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.
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.
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.
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.
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| Phosphorus placement in sorghum (observe the difference in seedling growth-left: phosphorus placed; right: broadcast application of phosphorus.) | Response of sorghum to phosphorus application (Observe flowering of crop with P application at the back and crop yet to be flower with no phosphorus at the front of the picture.) |
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.
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%.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The range of 17 to 54 kg of P2O5 response to phosphorus application was observed depending available phosphorus in the soil.
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.
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.
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.
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.
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.
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.
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.
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:
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.
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:
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.
Compiled by Dr. Diwarkar : 30 August 2004