assay for applying super absorbent polymer in a low input corn (zea mays l.) production system aimed to reduce drought stress under mashhad conditions

in order to investigate the effects of super absorbent polymer application on reduction of drought stress to corn, a split plot arrangement based on randomized complete block design with three replications was conducted at research field of agriculture faculty of ferdowsi university of mashhad during growing season of 2010-11. the main plot treatments were 1) application of 40 kg.ha-1 super absorbent, 2) application of 80 kg.ha-1 super absorbent and 3) no application of super absorbent polymer. three irrigation intervals (7, 10 and 14 days) assigned to sub plots. the results showed that super absorbent application affected plant height (h), and dry matter production (dm) as the highest of these traits resulted from level 2 of super absorbent application (140.5 cm, and 144.5 g.m-2, respectively). h, dm, canopy temperature (ct), cob number (n), fresh yield (fy), economic yield (ey) and 100-seed weight affected by irrigation intervals. there was no significant difference between 10 and 14 days irrigation interval as h, dm, ct, harvest index (hi) and 100-seed weight, these results could be important concerning to reduce used water to irrigate corn. as experimental treatments did not have any effect on leaf area index (lai), and hi, it seems the positive effects of treatments revealed due to improved soil water holding capacity, soil physical properties improvement and reduction of drought stress. interaction between super absorbent and irrigation intervals indicates that by level 2 super absorbent applications there are no significant differences between 14 and 10 days irrigation intervals, considering all traits. the same interaction just as before happened for 7 and 14 days irrigation intervals, except of ey and dm. in the other hand, by increasing application of super absorbent it could be possible to increase corn irrigation intervals from 7 to 14 days in mashhad conditions without any reduction in yield and yield components. in general, these results indicate that super absorbent application could increase soil water holding capacity, reduce drought stress and partially supply corn water requirement during the growing season without any reduction in yield.