diff --git a/src/Root_properties.m b/src/Root_properties.m
index 2dbf3834..6a0ad3dd 100644
--- a/src/Root_properties.m
+++ b/src/Root_properties.m
@@ -6,12 +6,16 @@
 %{
     This function is used to calculate the dynamic growth of root
     This part can refer to Wang et al. (2021) "Intergrated modelling of photosynthesis and transfer of energy, mass, and momentum in the SPAC system"
+    Input:
+        Rl: root length index at last step
+        Ac: the net assimilation of canopy
+        rroot: radius of root
+    Output:
+        Rl: root length index at current step
 %}
 
 function [Rl] = Root_properties(Rl, Ac, rroot, frac, bbx, KT, DeltZ, sfactor, LAI_msr)
-    %INPUTS
-    %global DeltZ sfactor LAI_msr
-
+    % calculate the fraction of root
     fr = calculateRootfraction(KT);
 
     DeltZ0 = DeltZ' / 100;