Yield and Harvest Index of Grain Sorghum as Influenced by Agronomic Practices under Summer Rice Fallow in Southern Kerala, India

A study was undertaken at College of Agriculture, Vellayani, during January 2024 to May 2024 to standardize tillage, plant population and nutrient management practices for grain sorghum under summer rice fallows. The experiment was laid out in RCBD with 2 x 2 x 3 treatments, replicated thrice and the treatments comprised of combinations of two tillage methods (T1-zero tillage, T2-conventional tillage), two levels of spacing (P1 – 45 x 15 cm, P2- 60 x 15 cm) and three NPK levels (N1 – 45:25:25 NPK kg ha-1, N2 – 50:25:75 NPK kg ha-1 and N3 – 50:25:50 NPK kg ha-1). Among yield attributes, sorghum grown under zero tillage with a spacing 45 x 15 cm and a nutrient dose of 50:25:50 NPK kg ha-1 (T1P1N3) resulted in higher panicle length (22.70 cm), number of grains per panicle (1836.67) and grain weight per panicle (35.96 g). Higher grain yield (5.14 t ha-1) was obtained in treatment T1P1N3, which was found on par with T1P1N2 (4.96 t ha-1) and higher stover yield (8.10 t ha-1) was obtained in treatment T1P1N2, which was found on par with T1P1N3 (7.81 tha-1). Harvest index was higher in treatment T2P2N1 (0.43) and remained comparable with T1P1N3 (0.40) and T1P1N2 (0.39).