Poplar based agroforestry system: Symmetry to maximize productivity and optimized nutrient acquisition in fodder sorghum–wheat rotation in semiarid region of Haryana

A field experiment was conducted during the kharif and rabi season of 2 years (2022–24) at the farm of agroforestry of Chaudhary Charan Singh Haryana Agricultural University, Hisar to evaluate the impact of different geometry of poplar on the yield and nutrient uptake of sorghum and wheat under poplar-based agroforestry sys- tems. The experiment was laid out in a randomized block design with 3 replications. The sorghum and wheat were sown as per the treatment comprising different spacing of poplar i.e. 3 m × 3 m, 4 m × 3 m, 5 m × 3 m, 6 m × 3 m, 7 m × 3 m, 8 m × 3 m and control (sole crops without trees). The results showed that sorghum (14.02 and 14.48 t/ ha) dry fodder yield and wheat grain yield (5.14 and 5.30 t/ha) and straw yield (7.17 and 7.28 t/ha) were maximum under control in 2022–23 and 2023–24, respectively. The yield of sorghum (13.62 and 15.54%), wheat grain (44.55 and 45.66%) and wheat straw (39.05 and 39.15%) were lower at 3 m × 3 m spacing compared to control in 2022–23 and 2023–24, respectively. The increase in spacing of poplar increase the yield of sorghum and wheat during both the years of study i.e. least yields at 3 m × 3 m popular spacing and highest under 8 m × 3 m spacing. However, popular based system yields of sorghum (8.01 and 8.42%), wheat grain (50.18 and 50.00%) and wheat straw (42.56 and 42.44%) were higher under 8 m × 3 m than 3 m × 3 m spacing in 2022–23 and 2023–24, respec- tively. Similar significant results were obtained in case of nutrient uptake N, P and K as yield of sorghum (143.9, 147.2, 18.3, 19.9 and 31.4, 29.2 kg/ha) and wheat in grain (81.8, 83.4, 13.7, 14.3 and 13.3 14.4 kg/ha) and straw (26.8, 28.4, 7.5, 8.7 and 64.2, 66.3 kg/ha) under 8 m × 3 m during 2022–23 and 2023–24, respectively. Hence, control has significant effect on the yield and nutrient uptake of crops than under agroforestry systems. While, among all the treatments of poplar-based alley crop systems, spacing of 8 × 3 m the significantly higher green for- age, and grain yields and nutrient uptake.