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785 |
Water consumption characteristic and irrigation schedule for different stubbles of alfalfa under sprinkler irrigation conditions |
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ZHENG Hexiang, LI Heping*, CAO Xuesong
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There are great differences in water consumption characteristic and irrigation schedule among different stubbles of alfalfa in a year. Irrigation experiments on alfalfa were conducted under sprinkler irrigation conditions in the water-saving irrigation demonstration field in pasture of Etuokeqin County, Ordos City. The water consumptions were calculated by using the principle of water balance, and the water consumption characteristic, yield, water productivity, and irrigation schedule for different stubbles were analysed. The results show that the water consumption exhibits an increasing trend for the first stubble to the third stubble, but the water consumption intensity is the maximum in the second stubble. The alfalfa yield varisd significantly across stubbles, among which the yield is the highest in the second stubble, followed by the first one, and the lowest in the third one. The corresponding water productivity demonstrates a similar variation pattern. Under sprinkler irrigation conditions, the recommended irrigation schedule is that there are 7 irrigations in the whole growth period of alfalfa with a quota of 270-315 mm, specially, there are 3 irrigations with a quota of 120-135 mm in the first stubble, followed 2 irrigations with a quota of 75-90 mm in the second stubble, and end up with 2 irrigations in a quota of 75-90 mm in the third stubble. The results have certain significance for decision-making of multi-stubble grass irrigation and design of water-saving irrigation projects in pasture. |
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2018 Vol. 36 (9): 785-789
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796 |
Effects of irrigation on growth and salt tolerance of Jatropha curcas |
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ZHAO Songyi, CHEN Jinling, YANG Qiliang*
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Appropriate irrigation is beneficial to the growth of Jatropha curcas. In order to study effects of irrigation on growth and salt tolerance of Jatropha curcas, seedlings of Jatropha curcas for 1a were used as experimental materials. The irrigation had three levels, i.e. 19.80 mm, 19.80 mm and 39.60 mm alternating irrigation, and 39.60 mm. NaCl was subject to three levels of analytical purity in 50 g air-dried soil such as 0 g, 0.15 g and 0.30 g. The morphology of Jatropha curcas, Na+ environment in its root zone and Na+ accumulation in its plant body were monitored. The results show that the Jatropha curcas has a certain salt tolerance, and the alternating irrigation is more conducive to the growth of Jatropha curcas at 0.30 g NaCl level. With increasing salt concentration, the increment of soil electrical conductivity in the root area of Jatropha curcas decreases gradually. At the same time, the increment of salt concentration also reduces with the increase of Na+ content in soil layer. The Na+ content in the organs of Jatropha curcas from the highest to the lowest is leaf, root and stem. The alternating irrigation of 19.80 mm and 39.60 mm can save 25% water in comparison with that in 39.60mm irrigation, but the growth of Jatropha curcas remains unaffected. Further, there is no significant difference in Na+ content in various organs. Under the conditions of this experiment, when Jatropha curcas is under different degrees of salt stress, the alternate irrigation of 19.80 mm and 39.60 mm is more conducive to growth, and can improve ability of salt tolerance. |
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2018 Vol. 36 (9): 796-801
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413 )
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689
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802 |
Simulation of reference crop evapotranspiration by using bat algorithm optimization based extreme learning machine |
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WU Lifeng, LU Xianghui*, LIU Xiaoqiang, ZHANG Suyang, LIU Mingmei, DONG Jianhua
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In order to improve the prediction accuracy of modelling reference crop evapotranspiration, the bat algorithm was used to optimize extreme learning machine(ELM). Meteorological data from 1966 to 2015 at Shantou Station(i.e., monthly maximum and minimum ambient temperatures, global solar radiation, wind speed and relative humidity)was used to train and test the proposed models of extreme learning machine. The bat algorithm was used to optimize the regularization coefficient and breadth of radial basis function of ELM with a cross-verification method. Finally, the performance of proposed models for the reference crop evapotranspiration estimation was evaluated by statistical indicators. The results show that the bat algorithm-based optimized ELM model provides better accurate and stable values of reference crop evapotranspiration in comparison with the evapotranspiration values estimated by the models optimized with traditional tuning method and genetic algorithm, respectively. |
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2018 Vol. 36 (9): 802-805
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433 )
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653
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806 |
Effects of moistube irrigation on growth and moisture-radiation use of coffea arabica under jujube shading cultivation |
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ZHU Yifei, LIU Xiaogang*, HE Hongyan, YANG Qiliang, SUI Long
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In order to find out the moisture-radiation coupling mode for young coffee tree, effects of water head of moistube irrigation on soil moisture distribution in the root zone, growth and photosynthetic characteristics of coffea arabica were studied under jujube shading cultivation by pot experiment. A design of experiment was completed by involving two factors and three levels, i.e. three water heads such as low(H1.0:1.0 m), moderate(H1.5:1.5 m)and high water head(H2.0:2.0 m), three jujube shade degrees, namely no shading(S0:100% natural light), moderate shading(S1:65%-75% natural light), and severe shading(S2:45%-55% natural light). The results show that the water head and shading degree have a significant effect on the mean soil moisture in the root zone of coffea arabica. The wetted zone size increases with increasing water head, and decreases slightly with increasing shading degree. The mean and uniformity of soil moisture in the wetted zone increases significantly with water head, but decreases slightly with shading degree. Compared with S0, height, stem diameter, crown width and number of leaves in S1 are increased by 20.31, 12.44, 24.45 and 52%, respectively. Compared with H1.0, the average net photosynthetic rate(Pn), transpiration rate(Tr), apparent light use efficiency(ALUE)and instantaneous water use efficiency(IWUE)of leaves are increased by 22.10%-60.75%, 28.02%-70.49%, 35.51%-81.65% and 26.42%-39.61% in H1.5 and H2.0, respectively, while the intercellular carbon dioxide concentration(CO2)is decreased by 14.16%-31.32%. Compared with S0, an increasing shading degree results in 12.20%-26.10% and 5.37%-26.28% increments in Pn and Tr, but 5.88%-11.97% reduction in intercellular CO2. In S1, ALUE and IWUE are increased by 15.02% and 15.53% in S2, however, decrease by 5.88% and 11.97%. In H2.0S1, the tree growth, Pn, IWUE and ALUE of leaves have been enhanced significantly. This treatment should be is a suitable cultivation mode to coffea Arabica young tree under coupled moistube irrigation and jujube shading conditions. |
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2018 Vol. 36 (9): 806-811
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441 )
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812 |
Spatial-temporal distribution characteristics of reference crop evapotranspiration and climate influence factors in Henan Province |
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HAN Yang,, CHANG Di,, HUANG Zhongdong,, LI Ping,, LIANG Zhijie,, QI Xuebin,*
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Based on the long-term observational data during 1951—2016 in 10 typical meteorological stations, Henan Province, the daily reference crop evapotranspiration(ET0)was calculated with the aid of the revised Penman-Monteith model recommended by FAO. The spatial-temporal distribution characteristics of ET0 and its major climate influence factors in 66 years in Henan Province were analysed by performing the Mann-Kendall test, Kriging spatial interpolation analysis in GIS and path analysis. The results indicate that the overall ET0 shows a yearly declining trend with the decreasing rate of around 1.37 mm/a, especially a significant decline trend is found in Anyang, Luoyang, Zhengzhou, Shangqiu, Xuchang, Baofeng, Xihua and Zhumadian. Additionally, the ET0 experiences a high-to-low mutation in the early 1980s, when the decrease is as large as approximate 62 mm. In recent 66 years, the annual ET0 was between 917 mm and 1 007 mm. In the central region, the ET0 was smaller. There is a significant difference in spatial distribution of ET0 before and after the mutation. The spatial distribution is distinct in four seasons, especially the distribution characteristics in spring and summer are close to the annual distribution. Effects of meteorological factors on ET0 from the most significant to the least significant are in the following sequence: wind speed, sunshine hours, average relative humidity and average temperature. Further, the wind speed, sunshine hour and average temperature are positively correlated to ET0, while the average relative humidity is negatively correlated to ET0. This study can provide a scientific basis for farmland water management in Henan Province. |
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2018 Vol. 36 (9): 812-818
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691 )
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528
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819 |
Effects of water deficit on growth and water use efficiency of summer maize under alternate partial root-zone irrigation |
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CHENG Minghui, FAN Junliang, ZHANG Fucang*, WANG Haidong, XIANG Youzhen
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In order to find the theoretical basis of water-saving irrigation for maize, effects of water deficit on growth, dry matter accumulation, grain yield, total water consumption and water use efficiency(WUE)of summer maize in various growth stages under alternate partial root-zone irrigation(APRI)were studied in a pot experiment. The results show that the plant height, leaf area and total water consumption under water deficit in seedling stage and the whole growth stage are significantly lower than those under conventional irrigation(CI)with sufficient irrigation, but WUE is increased by the water deficit occurred in the seedling stage. For the same irrigation method and deficit duration, the root dry weight, aboveground and total dry matter accumulation and grain yield in moderate water deficit are significantly higher than those in severe deficit. For the same irrigation method and irrigation level, the plant height, root dry weight, aboveground and total dry matter accumulation and total water consumption in seedling stage are significantly lower than those in milk stage, but the grain yield and WUE are substantially higher. For the same irrigation level and deficit period, the root dry weight and total water consumption under APRI are significantly lower than those under CI, but the grain yield and WUE under APRI are considerably higher than those under CI. This suggests that APRI with a moderate deficit in seedling stage is conducive to the regulation of vegetative growth to achieve the objective of water saving with high yield and WUE improvement. |
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2018 Vol. 36 (9): 819-823
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362 )
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552
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824 |
Numerical study and experiment on characteristics of pressure relief valve in large irrigation pipe network |
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YU Xianlei, CHEN Songshan, YANG Xiawei, ZHOU Mingyao*
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In order to explore a type of pressure relief valve type with an even more suitability to a large irrigation pipe network, a new type design of pressure relief valve was proposed, and its structure and working principle were explained. Using Gambit and CFX software, three-dimensional models of the valve were established at five openings(i.e. 0.8, 1, 1.2, 1.6 and 2.4 cm)of the valve clack and numerical simulations were conducted to analyze static characteristics of the valve body. The variation rules of inlet and outlet pressure difference and the driving force on the valve clack were demonstrated under various inlet flow conditions, Meanwhile, the pressure and velocity contours in the valve body and a few specially chosen cross-sections were also analyzed. The pressure differences between inlet and outlet under different inlet flow conditions were measured on an experimental model when the clack openings were at 1, 1.6 and 2.4 cm, respectively. The results show that the deviation between measurement and simulation is between 2.8% and 7.9%, suggesting the proposed design is reasonable. This outcome provides a theoretical guidance for hydraulic design of the valve body, and offers reference for similar product development in the future. |
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2018 Vol. 36 (9): 824-828
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418 )
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698
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829 |
Throat structure optimization and flow field analysis of ATP Venturi fertilizer applicators |
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WANG Qiuliang, WANG Zhenhua*, WU Wenyong, LIAO Renkuan
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In order to verify the correction of throat-to-outlet diameter ratio of nozzles, and clarify the superiority of the Venturi with this ratio and its related parameters variation rule further, software SolidWorks was used to generate 8 different Venturi 3D models, and a CFD software was launched to calculate fluid flows through them. The variation rules of pressure difference, Reynolds number, fertilizer suction flow rate, and minimum pressure were obtained, and the influences of λ on flow field characteristics under the same working condition were analyzed. The results show that the optimal λ simulated is different from that in literature by 8.6% and the error in the inlet flow rate between prediction and experiment is around 10%. The pressure difference varies with Reynolds number in terms of power function, but with minimum pressure linearly. The necessary conditions for a negative pressure in this series of fertilizer are obtained. The differential pressure for a negative pressure, pini, is 4.3 kPa when λ =1.27. pini decreases with increasing λ if 1.00≤λ<1.27. While pini increases with increasing λ but also shows a gradually increasing trend when 1.27≤λ<1.68. Pinitial decreases with increasing λ once more when 1.68≤λ<2.00. According to the calculated results, the flow field in the symmetrical plane of Venturis is analyzed and confirms that the suction performance of the Venturi with λ=1.27 is better than the other fertilizer applicators. Since λ=1.27 means a Venturi to be reliable, it should be the optimal value of λ for ATP 3, 4, 5, 6 series fertilizer applicators. |
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2018 Vol. 36 (9): 829-834
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441 )
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682
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835 |
Experiment and simulation of hydraulic performance of three-way pulse jet tee with various nozzle widths |
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FAN Erdong, WANG Xinkun, Xiao Siqiang, XU Shengrong, WANG Xuan, ZHANG Chenxi, XUE Zilong
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In order to improve the hydraulic performance of three-way pulse jet tee, effects of nozzle width of jet tee were simulated based on single phase fluid flow models and CFD method by employing 6 kinds of widths for the nozzle. Their influences on the frequency, amplitude and hydraulic perfor-mance of the jet tees were analyzed. The jet tees with 3, 4, 5 mm widths were manufactured and tested with water. The relationships between irrigation uniformity and pulse frequency, flow deviation rate and outlet flow rate were determined by a 70m long drip irrigation tape, the experimental comparison was made under the same conditions with an ordinary tee. The results show that the three-way pulse jet tee with 4 mm width is subject to a larger amplitude, higher frequency and better stability than the other tees. The uniformity of the jet with a width of 4mm is the best in experiments as well, especially the average uniformity is as good as 94.88%, which is 0.65% higher than the ordinary tee. With the increase of pressure head, the uniformity of irrigation is reduced, but it is still better than the ordinary tee, particularly, the difference between them is getting bigger and bigger. These results provide a theore-tical basis for three-way pulse jet tee structures and dropper anti-clogging systems. |
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2018 Vol. 36 (9): 835-839
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343 )
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673
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840 |
Field combination experiment on impact sprinklers with aerating jet at low working pressure |
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XU Zhengdian, XIANG Qingjiang*, WAQAR A Q, LIU Jun
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In order to examine effects of irrigation uniformity improvement between aeration sprinkler and impact sprinkler, the performances of two kinds of sprinklers were compared by field combination experiment when the sprinklers were working at low pressure. An aeration sprinkler was designed based on the structure of existing impact sprinklers by involving an air-liquid two phase jet. The combination sprinkler irrigation was evaluated by using average sprinkler irrigation intensity(including measured and theoretical values)and Christiansen uniformity coefficient. Particularly, effects of working pressure and sprinkler combination space on Cu were discussed. The experimental data show that the difference in average sprinkler irrigation intensity between theory and measurement was less than around 5% for both the types of sprinkler. It means that the wind evaporation and drift loss was small under the low pressure and breeze wind condition, and the performances of two types of sprinklers are comparable under this condition. When the sprinkler combination space is equal to one jet range, the experimental irrigation uniformity coefficient is increased in the aeration sprinkler, especially, the coefficient has reached and exceeded 75% that is specified in a national technical standard of China. When the combination spaces are 1.0, 1.1 and 1.2 times the jet range, respectively, the experimental irrigation uniformity coefficient of the aeration sprinkler is better by about 2.2%-5.8% than the impact sprinkler in the same model size. |
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2018 Vol. 36 (9): 840-844
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389 )
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616
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845 |
Numerically simulated effects of entry on hydraulic performance of hydro-turbine in hose reel irrigators |
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CHEN Weisheng, LI Yaojun*, YAN Haijun, ZHANG Mingzhen
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Turbulent flows in two hydro-turbines of hose reel irrigator respectively with two entries, i.e. nozzle and spiral case, were investigated numerically using SST k-ω turbulence model to uncover the differences between internal flow field characteristics and hydraulic performance caused by two different kinds of entries. The predicted hydraulic performance of the turbine with nozzle was validated with the corresponding experimental data available. It is indicated that large scale vortex and strong leakage flow cross the blade side tip clearance existes in the impeller of the turbine with nozzle entry. For the turbine with spiral entry, the pressure and streamlines inside the impeller are distributed relatively uniformly, no significant difference in the leakage flow pattern along the circumferential direction is noticed. It is found that the percentage of each component hydraulic loss to the total hydraulic loss across the turbine with nozzle remains constant basically at various flow rates, especially, the hydraulic loss in the impeller accounts for 55% of the total hydraulic loss. For the turbine with spiral case, the hydraulic loss in each component varies with flow rate. The performance curves of two turbines show nearly the same variation tendency, but the efficiency of the turbine with spiral case is 18%-22% higher than that of the turbine with nozzle at the same flow rate, especially the best efficiency of the former is 59.6% in comparison with 35.6% of the latter. These results can provide a reference for hydraulic design and structural improvement of hydro-turbine in hose reel irrigators. |
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2018 Vol. 36 (9): 845-850
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365 )
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497
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851 |
Design of irrigation forecast and automatic control system based on soil matric potential |
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ZHANG Youliang,, FENG ShaoYuan,, WANG Fengxin*
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An irrigation forecast and automatic control system was designed based on soil matric potential to make the system simple, cheap and widely applicable. By using pressure gauge with electric contact to measure the pressure of tensiometer, the irrigation upper and lower limits can be easily set with the knob on the pressure gauge for different crops, growth stages, and irrigation methods based on the soil matric potential. When the soil matric potential reaches the upper and lower limits, the automatic irrigation can be achieved with the pressure gauge and automatic control circuit. The irrigation duration, amount, and frequency can be recorded and stored with single chip microcomputer and displayed by remote-transmitting water meter and liquid crystal display during irrigation. The laboratory test show that this irrigation forecast and automatic control system is reliable and feasible. Moreover, based on the soil matric potential, the irrigation upper limit is approximately equal to -8 kPa for silt loam soil. |
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2018 Vol. 36 (9): 851-856
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405 )
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571
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857 |
Algorithm with variable downstream target depth based on balance of water volume in canal pond |
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ZHONG Ke, GUAN Guanghua*, LIAO Wenjun, XIAO Changcheng, SU Haiwang
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The operation mode with constant downstream depth is widely used in practical engineering for its feasibility and simple logic, however, confronted with huge flow change. As a result, the water volume can exceed an allowable value and the pressure of water source has been enlarged. Thus an algorithm for variable downstream target depth was proposed based on the balance of water volume in each signal canal pond. When the water volume in the pond changes less, the algorithm is in the ope-ration mode with constant downstream depth, otherwise it adopts the mode with variable downstream target depth. As a demonstrating example, a control model based on Matlab was constructed for the Middle Route of South-to-North Water Diversion and simulated to clarify control performance of the algorithm. The results indicate that the algorithm proposed in the paper performs well and perfectly reduces volume changes. The algorithm makes two operation modes switchable in a flexible and smooth manner. Compared with the constant downstream depth method, the new method moderates both the water-level fluctuation and flow rate variation in the canal system, and avoids overshoot and repeated regulation of gate opening. Though it causes some delay in stable time, but it leads to an even smooth regulatory process. |
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2018 Vol. 36 (9): 857-862
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347 )
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622
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863 |
Analysis of characteristics of seasonal drought in Southern China—a case study of Zhanghe Irrigation District |
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CHEN Mengting, LUO Yufeng,, YAN Chenegming,, LUO Hongying, CUI Yuanlai
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In order to study the characteristics of seasonal drought in Southern China, the daily meteorological data in Zhanghe Irrigation District from 1953 to 2016 was utilized to calculate three kinds of drought indexes, i.e. standardized precipitationindey(SPI), relative moisture(M)and Palmer drought severity index(PDSI), and against the actual drought information, the seasonal drought characteristics were analyzed. The results show that the three drought indexes have their own advantages in different aspects. From the degree of coincidence, SPI has the highest matching rate with actual drought. From the perspective of different durations of drought, SPI and M respond quickly to short-term drought, while PDSI is more sensitive to long-term drought. In terms of season, M is suitable to spring and summer and SPI is suitable to autumn, while PDSI is better to winter. The characteristics of seasonal drought in Zhanghe Irrigation District are as follows: single-seasonal drought is more frequent and lighter than multi-seasonal drought. Among the single-seasonal droughts, the frequency of summer drought is the highest, followed by autumn drought and spring drought, and the winter drought is the least. Summer and autumn droughts are of high level and more harmful. Among the multi-seasonal droughts, summer-autumn drought appears most frequently and has the highest drought level. The autumn-winter drought and spring-summer drought are less, and the spring-summer-autumn drought is the least. Compared with Northern China where the drought is closely related to precipitation, the drought in Southern China is less dependent on precipitation, especially it often occurs in summer and autumn even with more precipitation. The underlying mechanism for this effect is more complicated. |
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2018 Vol. 36 (9): 863-868
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638
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869 |
Fuzzy credibility-constrained quadratic programming model based on fuzzy weighted weights |
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WANG Youzhi, GUO Ping*, GUO Shanshan, LIU Xiao
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In order to maximize economic and social benefits of crop production in the Heihe middle reach, the water allocations for crops(wheat and maize)in Ganzhou District, Linze County and Gaotai County were optimized. In the optimization, the fuzzy weighted weights method was adopted to transform the multi-objective into a comprehensive benefit weight of crop, and then the weight was applied to the crop water production function. A quadratic programming model of fuzzy credibility-constrained constraint, where the triangular fuzzy number was used, was employed. In addition, the confidence levels of credibility were 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0, respectively. Taking the water allocations for crops in year 2011 as an example, the water allocation in different areas are decreased by 3.7×107 m3 and the crop yield increases by 1.3×107 kg, especially, the economic and social benefits are improved by 280 million Yuan and 18 000 people after optimization. Further, in planning year 2020, the water allocations of wheat and maize will be decreased by 4.98%-5.24% and 11.01%-12.07%, respectively, as compared with the status quo of year 2011, thus the water deficit situation can be improved, but still in a state of water shortage. These water allocations under various conditions can provide different scenarios for decision makers. |
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2018 Vol. 36 (9): 869-873
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341 )
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547
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874 |
Uncertainty of crop models under influence of climate change |
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YANG Weicai, MAO Xiaomin*
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Precise description of crop physiological growth process and accurate estimation of crop yield play a crucial role in social food safety and agricultural production. As a numerical simulation method for monitoring crop growth, the crop growth model has proven a powerful tool for crop growth analysis, yield simulation and scenario prediction. However, under the current background of climate change, the uncertainty of climate trend and the increase of extreme weather events have affected grain production largely. Therefore, how to simulate crop growth accurately under the climate change scenario has become a hot topic currently. Except the uncertainty of climate change, crop models are a simplified form of actual crop growth process. Thus these models have an imperfect physical structure. Additionally, randomness in data collection and regional heterogeneity of initial conditions can lead to poorer uncertainty in simulation results. Hence, based on a review of the state-of-the of crop models in China and abroad, the uncertainty of crop models and the impact of uncertainty of climate change on the models were discussed. Then, the types and characteristics of model-data fusion methods were outlined. The methods used to reduce the uncertainty of crop models in a regional scale were summarized. |
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2018 Vol. 36 (9): 874-879
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385 )
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840
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880 |
Effects of saline water irrigation on soil salinity movement and summer maize growth under subsurface drainage |
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FENG Genxiang,*, ZHANG Zhanyu,, FANG Guohua, ZHANG Zemin,
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A field experimental study was conducted to identify the effect of saline water irrigation on soil salinity movement and summer maize growth under subsurface drainage system. This study was comprised of nine treatments combined with three subsurface drainage depths, namely 0 m-no subsurface drainage(D0), 0.8 m(D1)and 1.2 m(D2)and three water salinity levels, such as 0.78 dS/m(S1), 3.75 dS/m(S2), and 6.25 dS/m(S3). The results indicate that the accumulated salt in the soil is effectively removed under subsurface drainage during the studied period. At the drainage depth of 80cm, the soil electronic conductivity within the root depth is decreased by 39.00%, 31.56% and 29.43% in S1, S2 and S3, respectively. But at the drainage depth of 120 cm, the soil electronic conductivity is decreased by 31.91%, 18.08% and 7.44% in S1, S2 and S3, respectively. The dry matter and yield of summer maize are reduced with increasing irrigation water salinity at the same drainage depth. The water use efficiency of summer maize from large to small is D1,D2 and D0 at the same irrigation water salinity. At the same drainage depth, the water use efficiency is decreased gradually with increasing irrigation water salinity. |
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2018 Vol. 36 (9): 880-885
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415 )
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886 |
Effects of water and fertilizer coupling on yield, water use efficiency and quality of tomato in greenhouse |
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LI Huanhuan, LIU Hao*, SUN Jingsheng, MA Xiaojian, CUI Yongsheng, MA Yanchuan
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In order to guide the fertigation of high yield and water-saving and best quality of tomato in greenhouse, effects of water and fertilizer coupling on water consumption, yield, water use efficiency and quality of tomato under drip irrigation were studied in this paper. Tomato was taken as the study object, 3 fertilization methods were set up, in which the total fertilizer quota was the same, but the fertilization frequency was different. In the first method F1, there was base fertilizer, 30% of the total fertilizer quota was applied with water after tomato transplanting, and the remaining 70% was equally divided into 6 portions and applied each afterwards. In the second method F2, the base fertilizer is half the total fertilizer quota, the remaining half was equally divided into 6 portions and applied each then. In the third method F3, the base fertilizer was the total fertilizer quota and applied once. There were 3 lower irrigation limits of soil matric potential(W1:-30 kPa, W2:-50 kPa, W3:-70 kPa)in treatments 1 to 3. The results show that fertilization methods don′t result in significant difference in water consumption for tomato, but the lower irrigation limit had a significant effect on water consumption, especially, the water consumption has a rather significant positive correlation with the irrigation quota(P<0.01). Compared with treatment F2W1 with the maximum yield of tomato, the yield of treatment F2W2 is decreased by 6.91%, the water saving efficiency, however, is raised by 14.83% and the water use efficiency is increased by 8.51%. TTS is negatively correlates with average fruit weight, but significantly positively correlated with the other factors except the sugar to acid ratio. By comprehensively considering production, WUE and TTS, and by using the TOPSIS comprehensive evaluation method, the optimal irrigation mode of water-saving with best quality of tomato under drip irrigation condition in greenhouse is determined, namely 50% of the total fertilizer is applied as the base fertilizer before transplanting, then irrigation quota is 20 mm after transplanting, the soil matric potential of 20 cm soil layer is controlled above -50 kPa, the irrigation requirement is 10 mm, and the remaining 50% of the fertilizer is equally divided into 6 times topdressing in flowering and fruit setting period. The results provide a theoretical basis for formulation of water-saving, high yield and best quality irrigation mode of tomato in greenhouse in north China. |
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2018 Vol. 36 (9): 886-891
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459 )
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892 |
Study on chlorophyll content and fluorescence parameters of grape under micro spray conditions |
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LIU Hongbo, BAI Yungang*, ZHANG Jianghui, DING Ping
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In order to study the chlorophyll content(Chl)and variation characteristics of fluorescence kinetic parameters of grape under micro spray condition in extreme drought land, the diurnal variation of chlorophyll fluorescence, Chl variation and the correlation between Chl and fluorescence parameters were analyzed by measuring the Chl and chlorophyll fluorescence in various growth stages of grape. The results show that there are significant differences in Chl and fluorescence parameters in fruit setting, expansion and maturity periods. The variation coefficients of Chl and Fv/Fm are all as small as 0.013-0.017 and 0.009-0.010, respectively. The variation coefficient of Fv/Fo is in 0.026-0.029 and was the largest. On the relationship between Chl and fluorescence parameters, Fv and Fo, Fm, Fv/Fm, Fv/Fo and Fv/Fm are significantly and positively correlated to Fv/Fo, with a correlation coefficient of 0.157-0.999. Fo/Fm is negatively correlated to Fm, Fv, Fv/Fo and Fv/Fm, and the correlation coefficient is in the range of -0.143-0.992. With the increase of water spraying duration, the measured values of Fv/Fm and Fv/Fo decrease obviously, indicating that an appropriate water spraying duration and period can improve the chlorophyll fluorescence characteristics of grape, thus the water stress effect can be reflected exactly. |
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2018 Vol. 36 (9): 892-896
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897 |
Drip irrigation schedules of maize in Tongliao |
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JIA Qiong, SHI Haibin*, LI Ruiping, FENG Yayang, LI He, ZHENG Jiawei
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A field experiment on drip irrigation schedule of maize was conducted in Tongliao, Inner Mongolia in 2016 in order to produce a more reasonable schedule for the maize in the background of "Water Saving and Grain Increasing Action" in China. A rainfall frequency analysis was made by using rainfall data of the experimental field in previous 34 years. By choosing meteorological data in typical years and combining with actual evapotranspiration rules obtained from the drip irrigation field experiment, six kinds of irrigation treatment were compared with each other in each growth stage. The maize plant height, leaf area index, productivity, etc. were measured. The results show that the characteristics and yield of maize in medium irrigation treatment are better than the others, and water use efficiency(WUE)was the highest, suggesting the best irrigation treatment. The medium irrigation treatment is used as the reference for drip irrigation schedule, then the reference evapotranspiration(ET0)is calculated based on the meteorological data. The actual water consumption is used to obtain the crop coefficient of each growth stage, and then the water requirement is calculated based on the ET0 of a typical year. According to the rainfall data, the drip irrigation schedules for different hydrological years are worked out, respectively. The film-covered drip irrigation quota is 1 575 m3/hm2, the non-film drip irrigation quota is 1 785 m3/hm2 in low flow year. The drip irrigation quotas with and without film cover in normal flow year are 1 125 m3/hm2 and 1 425 m3/hm2, respectively. Meanwhile, in flow year, the drip irrigation quotas with and without film cover are 600 m3/hm2 and 900 m3/hm2, respectively. |
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2018 Vol. 36 (9): 897-902
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588 )
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903 |
Effects of super absorbent polymer and nitrogen-phosphorus fertilizers on growth of rain-fed maize |
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WANG Yu, WEI Chenchen, YANG Peiling*, LIAO Renkuan, WEI Rong, YANG Fengru
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In order to improve water and fertilizer use efficiencies while crop yield is kept increasing and to slow down surface pollution in dry land farming, a field study was conducted by orthogonal design of experiment to clarify effects of super absorbent polymer(SAP)and nitrogen-phosphorus fertilizers(NPF)on fertility levels at different depths of soil, maize growth and nutrient use efficiency of rain-fed maize in the field. SAP and NPF application modes were sought for the optimal maize yield. The results show that the effects of three factors on fertility at different depths of soil, maize growth and nutrient use efficiency are inconsistent. SAP mainly affects soil fertility and crop nutrients, but NPF mainly influences soil nutrients and crop biomass. Under the conditions of this experiment, the maximum maize yield of 1.27 kg/m2 appears when SAP is in 45 kg/hm2 dose, and nitrogen and phosphorus fertilizers are in 120 kg/hm2 and 120 kg/ hm2 doses, respectively. The maximum increment in maize yield is 8% compared with the treatment without SAP and NPF, while the nitrogen fertilizer has achieved the maximum partial factor productivity of 105.83 kg / kg. |
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2018 Vol. 36 (9): 903-908
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367 )
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909 |
Soil nitrification process under different soil moisture and salinity conditions |
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LI Yawei,, XU Junzeng,, WEI Qi,, BAI Wenhuan,, LI Kunlin,, LIU Xiaoyin,*
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The nitrification process of salt-affected soil was studied through a laboratory incubation experiment at three soil moisture levels(50%, 75% and 100% of field capacity(FC))and four salinity levels(0.8, 3.0, 6.0 and 15.0 g/kg). The results showed that the NH+4-N consumption rates and the NO-3-N production rates increas significantly with increasing soil moisture, and ammonia oxidation and nitrite oxidation are promoted at higher soil moistures(75%FC and 100%FC)compared with 50%FC. In 3.0 and 6.0 g/kg treatments, the inhibition of soil salinity on nitrite oxidation is significantly stronger than that of ammonia oxidation, which accounts for NO-2-N accumulation. However, in 15.0 g/kg treatment, changes in the concentration of NH+4-N, NO-3-N and NO-2-N all remain at a low level, and a high soil salinity seriously inhibits both ammonia oxidation and nitrite oxidation. The non-synchronous response of ammonia oxidation and nitrite oxidation to soil salinity significantly affects the forms and transformation process of inorganic nitrogen in soil. |
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2018 Vol. 36 (9): 909-913
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423 )
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914 |
Effects of water and fertilizer coupling on photosynthetic and chlorophyll contents of jujube under drip irrigation in south Xinjiang sandy area |
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HOU Yusheng,, WANG Zhenhua,*, LI Wenhao,, BIAN Qingyong,, LI Chaoyang,
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In order to explore effects of water and fertilizer coupling on photosynthetic characteristics and chlorophyll relative contents of jujube in southern Xinjiang sandy area, the 8-year mature magnificent jujube trees were used as test plant, and water and nitrogen two-factor, three-level Latin square experiments were conducted in a small-sized land under drip-irrigation conditions. The results show that the diurnal variation of net photosynthetic rate(Pn)and stomatal conductance(Gs)of jujube presents two peaks, but the diurnal variation of transpiration rate(Tr)has a single peak. For case W2F1, the variation profiles of intercellular CO2 concentration(Ci)and leaf water use efficiency(WUE)present a single peak as well, and the maximums of Pn, Tr and Gs increase by 34.8%, 10.74% and 7.14%, respectively, compared with those under ordinary flooding irrigation(CK). For case W2F3, the peak values of Ci and WUE increase by 29.04% and 8.33%, respectively, compared with CK. Note that both chlorophyll relative content and nitrogen content are in the maximum in W3F3 treatment, especially 6.00% and 9.49% higher than in CK, respectively. Unfortunately, W3F3 shows no significant difference from W2F1(P>0.05). Pn is closely related to Tr and Gs, but Pn is just slightly related to chlorophyll relative content and nitrogen content. There is a close correlation between chlorophyll relative content and nitrogen content but a low correlation with WUE. According to the experimental results, a preliminary conclusion can be reached that irrigation 820 mm and fertilizer 450 kg/hm2(W2F1)are the best water-fertilizer supply mode for water and fertilizer saving in southern Xinjiang sandy area. |
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2018 Vol. 36 (9): 914-919
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920 |
Effects of aeration on root growth and water use efficiency of super rice under controlled irrigation conditions |
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LIAO Jiancheng, HU Deyong*, PEI Yi, CHEN Zhe, DING Xing, LUO Dongcheng
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Super rice—Lingliangyou 268 was used as test materials, by combing controlled irrigation and aeration technology. Four treatments, namely mechanically controlled irrigation aeration(JX), were set up super-micro-bubble controlled irrigation aeration(WP), controlled irrigation(CK)and flood irrigation(YS), to identify effects of aeration on root growth characteristics and water use efficiency of super rice under controlled irrigation conditions. The results show that the effective water saving is up to 15.3% in maximum due to aeration under the controlled irrigation compared with food irrigation condition. Additionally, the root growth is promoted and the dry matter weight of rice roots is increased and the dry matter weight of both stem and leaf are reduced. So the root volume and thickness as well as dry matter weight have been improved significantly, and the root activity is enhanced, the aging of rice roots is delayed. In terms of yield, the controlled irrigation aeration is similar to the flood irrigation, but the seed setting rate, 1000-grain weight, and water use efficiency are better than the latter. |
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2018 Vol. 36 (9): 920-924
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