Insights into the Physiological Characteristics of Cow-Pea - Maize in Intercropping System Exploring the Role of Mycorrhiza and Phosphorus Fertilizer

Abstract

Background and objectives: The use of biofertilizers, such as arbuscular mycorrhizal fungi (AMF), in intercropping systems has emerged as an innovative and sustainable approach to enhance crop growth and promote sustainable production. This study was conducted to investigate the effects of mycorrhizal biofertilizer and mineral phosphorus fertilizer on some physiological traits of cowpea (Vigna unguiculata) and maize (Zea mays) in an intercropping system using the replacement method.

Materials and methods: The experiment was carried out at two locations (the research farms of Shahrood University of Technology located in the Faculty of Agriculture and the Tarud research farm) as a factorial experiment in a completely randomized block design with three replications. The treatments included different cropping arrangements (pure cowpea, 75% cowpea + 25% maize, 50% cowpea + 50% maize, 25% cowpea + 75% maize, and pure maize) as the first factor; phosphorus fertilizer at three levels (0, 50, and 100 kg/ha) as the second factor; and mycorrhiza at two levels (application and no application) as the third factor.

Results: The results showed that the highest grain yield in cowpea plants (13.95 tons per hectare) and maize (6.2 tons per hectare) was observed in the treatment using mycorrhizal biofertilizer and 50 kilograms per hectare of phosphorus fertilizer in the Shahroud farm. The highest protein content, averaging 25.4%, in cowpea plants was achieved with the inoculation of mycorrhiza, 50 kilograms per hectare of phosphorus, and 100% cowpea planting in the Shahroud farm. All individual effects of the treatments significantly influenced the pigment content in cowpea. The highest chlorophyll content in cowpea (2.88 mg/g) and maize (3.8 mg/g) was observed in the 50% planting arrangement with the application of 50 kilograms per hectare phosphorus fertilizer. The highest carotenoid content in cowpea (3.56 mg/g) and maize (4.02 mg/g) was recorded at a 50% cowpea-maize planting ratio combined with 50 kilograms per hectare phosphorus application and the use of mycorrhiza in the Tarood region. The highest leaf area index in both plants increased by about 27% in the 50% planting arrangement compared to pure cropping. The highest land equivalent ratio, averaging 1.72, was obtained in the 75% maize and 25% cowpea planting treatment with 50 kilograms per hectare phosphorus fertilizer and mycorrhizal fungus application.

Conclusion: According to the results of this study, the mixed cropping system with the use of phosphorus fertilizer and mycorrhiza positively affected the physiological traits of cowpea and maize and can be recommended as a cropping model for agricultural producers.