Effect of application methods of novel macro-micro combined fertilizers on improving agronomic traits and grain yield of white bean (Phaseolus vulgaris L.)

Introduction: Common bean, due to its high protein content and rich composition of micronutrients, plays a critical role in food security. Declining soil fertility and increasing environmental stresses necessitate a revision of plant nutrition strategies. The application of modern technologies such as nanofertilizers, along with the integration of organic and mineral nutrient sources, represents an effective and sustainable approach to improving crop productivity. Sustainable agriculture requires precise nutrient management, including the optimal selection of fertilizer type, application method, and timing, in order to enhance the performance of field crops such as common bean.
Materials and Methods: This study was conducted in spring 2023 at the Borujerd Agricultural Research Campus as a factorial experiment based on a randomized complete block design with three replications. The experiment aimed to evaluate the effects of two factors: (1) fertilizer application methods, including fertigation and foliar spraying, and 2) five types of combined fertilizers, namely Solopotash, Superhumic, Organo-macro-micro, ZFM Superplus (complete micro), and Amino ZFM (micro + amino acids), along with a control treatment, on the performance of white bean cultivar Almas. Treatments were applied at the flower bud emergence stage. The measured traits included plant height, plant dry weight, number of pods per plant, number of seeds per plant, 100-seed weight, grain yield, straw yield, and reproductive index (ratio of pod dry weight to total plant dry weight). Data were collected after full physiological maturity and subjected to statistical analysis.
Results: Straw yield per plant, plant dry weight, and pod weight per plant exhibited the highest coefficients of variation, indicating variability among treatments for these traits. Fertilizer application method had effects on plant dry weight, harvest index, and straw yield per plant. Fertilizer type influenced number of pods per plant, 100-seed weight, plant dry weight, pod weight per plant, number of seeds per plant, and straw yield per plant. The interaction effect of fertilizer application method × fertilizer type was significant for all studied traits except 100-seed weight and grain yield. The mean grain yield across treatments was 5060 kg/ha. Super Humic fertilizer produced the highest grain yield (5477 kg/ha), while the control showed the lowest yield (4448 kg/ha). The control under foliar application resulted in the lowest values for most traits, except harvest index, reproductive index, and 100-seed weight. In contrast, the combination of Organo Macro Micro fertilizer under fertigation produced the highest values for plant dry weight, plant height, pod weight, number of pods, number of seeds, grain yield, and straw yield. Correlation analysis revealed that grain yield was positively associated with all traits except harvest index and reproductive index. Strong and positive correlations were observed between grain yield and plant dry weight, pod weight, number of pods, number of seeds, and straw yield.
Conclusion: The results demonstrated the positive effects of Super Humic and Organo Macro Micro fertilizers on most growth and yield-related traits of common bean. Fertilizer type and application method significantly affected the majority of traits, and their interaction was also influential for most characteristics. Application of Organo Macro Micro via fertigation and Solopotash via foliar spraying improved key agronomic traits. Overall, the use of fertilizers increased grain yield compared to the control treatment. These findings highlight the importance of selecting appropriate fertilizer types and application methods to enhance the productivity of white bean under field conditions.