Quality of soybean seeds in response to nitrogen fertilization and inoculation with Bradyrhizobium japonicum

Abstract

Nitrogen fertilization may interfere in the quality of soybean seeds. This study aimed to determine the physiological and sanitary quality of soybean seeds, in response to levels and times of nitrogen (N) application associated with Bradyrhizobium japonicum inoculation. Treatments were arranged in a randomized block design, in a 2 × 3 × 4 factorial arrangement [two soybean cultivars (BRS 1074 IPRO and ST 797 IPRO), three application times (sowing, 30 and 50 days after emergence) and four N levels (0 kg ha^-1, 20 kg ha^-1, 40 kg ha^-1 and 60 kg ha^-1), with four replicates. The 1,000-seed mass, moisture content, germination rate, seedling height, shoot length, primary root length, total seedling dry matter, electrical conductivity, mechanical damage, vigor and viability (tetrazolium test) and sanitary quality of the seeds were measured. The use of mineral N, associated with the inoculation of B. japonicum bacteria, does not prove to be consistent, in terms of its effects on the physiological quality of soybean seeds, although the incidence of pathogens may be reduced.