Study On The Regulation Effects Of Soil Moisture On Field-Grown Tomato's Root System Trait And Above-Ground Parts

【Object】The change of soil moisture in field-grown tomato root system was studied in this research, which may give a further understanding of soil moisture regulation on tomato growing process and yield.This research was conducted to make the physiological regulation mechanism of output and water use efficiency clear, and optimized irrigation system was provided for yield improvement and higher water use efficiency for field-grown tomato under mulching film drip irrigation in arid and semiarid area.【Methods】The li-Ge 87-5 was selected as experimrntal material and three water treatments were designed in this experiment. Irrigation indexs were collected from anthesis to maturity of the field-grown tomato.The root-soil water content was monitored by automatically carried system in various humidity soil conditions; root system distribution and plant adaptation to controlled soil water condition was collected by root auger sample measurement,image analysis methods and field experiment.【Results】(1) The water consumption of root zone was greatly influenced by root-soil water content. In the treatment of full drip irrigation, water consumption of root zone was irrelative to root-soil water content in 0~60 layers, while it was maily caused by surface layer transpiration, thus the root water consumption intensively was the largest , as a result root biomass was the largest in this treatment. In the treatment of regulated drip irrigation, water consumption intensively of root zone was depending on irrigation, consequently root biomass was reduced.The root zone water consumption intensively under proper water treatment is in the middle of three water treatments, and there was no significant difference on root biomass between full water treatment and proper water treatment.(2) The root system was developed more than 80 cm under soil surface, and its vertical distribution can be simulated by exponential equation. Root dry matter was advanced along with the increase of root-soil water content in 0~30cm soil layer during the fruit-formation stage. Root biomass amount to the highest in blooming-fruit stage, and it was 639.31g/m3, 574.17g/m3 and 477.43g/m3 under proper, full, regulated water treatment respectively. Compared with other two water treatments, the distribution of root biomass was significant higher during the late fruit stage under regulated water treatment while there was no significant difference of root length density distribution under water treatments.Horizontal distribution was advanced along with the increase of root-soil water content, most of the root system was far from tube.(3) Root length density was advanced along with the increase of root-soil water content in 0～30cm soil layer. Average root length density of vertical distribution and horizontal distribution was 0.16cm/cm3~0.20cm/cm3 and 0.0513cm/cm3~0.2803cm/cm3 respectively.The root area was firstly increased then decreased, the root area of regulated irrigation was greatly larger than other treatments 45 and 60 days after emergence.while it was significant lager under proper irrigation 80 days after emergence.There was no significant difference in root diameter under three water treatments.(4) Plant height, root drymatter, water flow and CAP were decreased under regulated water treatment,while the chlorophyll was increased.There was significant difference of CAP between different leaves position. Water flow under three water treatments was extreme significant difference, water flow of different leaves was new leaf >top leaf>old leaf. (5) There was different degrees of correlation between root dry matter and water consumption,RAI and LAI,above ground dry matter and water consumption,root dry matter and above ground dry matter of field-grown tomato.Root morphological traits and water use efficiency showed significant correlation, which can be better simulated by quadratic curvet.(6) Compared with proper irrigation, Water deficit would shorten the growth period of field-grown tomato by 3 days, and full irrigation would delay the growth period of field-grown tomato by 10days.【Conculusions】(1)The relative soil water content should be 60%~65%, 75%~80%, 80%~85%, 60%~65% at early blooming stage, blooming-fruit stage,fruit stage,late- fruit stage of field-grown tomato respectively. Consequently suitable root system can be formed and higher water use efficiency; larger LAI; greater dry matter accumulation can be achieved. Average mass of single fruit was 39.0g and total fruit in single plant was 3479g.(2) The rate of root/ shoot was increased along with the decrease of root-soil water content.The rate of root/ shoot, yield and water use efficiency under light water stress(60~65%)were better than full irrigation and deficit irrigation during early blooming stage of field-grown tomato.