Is fertilizer usually basic or acidic? I'm referring to fertilizers that contain nitrates, phosphates, and arsenic. Thanks for investigating this.
the fertilizers are not anything until in aqueous solution. Now in the ground, they can influnce the pH of the soil because of this.
1) What fertilizer contains arsenic? That would be most unwise.
2) nitrates are usually ammonium nitrates, which make the soil slightly more acidic. Calcium, magnesium, potassium and sodium nitrate make the soil more alkaline.
3) Sulfate and sulfur compounds make the soil more acidic.
4) Phosphates of potassium, sodium, calcium are very slightly alkaline, and ammonium phosphate has hardly any effect.
This assumes the soil was neutral before adding the fertizizer, which is seldom the case.