Estimating dry biomass by leaf area index

Estimating dry biomass is one of the important parts of production estimation. Among vegetation indices, leaf area index (LAI) is the most common used index to estimate water demand and yield. In this study, attempts have made to estimate LAI without destroying plant and by using the AccuPAR-LP80 crop scanner device. The case study performed in Magsal Agro-Industrial Company Qazvin, Iran with the aim of introducing relations to estimate the amount of dry biomass via LAI for three plant- maize, sugar beet and alfalfa. LAI values of above mentioned plants measured through nondestructive method by calibrated AccuPAR-LP80 crop scanner. Statistical evaluation showed that the highest correlation was for maize with R2 =0.96 and the lowest was for alfalfa with R2 =0.87. In addition, measured dry biomass was a linear function of fraction of photosynthesis active radation (fPAR). Statistical evaluation showed that correlation coefficient varies from 0.94 to 0.90 and PMSE from 2.85 to 3.3 kg ha-1for maize and alfalfa, respectively.