Silicon-Supplemented Balanced Fertilization Improves Growth and Yield of Chia (Salvia hispanica L.) under Old Brahmaputra Floodplain Soils in Bangladesh

Abstract

Chia (Salvia hispanica L.) has emerged as a high-value crop in Bangladesh. Its productivity is highly dependent on balanced macro- and micronutrient management. To assess the combined effects of N, P, K, Zn, B, and Si on the productivity of chia, a field experiment was conducted in the Old Brahmaputra Floodplain area. The experiment comprised eight treatments viz. N–P–K–Zn–B @ 90–60–75–4–2 kg/ha (F₁, recommended dose), F₁ + 13.26 kg/ha Si (F₂), N–P–K–Zn–B @ 90–120–75–4–2 kg/ha (F₃), F₃ + 13.26 kg/ha Si (F₄), N–P–K–Zn–B @ 90–60–150–4–2 kg/ha (F₅), F₅ + 13.26 kg/ha Si (F₆), N–P–K–Zn–B @ 90–120–150–4–2 kg/ha (F₇), and F₇ + 13.26 kg/ha Si (F₈). The experiment was conducted in a randomized complete block design (RCBD) with three replications. Fertilizer treatments significantly influenced plant height and branches plant^-1. The tallest plants (126.54 cm) and the highest number of branches plant⁻¹ (13) were recorded under F₆. Although inflorescence number and length were not significantly affected, seeds inflorescence^-1 and thousand-seed weight responded markedly to nutrient combinations. The highest seeds inflorescence^-1 (474) and seed yield (1.09 t ha^-1) were obtained from F₂, while elevated P without Si resulted in the lowest yield (0.68 t ha^-1) from F₃. Stover yield was maximized under the recommended N–P–K–Zn–B dose, whereas biological yield increased under K- and Si-enriched treatment. Harvest index followed a similar trend, indicating improved assimilate partitioning under Si-enriched balanced fertilization. Therefore, N–P–K–Zn–B @ 90–60–75–4–2 kg/ha, respectively supplemented with Si @ 13.26 kg/ha can be considered an effective nutrient management approach for improving chia productivity under Old Brahmaputra Floodplain soils.