Evaluation of the residual nitrogen effect liberated by the soybean straw on the maize yield in the second crop

The objective of this study was to evaluate the effect of Nitrogen (N) liberated by the early soybean straw, inoculated in function of dosage and application means of the inoculant, over the vegetative growth and grain yield of second crop corn, in succession. The hybrid corn Land® was sowed in January 1st, 2017 over the soybean straw from a former experiment in Sinop (MT). The trial design used was randomized blocks (DBC) with four replications and ten treatments. For the soybean treatments: witness without N application (only inoculated with Bradyrhizobium japonicum and B. elkanii); for the other treatments, it has been applied the dosage of 10 kg ha-1 of N in different phenological stages and ways of application (by haul at sowing; in V2 by haul and leaf fertilization; in V4 by haul and leaf fertilization; in R1 by haul and leaf fertilization; in R2 by haul and leaf fertilization). Plant height, stalk diameter, total chlorophyll and grain yield were evaluated. The N mineralization from the soybean straw is not enough to fulfill the corn N demand. Even though there were no significant differences among the treatments, the N application in V2 and R1 stages, by topdressing on former soybean, provided the highest grain yield of corn.