You can study number of leaves or stem length or flowers parameters by using charcoal on growth of Brassica

Thank you very much @Zahid Fazal

How much charcoal ash are we going to apply for each test?

Yes , dose is a major constraint for chorcaol to be really effective , addition to time taken to improve various soil physico-chemcial and biological properties plus agronomic response...

Thank you Anoop Kumar Srivastava for your response, may I ask what amounts of ash should we apply per seedling for each test?

You are going to take contaminated soil ,it means, you will carry out your study in pots under controlled conditions?

Yes Anoop Kumar Srivastava sir

We can used this either way , could 0.50% to 2.0% by weight of the soil or 30-180 g per kg of soil ( correct dose need to optimise ) , bit higher than usuallly recommended , since your soil is contaminated , charcoal has to perform addition work , apart from agronomic response.

Thank you very much Sir Anoop Kumar Srivastava, we would test different amounts of 0%, 0.50%, 2%, 3.5%, and 5% charcoal ash contaminated soil.

Better take 0,1,2 , 3, 4 and 5% rather than wha you suggest , keeping equal difference in doses...

Thank you again sir Anoop Kumar Srivastava

As you design your study you could think of horizontal cabbage head diameter as a growth indicator. Cabbage head diameter is easily measured in Chinese cabbage.

Thank you very much, Sir Joseph Kipkorir Cheruiyot. We have also added other crops such as corn and peanuts as other samples of our study as recommended by our adviser.

@John Joel Escober, with your advisor close, you'll progress well. With more crops you might need to reduce the number of treatments from the 5 to something like 3 to make the experiment wieldy.

Thank you for you response, Sir Joseph Kipkorir Cheruiyot. We would update our treatments to 1%, 3%, and 5%.

See this pdf