The AGRICOLA database, produced by the U. S. Department of Agriculture, is now a part of the National Agriculture Library's SEARCH discovery service. SEARCH includes AGRICOLA (an index of scholarly journal articles and books in botany, agriculture, forestry, and animal science), PubAg (mainly full-text articles authored by the USDA), and the NAL Digital Collections. There are selective links to full-text for some articles; you will also want to search WorldCat to determine if an article is available electronically.