AGRONOMIC RESPONSE OF SOYBEAN, INOCULATED WITH DIFFERENT DOSES OF BRADYRHIZOBIUM ONLY OF 1ST YEAR

Abstract

SOYBEANS ARE THE MOST PRODUCED AND CONSUMED OLEAGINOUS IN THE WORLD. THE INCREASE IN PRODUCTIVITY IS BEING OBTAINED EACH YEAR, PROVIDED BY NEW TECHNOLOGIES AND GENETIC IMPROVEMENT, DIRECTLY RESPONSIBLE FOR THE PRODUCTION OF CULTIVARS ADAPTED TO THE DIFFERENT BRAZILIAN REGIONS. SOYBEAN IS VERY DEMANDING IN NITROGEN, MAKING ITS SUPPLY VIA CHEMICAL FERTILIZERS ECONOMICALLY UNVIABLE, BUT THE FBN IS ABLE TO FULLY SUPPLY THE NEED FOR N AT A LOWER COST. THE OBJECTIVE OF THE PRESENT WORK WAS TO EVALUATE THE INFLUENCE OF BNF ON SOYBEAN PROMOTED BY BRADYRHIZOBIUM STRAINS IN SOIL OF 1ST YEAR. THE EXPERIMENT WAS CONDUCTED UNDER FIELD CONDITIONS FOR FIVE MONTHS, AND CULTIVAR SYN.13610 IPRO WAS USED. THE SEEDS WERE SUBMITTED TO THE FOLLOWING TREATMENTS: CONTROL WITH 200 KG OF CHEMICAL N, 4 DOSES OF INOCULANT, 6 DOSES OF INOCULANT, 8 DOSES OF INOCULANT AND 10 DOSES OF INOCULANT. THE FOLLOWING ITEMS WERE EVALUATED: LEAF NUMBER, LEAF AREA INDEX, SHOOT DRY MASS, ROOT VOLUME, ROOT DRY MASS, NUMBER OF PRIMARY AND SECONDARY ROOT NODULES, DRY MASS OF MAIN AND SECONDARY ROOT NODULES, POPULATION FINAL PRODUCTION AND KG.HA-1 PRODUCTION. THE PLOTS CONSISTED OF FIVE ROWS OF 5 M LONG, SPACED 0.50 M BETWEEN ROWS, WITH A TOTAL OF 12.50 M2, A RANDOMIZED COMPLETE BLOCK DESIGN WITH FOUR REPLICATIONS AND FIVE TREATMENTS. THE USE OF BRADYRHIZOBIUM CONTRIBUTED TO THE DEVELOPMENT OF THE ROOTS AND PART OF THE PLANT. AS THE INOCULANT DOSE INCREASED, THE NUMBER OF NODULES INCREASED. FOR SOYBEAN SOILS, THE DOSE FOR BETTER YIELD IS 10 DOSES OF BRADYRHIZOBIUM INOCULUM FOR 50 KG OF SEEDS