Temporal and Spatial Differences in Crop Yields of a Mature Silver Maple Alley Cropping System

Abstract

Although alley cropping practices improve ecosystem services, they can reduce crop yields, especially at the tree‐crop interface and progressively at increasing distances from that interface with time. The objective of this study was to evaluate temporal and spatial yield differences in a no‐till corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation in a mature (11–19 yr) silver maple (Acer saccharinum L.) alley cropping system in the claypan region of the temperate climatic zone. Silver maple saplings were planted in 20 m wide rows at 3.6 m spacing between trees in 1990. Crop yields were measured at 3.3, 6.7, and 10 m distances from the tree row from 2001 to 2008. Corn yields in 2002, 2004, 2006, and 2008 and soybean yields in 2001, 2003, 2005, and 2007 were determined using a small plot combine and analyzed in a split‐plot in space and time design. Corn yield was 86 and 24% lower at 3.3 and 6.7 m compared to 10 m. The greatest reductions were recorded in 2006 when the site recorded the greatest yields. Late planting may have affected the corn yield despite 156% of the normal rain in 2008. Soybean yield was 77 and 24% lower at 3.3 and 6.7 m, respectively, compared to yield at 10 m. Soybean yields declined over time at all three measured distances. A reduction of competition and selection of drought and shade tolerant crops may help increase productivity while providing ecosystem services of the perennial tree rows.