ALMaSS: avoid missing growth curves for low/high nutrients

src/crop/almass.jl

@@ -600,13 +600,21 @@ get_dddegs(model::SimulationModel) = bounds(supply_temperature(model))
 
 # TODO efficiency: the fertiliser check is done in many places
 function growthcurve(cs::CropState)
-    curve = if fertiliser in cs.events
-        cs.croptype.highnutrientgrowth
-    else
-        cs.croptype.lownutrientgrowth
+    if ismissing(cs.croptype.lownutrientgrowth) && ismissing(cs.croptype.highnutrientgrowth)
+        error("No growth curves available for cropstate:\n $cs")
     end
+    if fertiliser in cs.events
+        curve = cs.croptype.highnutrientgrowth
         if ismissing(curve)
-        error("Growth curve is missing for cropstate:\n $cs")
+            @warn "fertiliser used, but highnutrient growth curve is missing. Using lownutrient growth curve."
+            curve = cs.croptype.lownutrientgrowth
+        end
+    else
+        curve = cs.croptype.lownutrientgrowth
+        if ismissing(curve)
+            # @warn "fertiliser not used, but lownutrient growth curve is missing. Using highnutrient growth curve."
+            curve = cs.croptype.highnutrientgrowth
+        end
     end
     return curve
 end