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Nutrient Management

Nutrient Management

Zinc Deficiency



Poor stand and establishment, lack of growth and tillering.

• Unhealthy and sickly appearance of crop at 3-4 weeks after transplantion even after receipt of adequate quantities of N,P and K fer tilizers

• Basal mid rib bleaching of 3rd / 4th leaf from top at about 2-4 weeks after transplantion.

• Dark brown rusty spots on the upper par t near the tips of older and mature leaves.





 Application of  zinc  sulphate  @   20 kg/ac at  puddling is  suggested  as  a prophylactic measure in Zinc deficient endemic soils

•  Deficiency in the standing crop can be corrected by spraying zinc sulphate @

0.2% (2  g/L of water). The spraying should be repeated at 5 days interval depending on the severity of the problem

•  Zinc sulphate solution should not  be mixed with any insecticide / fungicide


Nutrient Management

Sufficient amount of nutrients should be supplied to the crop right from transplanting to harvesting as it helps in better crop growth finally giving better yields. Ensure soil fer tility tests are done to your field and apply the nutrients accordingly recommended by the soil health report .
• 3-4 tons of FYM should be applied to the field at the time of ploughing
• Both oversupply and under supply of nutrients to the crop is a threat.
• Oversupply of nutrients results to increased susceptibility of the crop to pests, lodging, etc. 



Basal fer tilization with 0.5 kg of `N’; 0.5 kg of `P and 0.5 Kg of ‘K’ per every 100 sq m  is required to get robust seedlings, followed by another 0.5 kg `N’ at 12 days after sowing.



Spray ZnSO4 @ 2.0 g /l for correction of Zinc deficiency  if deficiency  is observed.



Spray 5-10 g ferrous sulphate (or) ferrous ammonium sulphate with 0.5 to 1.0 gram of citric acid per litre of water to correct Iron deficiency in the nursery crop.


Main Field



Ameliorate soil acidity in upland soils of East Godavari, west Godavari and khammam districts by appropriate liming.



In soils of excessive percolation use urea in 3-4 split dosesor use coated nitrogen fer tilizers such as neem coated urea in kavali area of Nellore and par ts of chittoor.



Amelioration of salinity/alkalinity in east Godavari, west Godavari and Nellore districts through green manuring, drainage and appropriate Gypsum application



Nitrogen is to be applied in three splits (at basal, at active tillering Stage & at Panicle Initiation stage) P & ‘K’ may  be applied as basal in heavy soils. In case of light soils, ‘K’ may  be applied in two equal splits i.e., at basal and at panicle initiation stage.



For late planted conditions apply nitrogen in two splits only (65% basal and 35% at 20 DAT).



Limitations of Biofertilizer application

 Use of biofertilizers makes certain constraints generally related to production, market, resource and field level which are as follows.

(1) Production constraints:
  • Unavailability of appropriate and efficient strains
  • Unavailability of suitable carrier
  • Lack of standards in packaging
(2) Market level constraints:
  • Lack of awareness of farmers
  • Inadequate and inexperienced staff
  • Lack of quality assurance
  • Seasonal and un-assured demand
  • Limited scope of marketing
(3) Resource constraints:
  • Limited resource generation for biofertilizers production
  • Limited risk taking ability of farmers
(4) Field level constraints:
  • Soil and climatic factors
  • Native microbial population
  • Faulty inoculation techniques
  • Crop management
  • Quality control
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Application methods for Cyanobacteria and Azolla



  • Broadcast 10 kg soil based culture/ha.  5-7 days after transplanting of rice seedlings
  • Maintain sufficient water (5 –10 cm) for 15 days 
  • A thick algal mat is formed at 15 days
  • Drain off water and allow algal mat to settle 
  • Incorporate as green manure before transplanting of rice (500 kg/ha)
  • Dual culture with rice 7 days after transplanting & allow to multiply and incorporate (500 kg/ha)

File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Application methods for Azospirillum & Phosphate solubilizer

(i) Seed treatment for direct seeded rice

  • Keep the seeds required for sowing one acre in a heap on a clean cemented floor or gunny bag.
  • Prepare culture suspension by mixing one packet {200g}  each of Azospirillum  and PSB biofertilizer in approx. 800 ml water {1:2}
  • Sprinkle the culture suspension on the heap of the seeds and mix by hand so that thin coating is uniformly applied to the seeds.
  • Spread the seeds under shade for some time for drying and then sow 
  • In place of water, rice glue { Kanji} can also be used for better results
(ii) Seedling root dip method for transplanted rice
  • Prepare the suspension by mixing l kg {5 packets} each culture of Azospirillum and PSB in 15-20 litres of water.
  • Get the rice seedlings required for one acre and make small bundles of seedlings.
  • Dip the seedlings root in the suspension for 8-10 hrs and    transplant immediately.
  • Generally, the ratio of inoculants and water is 1:10 
Alternative method
  • Prepare a bed of size 2 m x 1.5 m 0.15 m in the field 
  • Spread a polythene sheet and fill upto 2 inches water
  • Suspend 2 kg each of Azospirillum and PSB culture required for one hectare & mix
  • Dip roots of rice seedling for 8-10 hrs and transplant
Flow chart of root dipping method

flow chart

File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Use of biofertilizer in rice

  •  There is a need to balanced supply of nutrients to the crops in an integrated fashion without over reliance on only one source of nutrients for sustainable production.
  • In this direction, bio-fertilizer has emerged as a promising component in integrated nutrient supply system for sustaining the crop production. 
  • Cyanobacterial nitrogen fixation helps to minimize the over dependence of chemicals, in particular, urea in rice farming and also enhances the use efficiency of nitrogen by releasing ammonia constantly to the rice crop. 
  • In addition to nutrient supplementation, Cyanobacteria and Azolla that grow on the soil surface and also as a floating mass act as live aerators in paddy field ecosystem and oxygen released during the photosynthetic activity got liberated as minute air bubbles and consequently aerate the water impounded in paddy field that resulted in increased dissolved oxygen content which ultimately decreased the methane flux. 
  • In addition to the aeration of water, Cyanobacteria and Azolla might alleviate the toxicity due to accumulation of reduced iron and sulphites in rice fields observed under continued submergence. 
  • In another study Banayo et al. (2012) at Philippines evaluated three different biofertilizers (based on Azospirillum, Trichoderma, or unidentified rhizobacteria) during four cropping seasons between 2009 and 2011, using four different fertilizer rates i.e. 100% of the recommended rate (RR), 50 per cent RR, 25 per cent RR, and no fertilizer as Control) and reported that relative terms, the seasonal yield increase across fertilizer treatments was between 5% and 18% for the best biofertilizer (Azospirillum-based), but went up to 24% in individual treatments. 
  • Integration 50 per cent RDN+ Biofertilizers (Azotobacter, Azospirillum and Azolla) +17.5 kg P+ 32 kg /K ha recorded the higher grain yield of rice over the recommended dose of nitrogen (Pattanayak et al., 2009).
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region


  •  The symbiotic association between plant roots and fungal mycelia is termed as Vesicular Arbuscular Mycorrhizae (VAM). 
  • VAM is a fungal biofertilizer mobilizes relatively immobile elements like Zn, Cu, K, S, Al, Mn, Mg, Fe, and speed up their uptake by plants. 
  • VAM inoculation improves the water relation to plants. 
  • Many of the graminaceous and leguminous plants harbour VAM (Gherbi et al., 2008). 
  • These plants contain special structures, which help in the transfer of nutrients from soil into the root system. 
  • The VAM fungi are inter-cellular and obligate endosymbionts. 
  • The fungi are mass-produced only in the presence of living roots. 
  • The production of inoculums needs a host plant and growth medium, usually soil, which provides congenial conditions for growth and reproduction of fungi. 
  • The inoculums should be applied 2-3 cm below the soil at the time of sowing (Sprent et al., 2007).
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Phosphate solubilizing microorganisms

  •  Phosphorus is the second important nutrient after nitrogen for plants and microorganisms. 
  • Further, there is build up of insoluble phosphates in soil where phosphatic fertilizers have been applied over long periods.  
  • Some heterotrophic bacteria and fungi are known to have the ability to solubilize inorganic P from insoluble sources. 
  • Important phosphate solubilizing organisms are Pseudomonas striata, Bacillus polymyxa, Aspergillus awamori and Penicillium digitatum etc. P solubilizing fungal population is generally found more in acid to neutral soils while the bacterial population in neutral to alkaline soils. 
  • Their microorganisms can grow on insoluble phosphatic sources such as tricalcium phosphate, ferric, aluminium and magnesium phosphate, rock phosphate and bone meal and convert them into soluble forms. 
  • These organisms secrete various organic and inorganic acids. 
  • They act on insoluble phosphates and convert them into soluble phosphates in the rhizosphere. 
  • Among the microorganisms, bacteria are found to be more efficient in the secretion of organic acids. 
  • Addition of organic manures helps in increasing the solubilizing power of the microorganisms. 
  • PSB are reported to facilitate P supply to plant by solubilising insoluble P and results in better P uptake following their inoculation (Rautela et al., 2001).
  • The utilization of native soil phosphorus is mostly unavailable to crops due to low solubility. 
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region


  •  Azolla is a free-floating fresh water fern (Azolla pinnata). 
  • Azolla is applied to the main field as a green manure and dual crop. 
  • As green manure crop it is allowed to grow on the flooded fields for 2-3 weeks before transplanting later water is drained and ploughing for mixing with the soil. 
  • Azolla is applied to the soil one week after transplanting when a thick mat forms, trampling to incorporate which supplies 30-40 kg N/ha (Liu et al., 1992). 
  • The results of several field trials in India have shown saving of 20-30 kg N/ha in rice cultivation by applying Azolla (Subba Rao, 1988).
  • It fixes nitrogen due to Anabaena species of blue green algae present in the lobes of Azolla leaves. 
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Blue green algae

  • Heterocysts are specialized cell in algal filaments, which act as seats of nitrogen fixation. 
  • The most important species are Anabaena and Nostoc. 
  • The amount of nitrogen fixed by blue green algae is range from 15-45 kg N /ha (Costa et al., 2002). 
  • Standing water of 2-10 cm in the field is a prerequisite for the growth of blue green algae. 
  • It can grow in a temperature range of 20-35oC. 
  • Bright sunshine increases the growth rate while rains and cloudiness slows growth rate. 
  • It grows well in a pH range of 7-8 and in soils high organic matter. 
  • Application of this algae preparation at a rate of 10 kg/ha in rice fields, one week after transplanting is recommended (Dobbelaere et al., 2007). 
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region


  • An associative micro aerophillic nitrogen fixer commonly found in loose association with the roots of cereals is of great interest. 
  • High nitrogen fixation capacity, low energy requirement and abundant establishment in the root of cereals. 
  • Sterilized FYM + soil are used as carriers. 
  • The carrier inoculants are made into slurry and mixed uniformly with seeds, dried in shade and sown. 
  • Azospirillum inoculum is used for sorghum. 
  • Positive interaction between Azospirillum and applied N has been observed in several cereal crops with the effect of Azospirillum being equivalent to 20-30 kg/ha of applied N (Elmerich et al., 1992). 
  • brasilense produced high amount of IAA in culture medium, caused an increase in number and length of lateral roots. 
  • In Indian condition many scientists reported that Azospirillum inoculation enhanced the grain yield of rice 5-25 per cent. 
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region


  • A dominant non-symbiotic free living heterotrophic nitrogen fixing bacteria encountered in neutral to alkaline soil not only provides the nitrogen but produce a variety of growth promoting substances. 
  • Some of these growth-promoting substances are indole acetic acid, gibberellins, B vitamins and antifungal antibiotics substances. 
  • Azotobacter chroococcum is dominant in arable soils and capable of fixing N2 10-15 kg N/ha (Johanna, 1997). 
  • The inoculants can be mixed with FYM and broadcast near the root zone. 
  • From the field experiments carried out in different part of India Azotobacter inoculants have shown to increase the yield by 3-34 % of many crops.
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region


Rhizobiums are however limited by their specificity and only certain legumes are benefited from this symbiosis. Symbiosis N2 fixation involves different hosts and micro-symbionts between legumes and bacteria belonging to the genera Rhizobium, Bradyrhizobium and Azorhizobium. 
  • These inoculants are known for their ability to fix atmospheric nitrogen in symbiotic association with plants forming nodules in roots. 
  • Nodulation and N2 fixation are observed under wide range of temperatures with optima between 20-30oC (Chandel et al., 2003). 
  • Most legumes are either sensitive or moderately resistant to salinity and growth depression is attributed to toxic Na and Cl ions. 
  • Low levels of Ca, P and Mo and excessive quantities of Al and Mn adversely affect nodulation. 
  • Cross inoculation group’s ability of one isolate of Rhizobium to form nodules on roots of limited species of legumes which are related to one another. 
  • The seven recognized species are Rhizobium leguminosarum (pea group), Rhizobium phaseoli (bean group), Rhizobium trifolii (clover group), Rhizobium meliloti (alfalfa group), Rhizobium lupin (lupini group), Rhizobium japonicum (soybean group) and Rhizobium sp. (cowpea group). 
  • Yield increases of crops planted after harvesting of legumes are often equivalent to those expected from application of 30 to 80 kg of fertilizer N/ha. 
  • Alfalfa, red clover, pea, soybean, cowpea, and vetch were estimated to fix about 23 to 300 kg of N ha/year (Claudine et al., 2009). 
  • The carryover of 35-65 kg N/ha from cowpea, blackgram, groundnut to succeeding cropping cropping sequences has been observed by many workers.
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Classification of Biofertilizers

 Biofertilizers classification

File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

What are Biofertilizers?

  • Preparation containing live or latent cells of efficient strains of N-fixing, PO4-3 solubilizing or cellulotytic micro organism used for application of seed, soil or composting areas with the objective of increasing the number of such micro organism and accelerate certain microbial process to augment the extent of the availability of nutrients in a form which can be assimilated by plants. 
  • The commercial history of biofertilizers began with the launch of ‘Nitragin’ by Nobbe and Hiltner, a laboratory culture of Rhizobia in 1895, followed by the discovery of Azotobacter and then the blue green algae and a host of other micro-organisms. 
  • Azospirillum and Vesicular- Arbuscular Micorrhizae (VAM) are fairly recent discoveries. In India the first study on legume Rhizobium symbiosis was conducted by N.V.Joshi and the first commercial production started as early as 1956. 
Table: Some milestones in research, production & promotion of biofertilizer in India


First study on legume Rhizobium symbiosis by N.V. Joshi.

Earliest documented production of Rhizobium inoculants by M.R. Madhok.

First Commercial production of Biofertilizer.

Study on solubilization of phosphate by microorganisms by Sen & Pal.

Scope for use of charcoal, lignite & FYM as alternate. 

Use of ISI mark for Rhizobium.

Setting up of National Facility for BGA collection at IARI by ministry of Agriculture, Govt. of India.

Setting up of National project on development & use of biofertiliser by Ministry of Agriculture, Govt. of India.

Setting up of National Facility for Rhizobium germplasm collection at Division of Microbiology, IARI.
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Scope of Bio fertilizers as Nutrient Sources in Rice Production


  • Indian agriculture is now facing the problem of land and water degradation, environmental pollution, lowering of water table and global competition.
  • There is a decrease in factor productivity, development of multi-nutrient deficiency, build of obnoxious weeds and pests, increasing cost of production, over the last two decades.
  • This means, Indian agriculture is now at the crossroads ecologically, economically, technologically and socially, our present growth rate in agriculture is not keeping pace with the population growth rate.
  • Our greatest living industry is in distress. Increasing the productivity and profitability of small farmers in an economically sustainable manner is the most effective step for reducing poverty and hunger in our country.
  • The major pathway has to be productivity enhancement. 
  • Deterioration of soil quality is mainly due to over/imbalance use of fertilizer and no/minimum use of organic sources of plant nutrients including biofertilizers.
  • A judicious use of organic amendment and biofertilizers may be effective not only in sustaining crop productivity and soil health, but also in supplementing a part of chemical fertilizers requirement of crops (Pandey et al., 2009). 
  • Role of biofertilizers for enhancing the soil productivity, either by fixing atmospheric nitrogen either solubilizing the soil nutrients or by stimulating the plant growth through synthesis of plant growth promoting substances, is well known in agricultural production system.
File Courtesy: 
R K Avasthe, Subhash Babu and Raghavendra Singh ICAR Research Complex for NEH Region

Micronutrient Content of Different Organic Product (ppm)



Iron (Fe)

Copper (Cu)

Zinc (Zn)

Manganese (Mn)

Boron (B)

Molybdenum (Mo)















Pig manure







Poultry manure







Goat manure








Nutrient interaction and plant nutrition


  • Low levels of N, S & Mg exhibited high Mn and low Fe uptake
  • P induced Zn deficiency: High level of available P
  • ZnSo4 application @15-20 kg/ha
  • Application of K decrease Mn & Fe content in rice plant
  • Increase in pH by lime application reduce Zn availability to plants
  • Application of Zn depress extractable Fe but increase Mn in submerged rice soil
  • Application of Cu decrease Fe & Mn in submerged rice soil
  • High Fe in soil suppress Cu absorption by rice
  • Fe plays an antagonistic role in relation to Zn in rice plant & waterlogged rice plant
  • Mn inhibit Zn absorption by rice root, but favored Zn translocation within plants
  • Mn interferes with translocation of Fe from root to shoot
  • Calcareous soil + high pH: Iron chlorosis due to iron remaining in ferric (oxidized state)
  • Inundation for 2-3 days or foliar application of iron
  • Iron toxicity: Acidic soil (liming is best way)
  • Zinc deficiency: Normal & saline-sodic soils- ZnSo4 application @40 kg/ha 

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security

Fixation of micronutrients in soil


  • Boron and molybdenum are generally fixed in rice soil. In case of boron main reaction occur when acid soils are limed.
  • Lime is able to replace Al+3 by Ca+2 and produce insoluble precipitation of aluminium hydroxide/iron hydroxide.
  • This precipitate adsorbs large quantities of boron.
  • Soil high in organic matter also have high Boron.
  • Molybdenum adsorbed strongly by iron/aluminium oxides.
  • Soils high in non crystalline iron on clay surfeces, tend to be low in available molybdenum due to fixation.

File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security

Symptoms and Control Measures for Molybdenum deficiency

 Molybdenum (Mo)


  • Molybdenum is an essential component of the major enzyme nitrate reductase in plants.
  • Its requirement of plants is influenced by the form of inorganic nitrogen supplied to plants, with either nitrite (NO2-) or ammonium (NH4+) effectively lowering its need.
  • It is also reported to have an essential role in iron absorption and translocation in plants.
  • Deficiency symptoms of Mo in rice resembles to nitrogen deficiency (older leaves become chlorotic).
  • Necrotic spots are seen at leaf margins because of NO3 accumulation.

Control Measures:

  • Molybdenum deficiency can be correct by liming of acid soils to pH 6.5 (not preferable if pH change is not desirable for other purposes).
  • Beside these dusting with Na/NH4 @ 100-500 g/ha is very much beneficial.
  • Foliar spay of Na/NH4 molybdate @ 0.1% is also beneficial.
File Courtesy: 
Shaon Kumar Das, Raghavendra Singh & Subhash Babu ICAR Research Complex for NEH Region - Published in Rice Knowledge Management for Food and Nutritional Security
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