Potential crop yield gains under intensive soybean/maize intercropping in China

Abstract

Aims Intensive soybean/maize intercropping, a specific form of intercropping, holds promise in addressing the challenges posed by increasing food demands, diminishing cropland areas, deteriorating soil quality, and escalating environmental pollution. Methods To evaluate the potential of this system, we conducted a national meta-analysis, quantifying its absolute yield gain (net effect, NE) and land use efficacy (land equivalent ratio, LER). We further investigated the underlying mechanisms by examining local climate, soil properties, and field management practices and then developed random forest (RF) models to assess the system's potential, incorporating current information on natural resources. Results In China, an average NE of 3.2 ± 0.1 Mg ha−1 and LER of 1.4 ± 0.02 were achieved by intensive soybean/maize intercropping. The variance of NE was significantly influenced by air temperature (10%), soybean delay days (8%), and maize plant density (9%). Similarly, the LER was strongly driven by soybean delay days (14%), sunshine hours (11%), and maize density (10%). Notably, this intensive intercropping system efficiently utilizes available resources, such as light, temperature (heat), accumulated temperature, and soil nutrients, particularly in regions characterized by low soil fertility and limited agricultural resources. Ultimately, the RF model estimated substantial overyielding of 2 800 kg per hectare, representing approximately 1.4 times the current soybean and maize production under China's monoculture. Conclusions The implementation of intensive soybean/maize intercropping is highly beneficial throughout China, especially in areas with limited agricultural resources. The Yangtze River Basin, in potentially, emerges as the most suitable region for adopting this intensive intercropping practice.

Macrogenomics-Based Analysis of the Effects of Intercropped Soybean Photosynthetic Characteristics and Nitrogen-Assimilating Enzyme Activities on Yield at Different Nitrogen Levels

“…Soil enzymes play a vital role in maintaining soil ecological balance and are indicators of soil ecosystem function [ 12 ]. For example, intercropping maize with soybean and groundnut significantly increased urease and catalase, respectively [ 13 , 14 ]. Urease promotes the hydrolysis of urea to ammonium nitrogen and CO 2 , providing plants with directly absorbable nitrogen and promoting their growth [ 15 ].…”