The Interactions Experiment was started in 1985 to provide a context for examining interactions between tillage and fertilizer. Experimental design is 3 tillage treatments (conventional tillage, no-till, and never-tilled) x 2 Nitrogen fertilizer treatments (with and without fertilizer) x 4 replicate plots. Four never-tilled plots in early successional vegetation provide a reference/control treatment (this treatment is shared with the LTER Main Cropping System Experiment (as MCSE treatment T8). Crops are usually the same as in the MCSE (corn-soybean-wheat). Four monolith lysimeters (each 1.2 m x 2.2 m x 2.2 m deep) are located in 2 replicate plots of the no-till no-fertilizer and tilled no fertilizer treatments.