Tillage and Fertilizer Effects on Crop Yield and Soil Properties over 45 Years in Southern Illinois

Reducing soil disturbance may limit erosion, but many still consider tillage essential for seedbed preparation, particularly on poorly drained soils. Our objective was to quantify tillage and fertilizer management effects after 45 yr {21 in continuous corn [ Zea mays L.] [CC] and 24 in corn–soybean [ Glycine max (L.) Merr.] [CS] rotation} on a somewhat poorly drained silt loam near Belleville, IL. Four tillage (moldboard plow [MP], chisel tillage [ChT], alternate tillage [AT], and no‐till [NT]) and five fertilizer (no fertilization, N‐only, N+NPK starter, NPK+NPK starter, and NPK broadcast) treatments were evaluated. With N, P, and K fertilizer, yields were similar for tilled and NT treatments, averaging 8.73 Mg ha −1 for CC and 11.93 Mg ha −1 and 3.70 Mg ha −1 for rotated corn and soybean. Below recommended soil‐test values resulted in NT yielding less than tilled treatments even though soil test P, K, and pH were similar. No‐till with N, P, and K increased soil organic matter (OM) to 27.6 g kg −1 (20.5 g kg −1 in all other treatments), with the greatest increase from 0‐ to 5‐cm. No‐till treatments showed stratification of P and K, but it had no effect on yield. No excessive pH stratification was observed. Overall, fertilizer management predominantly influenced crop yield and with complete NPK management non‐tilled yields were similar to tilled, even on flat, somewhat‐poorly drained soils. No‐till with NPK management therefore may allow farmers to maintain high yields while reducing soil and nutrient losses.