Steel Products, Hardware, Handtools, Ship-Chanders, Oil Refinery Equipment, Building Materials, Pipes.

钢材、大小五金、手工具、船舶用品、油田设备，建筑材料、钢管。

youdao

Zigta summed up the reasons: Handtools were not available then.

UNESCO: Title

Even though many farmers recognized the potential of checkdams, it was not easy to build them because there were no handtools and it took some years before enough land could be created to grow enough cereals to make a substantial contribution to the family diet.

UNESCO: Title