The Effect of Poultry Manure and Biofertilizers on Photosynthetic Pigments, Total Phenol, Yield Components and Grain Yield of Buckwheat (Fagopyrum esculentum Moench) in the Yasouj Region

Background and Objectives: In recent decades, the expansion of intensive agricultural systems and the excessive application of chemical nitrogen fertilizers have resulted in serious environmental problems such as nitrate leaching, groundwater contamination, and reduced nitrogen use efficiency.Therefore, developing sustainable cropping systems that improve nutrient uptake while reducing chemical fertilizer dependency has become a major challenge in modern agriculture.Intercropping systems, particularly those involving legume and non-legume species, have been widely recognized as effective strategies for enhancing resource use efficiency through complementary interactions in root systems, nutrient acquisition, and growth dynamics.Safflower (Carthamus tinctorius L.) is an important oilseed crop adapted to arid and semi-arid regions, valued for its high content of unsaturated fatty acids and its tolerance to drought and salinity.Mung bean (Vigna radiata L.), as a leguminous crop, plays a crucial role in biological nitrogen fixation and improving soil fertility.The integration of these two species in intercropping systems may enhance nutritional quality, improve nitrogen efficiency, and contribute to sustainable crop production.In addition, the use of biological nitrogen fertilizers such as Nitroxin, containing Azotobacter and Azospirillum, has attracted considerable attention due to their ability to fix atmospheric nitrogen, stimulate root growth, and increase nutrient availability.However, limited information is available regarding the combined effects of intercropping patterns and integrated application of chemical and biological nitrogen fertilizers on nutritional indices and nitrogen efficiency in safflower-mung bean systems.Therefore, the objective of this study was to evaluate the effects of different nitrogen fertilizer regimes and replacement intercropping patterns on nutrient concentration, yield components, oil yield, and nitrogen use efficiency of safflower and mung bean . Materials and Methods:This experiment was conducted during the 2020 growing season at the Kabutarabad Research Farm, Isfahan, Iran, using a split-plot arrangement based on a randomized complete block design with three replications.The main plot treatments consisted of three nitrogen fertilizer levels: no nitrogen application (control), integrated application of 50 kg N ha⁻¹ combined with Nitroxin biofertilizer, and 100 kg N ha⁻¹ as chemical fertilizer.Subplots included five cropping patterns: safflower monoculture, mung bean monoculture, and replacement intercropping ratios of 1:1, 2:1, and 1:2 (Safflower: mung bean).Seeds of both crops were inoculated with Nitroxin biofertilizer prior to planting.Nitrogen fertilizer was applied in split doses according to crop growth stages, while phosphorus fertilizer was uniformly applied based on soil test results.Nutritional elements including nitrogen, phosphorus, potassium, iron, and zinc were measured in both shoot and seed samples.Grain yield, oil percentage, and oil yield of safflower were determined at maturity.Nitrogen use efficiency indices, including Nitrogen Use Efficiency (NUE), Nitrogen Uptake Efficiency (NUPtE), and Nitrogen Harvest Index (NHI), were calculated using standard formulas.