Trial on corn cultivation under shade: the influence of shade on the photosynthetic and yield potential of corn

A study was conducted to determine the photosynthetic and yield potential of corn grown in artificial shade. A corollary objective is to stimulate corn productivity under shade and assess its applicability for coconut-based farming systems. A maize trial using Pioneer Hybrid 3246 was set-up to study the influence of different types of shading, namely, Shade Level 0, (0 percent or full sunlight); Shade Level 1 (ca 40 percent light reduction); Shade Level 2 (ca 60 percent) and Shade Level 3 (ca 80 percent) on growth, leaf gas exchange, grain yield, biomass production, and nutrient utilization. Reduced radiation delayed silking by as much as 2 weeks and resulted in sterile tassels. Shading also significantly decreased kernel yield by 17 percent in Shade Level 1 to 89 percent in Shade Level 3 relative to control plants but the 100-seed weights and shelling percentages were unaffected. Dry matter accumulation was reduced by 20 percent to 75 percent. Harvest indices and area of the leaf above the ear measured from Shade Levels 0, 1, and 2 were similar and significantly different from that of Shade Level 3. Gas exchange measurements, contrary to some plants, showed that photosynthetic response to light was not modified by the amount of available light. Compensation point appears to be identical for maize whether grown in shade or full sunlight. Analyses of N, P, K, Ca, and Mg of the ear leaf showed that all treatments were uniformly and sufficiently provided by the necessary nutrients. However, as light provision was reduced, the nutrients were not fully utilized N, P, K, and Mg concentrations were highest in Shade Level 3, but Ca content was decreased. N, P, and K use efficiency further deteriorated as the grain matured; high percentages of N, P, and K remained on the ear leaf, about 5 percent and 111 percent and 69 percent, respectively, when compared to the control plants