Table 4. The parameters of diffusion equation in soils with the water-soluble Zn application (Zn) and along with straw (Straw+Zn) at the periods of 120–165 and 180–210 days.

Incubation periods (day)	Treatment	Parameters for diffusion equation
		A	6 $\sqrt{D_a/\pi }$	Da (day-1)	r	P value
120–165	Zn	0.0025	0.049	2.09 × 10−4	0.994	0.003
	Straw+Zn	0.0009	0.063	3.46 × 10−4	0.955	0.004
180–210	Zn	0.0038	0.034	1.01 × 10−4	0.975	0.023
	Straw+Zn	0.0015	0.062	3.35 × 10−4	0.989	0.008