You can find scholarly research by searching a large multidisciplinary databases or by a searching smaller, agricultural database.
There are advantages to each database. If I'm really trying to be thorough, I will utilize several databases.
Note: There may be significant, but not complete, overlap in coverage within these databases.
Best Databases for Finding Agricultural Science Research
The Washington State University Library Catalog (Search It) locates pretty much everything you'd hope to find on a subject. This includes journal articles, books, newspapers, multimedia, extension resources, archival materials, etc. You will get the most search results using Search It.
Web of Science is a mostly STEM database. Although it will return less search results than Search It, they will typically be more scholarly. Web of Science has a terrific interface which allows the user to easily find useful research based on articles they have already found.
AGRICOLA is an agricultural sciences scholarly database. This database will return less search results than the previous two databases, but those results will more pertinent to your research. AGRICOLA is maintained by the U.S. Department of Agriculture's National Agricultural Library.
If you are interested in what databases are available to you at WSU, check out this list.
You can sync Google Scholar up to the WSU Libraries catalog. This way you can access PDF full texts in Google Scholar where a subscription is required.
To sync the two catalogs up, follow the directions in the link below.