Avaliação da relação entre o índice de área foliar e desempenho de Milho (Zea mays L.) e Feijão-Nhemba (Vigna unguiculata (L.) Walp.) no sistema de cultivo consociado

Abstract

Leaf Area Index (LAI) is an essential variable in the analysis of the physiological and productive performance of crops, as it directly reflects the radiation interception capacity and photosynthetic potential of plants. This study aimed to evaluate the relationship between leaf area index and the performance of maize and cowpea in an intercropping system. The trial was conducted in the experimental field of the Faculty of Agronomy and Forestry Engineering, in Maputo, between October 2023 and February 2024. The experimental area, of 576 m², was organized in a Randomized Complete Block Design, with a 3x2 factorial arrangement, totaling six treatments. The factors evaluated were three cropping systems (pure maize, pure cowpea, and intercropping between maize and cowpea) and two fertilization levels (with and without fertilization). Different fertilization levels were employed to promote distinct intensities of crop development and, consequently, variations in leaf area index (LAI), and the pure cropping system was used as a control to compare the relationship between LAI and the variables analyzed in the two cropping systems. LAI was determined by the gravimetric method, and correlation analyses were performed to evaluate the relationships between the variables. The results demonstrated that the intercropping system showed positive correlations between LAI and the evaluated variables. In maize, a strong correlation with aboveground biomass (R² = 0.85) and with the number of grains per ear (R² = 0.79) stood out, while grain weight showed a moderate correlation (R² = 0.61). In cowpea, there was a strong correlation for the number of pods per plant (R² = 0.81), number of grains per pod (R² = 0.77), and grain weight (R² = 0.71). Variables such as the number of ears/plant in corn and pod length in cowpea showed a very weak correlation. In terms of yield, a moderate correlation was observed in corn (R² = 0.61) and a strong correlation in cowpea (R² = 0.71). The regression equations demonstrated that yield and its components increase linearly as a function of the leaf area index; however, the efficiency of this relationship was higher in pure cropping systems for both crops.