Effects of tree planting geometry on Lentil nutritional quality, tree biomass, and economic returns in Melia dubia-based agroforestry system in Bundelkhand region of India

Pradyumna Prataprao Deshmukh¹Prabhat Tiwari^2*Manmohan Dobriyal²Ram Prakash Yadav²A K Handa³NARESH KUMAR³Dr ASHA RAM^3*INDER DEV⁴Dr.ASHOK YADAV³Hirdayesh Anuragi³A K Shukla⁵Varsha Shekhawat²Anuvarna K⁶Subhaprada Behera⁷

• ¹College of Forestry, Dr Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, India
• ²College of Horticulture and Forestry, Rani Lakshmi Bai Central Agricultural University, Jhansi, India
• ³ICAR - Central Agroforestry Research Institute, Jhansi, India
• ⁴Dr Y S Parmar University of Horticulture & Forestry, Nauni, India
• ⁵College of Agriculture, Rani Lakshmi Bai Central Agricultural University, Jhansi, India
• ⁶College of Forestry, Kerala Agricultural University, Vellanikkara, India
• ⁷ICFRE- Bamboo and Rattan Centre,, Aizawl, Mizoram, India

Low farm productivity, declining soil fertility, and climate vulnerability in the semi-arid Bundelkhand region necessitate sustainable land-use options such as agroforestry. Integrating Melia dubia into lentil-based cropping systems with optimized spacing can offer synergies between tree and crop components, improving resource-use efficiency, soil nutrient cycling, and economic returns. A field experiment was conducted during rabi season of 2023 at the Forestry Research Farm, RLBCAU, Jhansi, Uttar Pradesh. The study employed a split-plot design with three M. dubia spacings (5m × 5m, 5m × 4m, and 5m × 3m) along with sole cropping as main plots, and two Lens culinaris varieties (IPL 316 and L 4727) as sub-plots, replicated thrice. The findings indicated that tree spacing had a significant effect on the nutrient composition of lentil seeds, with the 5m × 4m spacing exhibiting the highest levels of protein (26.2%) and nitrogen (4.19%). Litterfall quantity reached its peak at a spacing of 5m × 3m (1.19 Mg ha⁻1), while nutrient concentrations exhibited significant monthly variation, with January and December demonstrating elevated nutrient release. PAR values decreased as tree density increased, impacting light availability for intercrops. The growth parameters and biomass accumulation of M. dubia were superior in intercropped conditions compared with sole trees. The 5m × 3m spacing exhibited the highest total biomass at 42.7 Mg ha-1, carbon storage at 21.3 Mg ha-1, and CO₂ sequestration at 78.3 Mg ha-1. The 5m × 3m spacing produced the highest net returns of $2783 ha-1 and a benefit-cost ratio of 2.92. IPL 316 variety of lentil demonstrated superior nutrient content and profitability compared to L 4727. The results indicated that a denser planting of M. dubia (5m × 3m) within agroforestry systems may increase productivity, enhance soil health via nutrient recycling, and elevate farm income, while also aiding in carbon mitigation in regions susceptible to climate change. This study is novel in assessing the impact of tree planting geometry on lentil quality, biomass production, and carbon sequestration in Melia dubia-based agroforestry systems under the semi-arid conditions.