How can I get fixed output in ode45

I only get 20 output with this code. How can I get fixed output?

clc
clear
Cmeasured = [0	101	160	239	645	766	766	827	1122	1158	1591	2181	2566	2654	2944	3163	3406	3751	3982	3982	4425	4621	4746	4809	5240	5479	5604	5761	5885	5885	515418	515511	515511	516128	516203	516203	516252	516554	516991	517579	517969	518040	518040	518315	518566	518818	519166	519426	519426	519864	519969	520125	520125	520275	520441	520584	520723	520793	520793	536458	536540	536540	1562585	1562585	1562861	1561528	1561753	1562065	1562947	1562947
];
tspan = 0:1:1562947;
sol = ode45(@mt ,tspan ,[8.850 2] );
plot(sol.x',sol.y')
cagdas = sol.y';

function y = mt(t, C)
Cin = 1.800;
Kd = 0.00125/(24*60); %1/min
KL	= 0.29/(24*60); %m/day
kl = 0.29/(24*60); %1/min
hw = 74.75;	%depth of lake m
A = 18500*10^6;	%Area m^2
L = 311*10^3;	%Length m
Qin = 6400*60;	%Inflow(niagara) m^3/min
Qout = 6700*60;	%Outflow m^3/min
hs = 0.07; %depth of sediment that have DCB concentration m
Vw = hw*A; %Volume of water body m^3
Vs = hs*A*10^6; %Volume of sediment m^3
wt = 106/(365*24*60);
y(1) = ( Qin*Cin -(Qout)*C(1)- KL*A*C(1)-Kd*Vw*C(1)-kl*A*C(1))/Vw;
y(2) = (KL*A*C(1)-KL*A*C(2) - Kd*Vs*C(2))/Vs;
y=y(:);
end

Answer 1

[Cris LaPierre]

Use the following calling syntax instead. This results in a value in y corresponding to each time point specified in tspan.

tspan = 0:1:1562947;
[t,y] = ode45(@mt ,tspan ,[8.850 2] );
plot(t,y(:,1),t,y(:,2))