其他摘要 | The Turpan study site represented traditional farming clay loam soil. This soil has a better retain of water and nutrients and poor water conductivity. The soil has a relatively low hydraulic conductivity and relatively high diffusion rate. The irrigation model should take as "less time large amounts", and the emitter should take a small discharge rate and large emitter spacing. The Shanshan study site represented Gobi desert improved gravel sandy loam soil. This soil and a poor water retain and fertilizer, and easy to produce deep leakage. This kind of soil has a relatively high hydraulic conductivity and relatively low diffusion rate. The irrigation model should take as "several time small amounts", and the emitter should take a large discharge rate and small emitter spacing.
The variation of grapevine length was small and can be ignored during the study periods. The number of branches, branch length, branch internode length, number of grape leaves, average leaf midrib length, and average leaf area and ground net biomass growth was increased rapidly in the shoot growing period. After flowering period, the growth rate gradually becoming slowly and the variation become slightly after the fruit enlargement period. The branch diameter growth rate was smaller in the shoot growth period, the growth rate accelerated in flowering and fruit enlargement period, and the speed gradually slowed down in the late fruit enlargement period. Grape leaf area index increases rapidly in the leaf expansion period, grape leaf area index began to slow down after flowering period and reached maximum value in grapes harvest period of one year. Leaf area index decreased rapidly thereafter, until the buried pier. The leaf chlorophyll content of mature grape showed chlorophyll a> chlorophyll b. The chlorophyll content showed no significant differences among high, middle water treatments and furrow irrigation treatment, but the chlorophyll content was significantly smaller for the low water treatment. Chlorophyll content in different position showed mature leaves for welcome light > backlight for mature leaves> welcome light for young leaves.
The longitudinal diameter, transverse diameter and single berry volume of grape fruit increases rapidly after fruit-development stage, and then slow down after fruit mature stage, but increased rapidly again before the harvest, showed a fast-slow-fast growth trend. The grape fruit sharp index decreased rapidly after fruit-development stage, and became stable after fruit mature stage. Grape sharp index were between 1.25-1.41 under different water treatments. Grape sugar increased after fruit-development stage, and increased rapidly after fruit mature stage, then slow down before harvest, showed a slow - fast - slow the trend. The grape sugar content expressed upper string> string middle> lower strings in same cluster and expressed as top> bottom > middle in same vine.
The distribution of grape roots for Shanshan improved sandy loam area showed relatively wide range. The maximum depth of vertical distribution was more than 1.4 m, and the maximum density presented at 40-60 cm. The horizontal root distribution was covering almost the whole ridge and furrow range, and concentrated in the furrow and 1.8 m toward ridge direction. The distribution of grape roots for Turpan traditional farming clay loam area was relatively concentrated. The maximum depth of vertical distribution was less than 1 m, and the maximum density presented at 20-40 cm. The horizontal root distribution was less than 2 m but concentrated in the 1.2 m range toward ridge direction. After using drip irrigation, the absorb root increased significant in the ridge and 0-40 cm under surface of furrow. The root density has little change Changes under 60 cm.
There existed a linear relationship among leaf length, leaf width, leaf midrib length of mature grape; there existed a linear relationship among leaf area, leaf length square, leaf length by leaf width; there existed a good power function relationship among leaf area and leaf length, leaf width, leaf midrib length; there existed a exponential function relationship among grape branch length, branch length of last third quarter, average number of leaves on branches, average leaves length; there existed a good linear relationship between grape berry weight and berry size; there existed a exponential function relationship between grape berry weight and longitudinal diameter; there existed a power function relationship between ground dry weight of shoot and branch length; there showed "S"-shaped relationship between ground dry weight of shoot and leaf number. In the grape harvest period, grape sugar content showed linear relationship to berry weight.
Changes of leaf area index growth process can be well expressed by Logistic model. The two-dimensional relative length density distribution of mature grape roots can be well simulated with exponential form for Shanshan and Turpan study sites.
Methods to determine and measure grape water consumption in field include water balance method, micro-meteorology method, and plant transpiration and soil evaporation method. The results of three methods are similar with the same variation. Water balance method to calculate the data for the average water consumption for several days, it is difficult to obtain instantaneous variation; Sap Flow with soil surface evaporation and micrometeorological methods were able to obtain continuous glucose water consumption, but due to individual differences in vine in the scaling there are certain problems, but the method requires accurate measurement of soil surface evaporation. Penman-Monteith method has a good linear relationship to the other 13 kinds of calculation methods. The best correlations between two methods were the ASCE Penman-Monteith, Kimberly Penman (1982) method. The poor correlations were FAO-24 Blaney-Criddle and Hargreaves method. The actual crop coefficient and water consumption are closely related. The crop coefficients were quite different at different growth stages and showed downward trend. The mature grape crop coefficient values of Turpan area were much higher than the FAO recommended under sufficient water supply condition. The initial stage was about 60% and mid-and late stages were about 100% higher than the recommended values.
The grape transpiration showed diurnal bimodal curve in sunny days. The grape transpiration rate fluctuated with air temperature fluctuations in cloudy days. The maximum transpiration rates of grapes in cloudy days were lower than sunny days. At night, the transpiration rates under two conditions were maintained at 0.08 mm / hr. Daily consumption of grape were gradually increased from bearing shoot stage, then reached max value at fruit-development stage, and gradually decreased at fruit mature stage, fruit mature stage. For drip irrigation, the grape consumption rate was increase with irrigation quote. The grape water consumption modulus showed two peaks under different water treatments. The first water modulus peak appeared at shoot growth period, the second water modulus peak appeared at fruit-development stage. The water modulus showed low values at flowering period and fruit mature stage, fruit mature stage. Ninety percent of irrigated water was consumed by grape with high irrigation efficiency. The furrow irrigation method showed low irrigation efficiency. Furrow irrigation efficiency was 31% for Shanshan gravel sandy loam soil and was 70% for Turpan clay loam soil. Soil surface evaporation occurs mainly in drip irrigation ditch and the interface of ridge and furrow. Water mainly consumed by transpiration from early growth to harvest but reach a larger proportion of soil surface evaporation after harvest.
The water consumption amount calculated by actual crop coefficient were similar than measured results. The soil surface evaporation process can well simulated by dual crop coefficient method. The soil water movement influenced by root water uptake of the two study sites can be well monitored by Hydrus 2D software and parameters in the front.
Water potential of grape leaves showed increase-decrease, single peak trend. Photosynthesis and transpiration of grapes both showed increases-decreases- increasing-decreasing changes in the day. Grape photosynthesis and transpiration showed same trend in the growth period, that increased after leaf developing stage, and reached the maximum values during flowering period, fruit-development stage and fruit mature stage, then decreased after late fruit mature stage.
Photosynthetic rate,transpiration rate and water use efficiency have significantly correlated with solar radiation, air temperature, relative humidity and soil moisture content. Among these factors, the net radiation was the most important factors, following by air temperature and soil moisture. Grape drought monitoring indicators, including soil moisture in the fruit enlargement period, 74-83% of FC; soil water potential, 400-420 cm; deficit between canopy temperature and leaf water potential, the critical value of -13 bar.
Grape yield presented good parabolic relationships between water consumption in the whole growth period; grape water use efficiency showed good parabolic relationship between water consumption in the growth period. In ensuring the maximum yield and maximum water use efficiency, the best grape water consumption amount was 628-663 m/mu for Trupan and 767-933 m/mu for Shanshan study sites. Aquacrop model can well 33simulate water productivity of grapes.
Key Words: Extremely drought region; mature grape; drip irrigation; water consumption; model simulation |
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