Objective Effects of intercropping cassava with soybeans on the growth, development, yield, and quality of the crop, as well as the enzyme activity in the field soil in Hunan were investigated for efficient farming soybeans for fresh consumption.

Method Jiaoda 18 soybean and Nanshi 199 cassava were intercropped with the plants spacing 0.10 (T1), 0.15 (T2), and 0.20 m (T3) apart, along with soybean monoculture as control (CK) at a experimentation station. Effects on the crop and soil were monitored.

Result The soybean plant height under T1 and stem diameter under T3 were seen as the best among all treatments. The roots grew progressively more vigorously under intercropping, especially under T1 at the stage when the gains were bulging. The leaf SPAD of the intercropped plants increased over CK but not significantly. The net photosynthetic rate and stomatal conductance changed in a unimodal function with peak values significantly higher under T1 than the others. The transpiration rate was significantly lower under T1 than under CK at all growth stages. In terms of crop yield, the pod and seed counts as well as the fresh pod weight per plant were significantly higher under T3 or CK than T1, but the15.90% greater than CK plot yield was significantly higher under T1 than the others. Nutritionally, the intercropping effectively raised the protein, starch, soluble sugar, and cellulose contents in the soybeans. Combining the performances of growth, yield, and quality of soybeans, a PCA analysis selected T1 to be the choice treatment. The intercropping with appropriate planting density significantly increased the activities of urease, catalase, and acid phosphatase in the soils under T1 and T3, but lowered the sucrase activity, over those of CK.

Conclusion When two rows of cassava were intercropped with two rows of soybean plants with a 0.10 m spacing between the rows, a superior overall performance of vegetable soybeans on growth, development, yield, and quality comparing to monocropping was observed.