- What is organic farming?
Organic farming is a system, which avoids or largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones, feed additives etc) and to the maximum extent feasible relies upon crop rotations, crop residues, animal manures, off-farm organic waste, mineral grade rock additives and biological system of nutrient mobilization and plant protection.
- Is there a need to practice organic farming?
With the increase in population our compulsion would be not only to stabilize agricultural production but also to increase it further in sustainable manner. Excessive use over years of agro-chemicals like pesticides and fertilizers may affect the soil health and lead to declining of crop yields and quality of products. Hence, a natural balance needs to be maintained at all cost for existence of life and property. The obvious choice would be judicious use of agro-chemicals and more and more use of naturally occurring material in farming systems.
- What are the benefits of organic farming?
- It helps in maintaining environment health by reducing the level of pollution.
- It reduces human and animal health hazards by reducing the level of residues in the product.
- It helps in keeping agricultural production at a higher level and makes it sustainable.
- It reduces the cost of agricultural production and also improves the soil health
- It ensures optimum utilization of natural resources for short-term benefit and helps in conserving them for future generation.
- It not only saves energy for both animal and machine, but also reduces risk of crop failure.
- It improves the soil physical properties such as granulation, and good tilth, good aeration, easy root penetration and improves water-holding capacity.
- It improves the soil’s chemical properties such as supply and retention of soil nutrients, and promotes favorable chemical reactions.
1. What is biofertilizer?
Biofertilizers are ready to use live formulates of such beneficial microorganisms which on application to seed, root or soil mobilize the availability of nutrients by their biological activity in particular, and help build up the micro-flora and in turn the soil health in general.
2. Why should we use biofertilizers?
With the introduction of green revolution technologies the modern agriculture is getting more and more dependent upon the steady supply of synthetic inputs (mainly fertilizers), which are products of fossil fuel (coal+ petroleum). Adverse effects are being noticed due to the excessive and imbalanced use of these synthetic inputs. This situation has lead to identifying harmless inputs like biofertilizers. Use of such natural products like biofertilizers in crop cultivation will help in safeguarding the soil health and also the quality of crop products.
3. What are the benefits from using biofertilizers?
- Increase crop yield by 20-30%
- Replace chemical nitrogen and phosphorus by 25%
- Stimulate plant growth
- Activate the soil biologically
- Restore natural soil fertility
- Provide protection against drought and some soil borne diseases.
4. What are the advantages of bio-fertilizers?
- Cost effective
- Suppliment to fertilizers
- Eco-friendly (Friendly with nature)
- Reduces the costs towards fertilizers use, especially regarding nitrogen and phosphorus.
5. What types of biofertilizers are available?
- For Nitrogen
- Rhizobium for legume crops
- Azotobacter/Azospirillum for non legume crops
- Acetobacter for sugarcane only
- Blue –Green Algae (BGA) and Azolla for low land paddy
- For Phosphorous
- Phosphatika for all crops to be applied with Rhizobium, Azotobacter, Azospirillum and Acetobacter
- For enriched compost
- Cellulolytic fungal culture
- Phosphotika and Azotobacter culture
(Insert jpeg pic. Biofert2)
- What biofertilizers are recommended for crops?
- Rhizobium + Phosphotika at 200 gm each per 10 kg of seed as seed treatment are recommended for pulses such as pigeonpea, green gram, black gram, cowpea etc, groundnut and soybean.
- Azotobacter + Phosphotika at 200 gm each per 10 kg of seed as seed treatment are useful for wheat, sorghum, maize, cotton, mustard etc.
- For transplanted rice, the recommendation is to dip the roots of seedlings for 8 to 10 hours in a solution of Azospirillum + Phosphotika at 5 kg each per ha.
- How biofertilizers are applied to crops?
200 g of nitrogenous biofertilizer and 200 g of Phosphotika are suspended in 300-400 ml of water and mixed thoroughly. Ten kg seeds are treated with this paste and dried in shade. The treated seeds have to be sown as soon as possible.
Seedling root dip:
For rice crop, a bed is made in the field and filled with water. Recommended biofertilizers are mixed in this water and the roots of seedlings are dipped for 8-10 hrs.
4 kg each of the recommended biofertilizers are mixed in 200 kg of compost and kept overnight. This mixture is incorporated in the soil at the time of sowing or planting.
- How could one get good response to biofertilizer application?
- Biofertilizer product must contain good effective strain in appropriate population and should be free from contaminating microorganisms.
- Select right combination of biofertilizers and use before expiry date.
- Use suggested method of application and apply at appropriate time as per the information provided on the label.
- For seed treatment adequate adhesive should be used for better results.
- For problematic soils use corrective methods like lime or gypsum pelleting of seeds or correction of soil pH by use of lime.
- Ensure the supply of phosphorus and other nutrients.
- What would be probable reasons for not getting response from the application of biofertilizers?
- On account of quality of product
- Use of ineffective strain
- Insufficient population of microorganisms
- High level of contaminants
- On account of inadequate storage facilities
- May have been exposed to high temperature
- May have been stored in hostile conditions
- On account of usage
- Not used by recommended method in appropriate doses
- Poor quality adhesive
- Used with strong doses of plant protection chemicals
- On account of soil and environment
- High soil temperature or low soil moisture
- Acidity or alkalinity in soil
- Poor availability of phosphorous and molybdenum
- Presence of high native population or presence of bacteriophages.
- What precautions one should take for using biofertilizers?
- Biofertilizer packets need to be stored in cool and dry place away from direct sunlight and heat.
- Right combinations of biofertilizers have to be used.
- As Rhizobium is crop specific, one should use for the specified crop only.
- Other chemicals should not be mixed with the biofertilizers.
- While purchasing one should ensure that each packet is provided with necessary information like name of the product, name of the crop for which intended, name and address of the manufacturer, date of manufacture, date of expiry, batch number and instructions for use.
- The packet has to be used before its expiry, only for the specified crop and by the recommended method of application.
- Biofertilizers are live product and require care in the storage
- Both nitrogenous and phosphatic biofertilizers are to be used to get the best results.
- It is important to use biofertilizers along with chemical fertilizers and organic manures.
- Biofertilizers are not replacement of fertilizers but can supplement plant nutrient requirements.
- What is a fertilizer?
A fertilizer is a chemical product either mined or manufactured material containing one or more essential plant nutrients that are immediately or potentially available in sufficiently good amounts.
2. Is application of fertilizers harmful to the soil/ plants/ humans?
Fertilizer applications at the recommended rates are not at all harmful. It is wrong to carry such doubts to the farmers and the consumers of farm products. Fertilizers carry the similar chemical elements which a soil or atmosphere contain. Secondly, the raw materials used for manufacturing fertilizers are natural products. For example, the air we breathe contains 79% nitrogen and is used to manufacture nitrogenous fertilizers like urea. Natural minerals like sulfur, rock phosphate are used to manufacture phosphatic fertilizers like super phosphate.
3. Why people comment that fertilizers are harmful?
Such comments are due to lack of sufficient knowledge about fertilizers. Farmers should clearly understand the role of fertilizers in crop production, use them where needed in a balanced way, and avoid excessive use of them even if they are given free not that they are harmful but it is waste of money to use for that crop.
4. What is fertilizer grade?
Fertilizer grade refers to the guaranteed content (analysis) of plant nutrient/s in a fertilizer. That is percentage of the major plant nutrients; NPK in that order, present in a fertilizer reflects the grade of that fertilizer. Thus 14-14-14-fertilizer grade refers to the fertilizer guaranteed to contain a minimum of 14% nitrogen (N), 14% of phosphorus (P2O5) and 14% of potassium (K2O).
5. What types of fertilizers are available in the market?
Three types of fertilizers are available in the market. They are straight fertilizers, Complex fertilizers, and Mixed Fertilizers.
Straight Fertilizers supply single plant nutrient either nitrogen (N), or phosphorus (P), or potassium (K). Example: Urea supplies 46% N; Super phosphate provides 7% P or 16% P2O5
Complex Fertilizers supply more than one plant nutrient. Example: Di-Ammonium Phosphate (DAP) contains 18% N and 20% P (46% P2O5).
Mixed Fertilizers are physical mixture of two or more straight and/or complex fertilizers to supply particular combination of plant nutrients. Example: one can buy DAP and Muriate of Potash and mix them in a ratio to get a fertilizer mixture containing a grade of 12-32-16 of N, P2O5, and K2O.
6. What are the advantages of Complex Fertilizers?
- The possibility of adulteration is generally less.
- Each granule is homogenous in nutrient content.
- Being granular, the drilling of fertilizer is easy.
- They are cheaper than straight or mixed fertilizers.
- Phosphorus availability is not affected (fixation is less) as the phosphorus in the granules will have less contact with soil particles.
7. Are there any disadvantages with Complex Fertilizers?
The disadvantage with Complex Fertilizers is that the ratios of the nutrients are fixed and the farmers may have to supplement with straight fertilizers to meet the crop requirements.
8. What are the advantages of Mixed Fertilizers?
- There will be considerable saving in time and labor in application to the crops, as all the nutrients required are present in the same packing.
- One can ensure balanced nutrient application if suitable mixture is chosen.
- Micronutrients can also be included in the mixtures.
Are there any disadvantages with Mixed Fertilizers?
- There is possibility for adulteration with inert material.
- Farmers themselves can mix the fertilizers provided they are knowledgeable about what fertilizers cannot be mixed together.
- What are the popular fertilizers available in the market to supply nitrogen to the crops?
Ammonium sulfate contains 20% N i.e. a bag of 50 kg of Ammonium Sulfate will provide 10 kg of nitrogen.
Urea contains 46% N i.e. a bag of 50 kg of Urea will provide 23 kg of nitrogen.
Calcium Ammonium Nitrate (CAN) contains 20% N i.e. a bag of 50 kg of Calcium Ammonium Nitrate will provide 10 kg of nitrogen.
2. What soil conditions decide the suitability or unsuitability of the above N fertilizers?
Fertilizer Suitable Unsuitable
Ammonium Sulfate Saline and alkali soils Continuous use in acidic
Soils without liming
Urea All types of soils In light paddy soils with
possible leaching losses
3. What are the principles governing the time of application of nitrogen?
- Plants throughout its growth take nitrogen.
- Nitrogen fertilizers are soluble in water. They are also mobile and is liable to be lost easily through leaching, especially in light soils.
Hence, it is better not to apply all nitrogen in one dose or at a time. Apply in split doses. This will ensure nitrogen supply to growing plants during the entire growth period.
For all cereal crops like rice, wheat, maize, pearl millet etc. it is recommended to apply nitrogen in 3 equal split doses, the first at sowing, the second at 30 days after sowing (active growing period), and the third at boot leaf stage. Application beyond boot leaf stage will not significantly increase yield.
Each application should be followed by light irrigation or there should be sufficient moisture in the soil at the time of the application of fertilizer.
In heavy soils, single application is as good as split application for sorghum.
4. Between ammonium sulfate and urea, which is to be preferred?
For most crops and soils both ammonium sulfate and urea are equally effective.
However as urea contains 46% N compared to 20% N in ammonium sulfate, the cost of transport, storage and handling will be very much less. Hence, urea could be preferred where both fertilizers are equally effective.
In acidic soils urea is preferred, as the acidity will not increase with regular use of urea compared to ammonium sulfate. Under waterlogged conditions where sulfide injury is suspected urea alone is recommended.
However, soils deficient in sulfur (not common in Andhra Pradesh) ammonium sulfate is useful.
5. What storage and handling characteristics of urea and ammonium sulfate?
Urea: The fertilizer absorbs moisture. So, use the entire bag as far as possible. Store bag in dry place. Inspect the bags frequently during rainy season and take needful precautions to separate the bags that are moist.
Ammonium sulfate: No difficulties in storing and handling.
- What are the popular fertilizers available in the market to supply phosphorus to the crops?
Super Phosphate contains 16% P2O5 i.e. a bag of 50 kg of Super Phosphate will provide 8 kg of phosphorus (P2O5).
Triple Super Phosphate contains 40% P2O5 i.e. a bag of 50 kg of Triple Super Phosphate will provide 40 kg of phosphorus.
Both these fertilizers are equally effective.
2. How can phosphatic fertilizers best applied to crops?
Phosphatic fertilizers give better response when placed in bands near the plant rows. This placement helps in reduced contact with soil particles and results in more availability of the nutrient phosphorus than broadcast application.
- Can phosphorus be applied as top dressing or it should be only a basal application?
It is always advisable to apply phosphate fertilizers as basal application i.e. at sowing or planting. This is for the reasons that phosphorus requirement is high during the early growth period and most of the phosphorus is taken up by plants in early stages of growth.
The primary advantage of early application is that it promotes early root growth, which in turn leads to better exploitation of soil nutrients.
- How much of phosphorus need to be applied for crops?
Phosphatic fertilizers are applied to bring the available P2O5 to a critical limit for a crop. By critical limit is meant the level below which no economic responses are possible to applied phosphates.
Knowing the initial soil test value and recovery of added phosphates, it will be possible to work out the amount of fertilizer phosphorus needed to build up the soil phosphate to a given critical limit. The critical value is found to be about 35 kg P2O5 per ha for crops like sorghum, pearl millet, rice, and maize.
If the initial soil phosphorus level is high, then maintenance application will be enough.
- What are the popular fertilizers available in the market to supply potash (K) to the crops?
Muriate of potash contains 60% K2O i.e. a bag of 50 kg of Muriate of potash will provide 30 kg of potash.
Potassium sulfate contains 48% K2O i.e. a bag of 50 kg of Potassium sulfate will provide 24 kg of potash.
2. When should potassic fertilizers be applied?
Potassic fertilizers can be applied in one dose as basal application. However, in sandy soils where there is possibility of potash being lost due to leaching, the recommended rate of potash should be applied in two equal splits, the first as basal and the second at flowering stage. Similarly for long duration crops like sugarcane, cotton etc. and also for crops where potash plays an important role like potato, potassic fertilizers are applied in 2 or 3 splits.
1. Is there a need to apply micronutrients to crops?
Application of good quantities of organic manures usually supplies the required micronutrients to crops. If the farmer is not able to apply such organic manures, then over time soils will be deficient in micronutrients. In such a situation, the soil analysis will help in identifying the deficiency of micronutrients in the soil and application of deficient micronutrients will lead to increased yields.
2. What are some good sources of micronutrients?
Organic manures (FYM, compost, green manure and green-leaf manure) are good sources.
Other specific sources include:
Boron Borax or boric acid
Zinc Zinc sulfate
Iron Ferrous sulfate
Manganese Manganese sulfate
Molybdenum Sodium molybdate, ammonium molybdate, lime
- How micronutrients are applied to the crops?
As micronutrients needed in small quantities, they are applied as foliar sprays.
Methods of Application of Fertilizers
- What are the different methods of application of fertilizers?
Generally 3 methods of application of fertilizers are in practice.
- Broadcasting: Uniform distribution over the whole cropped field.
- Placement: Application in bands or in pockets near the plants or plant rows.
- Foliar application: Using low or high volume sprayers, the fertilizers are sprayed covering the plants.
- Is there a choice to practice a particular method of application?
The method of application has to be chosen to suit the particular nutrient, the crop, as well as method of cultivation.
Nitrogen is generally applied as broadcast to irrigated crops. Phosphorus needs to be placed near the plant rows. Potassium is also applied as broadcast.
As all the 3 nutrients are applied using a complex fertilizer at the time of sowing or planting, it is a good practice to apply the fertilizer as placement.
Micronutrients are mostly applied as foliar sprays.
- When is broadcasting of fertilizers practiced?
- On all crops with a dense stand and not sown in rows
- In the case of plants whose roots spread widely in the soil.
- On very fertile soils
- When high rate of fertilizers are used
- When readily soluble nitrogenous fertilizers are applied
- When potassic fertilizers are applied in light soils.
(Insert jpg pic. Broadcasted)
- What are the drawbacks with broadcast application?
- May stimulate weed growth with the result that the crop does not derive full benefit of fertilizers.
- Fertilizers may come in contact with a large volume of soil and are likely to be fixed and unavailable for that crop. This is particular in the case of super phosphate application.
- What are the different methods of placing the fertilizers?
- Banding i.e. placing fertilizers in bands to one or both sides of the rows. This is also called as side dressing.
- Drilling in between rows
- Spot placement i.e. by placing in between the plants. This is mostly practiced for vegetable crops.
- By placing in a circular band away from the base of the plants as in the case of fruit trees.
No single method can be considered best for all the crops. The method of placement varies with the crop, fertilizer, and weather.
(Insert jpg pic. Bandplace, placement1, placement3, placetrees)
- When is placement of fertilizers practiced?
- When small quantities of fertilizers are to be distributed
- When phosphatic fertilizers are applied in acidic soils where fixation of phosphorus is a problem
- In the case of crops sown in wide rows
- In the case of shallow rooted plants
- On soils with low fertility
- What are the advantages of band placement?
- Placing fertilizers below the seeds without touching the seeds stimulates early growth of seedlings.
- For application of phosphatic fertilizers as phosphates are less mobile. Broadcast application will result in unavailability to roots.
- More availability of phosphates to crops grown in acidic soils where fixation of phosphates is a problem.
- Early root development will be rapid and extensive and plant growth will be stimulated.
- Under rainfed conditions, due to extensive and deeper root development, plants will be able to draw moisture from lower depths of soil and better withstand drought.
- What is seed cum fertilizer drill?
Seed cum fertilizer drill is an implement useful to sow the seed in rows as well as to apply the fertilizers at the same time. The implement is designed to place the fertilizer 5 cm (2”) below the seed and 5 cm (2”) away from the seed avoiding fertilizer injury to the seed.
Separate hoppers are provided for the seed and fertilizer. There is also arrangement to regulate the seed and fertilizer rates as per the crop requirement. This is efficient way of applying fertilizer and sowing the seed. Additionally, the drill ensures uniform stand and growth of plants.
Using seed cum fertilizer drill all most all crops can be sown.
(Insert jpg pic. Fertseeddrill)
- What is foliar application of fertilizers?
Fertilizers are dissolved in water and such diluted solutions are sprayed directly on the plants foliage. Hand operated sprayers are used for smallholdings. On individual farms a tractor drawn low volume sprayers can be used while on large scale aircrafts are used for foliar spraying.
- Can any chemical fertilizer be sprayed on crops?
Only those fertilizers that do not scorch (burn) leaves are sprayed.
Usually micronutrients, which are required in low rates, are foliar sprayed.
Urea sprays are used for supplying nitrogen.
Ammonium phosphate fertilizer is also used to spray to improve seed setting in multicut fodder legumes like Berseem.
For the reason that low concentration of fertilizers needs to be sprayed most of the fertilizers are not used for foliar application.
- What are the precautions to be observed for spraying urea?
- Size of sprayer’s nozzle is important. The increase in concentration depends on the nozzle type. The sprays should be fine as mist but not as droplets of water.
- Bigger droplets fall off from the leaf surfaces and are wasted. Also, leaves may be scorched if the droplets are retained on the leaves.
- Sprayings are best done after 0400 hours in the evening.
- While spraying the nozzle should be kept at least 1 to 2 feet away from the vegetative growth.
- The weather should not be cloudy.
- The concentration of urea should not exceed 3% in case of knapsack sprayers and 20% in case of power prayers (low volume high pressure sprayers).
- It is advisable to mix 1% of sugar or jaggery with the urea solution for better absorption.
- Can pesticides and herbicides be mixed with urea spray?
Yes. Pesticides and herbicides can be mixed with the urea spray.
- What is the optimum concentration for spraying micronutrients?
Zinc sulfate 0.2%
Ferrous sulfate 0.2%
Molybdic acid 0.05%
Manganese sulfate 0.2%
Copper sulfate 0.2%
- Can nutrients be applied through foliar sprays to fruit trees?
- Plant nutrients are generally applied as foliar sprays on fruit trees to prevent nutritional disorders of micronutrients.
- Nutrient deficiencies of nitrogen, phosphorus, potassium, calcium, and magnesium can be corrected through foliar sprays.
- Nutrient sprays can be applied at any time during the growing season to improve the appearance of foliage and color, size and quality of fruits.
- For most fruit crops, plant nutrients are sprayed along with the regular spray program of pesticides.
- The compatibility of nutrients and the pesticide chemicals should be ascertained before such mixtures are sprayed.
Fertilizer needs of some crops
Dry land crops
- Is it desirable to apply fertilizers to dry land crops? Will not fertilizers applied use up even existing moisture and scorch the crops?
This is a common belief among farmers, which is not true. Contrary to this belief, fertilizer application will help the plants to put up vigorous early growth and develop deep and extensive root system. Thus, the plants will be able to draw moisture from deeper soil layers and withstand any drought at a later stage.
2. What is the best method of application of fertilizers for dry land crops?
Under dry land farming, placement of fertilizers is important. Broadcast application is not efficient as the applied fertilizer will be above the feeding zone. Seed cum fertilizer drill is very useful under dry land conditions as better stand and early vigor of seedlings are important.
- When should be fertilizers applied to dry land crops?
Phosphatic and potassic fertilizers need to be applied as a single dose at the time of sowing. In heavy soils nitrogenous fertilizers can be applied in single dose as basal application. This is particularly true for rabi crops.
Split application of nitrogen is preferred in lighter soils where leaching of nitrogen beyond the root zone is likely occur. The first application is at the time of sowing and the second application should be made keeping soil moisture in view.
Sorghum and Pearl millet
- What is the recommendation of fertilizers for sorghum and pearl millet?
For rainfed sorghum 40 to 60 kg N is recommended. In heavy soils this dose of N may be applied in two equal splits, the first one as basal and the second dose could be either after 30 days of sowing or at flowering depending on soil moisture. In lighter soils and for rabi crop, the recommended rate is applied as basal dose only.
The phosphorus and potash application need to be applied based on soil tests. In the absence of soil test information about 30 kg P2O5 per ha could be applied. As most of Indian soils contain enough potassium to meet sorghum requirement, the application could be skipped.
The above fertilizer recommendations hold good for pearl millet also.
(Insert jpg pic. PonSor. Pplacesor)
1. Is it necessary to apply nitrogen to groundnut crop?
Groundnut is capable of utilizing atmospheric nitrogen for its growth through nodulation with the help of a type of bacteria. But the bacterial nodules do not develop on the roots until the plants are 15 to 20 days. Hence, during the early stages when the plants require easily available nitrogen for their good growth, a starter dose of nitrogen is important.
It is recommended to apply a starter dose of 10 to 20 kg N per ha at sowing time preferably by drilling the fertilizer along with phosphorus.
2. Should groundnut be top dressed with nitrogen?
Top dressing of nitrogen to groundnut depends on the type of groundnut cultivated.
Runner types are good at fixing atmospheric nitrogen. These types have dark green foliage. Top dressing of nitrogen to runner types may not be necessary.
Bunch types are comparatively poor nitrogen fixers. These types have pale green foliage. Hence, it is advisable to top dress with nitrogen at 15 to 20 kg N per ha at the time of 50% flowering stage or pegging stage depending on the soil moisture.
As available soil nitrogen decreases nodulation and there by the amount of nitrogen fixation. Hence, it is good to apply this top dressing of nitrogen by foliar application. With the high volume sprays, a 3% solution of urea may be used. With the low volume sprays, the urea concentration can be increased to 12 to 20%.
3. Is phosphorus application necessary for groundnut?
Yes. Phosphorus requirement of groundnut is high. So, it is recommended to apply 45 kg of P2O5 to groundnut as a basal dose. Phosphorus application enhances the root development and extension, which helps in better soil moisture utilization.
4. Which complex fertilizer is best suited for groundnut and why?
Among the available complex fertilizers, Diammonium Phosphate suits very well as this fertilizer contains the required proportion of nitrogen and phosphorus for groundnut to be applied as basal dose i.e. 18% N and 46% P2O5.
5. Is calcium important for groundnut?
Calcium is an important nutrient for pod development and kernel formation in groundnut.
Low availability of calcium leads larger number of unfilled pods called pops. Adequate supply of calcium results in healthy pods and well developed kernels.
Calcium absorbed by roots is not tanslocated to developing pods, which require calcium for proper kernel development. However, it is fortunate that pegs and developing pods could directly absorb calcium. Hence, calcium needs to be applied near the plants so that the pegs and developing pods could take up the applied calcium.
The best method of supplying calcium to the pegs and developing pods is by dusting well ground gypsum at 300-500 kg per ha around the plants at the time of early flowering i.e. 30 to 35 days after sowing. The gypsum falls around the plants in the zone of pod formation and will be available at the time when the need for calcium is great.
6. What are the micronutrients to be applied for groundnut?
Less availability of zinc and boron are usually observed in groundnut growing areas. Applications of these two micronutrients will help in increasing the groundnut yields.
7. In what form and dose the zinc is to be applied to groundnut?
Zinc is to be applied as zinc sulfate. Zinc sulfate is to be applied as basal dose at 10 kg per ha for the rainfed crop and 20 kg for irrigated groundnut.
8. Are there any precautions to be taken in the application of groundnut?
As the quantity of to be applied is small, zinc sulfate should be evenly distributed by mixing the chemical with the soil in the plough furrow. Secondly, zinc sulfate and phosphatic fertilizers should not be mixed and applied. They need to be applied separately so that the zinc is not converted into unavailable form.
9. Is boron nutrition is important for groundnut?
The boron deficiency symptoms are smaller leaves with irregularly shaped margins, stubby roots with dark areas at the internodes, cracked stem, delayed flowering, and production of less number of pegs and single kernel pods.
Sufficiency, deficiency and toxic limits of boron are very narrow. Hence, one should be careful about boron application. If any above symptoms are noticed confirm about boron deficiency from the soil test results.
Depending on the severity of deficiency, 3 to 5 kg of borax per ha may be applied before sowing along with the other fertilizers. For immediate recovery of plants, foliar spray of 0.1% borax may be practiced.
1. Is there a need to apply fertilizers to pigeonpea crop?
Fertilizers are not applied to pigeonpea in traditional systems perhaps due to the wrong belief that the crop does not respond to applied fertilizers. This belief may be partly true if long duration types are grown as intercrop. But, intensively grown short duration types require good amount of nutrients to produce good yields.
2. Is it necessary to apply nitrogen to pigeonpea crop?
Pigeonpea is capable of utilizing atmospheric nitrogen for its growth through nodulation with the help of a type of bacteria. But the bacterial nodules do not develop on the roots until the plants are 15 to 20 days. Hence, during the early stages when the plants require easily available nitrogen for their good growth, a starter dose of nitrogen is important.
It is recommended to apply a starter dose of 15 to 20 kg N per ha at sowing time preferably by drilling the fertilizer along with phosphorus.
3. Is phosphorus application necessary for pigeonpea?
Yes. Response to phosphorus application to pigeonpea crop was observed. So, it is recommended to apply 17 to 26 kg of P2O5 to pigeonpea as a basal dose. Phosphorus needs to be applied by placement at a depth of 10 to 15 cm in the soil.
4. Is potassium application necessary for pigeonpea?
If soil tests show low levels of available potassium in the soils, then potassic fertilizers can be applied at 20 to 30 kg per ha as Muriate of Potash (MOP). Pigeonpea seedlings are prone to chloride injury if MOP is placed too near the plant rows.
The potassium deficiency observed in a standing crop can be rectified by foliar spray of Muriate of Potash.
- Is there a need to apply any micronutrients to pigeonpea?
If the soil tests show low levels of available zinc in the soil, then 5 kg of zinc sulfate need to be applied at the time of sowing.
- Is nitrogen application necessary for chickpea?
A small starter dose of 15 to 20 kg per ha of nitrogen stimulates early growth of chickpea. 30 to 34 kg N was found to be profitable in rainfed chickpea crop.
- Is phosphorus application necessary for chickpea?
The range of 17 to 54 kg of P2O5 response to phosphorus application was observed depending available phosphorus in the soil.
- Is potassium application necessary for chickpea?
There will be no response, if not negative response, to potassium application to chickpea in soils with high levels of available potassium. If soils are low in available potassium, an application of 17 to 25 kg K2O is recommended.
- What are the micronutrients usually respond to their application to chickpea?
Deficiency of zinc usually occurs in soils with high pH and in chickpea-rice cropping system. Basal application of zinc sulfate at 10 to 25 kg per ha gives a positive response.
In calcareous soils with high pH chlorosis of leaves is caused by the non-availability of iron under waterlogged conditions. This deficiency can be corrected by foliar spray of 0.5% ferrous sulfate.
- Is fertilizers application important for maize?
Maize is very sensitive to the deficiency of plant nutrients. Hence, maize is considered to be a test plant for identifying the availability of many nutrients.
Maize crop should have a continuous supply of nitrogen at all stages of growth till grain formation. Nitrogen deficiency in maize plants even in the early stages of growth will reduce the yields substantially.
Young maize plants need higher amounts of phosphorus in the early stages. There after contribution of phosphorus through fertilizers decreases rapidly though plants take up phosphorus up to near maturity.
Maize utilizes large quantities of potassium from knee-high stage to post flowering. So top dressing potassium fertilizers can correct any deficiency of potassium observed in the early stages.
2. What is the fertilizer recommendation for maize?
For rainfed maize 80 to 100 kg nitrogen and 45 kg phosphorus are recommended. All phosphorus and 75% of nitrogen is to be applied as basal and the balance 25% nitrogen after 30 days of sowing.
For irrigated maize, application of 120 to 150 kg nitrogen and 60 to 80 kg phosphorus are recommended. Nitrogen is to be applied in 3 equal splits. The first application of nitrogen is applied at sowing along with phosphorus. The second dose of nitrogen is applied after 30 days of sowing and the third dose at tasseling stage of crop.
3. Is there any recommendation for micronutrient application to maize?
Many hybrid maize-growing areas may be deficient in zinc. Soil application of 25 to 50 kg of zinc sulfate is recommended once in every 3 years. If soil application is not done and zinc deficiency is observed on plants, 0.2% zinc sulfate solution is to be sprayed 2 or 3 times at weekly intervals till the symptoms do not reappear.
1. Is it necessary to fertilize rice nursery?
The nutrients contained in paddy grain are sufficient for about 14 days’ growth of the seedling. Beyond this period, application of fertilizers is necessary for raising healthy seedlings. Healthy seedlings well supplied with nutrients establish quickly and grow rapidly after transplanting.
2. Is it necessary to apply nitrogen as basal application to rice?
In soils with reasonable fertility there is no difference in yield whether the nitrogen meant for basal application is applied after final puddling or 15 to 20 days after transplanting. However, for soils of low fertility basal nitrogen application i.e. before transplanting is essential.
The nitrogen should be incorporated after draining the water and then water is allowed in the field after 2 to 3 days. Nitrogen fertilizers should not be applied in standing water.
3. What are the main guidelines for nitrogen application?
The optimum time and the rates of nitrogen application depend on various local factors such as soil type, water management, weather conditions etc. However, the following are some guidelines:
- Number of top dressings: Where flooding is not a problem, top dressings may be given every 2 to 3 weeks interval from transplanting till about a week after panicle initiation.
- Amount of nitrogen per top dressing: Preferably not more than 20 to 30 kg nitrogen per ha. However, this depends on the total quantity of nitrogen recommended.
- Soils with low nitrogen: More nitrogen at planting should be given.
- Soils with adequate nitrogen: Small amounts at transplanting and more nitrogen through top dressings.
- Low tillering variety: Relatively more nitrogen at early stages of growth.
- Early maturing variety: Relatively more nitrogen at early stages of growth.
- Long duration variety: More nitrogen as top dressings.
- Cool weather: Due to slow initial growth under cool conditions nitrogen should be applied more as top dressings.
- Direct sown crop: Less nitrogen at sowing, more as top dressings but to be completed by about 50 days after sowing.
- Rainfed crop: A few small top dressings on rainy days preferably coinciding with the physiological stages like tillering, panicle initiation, boot leaf stage, grain formation and grain filling stages.
- How much of phosphorus to be applied for rice crop?
The texture of the soil is important while considering phosphorus application. Recovery of phosphorus from added fertilizer is much less in heavy soils than in light soils. For example: in black clay soils the recovery is 20 to 40% compared 60 to 80% recovery in red sandy soils.
It is now known that the phosphorus status of soil should be built up to a particular level to achieve higher yields. At least 35 kg P2O5 per ha should be available in soil to get profitable returns to fertilizer application in rice. If soil analyses shows below this level, the phosphorus fertilizer requirement is calculated as given below:
Example: Optimal requirement is 35 kg P2O5
Soil test value is 20 kg P2O5
Say, the recovery of added phosphate is 25%
The amount of fertilizer needed to bring up the soil to 35 kg P2O5 per ha level is:
((35-20) x 100) / 25 = 60 kg P2O5 per ha
This amount of 60 kg P2O5 per ha in terms of super phosphate (16% P2O5) is:
((60x100) / 16 = 375 kg of super phosphate
Thus knowing the soil test value and percent recovery of added phosphate, it is possible to suggest the required rate of phosphorus to rice crop.
- Is it advantageous to apply potassium to rice?
It is important to identify the need to apply potassium to a field from the soil test results.
If there is a need, then potassic fertilizer is to be applied as basal application.
The split application of potassium is recommended when:
- The soils are very low in potassium,
- If the soil is too light to hold the potassium against leaching,
- If the potassium fixation power of the soil is very high as indicated in the soil test report.
Top dressing of potassium if needed is applied at the panicle initiation stage.
Also need for application of potassium should be based if high amounts of nitrogen and phosphorus are applied.
- How one can convert the nutrient recommendations to the quantity of fertilizers to be applied?
It is common to recommend the crop nutrient requirements in terms of the nutrient values. For example, recommendation for sorghum is 60-15-0 NPK per ha. But the field application has to be on the basis of the quantities of fertilizer/s required to meet the recommended rates of NPK. This conversion involves some amount of calculations.
For the procedure to calculate the amount of fertilizer/s, please click on the following ICRISAT web site.
- How to economize fertilizer use?
- The fertilizer recommendations should be based on soil test values.
- Balanced use of fertilizer should be advocated for better economic returns.
- Use of nitrogenous fertilizer in split doses economizes fertilizer use.
- Micronutrient deficiencies should be corrected as and when needed.
- Fertilizer schedule should be adopted for the whole crop sequence instead of a single crop.
- To get the maximum benefit from the applied fertilizers, crops should be irrigated at the critical growth stages.
- How do you identify which fertilizer is less expensive?
Fertilizers are compared based on the unit values. One % of nutrient ingredient present in one ton of fertilizer is treated as one unit. The unit value of nutrient ingredient is the price of one ton (or per bag of 50 kg of fertilizer) divided by the % content of that particular nutrient ingredient.
- Urea with 46% N is priced at Rs.5000 per ton (Rs. 250 per bag of 50 kg). Then,
Unit value of Urea is = 5000 / 46 = Rs.108.70
- Ammonium sulfate with 20% N is priced at Rs.2880 per ton (Rs.288 per bag of 100 kg). Then,
Unit value of Ammonium sulfate is = 1440 / 20 = Rs. 144
Comparing the unit value of Urea and Ammonium sulfate (Rs. 108.70 with R.144), one can conclude that Urea is cheaper than Ammonium sulfate.
Note: Ammonium sulfate also contains 16% sulfur, which will be added advantage over urea. Hence Ammonium sulfate may give better response than urea in soils deficient in sulfur. Such points also need to be considered before making any comparisons.
- How do you evaluate complex fertilizers containing more than one nutrient?
In the case of complex fertilizers, standard unit values of nutrient ingredients are considered in the calculation. The formula is:
Unit value of N in a complex fertilizer (CF) with N and P2O5 =
(Price per ton of CF x Unit value of N in Urea) / Unit values of N from Urea and
P2O5 from Super phosphate
Example: Di-Ammonium Phosphate (DAP) containing 18% N and 45% P2O5 costs
Rs.4800 per ton
Unit value of Urea for N is Rs.108.70;
Unit value of Supper phosphate for P2O5 is Rs.105
Unit values of N from Urea and P2O5 from Super phosphate =
(108.70+105.00) = Rs. 213.70
Unit value of N in DAP = (4800 X 108.70 / 213.70) / 18 = Rs.135.64
Unit value of P2O5 in DAP = (4800 X 105 / 213.70) / 45 = Rs.52.41
- How to know that fertilizer application is economical?
Use of fertilizer by the farmer for increased crop production depends almost entirely on its economics. Response per unit area or per unit nutrient applied usually indicates the profitability from fertilizer use.
The profitability from fertilizer use is calculated by deducting the costs of fertilizer/s and their application from the extra crop yields achieved from fertilizer application. A positive balance indicates the profitability.
Fertilizer recommendation for dry land sorghum is 30 kg N and 15 kg P2O5,
The sorghum yield with fertilizer application was 1800 kg per ha and without fertilizer application was 920 kg per ha.
The cost of the fertilizers applied (including labor to apply) were Rs.3866
The additional yield of sorghum with fertilizer = 1800 – 920 = 880 kg
The value of additional sorghum yield = 880 kg x Rs.8 per kg of sorghum
So, the profit from fertilizer application is = Rs.7040 – Rs 3866
= Rs. 3174
- What is the calculation procedure for foliar sprays?
Suppose the recommended foliar spray of Urea is 2% concentration. This means that 100 parts of spray solution should have 2 parts of Urea. To get this, 2 kg of urea should be dissolved in 100 liters of water or 4 kg of Urea in 200 liters of water and so on.
If the amount of water required to cover one hectare is 400 liters, then a 2% spray liquid is prepared by dissolving 8 kg of Urea in 400 liters of water.
The same calculation procedure is used for micronutrient foliar sprays.
Efficient use of Fertilizers
- What are the tips for efficient use of fertilizers?
- Select the most fertilizer responsive and best-suited crops and their varieties for the locality.
- High yielding varieties (HYV) of crops give higher yield than local varieties without fertilizer application as well as a higher unit response to fertilizers, even at the lower rate of application.
- Balanced fertilization should be practiced based on soil test. Fertilizer recommendations should be based on the crop sequence and not on individual crop basis.
- While all of phosphate and potash are applied as basal dressing, nitrogen should be applied in split doses.
- Urea can be cured with soil for top dressing to reduce nitrogen losses by thoroughly mixing 1 part of urea with 5 to 10 parts of moist soil and keeping it for 24 hours.
- Phosphate should be placed 4 to 6 cm below and 4 to 6 cm away from the seeds to ensure maximum availability.
- Top dressing nitrogen and potassic fertilizers should be mixed properly with the layer of soil.
- To the extant possible irrigate the field with just enough water. In dry soil, fertilizers should be placed only in the moist zone.
- Weeds if not effectively controlled during the first 40 days of crop growth, take away about 30 to 40% of plant nutrients applied to the crops. Therefore, it is necessary to control the weeds particularly during the early stage of crop growth.
- Sowing of crop should be done at the normal time suited for the locality to get the benefit of maximum efficiency of applied fertilizers.
- Optimum plant population of the crop needs to be maintained by adopting proper plant spacing.
- Timely control of pests and diseases will help in realizing maximum effectiveness from fertilizers.
- What is balanced fertilizer application?
Balanced fertilizer application refers to the practice of applying the required plant nutrients after taking into account available nutrients in the soil, crop requirement, cropping sequence and crop management practices like weed control, irrigation etc.
- What is integrated nutrient management?
Integrated nutrient management (INM) refers to the practice of integrated use of all natural and man-made resources of plant nutrients so that the crop productivity increases efficiently and environmentally friendly manner without sacrificing the soil productivity for the future generations.
Sufficient and balanced application of organic manures and fertilizers is the key component of INM.