Effect of red clover undersowing on foliage, leaf gas exchange, and yield of spring wheat

Abstract

The use of undersown plants, thanks to their favourable effect on multiple environmental characteristics, is an environmentally-friendly crop cultivation method. A valuable undersown crop is red clover, which is often grown with spring cereals. The aim of the study was to investigate the following issues: how will the cultivation of the spring wheat with undersown red clover (called intercropping) or growing spring wheat in a mixture with red clover affect the leaf gas exchange in this cereal? Will the process be modified by plant densities? Will the cultivation of the spring wheat mixture change the foliage characteristics and the wheat yield? The following parameters were studied: stomatal conductance, intercellular CO<sub>2</sub> concentration, assimilation rate, transpiration rate, limitation value, photosynthetic water use efficiency, leaf area, leaf area index, leaf mass per area, chlorophyll content, N<sub>area</sub>, P<sub>area</sub>, leaf temperature, and grain yield. It was demonstrated that the mixed sowing variant reduced the photosynthesis parameters in the leaves of wheat. In this species, a significant reduction in the stomatal conductance, intercellular CO<sub>2</sub> concentration, net assimilation rate, and transpiration rate and an increase in the limitation value and water use efficiency were noted. The wheat leaves were characterised by a higher temperature in the object with the mixed sowing variant. The wheat grain yield in the mixture was 12.6-17.5% lower than in the sole crop.