Abstract: Through series of experiments with 4 iterations, with statistical processing of reliability, we see: Toxicity in the environment in acid sulfate soil has very large and complex, this variation depends: 1-To dry out, the amount of toxins increases, which can cause rice death. To submerge the amount of toxins clearly decreased. The role is to flood rather than liming without washing alum. 2- Acid water with pH = 3.8 (A13 + <480ppm) can be used to irrigate rice. If it is contaminated with acid water with pH <2.9, the soil will become acidification after 5-6 days.