diff --git a/src/gbm/gbtree.cc b/src/gbm/gbtree.cc
index 16609619c..34915d53e 100644
--- a/src/gbm/gbtree.cc
+++ b/src/gbm/gbtree.cc
@@ -996,8 +996,9 @@ class Dart : public GBTree {
   }
 
   // set normalization factors
-  inline size_t NormalizeTrees(size_t size_new_trees) {
-    float lr = 1.0 * dparam_.learning_rate / size_new_trees;
+  std::size_t NormalizeTrees(size_t size_new_trees) {
+    CHECK(tree_param_.GetInitialised());
+    float lr = 1.0 * tree_param_.learning_rate / size_new_trees;
     size_t num_drop = idx_drop_.size();
     if (num_drop == 0) {
       for (size_t i = 0; i < size_new_trees; ++i) {
diff --git a/src/gbm/gbtree.h b/src/gbm/gbtree.h
index 10e6c415f..eb99822f3 100644
--- a/src/gbm/gbtree.h
+++ b/src/gbm/gbtree.h
@@ -111,8 +111,6 @@ struct DartTrainParam : public XGBoostParameter<DartTrainParam> {
   bool one_drop;
   /*! \brief probability of skipping the dropout during an iteration */
   float skip_drop;
-  /*! \brief learning step size for a time */
-  float learning_rate;
   // declare parameters
   DMLC_DECLARE_PARAMETER(DartTrainParam) {
     DMLC_DECLARE_FIELD(sample_type)
@@ -136,11 +134,6 @@ struct DartTrainParam : public XGBoostParameter<DartTrainParam> {
         .set_range(0.0f, 1.0f)
         .set_default(0.0f)
         .describe("Probability of skipping the dropout during a boosting iteration.");
-    DMLC_DECLARE_FIELD(learning_rate)
-        .set_lower_bound(0.0f)
-        .set_default(0.3f)
-        .describe("Learning rate(step size) of update.");
-    DMLC_DECLARE_ALIAS(learning_rate, eta);
   }
 };