Evaluation of lambert-beer method for estimates of leaf area index in cerrado Mato Grosso

Abstract

The study was developed in the Mãe Bonifácia urban park, a cerrado fragment, in the city of Cuiabá/MT, between October/2014 and September/2015, with the objective of evaluating the efficiency of the Lambert-Beer mathematical model for area index estimates leaf (IAFLB). Photosynthetically active radiation incident outside the canopy (PARincident), photosynthetically active radiation transmitted by the canopy (PAR transmitted) and leaf area index (LAI) were measured monthly with a ceptometer at 30 fixed points, from 10 to 12h, schedule of higher incidence of solar radiation. Spearman's bivariate correlation was applied, with a positive and significant correlation for IAFmed and PARincident, and a significant negative correlation between PARincident and PAR transmited. The IAFmed values ​​ranged from 6.5 m2m-2 in December/2014, rainy season, and 2.7 m2m-2 in September/2015, dry period. We compared the values ​​of IAFmed and IAFLB for the twelve months using simple linear regression, finding a coefficient of determination above 0.7 for 11 of the 12 months analyzed, and Wicoxon-Mann-Whitney test was applied for comparison of means, there being no significant statistical difference between the analyzed groups, indicating that from the measurement of incident and transmitted radiation it is feasible to apply the Lambert-Beer equation to model leaf area indices for the cerrado stricto sensu, both in dry and rainy periods.