Estimation of water requirements of Robinia pseudoacania and Ailanthus altissima Mill For afforestation under different water stresses (Case study: Robat Karim town)

Since the creation of green space depends on the availability of water and dedicated water for irrigation of urban green space, green belts and afforestation in arid and semi-arid climates. Water availability has great value and should be used optimally with high efficiency. For this reason, in order to save water, planting species that need less water and at the same time have optimal growth efficiency has always been as an executive policy. The aim of current study is to estimate the water requirement of tree species in the field and greenhouse under different water stresses in Robat Karim town of Tehran province. This research has been done in both space of greenhouse and field by saplings of Robinia pseudoacania and Ailanthus altissima Mill and it was done in a completely random design in the field and greenhouse. This research has two stages and each stage consists of several phases. In the first stage, respectively soil field capacity, determining of MAD, determining water requirement of saplings through evapotranspiration were examined and in fact, by determining the water requirement of saplings, the irrigation cycle was determined. In the second stage, the studied saplings were subjected to water stresses 2, 4 and 6 days after reaching MAD and at each period, the physical characteristics data of the saplings were collected. Generally, the results of this study have shown that Robinia pseudoacania has a higher water requirement and more irrigation cycles in the field and greenhouse than Ailanthus altissima Mill.