Question about necessary concentration of urea for radish growth

[Millacol88]

I have a project in my grade 11 biology class to design a controlled experiment showing how some factor affects plant growth, specifically radishes. I have decided to add urea as a nitrogen fertilizer to one group and do nothing to the other leaving all other factors the same between the two groups.

I have found this pdf: http://www.fspublishers.org/ijab/past-issues/IJABVOL_6_NO_3/19.pdf
This experimentation shows a significant increase in plant height, root length, and number of leaves when the plants were enriched with urea. The concentrations of urea are given.

My experiment, however, will be on a much smaller scale. I am growing 24 plants, each in its own individual compartment, around 4cm long by 4cm wide by 5cm deep. I need to know if I can use the same concentration of urea as was used in the study I linked to.

 

[bobze]

I have a project in my grade 11 biology class to design a controlled experiment showing how some factor affects plant growth, specifically radishes. I have decided to add urea as a nitrogen fertilizer to one group and do nothing to the other leaving all other factors the same between the two groups.

I have found this pdf: http://www.fspublishers.org/ijab/past-issues/IJABVOL_6_NO_3/19.pdf
This experimentation shows a significant increase in plant height, root length, and number of leaves when the plants were enriched with urea. The concentrations of urea are given.

My experiment, however, will be on a much smaller scale. I am growing 24 plants, each in its own individual compartment, around 4cm long by 4cm wide by 5cm deep. I need to know if I can use the same concentration of urea as was used in the study I linked to.

It might be better to vary your concentrations with say 5 or 6 plants in each experimental concentration group. For instance try it with their concentration, double their concentration and half their concentration (and a control group with none).

 

[Millacol88]

I'm sorry, I should have clarified that I only have 24 radish plants to grow in total. That's including the test group and the control. I could try a twelve-plant control and a twelve plant test group, with that test group split up into three different levels of concentration. I'm still not sure what those concentrations should be.

 

[Millacol88]

Sorry to bump a thread, but I killed one of my test groups with too much urea, and I'm struggling to find any information about what specifically too much of a nitrogenous compound does to plants. Could anybody point me to a source that has anything on this?

 

[LudusRex]

Thank you for sharing your project with me. It is great to see students interested in conducting controlled experiments to understand how different factors affect plant growth.

Based on the study you have shared, it seems that the addition of urea as a nitrogen fertilizer can significantly increase plant growth in radishes. However, the concentration of urea used in the study may not necessarily be applicable to your experiment on a smaller scale.

The concentration of urea used in the study was 100 mg/L. This concentration may be suitable for larger scale experiments, but for your small-scale experiment with 24 plants, it may be too high. I would recommend starting with a lower concentration, around 25-50 mg/L, and then adjusting it based on the growth and health of your plants.

It is also important to consider the type of soil and other environmental factors that may affect the uptake of urea by the plants. I would suggest conducting a pilot experiment with a few plants to determine the appropriate concentration of urea for your specific setup.

Overall, I think your experiment is well-designed and I am looking forward to seeing your results. I wish you all the best in your project and feel free to reach out if you have any further questions.