Application of boron and water replacement in soil in the crop of forage corn

Among the cultural treatments, both irrigation and fertilization become indispensable during the conduction of corn crop. Among the nutrients, boron plays an important role in plants' growth. It was intended to evaluate the performance of forage corn (till the cutting phase for roughage), submitted to different concentrations of boron and water replacement levels. The experimental design was completely randomized with 16 treatments (4x4), four soil water replacements (70%, 100%, 130% and 160% of the daily evapotranspiration) and four doses of boron (0 mg dm(-3); 0.5 mg dm(-3); 1.0 mg dm-3 and 1.5 mg dm(-3)) with four replicationsbeing tested. The evaluated variables were green and dry matter at 35 days after sowing (DAS), 55 DAS and 90 DAS and water use efficiency (E.U.A.). The crop cultivar 30F90 is sensitive both to deficit and excess irrigation water; when irrigating with 70% of replacement, there was increased E.U.A. at 90 DAS, the estimated replacement which afforded the greatest mean of dry matter was of 113.6% with a dose of boron of 0.69 mg dm(-3).