We have access to four 1 acre fields that have been divided into low and high nitrogen split plots.
These fields were under normal agronomic practices till the Roots Lab took them over in 2009. We incorporated high C:N ratio organic matter such as straw and sawdust each year to the entirety of each field in order to immobilize nitrogen. Chemical nitrogen was then added back to the high nitrogen split plots. The low N plots are now permanently low. 40% reduction in biomass is the expected level of nitrogen stress.
Root system architecture traits such as nodal root angle and number, and anatomical traits such as aerenchyma are currently being studied in these high and low N plots.
The Root Lab is one of the few groups excited to see such stressed plants as these low N maize plants in the foreground with yellow leaves.
Many hands make for light work when plant 4 acres by hand using jab planters. If used carefully, both planting depth and density can be held constant.