diff --git a/modules/purchase_trade/service.py b/modules/purchase_trade/service.py
index ef7cbdc..ef736e1 100644
--- a/modules/purchase_trade/service.py
+++ b/modules/purchase_trade/service.py
@@ -49,7 +49,7 @@ class ContractFactory:
             parts = c.currency_unit.split("_")
             contract.currency = int(parts[0]) or 1
             contract.party = c.party
-            contract.crop = c.crop
+            contract.crop = cls._get_crop(c, base_contract)
             contract.tol_min = cls._get_tolerance(c, 'tol_min')
             contract.tol_max = cls._get_tolerance(c, 'tol_max')
             contract.payment_term = c.payment_term
@@ -197,6 +197,13 @@ class ContractFactory:
         value = getattr(party, field, None)
         return value if value is not None else Decimal(0)
 
+    @staticmethod
+    def _get_crop(contract_detail, base_contract):
+        crop = getattr(contract_detail, 'crop', None)
+        if crop:
+            return crop
+        return getattr(base_contract, 'crop', None)
+
     @staticmethod
     def _normalize_quantity(quantity):
         return abs(Decimal(str(quantity or 0))).quantize(Decimal('0.00001'))
diff --git a/modules/purchase_trade/tests/test_module.py b/modules/purchase_trade/tests/test_module.py
index 6587ecb..ef693d6 100644
--- a/modules/purchase_trade/tests/test_module.py
+++ b/modules/purchase_trade/tests/test_module.py
@@ -2776,6 +2776,16 @@ class PurchaseTradeTestCase(ModuleTestCase):
             ContractFactory._get_tolerance(contract_detail, 'tol_max'),
             Decimal('5'))
 
+    def test_contract_factory_uses_base_crop_when_line_is_empty(self):
+        'hidden crop falls back to the source contract crop'
+        crop = Mock()
+        contract_detail = Mock(crop=None)
+        base_contract = Mock(crop=crop)
+
+        self.assertEqual(
+            ContractFactory._get_crop(contract_detail, base_contract),
+            crop)
+
     def test_contract_factory_delivery_dates_fallback_to_period(self):
         'hidden delivery dates are still derived from delivery period'
         period = Mock(beg_date='2026-05-01', end_date='2026-05-31')