Amaggi, the Brazilian soybean group owned by entrepreneur-turned-politician Blairo Maggi, is in advanced talks to buy the local unit of Argentina’s El Tejar to capitalize on increasing crop demand from China, people with knowledge of the matter said. The proposed acquisition of O Telhar encompasses all assets in Brazil, including about 70,000 hectares (173,000 acres) of farming land, cotton mills, warehouses and machinery, one of the people said, asking to not be identified as talks are private. Amaggi declined…