短語詞組短語agricultural melioration 農(nóng)業(yè)土壤改良soil melioration 土壤改良land melioration 土地改良idioplasm melioration 種質(zhì)改良Melioration Theory 改善理論channel melioration 渠道改進coefficient melioration 系數(shù)改進melioration measurement 改良措施 返回 melioration