Reduced pests, improved grain quality and greater total income: benefits of intercropping rice with Pontederia cordata.

Background: Intercropping, which is growing two or more different crops in the same field simultaneously, is an effective traditional agricultural practice for productivity, resource utilization, and pest control. However, study on intercropping in paddy fields is limited. So in this study, field experiments of 2 years/four seasons (early and late seasons in 2016 and 2017) were conducted to examine the effects of rice-Pontederia cordata intercropping on rice plant growth, pest control, yield, income, and grain quality.

Results: We found rice-P. cordata intercropping significantly decreased the occurrence of rice diseases and pests, with a 22.0-45.9% reduction in sheath blight and a 33.8-34.4% reduction in leaf folders. The mean land equivalent ratio (LER) (1.09) result indicates that intercropping rice and P. cordata generated positive yield effects. In addition, due to the economic profit from the replacement stripe of P. cordata in the rice paddy field, intercropping rice with P. cordata could greatly enhance farmer income. The average total income of rice intercropped with P. cordata was 2.5-fold higher than that of rice monoculture. Furthermore, intercropping significantly improved grain quality compared with the rice monoculture. It significantly increased the milled rice rate and whole milled rice rate by 11.2% and 12.8%, respectively, but decreased the chalky rice rate by 30.9-39.8% and chalkiness degree by 32.2%.

Conclusions: We suggest that rice-P. cordata intercropping provides an environmentally effective way to control rice diseases and pests, results in higher overall productivity and total income, and improves grain quality. © 2021 Society of Chemical Industry.