Effects of a maize - soybean strip intercropping system on canopy level wind velocities in a semi-humid region of central Europe
摘要
Intercropping has been proposed as an alternative to conventional monoculture systems by improving biomass water use efficiency (WUE) and grain yield based WUE through modified microclimatic conditions. However, little is known about its potential to mitigate wind velocities (WV) in semi-humid Central European environments. A two-year field experimental case study (2023–2024) was conducted to assess wind-breaking effects in a maize–soybean strip intercropping system. Treatments included sole crops and strip-intercropping plots, where microclimatic and crop data were collected. WV and wind direction (WD) of the treatments were measured at 1 m and 2 m above ground. Reference 2 m above ground wind velocities from the Integrated Nowcasting through Comprehensive Analysis (INCA) in both years were used for comparison between the two years. Wind reduction effects were further analyzed in relation to wind direction sectors. Strip intercropped plots showed significantly reduced WV in respect to the 2 m INCA reference, with the strongest effects in soybean strips and maize strips at 1 m measurement height. In 2023, mean reductions ranged from 0.6 to 1.0 m/s (soy strip) and 0.5–1.4 m/s (maize strip), while in 2024, reductions ranged from 0.7 to 1.2 m/s (soy strip) and 0.7–1.1 m/s (maize strip). The highest wind reduction effect (WRE) occurred in the climatological main wind directions (270–360° in 2023; 315–360° in 2024), consistent with the north–south strip and row orientation. Above ground dry biomass (AGDB) precipitation-based WUE largely confirmed positive effects of wind reduction with some differences between 2023 and 2024 due to weather conditions. WUE of AGDB of the strip variants compared to the mono cropped plots was higher in 2023 (+ 14.9 kg/m³ (soy strip) and 58.1 kg/m³ (maize strip) but in 2024 higher for only for the maize strip (+ 149 kg/m3) and negative for the soy strip. (-181.7 kg/m3). In spite of wind reduction within the strips, however, WUE did not improve for grain yield for the two crops in both years (2023: -7.7 kg/m³ (soy strip), -25.8 kg/m³ (maize strip); 2024: -21.7 kg/m³ (soy strip), -13.4 kg/m³ (maize strip) in comparison to the mono cropped plots). Our results are limited to our specific experimental design, highlighting the effects of the strip design such as strip orientation in respect to the small-scale wind velocities which affect microclimatic conditions. Uncertainties remain on the effects of determined WUE where small strip width and can force crop-specific interactions and responses (i.e. shading and competition on soil water and nutrient resources), supporting further research needs.