What two activities formed the basis of sumer's economy?

Sumerians was one of the first civilizations which were recorded in history due to their development of writing system. They flourished in the southern regions of Iraq in from 4000 CE. Sumerian economy was dependent on agriculture, they used to grow beans, lettuces and onions. The most cultivated crop was barley, which was used for the production of alcohol, bread and ale. Ale was important as it was offered as gift to the goddess Ninkasi. The land of Sumer was fertile as Tigris and Euphrates river brought fertile soil with the water. Trade was also important for their economy. Discoveries has shown that lapis lazuli was imported form Afghanistan, beads from Bahrain. The Indus valley seals has also been found in the area of Sumerian civilization.