Melhoria das medições indiretas do índice de área foliar com uso da altura do dossel

The objective of this work was to evaluate the use of plant height as a calibration variable for improving indirect measurements of the leaf area index (LAI). Three experiments were conducted with different crops – corn ( Zea mays ), soybean ( Glycine max ), and sugarcane ( Saccharum officinarum ) –, to compare the performance of the LAI measured indirectly (LAI ind ) and corrected by the calibration variable with the LAI measured directly (LAI ref ). Without the proposed correction, the LAI ind tended to be overestimated by 20%, on average, compared with the LAI ref , for the three crops. After crop height was used to adjust the LAI ind , a strong positive relationship was observed between the LAI ref and the corrected LAI ind (R 2 = 0.96); overestimation was reduced to 4% and the mean square error decreased to 0.07 m 2 m -2 . The variable canopy height is promising for the correction of the LAI of the soybean, corn, and sugarcane crops.