Background and aims In Vietnam, Si accumulator crops like rice and maize crops are commonly rotated, but rice straw is often removed for animal feed. This study assessed whether rice straw mulch could improve soil available Si and maize growth. Methods A field experiment was conducted over three years in two fields with different soil Si levels. Four rice straw mulch levels (0, 3.5, 7, and 10.5 t ha⁻ 1 ) were applied during th...