Effects of Root Hydraulic Lift on Soil Salt and Tomato Yield under Water and Salt Stress

Aiming to study the possibility of tomato root hydraulic lift and its effect on soil salt and yield under salt and water stress, different water levels (W1,W2 and W3 stands for soil moisture content was 60%~70%, 50%~60% and 40%~50% of field capacity, respectively) and salt levels (S0, S1 and S2 stands for NaCl addition was 0, 0.2% and 0.4% of dry soil weight, respectively) of upper pot was set to analyze the quantity of root hydraulic lift, salt distribution and yield in upper pot by a soil compartments with upper and lower pots. The results indicated that with the development of growth period, the root hydraulic lift quantity was increased first and then decreased, on which the salt had a significant effect, and under the same water level treatment, the higher the salt content was, the greater root hydraulic lift quantity was; under water and salt stress, there was a linear positive correlation between the salt content and root hydraulic lift quantity in the upper pot, and except for the control group, the electric conductivity of upper pot soil was increased when the hydraulic lift quantity reached the maximum value; compared with the control, water and salt inhibited the root growth, and thus significantly reduced the root activity, and under the same water level, root length, root surface area and root volume were decreased when salt content was increased; salt had a significant effect on tomato water productivity, and under the same water level treatment, the higher the salt content was, the greater the water productivity was, moreover, water productivity was the greatest under W2S2 in all treatments and root hydraulic lift quantity accounted for 17.73% of water demand, but yield was not significantly decreased compared with that of control. The research results had scientific and productive value for further understanding that crop could make full use of the deep water of soil profile to maintain the survival of upper roots and improve the water productivity in "up dry and down wet" condition under water and salt stress. © 2020, Chinese Society of Agricultural Machinery. All right reserved.