Improving grain yield in crop/forage intercropping systems by altering forage cutting date

Improving grain yield in crop/pasture intercropping systems is important for ensuring food security. The grain yield advantage of intercropping systems originates from the border row effect and recovery growth, both of which are influenced by forage cutting dates. However, there is a lack of research on improving grain yield in intercropping systems by adjusting forage cutting dates.

An experiment was conducted over two years (2021–2023), with cropping patterns including wheat/alfalfa strip intercropping and sole wheat cropping. The intercropped alfalfa had four cutting dates (T-20, 20 days before the first flowering stage; T-10, 10 days before the first flowering stage; T, the first flowering stage; T + 10, 10 days after the first flowering stage).

After cutting alfalfa, the increase in intercropped wheat yield was greater in T-10 compared to T-20. The T-10 treatment led to the largest yield improvement over sole wheat in both years, with intercropped wheat yield being 9.1% and 2.9% greater than sole wheat yield in each respective year. T-10 significantly increased yield by 46.2% and 17.9% compared to T in 2022 and 2023, respectively. The yield advantage of intercropped wheat in the T-20 and T-10 treatments was primarily observed in the center rows and the second border rows.

These results indicate that cutting alfalfa 10 days before the first flowering stage can maximize the productivity of grain crops in wheat/alfalfa strip intercropping system. It can provide scientific evidence and technical support for crop management in rainfed agriculture on the Loess Plateau.