The Significance of NPK Fertilizers on Yield and Smut Incidence of Corn

Abstract

The significance of N, K and P fertilizers on corn yield and smut incidence was evaluated in the field during the seasons 1988 and 1989. Rates of fertilizers were 30, 60 and 90 kg N/acre; 0, 50 and 100 kg K2O/acre and 0 and 30 kg P2O5/acre. The corn plants were artificially inoculated with U. maydis spore suspension at 6‐leaf growth stage. The results showed that N fertilization acted to enhance N content of ear‐leaf and smut index and imposed depressing effects on leaf K. Unlike N, enhanced K‐fertility performed opposite results on leaf N and smut index. A significant N x K interaction was detected on ear‐leaf K and smut index, due to the antagonistic effects between ions. Grain yield data showed positive response to each N, K and P application, but the effect was much greater at the highest application rates. Yield losses were clearly pronounced, along all of the applied nutrient fertilizers, on plants where galls are located above ear than those with galls below ear. On average, the relative losses were 12.8 and 5.9 %, respectively, compared with 3.7 % for the main plot treatment. The 2‐way interaction (except N × P) showed variable effects on yield performance.

Environmental nutrient supply alters prevalence and weakens competitive interactions among coinfecting viruses

“…Thus, even relatively closely related pathogenic microbes can respond differently to changes in the nutrient supply to hosts. These results reflect contrasting effects (positive, negative, or no effects) of both P and N fertilization reported across various host-parasite systems (Spencer, 1941;Bawden & Kassanis, 1950a,b;Selman & Grant, 1957;Kostandi & Soliman, 1991;Brennan, 1992;Reuveni et al, 1997;Kirkegaard et al, 1999;Hoffland et al, 2000;Mitchell et al, 2003;Gent et al, 2005;Clasen & Elser, 2007;Borer et al, 2010Borer et al, , 2014bRousk et al, 2011;Rua et al, 2013;Seabloom et al, 2013). These contrasting results might be caused by different responses of viruses to nutrient addition.…”

Influences of Plant Density on Common Smut Resistance Under Artificial and Natural Infection in Maize.

“…They also added that relative yield was highest for resistant maize hybrids to smut infection, and lowest for susceptible ones. Kostandi and Soliman (1991) concluded that infection of maize with common smut reduced yield per plant from 5 up to 93%. Infection with one gall above the ear drastically affected the yield than infection with one or more galls bellow the ear.…”