(1) Ammonium nitrogen fertilizer mixed with alkaline substances will release ammonia and reduce fertilizer efficiency, so ammonium nitrogen fertilizer cannot be mixed with alkaline substances.

(2) The transformation of iron from Zeng Qing to copper means that iron reacts with copper sulfate solution to produce copper and ferrous sulfate, and the chemical equation is Fe+CuSO 4 =Cu+FeSO 4.

So the answer is: Fe+CuSO 4 = Cu+FeSO 4.

So the answer is: (1) Ammonium nitrogen fertilizer mixed with alkaline substances can release ammonia and reduce fertilizer efficiency; (2) Iron+copper sulfate = copper+ferrous sulfate.