Impact of intercropping on the photosynthetic activity of coffee

Conducting studies that assist in the evaluation of agroecosystems is essential for advancing biodiverse and sustainable agriculture. This study aimed to assess the impact of intercropping on the photosynthetic activity of Arabica coffee plants. The experiment was conducted in the municipality of Alegre, Espírito Santo, southeastern Brazil. Three coffee cropping systems were studied: Arabica coffee monoculture; Arabica coffee intercropped with Nanicon variety banana; and Arabica coffee intercropped with Nanicon variety banana and Juçara palm. The Arabica coffee variety used was Catuaí Vermelho IAC 44, planted in 1991, with a spacing of 3.0 m between rows and 2.0 m between holes, accommodating two plants per hole. In 2010, coffee trees underwent mid-height pruning (low-cutting pruning), and the Nanicon bananas were planted between rows with a spacing of 5.0 x 3.0 m. Three years later, palm seedlings were planted in the same rows as the banana plants, with a spacing of 5 x 3 m. Five experimental units were randomly selected for each cropping system. The evaluated variables included chlorophyll indexes (chlorophyll a, chlorophyll b, total chlorophyll, and chlorophyll a/b ratio) and gas exchange parameters (net CO2 assimilation rate, stomatal conductance, intercellular CO2 concentration, transpiration, intrinsic water use efficiency, instantaneous water use efficiency, and carboxylation efficiency). Regarding chlorophyll indexes, differences were observed only in chlorophyll b, with monoculture coffee displaying the highest values. In terms of gas exchange, intercropped coffee exhibited lower values of intrinsic and instantaneous water use efficiency, and higher values of stomatal conductance and transpiration. The highest net assimilation rate values were observed in coffee with banana intercropping, while the highest water use efficiency was found in coffee in monoculture. In summary, monoculture coffee showed the highest values for most of the variables related to photosynthetic activity, followed by Arabica coffee intercropped with banana, which stood out for achieving the highest net assimilation rate.