This paper analyzed the status and results of the research at home and abroad for its
problems, experiment was done at the pear-jujube water-saving demonstration bases in
Mizhi County. In this experiment, two water treatments were set to research the soil
moisture dynamics under different water supply and water conditions of 4 years old
pear-jujube tree in three consecutive years of critical water demand period (flowering fruit
set and fruit enlargement period), which reveals jujube water rules in key water demand
period. The changes of soil properties and growth physiological indexes( such as jujube
tree stem diameter, canopy structure etc. ) were also monitored under different soil water
potential treatment conditions. Combined with the meteorological elements, appropriate
cultural climate and environment of pear-jujube would be analysised, and the main factors
affecting stem diameter Minute changes and the amount of water consumptions would be
clear. All of these can provide decision indicators and theoretical basis to the water-saving
irrigation technologies of precision Irrigation modern. The two water treatments were: T1,
soil water potential is controlled within the range of -41~ -51 kPa (0.233 ~ 0.196 cm 3 /cm 3 );
T2, soil water potential is controlled within the range of -311 ~ fruit wilting~ -311 kPa
(0.061 ~ fruit wilting ~ 0.061 cm 3 /cm 3 ) in 2010. T1, soil water potential is controlled
within the range of -41 ~ -51 kPa (0.233 ~ 0.196 cm 3 /cm 3 ); T2, soil water potential is
controlled within the range of water stress ~-41 kPa ~ arid (water stress ~ 0.233 cm 3 /cm 3 ~
arid) in 2011. T1, soil water potential is controlled within the range of -41 ~ -68 kPa (0.233
~ 0.151 cm 3 /cm 3 ); T2, soil water potential is controlled within the range of -10～-84 kPa
（0.375～0.123 cm 3 /cm 3 ）in 2012. The main conclusions were as following:
(1) MXTD curve showed significantly different under different soil moisture
treatments in the critical water demand period of pear-jujube. The lower soil moisture, the greater DG and the faster MXTD growth rate. Irrigation can effectivly promote the growth
of stem diameter. Jujube MDS differences significantly with the different soil moisture.
water shortage increases jujube MDS to a certain extent. The MDS are greater in
flowering and fruit setting period, but smaller in the late of fruit enlargement period, each
processing MDS are small. Diurnal variation of pear-jujube stem diameter is influenced by
the growth duration.
(2) The research of stem diameter dynamic changes indicators of pear-jujube in three
consecutive years of flowering fruit set and fruit enlargement period show that the
variation of MTD and MXTD are consistency in each processing, and the growth rate of
them differences due to different water treatments. This tell us that the MTD and MXTD
can be used as indicators of tree growth, and they has same result on characterization of
both plants and soil water.
(3) The research of water consumption conditions of pear-jujube in three consecutive
years of flowering fruit set and fruit enlargement period show that the water consumption
increases with the increase of the amount of soil water supply, the maximum daily water
consumption of each treatment was appeared in one week after irrigation. Each water
consumption curve showed an increasing trend in three years, and water consumption
reached the maximum in the the fruit expansion period. The water consumption intensity
of flowering and fruit setting period is less than fruit enlargement period.
(4) Soil moisture and meteorological factors has a combined effects on the change of
stem diameter indicators, soil moisture influence the sensitivity of jujube MDS to weather
changes. The jujube tree MDS is most sensitive to the changes of weather in the treatment
which water is suitable. For other water treatments, jujube MDS variation consistent with it,
but less volatile.
(5) In this paper, the path analysis of meteorological factors as well as water
consumption in full irrigation conditions with the changes of stem diameter tell us: ET 0 、
VPD are positive related with water consumption changes, they are decision variables.
ET 0 、VPD are positive related with MXTD、MDS，in this, ET 0 is the main decision variables
of MXTD, Water consumption has negative correlation with MDS changes, as the main
decision variable, water consumption has a very significant impact on MDS.
Comprehensive analysis: ET 0 is the main factor to affect the change of stem diameter and water consumption, MDS as the appropriate moisture deficit sensitive indicator of pear
jujube, can well characterize the laws of water consumption.
(6) The performance of canopy structure indicators (leaf area index, gap fraction, light
transmission rate) is significantly different under different soil moisture treatments. Mild
water stress in fruit growth period affect canopy structure indicators, and the rehabilitation
of irrigation show some compensation effect. Leaf area index, gap fraction and the
transmittance has a good correlation under different treatments, leaf area index has a
negatively correlated with gap fraction and light transmittance, while, gap scores positively
correlated with light transmission rate.
Key words: pear-jujube; Soil water potential; Physiological growth; Stem diameter; water
consumption; meteorological factors