Anova: Single Factor. Help with P-value


I am running statistics on my data.

Independent variable. Fertilization (0, 1, 2, 3 g/L)
Dependent variable. Relative water content

The ANOVA analysis returned a p-value of 7.20244056705398E-06

What do the ...E-06 means?

Can anyone help me fix this issue? PDF of my spreadsheet in attachment.

Thank you!