20 square meters are enough to obtain half a ton of rice. This is the rendition of a Chinese roof. In Wenling, Zhejiang Province, Tao Zhengrong at the end of July - the harvest time - obtained 500 kilograms of rice on the flat roof on the sixth floor of an apartment building. Covered with earth and with adequate irrigation (rice is born in water, say the Chinese; and dies in wine, say the Italian gourmets of risotto) even a roof can lend itself to intensive cultivation. According to Tao, the system has many advantages. It allows the use of cultivated land to be reduced, and the 'field on the roof' acts as an insulator and keeps the apartment below cool in the summer.
Price also comes into play. Rice prices are far from the paroxysmal peaks reached in 2008 (almost a thousand dollars a ton) but are slowly recovering, after having collapsed to 460 dollars in mid-2010. Today, at more than 600 dollars a ton, the price is almost double to what prevailed in mid-2007 ($313).
http://europe.chinadaily.com.cn/business/2012-08/01/content_15638729.htm
http://www.indexmundi.com/commodities/?commodity=rice&months=60
