During June and July 2023, Professor Long Li and Dr. Rui-Peng Yu organized two field trips to visit the maize/soybean intercropping experiment in Zhangye, Gansu Province, PR China, which is included as one of the meta-experiments in WP 2 in IntercropVALUES Project. China Agricultural University (CAU) is one of the participants in WP2, and this experiment aims to investigate the effects of synchronously increasing nitrogen application rate and crop density on productivity and ecosystem services.

There were more than 40 participants involved in the two field trips. The participants included researchers, Ph. D students and master students from three eduation institutions: China Agricultural University, Gansu Agricultural University, and Gansu Academy of Agricultural Sciences.

The experiment was established in 2017, with three factorial design with three replications. The first factor was four N application rates: 0, 180, 240, 300 kg N/ha for sole maize; 0, 40, 80, 120 kg N/ha for sole soybean; 0, 110, 160, 210 kg N/ha for maize/soybean intercropping for conventional plant density; 0. 220, 320, 420 kg N/ha for maize/soybean intercropping for increased plant density) and four crop combinations (i.e. sole maize, sole soybean, maize/soybean intercropping for conventional plant density, and maize/soybean intercropping for increased plant density). Several monoculture and intercropping plots with no, half, and full N application rates are selected in the IntercropVALUES project.

Left right top down: location, experimental design, and field photos of the soybean/maize intercropping experiment.

Following the assessment list, Dr Rui-Peng Yu collected plant and soil samples in early July, at the flowering stage of soybean. CAU team would measure the physical (e.g., soil aggregates), chemical (e.g., soil organic carbon, pH, mineral N, and available P), and biological (e.g., enzymes) properties of soils. Weather and crop parameters will also be recorded. They will also calculate the temporal stability of productivity during the last 7 years to examine whether maize/soybean intercropping could enhance the sustainability of grain production.

The team from CAU, led by Professor Long Li would also explore how N application rate and cropping system interactively affect multiple ecosystem services, which probably improves our understanding of establishing a desirable intercropping system with lower N inputs and environment-friendly farming systems.

Picture above: field photo of maize/soybean intercropping.

This news item was written by Rui-Peng Yu and the team at China Agricultural University