Optimizing purslane cultivation through legume intercropping and crop rotation: a study on yield and rhizosphere bacterial communities

Mixed cropping systems such as intercropping and crop rotation have been proven to be sustainable agronomic tools that provide agro-ecological services and improve crop yield through soil physical, chemical and biological changes in the soil. In this study, we aimed to assess the impact of different mixed cropping systems on a crop well-adapted to high temperatures and low precipitation, like purslane (Portulaca oleracea L.) and to study the underlying microbial mechanisms involved.

A field experiment in a semiarid region of southern Spain was conducted to study the short-term effects of crop rotation (R) and intercropping (I) with peas or cowpeas, as well as a combination of both (IR) on purslane yield and soil quality parameters such as microbial enzymatic activity, bacterial diversity, microbial composition and functionality.

All the tested treatments increased purslane yield without significant differences among each other, but only the R and IR treatments affected the rhizospheric soil properties, through the increase of the enzymatic activities and the modification of the bacterial composition and functionality, and promoted organic matter degrading bacteria such as Bacillaceae, Myxococcaceae, and Planococcaceae and nitrogen-fixing bacteria, mainly Rhizobiaceae and Beijerinckiaceae.

This study demonstrates how sustainable cropping practices may improve the yield of a low maintenance crop like purslane under low-maintenance conditions by improving soil fertility in semiarid areas and also provides insights into the biological mechanisms responsible for the recorded effects.