This is a time when the school librarian would be a great resource. If he/she teaches your son how to conduct a search, that skill will move forward with him in his studies.
Lucky for you I work in a university research library and can give you a few tips (I won't give you the full university message - we'll give him time to get there first!).
For a good online source to filter the results, I suggest your son visit
Google Scholar and figure out the keywords that will bring in results he can use for this topic. By going to Google Scholar you will filter out the general sites that use the words but don't have any research to back their opinions.
I entered a boolean search string
"mulch" and "irrigation" and "water usage" and "gardening" (put "and" between each keyword or phrase). If you do the boolean search without the quote marks on each keyword (
mulch and irrigation and water usage and gardening) you get a lot of USDA results - more technical papers, but something you might want to also look at.
This is what a
Boolean Search is:
Quote:
A type of search allowing users to combine keywords with operators such as AND, NOT and OR to further produce more relevant results. For example, a Boolean search could be "hotel" AND "New York". This would limit the search results to only those documents containing the two keywords.
I could post a link to the results I got, but let's see what your son comes up with. If he needs more help, post again or have him post and ask his question and I'll dig a little deeper to see if we can find something right on target.
Good luck with the paper! This sounds like a great activity to do together. I hope you enjoy your time out in the garden mulch!