As the Diverfarming website explains, intercropping involves growing two or more species in the same plot at the same time. The idea is not only to increase crop productivity, but to improve soil quality and enjoy other advantages, such as reduced pest and disease problems and a greater diversity of microbes and beneficial insects.

Intercropping, sometimes known as milpa, has a long history in Mesoamerica, typically including maize, beans and squash. In the Diverfarming experiment, researchers sought an intercrop for melons, which are the main summer export crop in the Murcia region.

The Diverfarming website reports: “To deal with the issue of soil and water degradation caused by the excessive use of pesticides and fertilisers in intensive melon cropping, researchers from the CEBAS – CSIC, the Universidad Politécnica de Cartagena (UPCT) and the University of Murcia have analysed the soil nutrients, their physico-chemical properties, the enzyme activity and the soil microbial community (by means of high performance sequencing) of an intercrop of cowpea and melon using ecological farming practices, different growing patterns, and 30% less fertilisation than is usually used in the monocrop.

“The results have shown a significant increase in total nitrogen levels, available phosphorus, and total organic carbon, as well as in the melon yield in the first year of intercropping, irrespective of the intercropping patterns followed.”

Researchers also identified changes in the bacterial community structure “which correlated with an increase in the concentrations of total nitrogen and phosphorus in the soil and in the melon crop yield”. Additionally, they noted a greater abundance of beneficial microorganisms.

They conclude: “Thus, in the first year the combination of cowpea with melon gave as its result a sustainable growing system that used fewer external inputs and increased the melon yield, as well as improving the soil quality. Taking into account that from the first year, the use of diversified growing systems provides a regular supply of food and income, longer term analysis of these intercropping systems will be required. This should reinforce the findings on the positive interaction between the cowpea microbiota and melon and their functions and to study in greater detail which intercropping pattern would be the most beneficial for the grower.”

For more information:

• Read more on the Diverfarming website here
• See the full paper: Cuartero, J., Pascual, J.A., Vivo, J., Özbolat, O., Sánchez-Navarro, V., Egea-Cortines, M., Zornoza, R., Martinez-Mena, M., Garcia, E., Ros, M., (2022) A first-year melon/cowpea intercropping system improves soil nutrients and changes the soil microbial community, Agriculture, Ecosystems & Environment, Vol. 328, 107856, ISSN 0167-8809, https://doi.org/10.1016/j.agee.2022.107856