Effects of irrigation amount on morphological characteristics and water use of Jatropha curcas.

Jatropha curcas is the most promising energy tree, and soil moisture is the key factor which affects the seedling quality and water use efficiency of J. curcas. With aims to evaluate the effect of different irrigation amount on growth, morphological characteristics and water use of J. curcas, a pot experiment was conducted with four irrigation amounts, i. e. , W₁:472. 49 mm, W₂: 228. 79 mm, W₃:154. 18 mm and W₄:106. 93 mm, respectively. Compared with W₁ treatment, the leaf area and stem cross-section area of base significantly decreased in W₂, W₃ and W₄ treatments, but Huber value significantly increased, which could improve the efficiency of water transfer from root to shoot, thus enhance the capability of resistance to drought stress. Compared with W₁ treatment, the healthy index of J. curcas seedlings decreased slightly in W₂ treatment but significantly decreased in W₃ and W₄ treatments. Hence, the irrigation amount from 228. 79 to 472. 49 mm was beneficial to increase the healthy index of J. curcas seedlings. Compared with W₁ treatment, irrigation water was saved by 67. 4% in W₃ treatment, and the total dry mass and evapotranspiration significantly decreased by 17. 4% and 68. 6%, and the irrigation water use efficiency and total water use efficiency increased by 153. 2% and 163. 2%, respectively. In the condition of this study, the irrigation amount of 154. 18 mm was beneficial to increase water use efficiency. [ABSTRACT FROM AUTHOR]