Figure 1. Daily PAR received in Johnston, Iowa, under rainy, cloudy and sunny conditions on 4 different days in summer.
Table 1. Effect of shade treatments on yield (Tollenaar, 2009.)
1 Weeks relative to silking: a-5 to -1, b-1 to +2, c+2 to +5.
NS=not significant, **= highly significant, (Prob>F=0.05.)
Table 2. Effect of shade treatments on yield (Reed, et al, 1988.)
Figure 2. Average U.S. daily light integral (DLI) by month (Korczynski, et al., 2002).
Figure 3. 2015 deviation from normal (2006-2015 avg.) solar radiation during the "lag phase" of development.
"Lag phase" is the time from pollination to the beginning of the linear phase of rapid dry matter accumulation in the kernel, and corresponds with the R1 (silking) through R2 (blister) stages of development.
Liu, W. and M. Tollenaar, 2009. Physiological mechanisms underlying heterosis for shade tolerance in maize. Crop Sci. 49:1817-1826.
Korczynski, P., J. Logan and J. Faust, 2002. Mapping monthly distribution of daily light integrals across the contiguous United States. Hort. Tech. 12:12-16.
Reed, A., G. Singletary, J. Schussler, D. Williamson and A. Christy, 1988. Shading effects on dry matter and nitrogen partitioning, kernel number, and yield of maize. Crop Sci. 28: 819-825.