Establishment Of Water Uptake And Root Distribution Model Of Tomato Under Salt Stress

Based on the present situation of greenhouse soil salinization in North China,the effects of saline water irrigation on the distribution of soil water and salt,and the growth of greenhouse tomatoes was determined through the greenhouse culture experiment in Langfang city,Hebei province.The root water uptake and root distribution models of tomato were established and validated using the experimental data.The results were as follows:(1)The growth of tomato was inhibited by salt stress.The yield was also decreased.T2 and T3 were 37.8%and 48.8%less than T1 respectively.Under higher degree of salt stress,the more serious effect on tomato growth and yield were obtained.However,the lower salt stress could promote the growth of tomato.For example,leaf dry weight were 458.4,450.4 and 409.4 g,respectively.Stem dry weight were 211.9,202.4 and 182.1 g,respectively.The root dry weight were 1.8,1.4,1.2 g,respectively.The relationship among the treatments were T2>T1>T3.(2)The distribution of soil water and salt were influenced by salinity of irrigated water.The trend of soil water content distribution was similar under different salt treatments.The soil water content increased with the soil depth.The salinity of irrigation water was proportional to the average soil water content,but not significant.The accumulated salt in soil increased with irrigation water salinity increasing.After 4 period of fresh water irrigation treatment the average moisture content were 0.16,0.15,0.14,0.14 cm3cm-3,T2 and T3 contain four periods were higher than fresh water irrigation treatment Tl,which salt stress average moisture content were 0.18,0.17,0.16,0.16 cm3cm-3,0.19,0.18,0.18,0.19 and cm3cm-3.The accumulation of salt was appeared in surface soil.The tomato root water uptake was greatly inhibited under higher salt concentration conditions.(3)Using the experimental data and inverse method,the root water uptake rate and salt stress factors of tomatoes were estimated,and the parameters of salt stress factors were optimized,obtained ?050=-4301.00 and p=1.13.Therefore the root water uptake model of greenhouse tomato under salt stress was constructed.The model validation results showed that the simulated tomato root water uptake rate agreed well with the estimated values using the inverse method.(4)The root distribution model of tomato under salt stress condition was established based on using measured root distribution data,the fitting coefficient were a=0.35,b=1.01,c=2.12,d=0.16,which provided convenience for the application of tomato root water uptake model.Based on the study of tomato root water uptake under saline stress,it can provide the theoretical basis for the management of vegetable water efficiency.It had great significance to promote the sustainable development of facility agriculture in China.