Question: which layer of soil is the most fertile
[{'answer': 'Topsoil', 'provenance': [{'wikipedia_id': '1251925', 'title': 'Soil fertility', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 7, 'bleu_score': 1.0, 'section': 'Section::::Soil depletion.\n'}]}, {'provenance': [{'wikipedia_id': '1251925', 'title': 'Soil fertility', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 445, 'bleu_score': 0.9712154609069981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16941409765265207673}, 'section': 'Section::::Soil depletion.\n'}]}]