reduced yield levels. As agriculture has become increasingly intensive, the extent of nutrient deficiencies in the soil-plant system is increasing day by day. This makes it imperative to include deficient secondary and micronutrients in balanced fertilisation strategies along with N, P and K.

 

 

DFPCL and Crop Nutrition

DFPCL Fertilisers Deepak Fertilisers and Petrochemical Corporation Limited has a range of basic fertilisers.

Complex Fertiliser (23:23:0)

• MAHADHAN Power: This is manufactured by DFPCL and is the only four-in-one fertiliser.
  
• MAHADHAN Chetak: This traded DAP fertiliser is the highest-nutrient content fertiliser.

Potassic Fertiliser

• MAHADHAN Potash: This traded MOP fertiliser helps in quality improvement in crops.

Mixture Fertiliser

• Bhoodhan: This traded fertiliser mixture is easy for application due to bigger and bolder granular size.

DFPCL Micronutrient Products DFPCL's speciality agro products cater to the micronutrient needs of a wide range of plants.

• Mahadhan Bensulf - a uniquely designed controlled release Sulphur nutrient.
  
• Mahadhan Shakti - a range of micronutrient formulations to suit different soil and crop types in different agro climatic regions in India.
• Mahadhan Amruta - fully water-soluble fertilisers containing NPK (nitrogen, phosphorus and potassium) with or without micronutrients designed to be delivered through drip irrigation systems and foliar application.
• Mahadhan Sahaj - Organic manure designed to maintain soil health and fertility.
• Mahadhan Zinksulf - helps overcome problems of zinc deficiency.

 

 

Role of micronutrients

The roles of some of the micronutrients within the plant system are as follows:

• Iron (Fe): Iron plays a vital role in the synthesis of chlorophyll, carbohydrate production, cell respiration, reduction of Nitrate sulphate and N assimilation.
• Manganese (Mn): Manganese activates a number of enzymes. It is essential for splitting the water molecule during photosynthesis. It is also important in N metabolism and CO2 assimilation.
• Zinc (Zn): Zinc is essential for auxin and protein synthesis, seed production and proper maturity.
• Copper (Cu):Copper is involved in chlorophyll formation and is a part of several important enzyme systems involved in proper growth and development of plant. It is also essential for the production of vitamin A and also encourages the reproduction process.
• Boron (B):Boron is essential for membrane integrity, cell wall development, cell division and cell elongation. It is also required for the proper growth of pollen tube and for the process of reproduction.
• Molybdenum (Mo): It is directly involved in protein synthesis and nitrogen fixation by legumes.

 

 

Role of nutrition in Viticulture

The essential role of nutrition in:

• Cereals
• Maize
• Oilseeds
• Legumes
• Potato
• Sugar Beet
• Citrus Fruits
• Pip Fruits
• Stone Fruits
• Strawberries and Blueberries
• The Phosphorus Problem
• Potato Dry Petiole Analysis
• Nutrition management in Oilseed crops

 

Essential Role of Nutrition for Cereals

Good Nutrition Improves crop establishment, winter hardiness and tillering Enhances disease resistance (take all, snow rot) Increases fertility (more grains per ear) Gives better grain quality

Key Nutrients Iron (Fe) Magnesium (Mg) Manganese (Mn) Copper (Cu) Zinc (Zn)

A deficiency of one or more of these elements seriously affects vigour, productivity, quality and yield

Iron Iron is very important for chlorophyll formation, photosynthesis and protein synthesis Deficiency symptoms are... Pale yellow plants Stunting Reduced tillering Interveinal yellow chlorosis on younger leaves

Magnesium Vital for good crop establishment Deficiency symptoms... Alternate green and pale yellow bands along leaves Older leaves affected first Leaves dieback prematurely

Manganese Improves crop establishment winter hardiness, disease resistance and gives a better grain quality Deficiency symptoms... Pale yellow streaks and random brown flecks on leaves leaves may appear floppy Usually seen in patches across a field

Copper Essential for ear and grain development Deficiency symptoms Spiralling of younger leaves Leaf tips shrivel Ears show blind grain sites or poor grain formation

Zinc

• Necessary for ear development and grain quality
• Deficiency symptoms...

1. Parallel yellow bands appear at either side of the leaf midrib
   
2. There may be a yellow/orange tint during early growth stages

 

Essential Role of Nutrition for Maize

• Seed companies have produced hybrid maize varieties to ensure maximum performance in many conditions
• Optimum nutrition is essential at all stages of the growing season to ensure that the genetic potential of the crop is not limited
• At the key early stages of crop development adverse climatic or soil conditions and small root volume often mean that nutrient supply from the soil is less than adequate

Key Macronutrients

• Maize is a fast growing crop producing a large biomass
• Adequate macro-nutrient fertilisation is essential for optimum yield and quality
• Unfortunately pre-plant fertiliser or even post-emergence localised soil applications may not always be sufficiently available at critical times of the season
• Key macronutrients essential for maize are Phosphorus and Zinc. Other micronutrients are also required.

 

PHOSPHORUS Role of Phosphorus Phosphorus is involved with... Cell division, energy transfer, nucleic acid formation, protein synthesis and carbohydrate metabolism It is important for... Crop establishment Root development Early crop growth Phosphorus Deficiency Symptoms Stunted plants Purple or red coloration on stems and leaves Dark green leaves Dark yellow chlorotic and necrotic leaf tips Foliar phosphorus is an effective supplement to soil applied treatments

ZINC Role of Zinc Zinc is without doubt the most widely deficient nutrient for maize production Inadequate zinc nutrition affects early crop development and can have a serious affect upon yield potential and crop quality Zinc is important for - the correct functioning of many enzyme systems, the synthesis of nucleic acids and auxin (plant hormone) metabolism normal crop development and growth Zinc Deficiency Symptoms Pale yellow stripes parallel to the leaf midrib starting at the base of the youngest leaves Reduced internodes and stunted plants Red colour when plant severely affected Partially filled cobs at harvest Reduced yield Zinc deficiencies are made worse by... Cold wet weather conditions Soils receiving high phosphorus applications (common for maize) Soils rich in phosphorus High pH soils Organic soils Zinc Treatment Adequate zinc nutrition is vital in the early part of the season Soil application (before sowing) Seed treatment, and Foliar spraying (4-8 leaf stage) are all effective

Other Important Micronutrients

1. Manganese, copper and boron deficiency can affect maize if soil levels are low
2. Yield and quality will be reduced unless appropriate treatments are made
3. Foliar sprays at the 4-8 leaf stage will be effective in overcoming deficiencies
    

The Essential Role Of Nutrition For Oilseed Rape

Good Nutrition...

• Reduces plant losses over winter
• Gives a better crop establishment
• Improves spring regrowth
• Improves flowering and provides more even maturity
• Boosts seed yield and oil content

Key Nutrients

• Secondary Nutrients
  1. magnesium (Mg)
     
  2. sulphur (S)
• Micronutrients
  1. boron (B)
     
  2. manganese (Mn)
     
  3. molybdenum (Mo)

Better Crop Establishment And Reduced Plant Losses Over Winter

• Magnesium
1. strongly influences crop establishment
• Manganese
  1. increases winter hardiness
     
  2. improves disease resistance
• Sulphur
  1. ensures a good nitrogen/sulphur ratio (around 16 to 1)

Increased Nutrient Levels In The Crop For Better Spring Regrowth

• Good nutritional status of the crop at this time helps to counteract the effects of:
  1. cold wet soils
     
  2. slow root growth and development
     
  3. poor nutrient uptake
     
  4. frost damage

Improved Flowering And More Even Maturity

• Boron
1. ensures a more even and stronger pollination
• Molybdenum
  1. increases nitrogen utilisation

Boost Seed Yield And Oil Content

• Boron enhances pod set
• Magnesium ensures high chlorophyll content of leaves and maximum photosynthesis
• Manganese ensures optimum utilisation of photosynthetic products (i.e. sugars) and their conversion to oil.
• Molybdenum ensures proper nitrogen and phosphate utilisation during this key production stage
• Sulphur maintains a good nitrogen/sulphur (N/S) ratio, important for oil yield and quality

Essential Role of Nutrition for Legumes

Important Nutrients For Peas, Beans, Alfalfa, Soya etc.

Major nutrients

• Nitrogen (nodulation)
• Phosphorus
• Potassium

Secondary nutrients

• Magnesium
• Sulphur

Trace Elements

• Boron
• Manganese
• Molybdenum

Molybdenum

• Vital for conversion of atmospheric nitrogen into plant usable nitrogen
• In legumes this process is carried out by nitrogen fixing bacteria
• Nitrogen fixing bacteria are found in nodules on the root surface

Molybdenum - "The Key"

• Molybdenum is less available in acidic soils
• At pH below 5.6 almost all molybdenum is locked up
• Without molybdenum, legumes cannot fix nitrogen
• Molybdenum deficiency leads to nitrogen deficiency and yield losses

Manganese And Marsh-Spot

• Manganese deficiency during flowering
• Causes an internal browning in center of peas
• Applications against Marsh-Spot must be made during flowering
• Similar disorder occurs in beans

Other Nutrients Identifying Deficiencies

• Analysis should be used to detect deficiencies
• For most deficiencies yield may be reduced without any visual symptoms

Treating Deficiencies Boron, Manganese, Magnesium

Leguminous crops should be treated for deficiencies when the plants are 10 to 15 cm tall.

 

The Essential Role Of Nutrition For Potatoes

Good Nutrition...

Increases quality and yield

Crop Cycle

• Vegetative Growth
1. Emergence
2. Root and leaf growth
3. Stolon development
    
• Reproductive Growth
1. Tuber initiation
2. Tuber bulking
3. Maturation

Good Nutrition Is Vital During The Vegetative Stage To Produce A Quality Crop Phosphorus

• Magnesium
1. Central component of chlorophyll molecule (no chlorophyll - no green leaves)
2. Part of water uptake mechanism (no water - no crop)
3. Factor in P and N metabolism (no P or N - no yield)

• Manganese
  1. Enzyme activator in photosynthesis (no photosynthesis - no growth)
  2. Part of leaf detoxification system (unhealthy leaves - no growth)

Tuber Initiation

• When tuberous swellings reach twice the diameter of the rest of the stolons
• Plant produces more sugar and energy than is needed for growth - this accumulates behind stolon tips
• With extra energy rapid cell division occurs and the tuber is formed
• Even-ness and frequency of tubers is connected to nutrition
• Phosphorus is particularly important

Phosphorus

• Involved in sugar and energy manufacture in the leaves
• Supplies the plant with power to set tubers
•  Increases tuber numbers

Tuber Bulking

• Cell division ceases and cell expansion begins
• cells grow 7 to 18 times in size
• starch and carbohydrates deposited in tuber cells
• dry matter and specific gravity increase
• Phosphorus and magnesium are both important at this stage

Phosphorus

• Phosphorus moves from leaves to tubers in large quantities
• Inadequate leaf P levels may result in premature senescence
• Premature senescence seriously reduces yield
• Phosphorus increases tuber size

Magnesium

• Extra Magnesium Means...
  1. Greener Leaves For Longer Periods Of Time
  2. Optimum Sugar Production
  3. More Energy
  4. Higher Yield

Essential Role of Nutrition for Sugar Beet

Good Nutrition...

• Improves crop establishment
• Promotes healthier foliage
• Reduces heart rot
• Boost root yields
• Increases sugar levels

Key Nutrients

• Boron


Important for sugar beet, it...
 
1. reduces heart rot
2. boosts root yields
3. increases sugar levels

Deficiency symptoms...
 

1. Patchy yellowing of leaves
2. Rubbery older leaves
3. Cracking of leaf mid rib
4. Dying growing points
5. Heart rot

 

• Manganese
  
  An important nutrient...
   
  1. promotes healthier foliage
  2. boosts root yields
  3. increases sugar levels

  Deficiency symptoms...
   

  1. Yellowing of older leaves
  2. Dead patches on leaves (cigarette burn)
  3. Drooping leaves
  4. Poor root development
     
      
• Magnesium

  An important nutrient...
   

  1. improves crop establishment
  2. promotes healthier foliage
  3. boosts root yields
  4. increases sugar levels

  Deficiency symptoms...
   

  1. Yellowing of older leaves
  2. Dead patches on leaves (cigarette burn)
  3. Drooping leaves
  4. Poor root development
      

Essential Role of Nutrition for Citrus

Good Nutrition...

Combats chlorosis giving healthier greener trees Improves resistance to cold weather and late frosts Improves bud development, flowering and fruit set

Key Nutrients

A deficiency of one or more of these elements seriously affects vigour, productivity, fruit size and quality.

• Phosphorus Deficiency Symptoms
  
  Phosphorus is essential for cell division and reproduction. It is needed at all growth phases of the crop especially at germination and seed development.
  
  Deficiency symptoms are...
   
  1. Bronze or dull green leaves, older leaves may have necrotic patches
  2. Soft spongy fruit with thick rinds, misshapen with hollow centres

   

  • Potassium Deficiency Symptoms
    
    Potassium plays a key role in plant physiology
    
    Deficiency symptoms are...
     
    1. twisted leaves that curl and pucker, yellow spots
    2. small thin skinned fruit with an unusually smooth peel texture
       
        
• Iron Deficiency Symptoms
   
  1. As deficiency develops the leaves become cream-coloured to white
  2. In severe deficiency the leaves become small and completely bleached
  3. Fruit is small and of poor quality
  4. Twigs and branches die back
     
      

• Zinc Deficiency Symptoms
   
  1. Leaves develop a pale mottling
  2. Leaves are smaller and pale in colour
  3. Growth points are affected
  4. In severe cases, twigs die back and trees become bushy and stunted
     1. Symptoms are usually more noticeable on the south side of the tree
         
• Manganese Deficiency Symptoms
   
  1. Leaves become lighter between the veins
     1. Symptoms are usually more noticeable on the north side of the tree and are more pronounced during the spring flush of growth
         
• Magnesium Deficiency Symptoms
   
  1. Tree becomes bronze as the deficiency extends
  2. Leaves then become necrotic and fall from the tree leaving it almost bare
     1. Symptoms are only present in mature leaves and are more easily seen at the end of the summer, in autumn and winter

Combat Chlorosis Giving Healthier Greener Trees

• Iron
   
  1. necessary for photosynthesis and the formation of chlorophyll and proteins
      
• Magnesium
   
  1. part of the chlorophyll molecule
      
• Manganese
   
  1. important for photosynthesis
      
• Zinc
   
  1. necessary for the correct functioning of many enzyme systems

Improves Resistance To Cold Weather And Late Frosts

• Good nutritional status of the crop at this time helps to counteract the effects of:
   
  1. cold wet soils
  2. poor nutrient uptake
  3. frost damage

Improved Bud Development Flowering And Fruit Set

• Zinc
   
  1. necessary for the correct functioning of many enzyme systems
  2. important for the synthesis of nucleic acids
  3. needed for auxin (plant hormone metabolism)

Essential Role of Nutrition for Pip Fruit

For Quality Fruit, The Health Of The Tree Is Important At All Stages

• Bud break, flowering and fruit set affect potential yield
• Vegetative growth - it is essential to prevent deficiencies
• Fruit development - nutrients are vital at this stage for quality factors such as size, colour and firmness

A Healthy Tree Will Ensure Maximum Yield

• The main consideration is that bud break is even and strong (zinc and boron)
• Also that the new leaves are healthy and green with no sign of yellowing/chlorosis (zinc, manganese, magnesium and iron)
• Chlorosis or stunted new growth will later reduce the number, size and quality of fruit produced

Bud Break And Early Shoot Growth

• Both zinc and boron are needed for the correct growth and development of new tissues (shoot and leaves)
• Root absorption only starts at 5 to 6 leaf stage so tree nutrient reserves are crucial

Flowering To Fruit Set

• Zinc and boron - 2 essential nutrients for flower development and fruit set.
• Parameters affected include:
   
  1. Fruit number (number of flowers that set)
  2. Fruit size (number of seeds that form)
  3. The potential for good fruit skin finish is established now
• in Autumn or Spring or both

Early Fruit Development Affects Quality

During the 6-week period after petal fall, cell division occurs in the developing fruits with important implications for the final structure of the fruit i.e.:

• fruit size
• fruit firmness
• resistance to bruising
• reduction of internal breakdown etc.
• storage potential of fruit

Calcium and Phosphorus are the key nutrients!

Fruit Size Is Influenced By...

• Initial cell division (phosphorus)
• Cell expansion during season (general nutrition but with sugar production a key factor, the micronutrients that influence photosynthesis are important
  1. i.e. avoid yellowing of leaves (zinc, manganese, iron or magnesium)

Fruit Firmness Calcium And Phosphorus

• Calcium increases firmness:
  1. Cell to cell adhesion is improved with better calcium status which means a harder flesh
      
• Phosphorus increases firmness:
  1. Phosphorus is crucial for cell division
  2. more cells means a denser, firmer fruit

A firmer fruit is less prone to bruising or tissue breakdown = better storage potential!

Phosphorus Deficiency Can Lead To Internal Breakdown Of Apple Flesh

• Reduced firmness during storage
• Low temperature breakdown (starts in central tissues)
• Senescent Breakdown (starts under skin)

Other Quality Problems Are Clearly Influenced By Calcium

• Bitter Pit
  1. A localised cell breakdown greatly influenced by fruit Calcium
      
• Cork Spot in Pears
  1. Cell breakdown related to calcium deficiency
• Superficial Scald - calcium can help

Iron Deficiency Will Produce A Strong Chlorosis (Almost White) In Some New Leaves

• New leaves are evenly chlorotic except for midrib and veins
• Brown, necrotic regions develop on leaves
• Die-back may occur
• Extension growth can be thin and stunted

Zinc Deficiency Can Produce `Little Leaf' And Yellowing

• Small malformed younger leaves
• Yellowing between veins
• Formation of leaf rosettes
• Poor flowering and fruit set
• Poor skin finish of fruit

Manganese Deficiency Shows A Blotchy Yellowing

• Light green mottling between main veins of recently matured leaves
• New growth may be retarded
• Fruit yield and quality may be reduced

Magnesium Deficiency Is Seen In Older Leaves First

• Chlorotic areas are later scorched and premature leaf fall is common
• Extension growth can be inhibited
• Fruit ripen prematurely
• Pre-harvest fruit drop is accentuated
   

Essential Role of Nutrition for Stone Fruit

Good Nutrition

Improves fruit appearance (russet) Reduces both fruit and stone splitting Increases fruit size Improves Brix Gives fruit better colour Results in firmer fruit Enhances storage potential of fruit

Key Nutrients

• Nitrogen - can boost yield but promotes yellowing of skin colour
• Phosphorus - analysis is important as quality and yield can be affected without any visual symptoms
• Potassium - important for fruit size as well as flesh and skin colour development
• Calcium - calcium carbonate is important for vigour of old, established orchards. Also crucial for fruit quality
• Zinc, boron and iron - all important in for yield and quality

Bud burst, Flowering and Fruit set

Zinc, boron and phosphorus are all essential at this stage

From the hardening of the stone to harvest

• This is an important period for:
   
  1. Fruit maturity
  2. Brix (sugar/acid ratio)
  3. Fruit firmness fruit colour
      

Essential Role of Nutrition for Strawberries and Blueberries

Strawberries and blueberries have similar nutritional requirements in order to achieve...

Even fruit set and bearing which improves    harvest timing and total fruit yield   High fruit quality which means    berry size and bold colour firmness good post-harvest/shelf-life characteristics

Even Fruit Set And Bearing Depend On...

• Winter hardiness of plants/shrubs and high flower bud survival through low temperatures
• High blossom/flower number
• Strong, even pollination
• Good zinc and boron status

High Fruit Quality

• Berry size and "boldness"
• Fruit firmness
• Freedom from disease (Botrytis)
• Post-harvest/shelf life
• High fruit phosphorus levels

The Phosphorus Problem

The Phosphorus Puzzle

• Crops only take up soil applied phosphorus as phosphate dissolved in the soil solution
• At best, in any soil, the maximum phosphate that exists in the soil solution is less than 1 kg/ha
• Most of phosphorus in the soil is not available to the crop at any one time
• Phosphates have poor mobility in the soil
• Many crops are inefficient users of soil phosphate (e.g.. potatoes - as little as 10% of soil applied P)

Phosphorus uptake from the soil is further reduced by...

• Cold or wet weather conditions
• Crops with a poorly developed root system
• Acidic or very alkaline (calcareous) soils
• Soils with low organic matter content
• Soils with low phosphate reserves
• Soils with a high phosphate fixing capacity
• Soils rich in Iron

A drop from 21°C to 13°C reduces phosphorus availability by almost 70%!

 

Plants only absorb phosphate that lies very close (1mm) to the root surface

 

Soil Ph Affects Phosphorus Availability

• The optimum soil pH for phosphorus availability is around 6
• Under more acidic (lower pH) soil conditions soil phosphate is locked up by iron, manganese and aluminum
• In high pH soils (ph > 7) phosphorus is fixed as insoluble calcium phosphate

Soil pH and phosphorus availability
 

 

Potato Dry Petiole Analysis

The importance of nutrition throughout the season

• The potato is a hungry crop 
• It can quickly run short of nutrients due to crop demands, dry conditions etc. 
• Nutritional stress means disease pressure
• It is vitally important to monitor the crop through the season
• Analysis cuts out the guesswork
   

Choosing the right analysis

• Soil analysis is essential for seedbed fertiliser inputs 
• Leaf analysis identifies early nutrient problems 
• After tuber initiation Dry Petiole Analysis provides an accurate assessment of nutritional needs

Dry Petiole Analysis is proven after 3 years experience in the UK including trials at Askham Bryan College, near York and in independent trials in Holland.

Many leading growers now use the service.

Dry Petiole Analysis

Even Fruit Set And Bearing Depend On...

• The technique was developed in the 1970's in North America
• It is now well established in scientific papers and research
• It is widely used in USA and Canada by potato growers
• It has shown to be more reliable test during the bulking phase than either dry leaf or sap juice analysis

Fast and effective nutrient monitoring

How is it done?

• The 4th petiole is taken from the plant
• At 20 locations take 3-4 petioles from 3-4 plants

When to take samples?

• Soil Analysis prior to planting
• Leaf Analysis 14-21 days after crop emergence
• 1st Petiole sampling at 10% flower
• 2nd Petiole sampling 14-21 days later
• 3rd Petiole sampling 14-21 days late

What is analyzed?

• Nitrogen, Phosphorus, Potassium, Sulphur, Calcium, Magnesium, Manganese, Boron, Zinc
• The analysis compares the test level with the established guideline level for each nutrient at that growth stage
• The result sheet also indicates where treatment may be beneficial

Summary

Dry petiole analysis...

• Well proven
• Now enables the crop to be accurately monitored throughout the season
• Identifies nutrient requirements during the crucial bulking phase
• Improves tuber size and quality
• Allows the grower to maximise yield potential

Nutrition Management In Oil Seed Crops

Mineral Fertilizer

Balanced fertilization of NPK proved beneficial in all the oilseed crops both under rainfed and irrigated conditions. Application of P to raya, in K-deficient soil, is more effective when combined with N and K. As a general guideline, N and P2 O5 are recommended in the 2:1 ratio except in legume oilseeds. Under Ca-deficient conditions, application of Ca improves the uptake of B and K in groundnut besides Ca.

Doses of a particular nutrient in balanced proportion is also equally important considering cost of mineral fertilizer and the antagonistic or synergistic effect of different nutrients. Several studies have shown the interaction effects of NxP, NxS, KxS, CaxS, and SxZn are synergistic whereas PxS (high level), SxMo and KxMg are antagonistic in influencing yield, nutrient uptake of different oilseed crops.

Application of more than required N and P often has deleterious effect of NxP interaction on seed yield of sunflower. The decrease in seed yield with higher N and P can be due to large proportion of unfilled seeds in the flower heads. Excessive N prolongs growth period and delays maturity. At lower levels of N, Indian mustard responded to S significantly up to 10 Kg/ha, however, with the increased supply of N from 60 to 90 kg N/ha, the S need of the crop was significantly raised to 30 kg S/ha.

An application of 40 kg P2 O5 and 45 kg S as basal gave maximum pod yield, oil yield and protein content of groundnut kernel.

Organics

Various organic sources like FYM, poultry manure, green manure, crop residues and compost can supply adequate amounts of nutrient, including micronutrients to crops. In groundnut application of FYM @ 7.5 t/ha increases the pod yield by 60% over 25:50:25 NPK kg/ha. Application of 5 t/ha poultry manure to groundnut of P-deficient soils increases the pod yield compared to FYM alone.

Crop wastes and residues are renewable and readily available resources. Recycling of crop residues is a viable strategy to meet at least a part of the nutrient requirement of oilseed crops.

Although the role of organic manures in improving nutrient use efficiency is well established by now, the actual consumption continues to be very low. As most of the recommendation includes FYM / compost and green manure as organic nutrient sources, their limited availability deprives the farmer from adopting recommended packages. What is actually required is to develop and popularize location specific technological recommendations in non-traditional sources such as on-farm and off-farm wastes and by-products of agro-industries. Experimental evidences suggest a fairly higher crop response to combination of these materials. Further, to reduce the use of mineral fertilizer, to make a balanced proportion of nutrients supply and to prevent depletion of soil nutrients there is a good possibility for utilizing nutrients potential of biological and industrial wastes in an integrated manner.
 

Biological sources:

Biofertilisers are a potential source of supply of low cost nutrients. Nitrogen requirement of the crop through fertilizer source was reduced when it was inoculated with the bio fertilizers. In groundnut, yield improvement of 5.5-17.1% was obtained due to the use of Rhizobium cultures. The new rhizobial strains, viz. IGR 6 and IGR 40 were found to be tolerant to thiram; hence, seed treatment with fungicide and application of Rhizobium can be combined. Azospirillum seeds treatment in sesame and Azotobactor in toria and sunflower reduces the N requirement of the crops by half. Combined use of super phosphate @ 13.2 kg P/ha and Pseudomonas striata could save 13.2 kg P/ha. Rock Phosphate @ 13.2 kg P/ha with Pseudomonas striata could also be a more economic and alternative source of phosphorus. Use of Pseudomonas striata with both the sources of phosphorus (super phosphate and rock phosphate) proved more effective P-solubilizer than Aspergillus awamori in medium black soils. Use of phosphate solubilising bacteria in conjunction with neem cake, castor cake, or FYM gave higher yields of sesame. Also 26.4% increase in soybean and 20.9% increase in groundnut yields were reported with inoculation of mycorhiza. Glomerella fasciculatum.

Conjunctive use of mineral fertilizer with organic and biological sources of plant nutrients commonly referred as integrated nutrient supply system, is an established agro-technique for sustaining yield levels, enhancing nutrient use efficiency and restoring soil physical, chemical and biological health.

The fertilizer consumption ratio throughout the country in all the production systems is highly imbalanced with higher even undesirably excess dose of N at the cost of other major nutrients particularly K. Soil test based fertilizer application is the only way of balanced nutrition. In fact, scientific basis of fertilizer application should be on soil test value. This concept is important particularly for micronutrients. Application of micronutrients without soil test may become toxic because its direct effect is much less than macronutrient. Also fertilizer application without soil test increases the cost of cultivation. Soil test based balanced fertilizer application has resulted in 18-26% increase in crop yield. Integrated use of fertilizers and organic sources as per STCR approach holds promise for sustaining the oilseed production at higher level. However, it necessitates efforts on three points

• strengthening of Government run soil testing laboratories with modern equipments and trained human resources.
• building confidence among the farmers towards these soil testing services, which largely lacks at present, and
• creating mass awareness on emerging plant nutrient deficiencies and long term benefits of soil fertility maintenance and balanced fertilizer use.

Mineral fertilizer

If a cereal or non legume crop succeeds Kharif groundnut, 20-25 kg N/ha can be reduced; and P application is not required if groundnut has already been supplied with P. Leguminous crops in general can more effectively utilize less soluble Ca-phosphate. Groundnut being legume crop has relatively higher nutrient absorption efficiency from soil P.

In case of soybean-wheat system, as the total P requirement of soybean is much higher (80 kg P2 O5) than groundnut (20-40 kg) it can only partially meet its P requirement from the residual P left in the soil from adequately fertilized wheat crop.

Higher S-use efficiency in cropping systems can only be obtained when S is applied to a higher responsive crop in crop sequences and when better land management is practiced which conserves S for the succeeding crop.

Organic manures: Cropping systems based nutrients management is one of the key approaches of integrated nutrient management. The low level of utilization of nutrients supplied through fertilizers and manures calls for choosing appropriate combination or system of crops to effectively utilize the nutrients for long-term sustainability.
 
Source, Time and Methods of Application

Application of right kind of plant nutrient at proper time with appropriate method is one of the strategies to reduce various losses of the nutrient that, in turn, increases the nutrient-use efficiency.

In sesame, it is highly desirable to apply 50% N at sowing and 50% N at 30 DAS. Similarly, split application in hybrid sunflower (50% N as basal and 25% N each at 45 and 70 days after sowing) is advantageous. Practice of split application of N is more beneficial to use opportunistically the rainfall distribution pattern under rainfed conditions that helps to reduce the risk and cost, with concomitant increase in the N-use efficiency.

Since top dressings of N are commonly practiced, ammonium sulphate is an ideal fertilizer for correcting S deficiency in standing crops and providing an integrated N plus S supply. All phosphate fertilizers should be applied at the time of sowing. The efficiency of phosphate fertiliser depends on the source from which it is derived. Single super phosphate (SSP) is largely preferred for oilseed crops as it contains Ca (19.5%) and S (12.5%) besides few micronutrients. Given the predominance of ammonium sulphate and single super phosphate in the market place, they remain as important sources for N, P and S fertilization.

Calcium nutrition is groundnut is beneficial for the development of well filled pods and kernels and improved shelling percentage. The SSP and gypsum are superior to ammonium sulphate for groundnut as source of S and Ca. However, in acid soils, gypsum may not be as effective as CaCO3 because of the latter's effect in eliminating exchangeable. A1 besides providing Ca. Similarly, in some calcareous soils like in medium black soils, the presence of high amount of lime could become a problem. The best method of applying gypsum is to band place the material near the pegging zone at the early flowering stage.

Application of Zn increases nodulation; chlorophyll content and pod yield of groundnut. In Zn deficient soils, application of zinc sulphate @ 10-50 kg or 0.02% foliar spray is suggested. Application of 10 kg Zn improved the seed. Boron appears to be the most essential micronutrient element for sunflower. Only small but adequate amount of B is required by different soilseeds. Sunflower yield can be increased to be extent of 30% by dusting Borax @ 2 kg/ha on capitulum only during ray floret opening stage.
 

Soil Moisture Availability

Availability, mobility and uptake of plant nutrients are primarily dependent on soil moisture. In general, oilseed takes up more nutrients per metric tonne of grain than cereals for a given availability of water. Increased available soil moisture from 25-75% improves the mustard response to 60 kg N + 40 kg P2O5 / ha by 2.3 times.

At low level of P (15 kg/ha) application, adequate soil moisture has enhanced the P utilization by four folds in mustard. Adequate water supply enhances the mass and distribution of the root system. The roots that are actively growing are capable of taking up nutrients by exploiting a greater volume and depth of soil compared to other roots. In-situ soil moisture conservation practices like broad bed and furrow system, set row cultivation have been recommended for efficient utilization of the applied nutrients in groundnut crop.

Genotypes

Plant genotypes differ in their ability to respond and utilize nutrients. In calcareous soils where lime-induced iron chlorosis is a major problem causing yield reduction in groundnut, genotypes like Dh 8, PKVG 8, GG 2 identified as iron efficient genotypes should be grown to prevent any further yield loss.

Sulphur efficient genotypes showed more chlorophyll (both a and b) and carotene contents than the sulphur inefficient genotypes.

Plant Nutrient Use and Oilseed Quality

The quality decides the market price. Phosphorus application has been found to increase crude protein, oil content and iodine number of oil in groundnut and sunflower mainly due to the role of certain P containing enzymes in fatty acid synthesis in seeds. Sulphur plays an important role in improving the quality and marketability of produce. On an average the improvement in oil content in major oilseeds due to S application is 11.3% in groundnut. 9.6% in mustard, 9.2% in soybean, 6.0% in linseed and 3.8% in sunflower.



Role of nutrition in individual crops

DFPCL Agrilab Services

Collection and Preparation of Soil Samples for Analysis

Potassium in plant physiology, its effect on yield & quastrongty formation

Agronomic aspects of Nitro phosphate based complex fertistrongsers

The Indian Vegetable Seeds Industry

Sulphur status of Maharashtra soils and crop responses to sulphur appstrongcation