完璧に動作しています。

テスト	結果
確定取消 API	✅ is_confirmed: false, confirmed_at: null
USE トランザクション削除	✅ current_stock が 27.5→32 に復帰
引当再作成	✅ reserved_stock = 5.000 に復帰
追加した変更:

stock_service.py:81-93 — unconfirm_spreading(): USE削除→確定フラグリセット→引当再作成
fertilizer/views.py — unconfirm アクション（POST /api/fertilizer/plans/{id}/unconfirm/）
fertilizer/page.tsx — 一覧に「確定取消」ボタン（確定済み計画のみ表示）
FertilizerEditPage.tsx — 編集画面ヘッダーに「確定取消」ボタン + 在庫情報再取得

backend/apps/fertilizer/migrations/0006_fertilizationplan_confirmation.py

@@ -0,0 +1,21 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fertilizer', '0005_fertilizer_material'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='fertilizationplan',
+            name='is_confirmed',
+            field=models.BooleanField(default=False, verbose_name='散布確定済み'),
+        ),
+        migrations.AddField(
+            model_name='fertilizationplan',
+            name='confirmed_at',
+            field=models.DateTimeField(blank=True, null=True, verbose_name='散布確定日時'),
+        ),
+    ]

backend/apps/fertilizer/models.py

@@ -43,6 +43,8 @@ class FertilizationPlan(models.Model):
         related_name='fertilization_plans', verbose_name='品種'
     )
     calc_settings = models.JSONField(default=list, blank=True, verbose_name='計算設定')
+    is_confirmed = models.BooleanField(default=False, verbose_name='散布確定済み')
+    confirmed_at = models.DateTimeField(null=True, blank=True, verbose_name='散布確定日時')
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
 

backend/apps/fertilizer/serializers.py

@@ -3,9 +3,25 @@ from .models import Fertilizer, FertilizationPlan, FertilizationEntry, Distribut
 
 
 class FertilizerSerializer(serializers.ModelSerializer):
+    material_id = serializers.SerializerMethodField()
+
     class Meta:
         model = Fertilizer
-        fields = '__all__'
+        fields = [
+            'id',
+            'name',
+            'maker',
+            'capacity_kg',
+            'nitrogen_pct',
+            'phosphorus_pct',
+            'potassium_pct',
+            'notes',
+            'material',
+            'material_id',
+        ]
+
+    def get_material_id(self, obj):
+        return obj.material_id
 
 
 class FertilizationEntrySerializer(serializers.ModelSerializer):
@@ -26,12 +42,15 @@ class FertilizationPlanSerializer(serializers.ModelSerializer):
     entries = FertilizationEntrySerializer(many=True, read_only=True)
     field_count = serializers.SerializerMethodField()
     fertilizer_count = serializers.SerializerMethodField()
+    is_confirmed = serializers.BooleanField(read_only=True)
+    confirmed_at = serializers.DateTimeField(read_only=True)
 
     class Meta:
         model = FertilizationPlan
         fields = [
             'id', 'name', 'year', 'variety', 'variety_name', 'crop_name',
-            'calc_settings', 'entries', 'field_count', 'fertilizer_count', 'created_at', 'updated_at'
+            'calc_settings', 'entries', 'field_count', 'fertilizer_count',
+            'is_confirmed', 'confirmed_at', 'created_at', 'updated_at'
         ]
 
     def get_variety_name(self, obj):

backend/apps/fertilizer/views.py

@@ -4,12 +4,19 @@ from django.http import HttpResponse
 from django.template.loader import render_to_string
 from rest_framework import viewsets, status
 from rest_framework.decorators import action
+from rest_framework.exceptions import ValidationError
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
 from rest_framework.views import APIView
 from weasyprint import HTML
 
 from apps.fields.models import Field
+from apps.materials.stock_service import (
+    confirm_spreading as confirm_spreading_service,
+    create_reserves_for_plan,
+    delete_reserves_for_plan,
+    unconfirm_spreading,
+)
 from apps.plans.models import Plan, Variety
 from .models import Fertilizer, FertilizationPlan, DistributionPlan
 from .serializers import (
@@ -33,7 +40,7 @@ class FertilizationPlanViewSet(viewsets.ModelViewSet):
 
     def get_queryset(self):
         qs = FertilizationPlan.objects.select_related('variety', 'variety__crop').prefetch_related(
-            'entries', 'entries__field', 'entries__fertilizer'
+            'entries', 'entries__field', 'entries__fertilizer', 'entries__fertilizer__material'
         )
         year = self.request.query_params.get('year')
         if year:
@@ -45,6 +52,20 @@ class FertilizationPlanViewSet(viewsets.ModelViewSet):
             return FertilizationPlanWriteSerializer
         return FertilizationPlanSerializer
 
+    def perform_create(self, serializer):
+        instance = serializer.save()
+        create_reserves_for_plan(instance)
+
+    def perform_update(self, serializer):
+        if serializer.instance.is_confirmed:
+            raise ValidationError({'detail': '確定済みの施肥計画は編集できません。'})
+        instance = serializer.save()
+        create_reserves_for_plan(instance)
+
+    def perform_destroy(self, instance):
+        delete_reserves_for_plan(instance)
+        instance.delete()
+
     @action(detail=True, methods=['get'])
     def pdf(self, request, pk=None):
         plan = self.get_object()
@@ -99,6 +120,67 @@ class FertilizationPlanViewSet(viewsets.ModelViewSet):
         response['Content-Disposition'] = f'attachment; filename="fertilization_{plan.year}_{plan.id}.pdf"'
         return response
 
+    @action(detail=True, methods=['post'], url_path='confirm_spreading')
+    def confirm_spreading(self, request, pk=None):
+        plan = self.get_object()
+
+        if plan.is_confirmed:
+            return Response(
+                {'detail': 'この計画は既に散布確定済みです。'},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
+
+        entries_data = request.data.get('entries', [])
+        if not entries_data:
+            return Response(
+                {'detail': '実績データが空です。'},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
+
+        actual_entries = []
+        for entry in entries_data:
+            field_id = entry.get('field_id')
+            fertilizer_id = entry.get('fertilizer_id')
+            if not field_id or not fertilizer_id:
+                return Response(
+                    {'detail': 'field_id と fertilizer_id が必要です。'},
+                    status=status.HTTP_400_BAD_REQUEST,
+                )
+            try:
+                actual_bags = Decimal(str(entry.get('actual_bags', 0)))
+            except InvalidOperation:
+                return Response(
+                    {'detail': 'actual_bags は数値で指定してください。'},
+                    status=status.HTTP_400_BAD_REQUEST,
+                )
+            actual_entries.append(
+                {
+                    'field_id': field_id,
+                    'fertilizer_id': fertilizer_id,
+                    'actual_bags': actual_bags,
+                }
+            )
+
+        confirm_spreading_service(plan, actual_entries)
+        plan.refresh_from_db()
+        serializer = self.get_serializer(plan)
+        return Response(serializer.data)
+
+    @action(detail=True, methods=['post'], url_path='unconfirm')
+    def unconfirm(self, request, pk=None):
+        plan = self.get_object()
+
+        if not plan.is_confirmed:
+            return Response(
+                {'detail': 'この計画はまだ確定されていません。'},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
+
+        unconfirm_spreading(plan)
+        plan.refresh_from_db()
+        serializer = self.get_serializer(plan)
+        return Response(serializer.data)
+
 
 class CandidateFieldsView(APIView):
     """作付け計画から圃場候補を返す"""