An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Experimental design. Darkly shaded and unshaded squares represent high and low soil nutrient patches, respectively; lightly shaded squares received the mean of the high and low levels. Black circles mark positions where plants of Alternanthera philoxeroides were planted.