Determination of crop coefficient of Cercis siliquastrum L. in different soil textures and irrigation levels

Not only urban development and consequently the need to increase the green space, but also the shortage in water resources, the need for optimal allocation of water to different demands, and limited information of urban green space make a necessary to determine the crop coefficient and water requirements of green space species. The factorial experiment aimed to investigate the evapotranspiration (ETc) and crop coefficient (Kc) of Cercis siliquastrum L. with two factors of soil texture (clay loam and sandy loam) and drought stress (0.3, 0.5, and 0.7 of MAD) based on a completely randomized blocks design (CRBD) with 10 replications in the climatic conditions of Karaj during 2019-2020. Our findings indicated that 10-day ETc under 0.3, 0.5, and 0.7 MAD were 15.56, 14.86 and 14.24 mm in clay loam and 21.57, 19.02 and 18.06 mm in sandy loam soil, respectively. The ETc increased with progressing in drought stress (from 0.7 to 0.3 MAD) in both clay loam and sandy loam soils. The total net water requirements of Cercis siliquastrum L. in clay loam soil under 0.3, 0.5 and 0.7 MAD were 45.15, 388.58 and 381.41 mm, respectively, and it was recorded as 353.02, 317.59 and 290.54 mm, respectively, in sandy loam soil. The mean Kc of Cercis siliquastrum L. during the growing period in clay loam soil under 0.3, 0.5, and 0.7 MAD were obtained to be 0.36, 0.32, and 0.31, respectively. In sandy loam soils, this value was determined as 0.27, 0.26, and 0.24 under 0.3, 0.5, and 0.7 MAD, respectively.