Effect of maize-legume intercropping on maize physio-agronomic parameters and beneficial insect abundance

Authors: FILS PIERRE, JACQUES - National Technological Institute Of Mexico; MORENO, LUIS LATOURNERI - National Technological Institute Of Mexico; GARRUNA, RENE - National Technological Institute Of Mexico; JACOBSEN, KRISTA - University Of Kentucky; US-SANTAMARIA, ROBERTH - Centro De Investigacion Cientifica Y De Educacion Superior De Ensenada; RUIZ-SANCHEZ, ESAU - National Technological Institute Of Mexico

Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2022
Publication Date: 9/29/2022
Citation: Fils Pierre, J., Moreno, L.E., Garruna, R., Jacobsen, K.L., Laboski, C.A., Us-Santamaria, R., Ruiz-Sanchez, E. 2022. Effect of maize-legume intercropping on maize physio-agronomic parameters and beneficial insect abundance. Sustainability. 1-15. https://doi.org/10.3390/su141912385.
DOI: https://doi.org/10.3390/su141912385

Interpretive Summary: In the Yucatan region of Mexico, maize (Zea mays L.) yields remain low, despite consistent fertilizer and pesticide inputs in traditional intercropping systems. There is little information about how intercropping legumes with maize affects phytosynthetic capacity and insect (both beneficial and pest) populations. A field experiment was carried out in the Yucatan Peninsula in 2021 to assess the impact of maize-legume intercropping systems on maize yield, physiological characteristics as evaluated by gas exchange measurements, and the abundance of beneficial insects in traditional and novel maize intercropping systems. The maize/cowpea intercrop increased the photosynthesis rate by 12.9% and 9.84% and the transpiration rate by 6.5% and 8.5% compared to the maize/crotalaria and maize, respectively. Both intercropping treatments attracted more beneficial insects than maize alone. Maize/Cowpea and maize/crotalaria increase grain yield by 24,48 % and 31,88 %, respectively, compard to maize alone. However, only the maize/crotalaria intercropping resulted in yields that were statistical greater than maize alone. Maize/Cowpea intercropping system represents a sustainable planting alternative for promoting maize grain yield and also promoting edible legume production within the system.

Technical Abstract: In developing countries, intercropping is commonly used to boost land productivity and agricultural benefits. However, in the Yucatan region of Mexico, maize (Zea mays L.) yields remain low, despite consistent fertilizer and pesticide inputs in traditional intercropping systems. Furthermore, little is known about the photosynthetic mechanisms that occur when maize plants interact with legumes, as well as there is a lack of understanding of how intercropping systems affect other organisms in the system, such as beneficial and insect pest population dynamics. A field experiment was carried out in the Yucatan Peninsula in 2021 to assess the impact of maize-legume intercropping systems on maize yield, physiological characteristics as evaluated by gas exchange measurements, and the abundance of beneficial insects in traditional and novel maize intercropping systems. The experiment was carried out with a randomized complete block design with three replicates. Treatments included maize intercropped with a novel legume, crotalaria (Crotalaria juncea L.), maize intercropped with a traditional legume, cowpea (Vigna unguiculata (L.) Walp.), and sole as a control. Significant differences in plant height were shown at growth stages (45 DAS and 60 DAS). No differences were observed in stem diameter, leaf area index, or chlorophyll content. The maize/cowpea intercrop increased the photosynthesis rate by 12.9% and 9.84% in the Maize/Crotalaria and sole maize respectively (p < 0.001) and transpiration rate by 6.5% and 8.5% maize intercropped with crotalaria and sole maize treatments respectively (p < 0.001) of maize plants. No significant effects on stomatal conductance or water use efficiency were observed, but there was a reduced carbon intercellular rate by 9.74% and 9.15 when compared to the Maize/Crotalaria and the sole maize treatments respectively. Overall, intercropping treatments attracted more beneficial insects than sole maize. For predators, the families that stood out were Coccinelidae, Formicidae, Araneidae, Thomisidae, Syrphidae, Chrysomelidae, Oxypidae, Vespidae, Reduviidae, Carabidae, Asilidae, Salthicidae, Dolichopodidae, while among parasitoids, the most frequent families were Eurytomydae, Braconidae, Tachinidae, Pteromalidae, Scelionidae, and Figitidae. In comparison to the Maize/Cowpea and Maize/Crotalaria treatments, the sole maize treatment resulted in a grain yield increase of 24,48 % and 31,88 %, respectively. However, sole maize was not statistically different to that of maize/cowpea intercropping. In conclusion, our findings suggest that maize/cowpea intercropping could be a viable alternative to sole maize cropping systems for enhancing maize yield and the abundance of beneficial insects without increasing interspecific competition with the maize crop. Therefore, Maize/Cowpea intercropping system represents a sustainable planting alternative for promoting maize grain yield and also promoting edible legume production within the system. Furthermore, the outcomes of this study can serve as a theoretical framework for increasing maize-legume intercropping profitability under growing conditions on the Yucatan Peninsula.