Effect of Inoculation Techniques on Production of Potential of Soybean Varieties Intercropped in Spring Maize

Conventional cropping systems in Pakistan have been depleting soil fertility, while an increasing population pressure demands more efficient land-use strategies. To address these challenges, maize—soybean intercropping has emerged as a potential solution for enhancing soil fertility and increasing food production. Inoculation with Bradyrhizobium japonicum was also adopted, as he literature suggests it can boost nitrogen fixation in both soybeans and maize, playing a critical role in improving soil fertility and overall crop performance. In order to assess the performance of three soybean varieties, Ajmeri, Rawal-1, and NARC-2, when intercropped with maize, this study was carried out over the course of two consecutive growing seasons (spring 2018 and 2019) at the Agronomic Research Area, University of Agriculture Faisalabad, using three different inoculation techniques: no inoculation, soil inoculation, and seed inoculation with Bradyrhizobium japonicum. In this experiment, three replications of a Randomized Complete Block Design (RCBD) were used to intercrop different soybean cultivars with maize in double-row strips. Soil-inoculated Rawal-1 soybeans consistently produced the maximum 1000-grain weight and maize grain yield throughout the course of the two seasons, with values rising from 287.33 g and 6.82 t ha⁻¹ in 2018 to 295.00 g and 7.10 t ha⁻¹ in 2019. On the other hand, untreated Ajmeri soybeans showed the lowest 1000-grain weight and grain yield. Nevertheless, they did show some improvement from 235.00 g and 4.10 t ha⁻¹ in 2018 to 240.00 g and 4.30 t ha⁻¹ in 2019. In soybeans, seed-inoculated Rawal-1 had the highest number of pods per plant, 1000-seed weight, and grain yield; in 2018, it was measured at 125.74 pods, 147.07 g, and 1.23 t ha⁻¹; and in 2019, it increased to 130.00 pods, 150.00 g, and 1.30 t ha⁻¹. Untreated Ajmeri soybeans consistently yielded the lowest values for these parameters: in 2018, 76.99 pods, 87.16 g, and 0.53 t ha⁻¹; in 2019, 80.00 pods, 90.00 g, and 0.55 t ha⁻¹. Pods per plant, 1000-seed weight, and grain yield increased significantly. In conclusion, intercropping maize with Rawal-1 soybeans using both soil and seed inoculation proved to be an economical and sustainable strategy under Faisalabad's agro-ecological conditions across both growing seasons.