Nitrogen content or concentration are same. In the recent past concentration is used in place of content.The nutrient concentration multiplied with dry matter/ 100 gives uptake either in grain or straw. Dry matter is expressed in tonnes or kgs/ha.For calculating uptake it is convenient to express dry matter of grain or straw in kg/ha.So the formula we use to calculate the uptake of any nutrient is

N% in grain or straw*dry matter of grain or straw in kg/ha ÷100=uptake in kg/ha in grain or straw    

If % N  in grain is 1% and %N in straw is 0.2% ,grain yield is 5000kg/ha and straw yield is 6000kg/ha then uptake in grain and straw is

1×5000÷100=50kg/ha N in grain

0.2×6000÷100=12kg/ha N in straw

Mr.Sarker ,nutrient content and concentration in plant body is same. Recently the term concentration is preferred over content.For macronutrient like N the unit for concentration is percentage. The dry matter is expressed in kgs/ha.The nutrient uptake is obtained by multiplying the nutrient concentration with dry matter and dividing  with 100.For example the grain yield of rice is 5000kg/ha and N concentration in grain is 1.0%.Then N uptake in grain is 5000×1.0÷100=50kg/ha N.Similarly if rice straw yield is 6000kg and N concentration in straw is 0.4%,the N uptake in straw is,=6000×0.4÷100=24 kg/ha N.

U can find the uptake from the following formula,

Uptake from Gain or Straw = N content in garin or Straw * yield (kg/ha)/100

and I am agree with the Mr. Rao suggestion

Thanks to  Annangi Subba Rao and Chaudhary Mahendra Mafabhai for your kind response.

Rao explanation is correct

May I ask  If there was any other method to calculate the uptake of nutrients in the different parts of plant? In another unit like mg/plant 

You have to analyze N-content of grain and straw of rice.

N-uptake kg ha-1 by grain and straw of rice crop is calculated by multiplying yields of grain or straw with contents of nutrient (Black, 1965) by using the following formula:

You have to analyze N-content of grain and straw of rice.

Uptake (kg ha-1) = Nutrient (%) in Grain or Straw x Grain or

Straw yield (kg ha-1)/100

and if yield is in q/ha ...... then.............?

@Annangi Subba Rao Sir CAN I FIND N uptake in whole plant by crushing the whole plant? If Yes then how?

Dear Dr.Archana,hope everyone is fine in Tahiti.If yield is in q/ha,then multiply with 100 to get the yield in kg/ha.Rest of calculation is same as described earlier in my replies.

Dear Dr.Ali, if you wish to determine the uptake of N in whole plant,then dry and crush/ grind the material and determine the N concentration following usually recommended method.Before grinding the dry material, determine the dry weight and express in kg per ha.Follow the same procedure mentioned earlier and obtain the uptake in kg/ha.In pot culture the dry material weight can be expressed in g/ pot.The update is also expressed in g/ pot.

I want to know Nitrogen, phosphorus and potassium average range in wheat grain ... If 120:60:60 kg/ha recommended dose of NPK is given to wheat crop...

how can find total uptake of wheat biomass when given the value of wheat grain and straw ratio, n content in grain and straw of wheat crop

The protocol is as follows.By this you can estimate protein as well as non protein (soluble nitrogen).

Crush desired amount (50 mg) of plant material with 5.0ml distilled water.Take 2.0 ml from this and add 3.0 ml 10% cold TCA and centrifuge.Supernatant and residue are used for non protein and protein nitrogen respectively.Digest supernatant and residue separately with 2.0 ml conc.sulphuric acid and a pinch of catalyst (CuSO4 :K2SO4:SeO2 :: 1:8:1).Appearance of apple green colour confifms digestion.Make the volume of the digest to 15 ml with distilled water.This will act as stock solution.

Now,take 1.0 ml of stock solution and to this add 14 ml distilled water and 2.0 ml of 6 N NaOH and keep in an ice bath for 30 minutes.After 30 minutes add freshly

prepared Nessler reagent and read the O D at 490 nm with help of spectrophotometer.

Caliberate the nitrogen content against standard curve. Prepare the standard curve for nitrogen by dissolving 66.0 mg of Ammonium sulphate in 100.0 ml water.

Preparation of Nessler reagent -----

Dissolve 100 g mercuric iodide and 70 g potassium iodide in about 400 ml water (solution A) .A separate solution of NaOH is prepared by dissolving 100 g in about 300 ml water (solution B).Now mix solution A and B and make the volume

to 1000 ml.When the small amount of brownish red ppt. settles down,pour of the

supernatant and use.

Excellent explanation by Dr. Annangi Subba Rao!

If the content of micronutrient in mg/kg then i have to convert in percentage?

And yield in g/pot please explain the exact formula

Anushka Mishra ,the following are conversion steps

ppm=u/g=mg/kg

mg/kg if you divide with 1000,

you will get g/kg i.e.mg/kg/1000

g/kg if you divide with 10 i.e.g/kg/10 =g per 100g

g/100g is percentage.

yield g/pot =what you want to calculate?

If you want to calculate micronutrient uptake , you can express in mg/kg plant material or microgram/pot (how many kg (soil) pot?

If micronutrient concentration in plant material is in ppm=ug/g, you can multiply the concentration with g dry matter/pot , you will get ug micronutrient uptake per pot.

8kg soil per pot i used

Sir if the zinc conc. In straw is 28.59mg/kg and stover yield is about 27.95g/pot

Zinc conc. In grain is 30.15mg/kg and grain yield is about 23.13 g/pot how i calculate total Zn uptake by plant please ans

Zn uptake (mg/pot) =(30.15*23.13)/1000

= 0.697 mg / pot

If you want to get Zn uptake in mg /kg then

=0.697 mg/8 kg

=0.087 mg/ kg

Anushka Mishra ,First you may multiply Zn concentration in stover with stover yield 28.59 ug/g x 27.95 g = 799.09 ug/pot

Then multiply Zn concentration in grain with grain yield 30.15 ug x 23.13 g = 697.37 ug/pot

Total Zn uptake 799.09 + 697.37 =1496.46 ug/pot = 1496.46/1000 = 1.496 mg/pot

Excellent description A S Rao Sir.

Thanks AS rao sir and mahipal choudhary sir for sharing ur details

Really excellent description for all

What will Zn uptake (g/ha)??

I am using the formula for nutrient uptake, as follow

Uptake (kg / ha)={(conc. in plant (% or ppm × Dry matter (t/ha)×0.375} /100

My Zn concentration is 35.34 ppm in whole plant and dry matter is 33.22 t/ha.

First decide the units of concentration and dry matter

Concentration ppm=ug/g or mg/kg

Dry matter tonnes/ ha or kg/ha

dry matter in tonnes /ha x1000 =kg/ha

To convert uptake in mg/kg to g/kg = mg/kg /1000= g/kg

Uptake of Zn in g/ha =Zn concentration mg/kg X dry matter kg/ha/1000

=35.34x33.22x1000/1000=1173.99 g/ha

Please check and point out in case of any confusion.

Thanks Rao

how to measure nitrogen assimilation in plants ?