So far, various methods have been presented for determining reference crop evapotranspiration in different parts of the world. The most popular and prestigious of them are probably the combined methods of Penman family, modified Blany-Criddle, Hargreaves - Samani and thornthwaite. Due to lack of lysimeter data in many parts of Iran, presenting an equation according to the regional condition wit...

Human food security requires the production of sufficient quantities of both high-quality protein and dietary energy. In a series of case-studies from New Zealand, we show that while production of food ingredients from crops on arable land can meet human dietary energy requirements effectively, requirements for high-quality protein are met more efficiently by animal production from such land. W...