Update

app/Http/Requestes/RiceShrimpFlowStoreRequest.php

@@ -17,7 +17,7 @@ class RiceShrimpFlowStoreRequest extends FormRequest
         return [
             'year' => ['required', 'int'],
             'quarter' => ['required', 'int', Rule::in([1, 2, 3, 4])],
-            'area' => ['required', 'string'],
+            'area' => ['required', 'int'],
             'sales' => ['required', 'int', 'min:0'],
         ];
     }

app/Http/Requestes/RiceShrimpFlowUpdateRequest.php

@@ -14,7 +14,7 @@ class RiceShrimpFlowUpdateRequest extends FormRequest
     public function rules()
     {
         return [
-            'area' => ['filled', 'string'],
+            'area' => ['filled', 'int'],
             'sales' => ['filled', 'int', 'min:0'],
         ];
     }