UPLAND RICE YIELD UNDER DIFFERENT SOIL MANAGEMENT SYSTEMS AND NITROGEN APPLICATION TIMES

Abstract

Proper soil management and N application time can significantly increase upland rice yield. Thus, the objective of this study was to evaluate the interaction between soil management and nitrogen application time on upland rice development and yield. The experimental design was randomized blocks, in a 5x2 factorial scheme, consisting of five soil management systems (moldboard plow and leveling disc harrow; harrow plow and leveling disc harrow; “matabroto”-type scarifier; no-tillage; and “Aeromix” - superficial scarification equipment) and two N application times (all N in the base, being 45 kg ha^-1 of N applied with the aid of a mechanical traction fertilizer machine, 1 day before rice sowing, + 45 kg ha^-1 of N at sowing; and 45 kg ha^-1 of N at sowing + 45 kg ha^-1 at the beginning of plant tillering), with 4 repetitions. There was no interaction among factors, concerning final plants stand. For treatments where the soil was plowed by using moldboard plow and disk harrow, yield was higher when the nitrogen was parceled out. When nitrogen was all applied during the planting time, the treatment with the “matabroto”-type scarifier presented the highest yield, differing statistically from all the other treatments. Conventional tillage yield (moldboard plow or disk harrow) was similar to no-tillage, when all N was applied during the planting time.

KEY-WORDS: Oryza sativa; no-tillage; conventional tillage; scarification.