Simulation of wheat yield by nitrogen and ear components in harvest prediction analysis
The application in a single or split dose of nitrogen in wheat affects the expression of ear components. Models that simulate these effects can help predict yield. Our objective was to identify wheat ear components that are responsive to the forms of nitrogen supply in a single versus split dose d. This was achieved by testing variables in the construction of a multiple linear regression model for grain yield simulation in harvest simulation analysis. The study was carried out in 2018 and 2019, in a randomized block design with four replications in a 3 x 3 factorial scheme, for three doses of nitrogen (30, 60, 120 kg ha-1) and three forms of nutrient supply [ single dose (100%) at phenological stage V3 (third expanded leaf); split dose (70% and 30%) at phenological stage V3/V6 (third and sixth expanded leaf) and split dose (70% and 30%) at phenological stage V3/R1 (third expanded leaf and beginning of grain filling)] , respectively, in the soybean/wheat and corn/wheat succession systems. This form of fractionation of 70% and 30% is the form commonly used in commercial wheat crops. The wheat cultivar used was BRS Guamirim. Twenty ears of wheat per experimental unit were randomly collected, which were sent to the laboratory. Ear mass (EM, g), ear grain mass (EGM, g), ear grain number (EGN, n), ear length (EL, cm) and ear harvest index (EHI), given by the ratio of ear grain mass to ear mass, dry weight were measured. Nitrogen supplied in single and split doses modifies with greater intensity the wheat ear components ear mass and ear grain mass. The nitrogen in a single dose supplied at stage V3 provides significant superior grain yield compared to split doses, regardless of nutrient dose, crop season and succession system.