Document Type : Research Paper

Authors

• Mohammad Reza Khaleghizadeh Dehkordi ¹
• Amir Aynehband ²
• Esfandiar Fateh ³

¹ Former student Department of Production Engineering and Plant Genetic,Agricultural Faculty, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

² Professor of Department of Production Engineering and Plant Genetic, Agricultural Faculty,Shahid Chamran University of Ahvaz, Ahvaz, Iran.

³ Associate Professor of Department of Production Engineering and Plant Genetic, Agricultural faculty, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

Abstract

Objective: Intercropping is a globally recognized strategy to improve resource-use efficiency and support food security, diversification of cropping systems, sustainable agricultural development, and labor efficiency on smallholder farms. A key aspect of intercropping is providing adequate nitrogen, which is essential for optimal plant growth. This study investigates the yield, yield components, and useful indicators of Dragon’s head when intercropped with castor at varying nitrogen levels.
Materials and Methods: Experimental design was split-plot randomized complete block design with three replications, conducted at the Research Farm of the Faculty of Agriculture, Shahid Chamran University, during the 2022–2023 growing year. The main plots were Nitrogen fertilizer amounts at three levels (0, 50, and 100 kg N ha⁻¹). The sub-plots were plant-density treatments with five levels (pure castor; castor + Dragon’s head at 20, 40, and 60 plants m⁻²; and pure Dragon’s head). The experiment used additive intercropping, with castor as the main crop at a constant density of 8 plants m⁻². The response variables were seed yield, biomass yield, yield components, land equivalent ratio (LER), and management indices such as MAI.
Results: Seed yield and biomass yield of Dragon’s head increased by 89.3% and 86.4%, respectively, under 100 kg N ha⁻¹ compared with the control; the highest seed yield and biomass yield were 892 kg ha⁻¹ and 2,128 kg ha⁻¹, respectively, in the 100 kg N ha⁻¹ treatment. Plant density effect: Among densities, the highest average seed yield and biomass yield of Dragon’s head occurred in pure cultivation, at 1,000 kg ha⁻¹ and 2,224 kg ha⁻¹, respectively. Relative to densities of 20, 40, and 60 plants m⁻², this represented increases of 121.8%, 71.1%, and 36.2% in seed yield and 113.7%, 70.2%, and 21.4% in biomass yield, respectively. Under 50 and 100 kg N ha⁻¹, intercropping yielded 2,316 and 3,026 kg ha⁻¹, respectively, representing increases of 57% and 105% over the zero-N control. LER increased with higher Dragon’s head density; the 40 and 60 plants m⁻² intercropping with castor showed 14% and 26% higher LER than the 20 plants m⁻² treatment (LER= 1.34 and 1.47, respectively). The highest LER (1.47) occurred in the 60 plants m⁻²+ castor treatment with 100 kg N ha⁻¹, indicating a 47% gain over pure cultivation. The maximum MAI observed was 942 in the 60 plants m⁻² density with 100 kg N ha⁻¹.
Conclusion: Intercropping Dragon’s head with castor, particularly at higher nitrogen levels and intermediate densities, significantly enhances total yield and land-use efficiency (LER). These results suggest that intercropping two relatively low-competition species can improve resource utilization and input efficiency in tropical and subtropical regions. Further studies are recommended to optimize density combinations, nitrogen management, and economic analyses for broader adoption.

Keywords

• Agronomic nitrogen efficiency
• Competition
• Grain yield
• Land Equivalent Ratio
• Monetary advantage index