Project

Maize photosynthesis in intercropping: connecting leaf traits to crop performance

Intercropping is the mixed cultivation of crop species on the same field. It is known that intercropping increases productivity. In order to understand the high performance of intercrops, we investigate the effect of intercropping on crop resource uptake and conversion. We also investigate the responses of plant and leaf traits to species mixture. We focus on maize in intercropping, because maize is frequently used in intercropping, and it often contributes substantially to intercropping yield advantages.

Background

Productivity increases in intercropping can result from greater resource capture and (or) from higher resource conversion efficiency than sole crops. In intercropping, crop species with different sowing time, plant height, rooting patterns, and phenology grow together, creating different resource availability as compared to sole crops. To explain yield performance of intercrops, it is necessary to explore the effect of intercropping on the capture and conversion of resources in terms of light and nitrogen. In addition, plants in intercropping can adjust their morphological and physiological traits to the changing growing conditions caused by interspecific interaction. The altered plant traits of intercrops can further lead to different resource capture and conversion as compared to sole crops. Exploring the response of plant traits to intercropping will enable a better understanding of yield performance of intercrops.

Most research on the effect of intercropping has been performed on single species combination. It is necessary to explore the effect in different species combinations, to have a better understanding of how intercrops respond to companion species with different traits.

Project description

The main objective is to use changes in resource capture and conversion, plant architecture and leaf photosynthesis to explain the yield of maize in intercropping. We have four work packages (WP).

WP1: Productivity, nitrogen capture, and nitrogen conversion of maize in intercropping

In this package, we compare the yield of maize in three crop systems: sole maize, maize-faba bean (cereal-legume) and maize-wheat (cereal-cereal) intercropping. We also compare nitrogen capture and conversion of maize in the three crop systems.

WP2: Plant architecture of maize in intercropping

In this package, we explore shading responses and shade avoidance mechanisms in terms of plant architecture in intercropping. We also explore the response of plant architecture to the changing red to far-red ratio in intercropping. We compare maize responses in sole maize, maize-faba bean and maize-wheat intercropping.

WP3: Photosynthesis and leaf traits of maize in intercropping

In this package, we explore the differences in light distribution in maize canopy in sole maize, maize-faba bean and maize-wheat intercropping. We explore the responses of maize leaf photosynthetic capacity and the associated leaf traits to the changing light and nitrogen availability, when maize compete resources with other maize plants or with faba bean or wheat.

WP4: Leaf photosynthetic parameters of maize in intercropping

In this package, we explore the responses of leaf photosynthetic parameters, such as the capacity of enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), enzyme phosphoenolpyruvate carboxylase (PEPc), and the capacity of ATP production rate, to the changing light and nitrogen availability of maize in sole maize, maize-faba bean, and maize-wheat intercropping. We further use those responses to explain changes in leaf photosynthetic capacity of maize in the three crop systems.