Temporal and Spatial Differences in Crop Yields of a Mature Silver Maple Alley Cropping System
2014
Udawatta, Ranjith P. | Motavalli, Peter P. | Jose, Shibu | Nelson, Kelly A.
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.
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