Evaluation of Efficiency in Fenugreek-Black Cumin Intercropping Under Application of Growth-Promoting Bacteria and Nitrogen Fertilizer Amounts

This field experiment is arranged in a split-split plot based on a randomized complete block design replicated three times during the growing season of 2019 at Shahid Bahonar University of Kerman, Iran. Nitrogen fertilizer rates (no-application, 50%, and 100%; 0, 75, and 150 kg urea per hectare) serve as the main factor, inoculation with growth-promoting bacteria (non-inoculation and inoculation with Pantoea agglomerans) as sub factor, and different fenugreek and black cumin cropping systems (100:0, 75:25, 50:50, 25:75, and 0:100) as sub-sub factor. Biomass, yield, nitrogen use efficiency (NUE), agronomy efficiency of fertilizer (AEF), and land equivalent ratio (LER) are determined. The results show that the highest biomass and NUE of studied plants are obtained from 100% fertilization and bacteria inoculation in monoculture. The total LER is also significantly improved by fertilization (between 28-51%) and bacteria inoculation (23%), showing a higher advantageous in 25:75 and 50:50 cropping patterns with LER values of 1.732 and 1.688, respectively. In contrast, reducing 50% of fertilization under bacterial inoculation increases the AEF, especially in fenugreek monoculture. Fertilization increasing the total NUE and bacteria inoculation results in the highest NUE, particularly at increased ratios of fenugreek. Fenugreek:black cumin cropping ratio of 25:75 under 100% N fertilization and bacteria inoculation with LER ≈ 2 has been the best treatment combination for gaining maximum overall productivity. Fertilization with 50% N inoculated with bacteria in the same cropping pattern can be recommended when fertilizer application is restricted. The present research suggests that the integrated application of bacteria and fertilization can enhance the overall efficiency of intercropping.