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 Agriculture and Food 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.
Web of Science is a very powerful, mostly STEM, database. It is great for finding scholarly research. There is also a lot of useful advanced functionality for those who want to dive deeper.
AGRICOLA is an agricultural sciences scholarly database maintained by the U.S. Department of Agriculture's National Agricultural Library. There is also a free version (that doesn't link to the text in the WSU catalog).
If you are interested in what databases are available to you at WSU, check out this list.