From 8e67f287ab76b916be46e1071077922af5dbae6a Mon Sep 17 00:00:00 2001
From: Sam Rabin <sam.rabin@gmail.com>
Date: Mon, 21 Aug 2023 17:46:54 -0600
Subject: [PATCH] max_tillage_depth is now a namelist parameter.

---
 bld/namelist_files/namelist_defaults_ctsm.xml   | 1 +
 bld/namelist_files/namelist_definition_ctsm.xml | 5 +++++
 src/soilbiogeochem/TillageMod.F90               | 8 ++++++--
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/bld/namelist_files/namelist_defaults_ctsm.xml b/bld/namelist_files/namelist_defaults_ctsm.xml
index f65dc47ce6..d0b29f48f4 100644
--- a/bld/namelist_files/namelist_defaults_ctsm.xml
+++ b/bld/namelist_files/namelist_defaults_ctsm.xml
@@ -2729,5 +2729,6 @@ use_crop=".true.">lnd/clm2/surfdata_map/ctsm5.1.dev052/landuse.timeseries_mpasa1
 
 <tillage_mode>off</tillage_mode>
 <use_original_tillage>.false.</use_original_tillage>
+<max_tillage_depth>0.32d00</max_tillage_depth>
 
 </namelist_defaults>
diff --git a/bld/namelist_files/namelist_definition_ctsm.xml b/bld/namelist_files/namelist_definition_ctsm.xml
index 6335953fcc..91e74e347e 100644
--- a/bld/namelist_files/namelist_definition_ctsm.xml
+++ b/bld/namelist_files/namelist_definition_ctsm.xml
@@ -2895,4 +2895,9 @@ Whether to till crop soil, and if so, with what intensity.
 Toggle to use original tillage logic, with bug for seasons crossing into a new calendar year
 </entry>
 
+<entry id="max_tillage_depth" type="real" category="physics"
+       group="tillage_inparm" valid_values="" value="0.32d00">
+Maximum depth to till soil (m).
+</entry>
+
 </namelist_definition>
diff --git a/src/soilbiogeochem/TillageMod.F90 b/src/soilbiogeochem/TillageMod.F90
index 2d4d61277d..35f487db80 100644
--- a/src/soilbiogeochem/TillageMod.F90
+++ b/src/soilbiogeochem/TillageMod.F90
@@ -30,7 +30,7 @@ module TillageMod
   logical  :: use_original_tillage ! Use get_tillage_multipliers_orig?
   real(r8), pointer :: tillage_mults_allphases(:,:) ! (ndecomp_pools, ntill_stages_max)
   integer, parameter :: ntill_stages_max = 3 ! How many different tillage phases are there? (Not including all-1 phases.)
-  real(r8), parameter :: max_tillage_depth = 0.32_r8 ! Maximum depth to till (m)
+  real(r8)           :: max_tillage_depth ! Maximum depth to till (m)
 
 !==============================================================================
 contains
@@ -53,11 +53,13 @@ subroutine readParams_namelist()
 
     namelist /tillage_inparm/    &
         tillage_mode,            &
-        use_original_tillage
+        use_original_tillage,    &
+        max_tillage_depth
 
     ! Default values
     tillage_mode = 'off'
     use_original_tillage = .false.
+    max_tillage_depth = 0.32_r8
 
     ! Read tillage namelist
     if (masterproc) then
@@ -75,12 +77,14 @@ subroutine readParams_namelist()
      endif
      call shr_mpi_bcast(tillage_mode, mpicom)
      call shr_mpi_bcast(use_original_tillage , mpicom)
+     call shr_mpi_bcast(max_tillage_depth, mpicom)
 
      if (masterproc) then
         write(iulog,*) ' '
         write(iulog,*) 'tillage settings:'
         write(iulog,*) '  tillage_mode  = ',tillage_mode
         write(iulog,*) '  use_original_tillage   = ',use_original_tillage
+        write(iulog,*) '  max_tillage_depth = ',max_tillage_depth
      endif
 
      ! Assign these