High salinity in soil can prevent root growth of most plants. To investigate soil salinity dynamics under drip irrigation with mulch film (DI) and its effects on cotton root length, we conducted field experiments in...High salinity in soil can prevent root growth of most plants. To investigate soil salinity dynamics under drip irrigation with mulch film (DI) and its effects on cotton root length, we conducted field experiments in saline soil based on a monolith method using flooding irrigation with mulch film (FI) as a control at the Korla Experimental Station of the Xinjiang Academy of Agricultural Sciences, China in 2009 and 2010. The results showed that the total root length decreased 120 days after sowing (DAS) under DI, and was mainly centered in the 0-30 cm soil layer and at distances of 30-70 cm from the drip-lines. There was almost complete overlap in the area of root length decline and salt accumulation. In the soil depth of 0-30 cm and at distances of 30-70 cm from the drip-lines at 110 to 160 DAS in 2009 and 171 DAS in 2010, the electrical conductivity (EC) in all soil samples was at least 3 mS/cm and in some cases exceeded 5 mS/cm under DI treatment. However, EC barely exceeded 3 mS/cm and no reduction in root length was observed under FI treatment. Correlation analysis of soil EC and root length density indicated that the root length declined when the soil EC exceeded 2.8 mS/cm. The main reason for the decrease of root length in cotton under DI was localized accumulation of salinity.展开更多
The primary purpose of this research was to give suitable irrigation program according to the growth period and water requirement.A cotton field experiment with mulched drip irrigation was conducted at the National Fi...The primary purpose of this research was to give suitable irrigation program according to the growth period and water requirement.A cotton field experiment with mulched drip irrigation was conducted at the National Field Observation and Research Station for Oasis Farmland Ecosystem in Aksu of Xinjiang in 2008.Water balance method was adopted to study the water requirement and water consumption law of cotton under mulched drip irrigation in Tarim Irrigated Area.Statistical analysis of experimental data of irrigation indicates that the relationship between yield of cotton and irrigation presents a quadratic parabola.We fit the model of cotton water production on the basis of field experimental data of cotton.And the analysis on water saving benefit of cotton under mulched drip irrigation was done.Results indicate that water requirements for the irrigated cotton are 543 mm in Tarim Irrigated Area.The water requirements of seedling stage is 252 mm,budding stage is 186 mm,bolling stage is 316 mm and wadding stage is 139 mm.the irrigation amount determines the spatial distribution of soil moisture and water consumption during cotton life cycle.However,water consumption at different growth stages was inconsistent with irrigation.Quantitatively,the water consumed by cotton decreases upon the increase of irrigation amount.From the perspective of water saving,the maximal water use efficiency can reach 3 091 m3/ha.But the highest cotton yield needs 3464 m3/ha irrigation water.In summary,compared to the conventional drip irrigation,a number of benefits in water saving and yield increase were observed when using plastic mulch.At the same amount of irrigation,the cotton yield with plastic mulch was 30.2% higher than conventional approaches,and the efficiency of water utilization increased by30.2%.While at the same yield level,29.3% water was saved by using plastic mulch,and the efficiency increased by 41.5%.展开更多
Furrow irrigation with film-mulched agricultural beds is being promoted in the arid region of northwest China because it improves water utilization. Two-dimensional infiltration patterns under film-mulched furrows can...Furrow irrigation with film-mulched agricultural beds is being promoted in the arid region of northwest China because it improves water utilization. Two-dimensional infiltration patterns under film-mulched furrows can provide guidelines and criteria for irrigation design and operation. Our objective was to investigate soil water dynamics during ponding irrigation infiltration of mulched furrows in a cross-sectional ridge-furrow configuration, using laboratory experiments and mathematical simulations. Six experimental treatments, with two soil types (silt loam and sandy loam), were investigated to monitor the wetting patterns and soil water distribution in a cuboid soil chamber. Irrigation of mulched furrows clearly increased water lateral infiltration on ridge shoulders and ridges, due to enhancement of capillary driving force. Increases to both initial soil water content (SWC) and irrigation water level resulted in increased wetted soil volume. Empirical regression equations accurately estimated the wetted lateral distance (Rl) and downward distance (Rd) with elapsed time in a variably wetted soil medium. Optimization of model parameters followed by the Inverse approach resulted in satisfactory agreement between observed and predicted cumulative infiltration and SWC. On the basis of model calibration, HYDRUS-2D model can accurately simulate two-dimensional soil water dynamics under irrigation of mulched furrows. There were significant differences in wetting patterns between unmulched and mulched furrow irrigation using HYDRUS-2D simulation. The Rd under the mulched furrows was 32.14% less than the unmulched furrows. Therefore, film-mulched furrows are recommended in a furrow irrigation system.展开更多
Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation ...Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation with muddy water and fertilizer.The relationship between the single-line interference infiltration parameters,the sand content,the wetting front movement distances,and the sand content were all established.The model of the cumulative infiltration volume of per unit film pore area,the vertical and horizontal wetting front movement distance of the free surface,and the wetting front movement distance of the interference center with sand content and infiltration time were proposed.Reveal the law of the change of soil water content and the distribution of NO_(3)^(-)-N content based on different muddy water sand content.The results indicate that at the same infiltration time,as the muddy water sand content increases,the cumulative infiltration volume per unit pore area decreases.The infiltration index of the free infiltration and the single-line interference vary little when the sand content increases,mainly are around 0.64 and 0.58.The relationship between infiltration parameters a,b and the sand content is linear function.At the same location,the more the sand content,the smaller the wetting front movement distance in free surface and the single-line interference surface,the less the NO_(3)^(-)-N content.展开更多
The results of researches of condensation processes in the vapour channel similar to the Laval nozzle of short linear heat pipes are presented. Capacitive sensors are additionally installed in cooled top covers of the...The results of researches of condensation processes in the vapour channel similar to the Laval nozzle of short linear heat pipes are presented. Capacitive sensors are additionally installed in cooled top covers of the heat pipes, and electromagnetic pulses were supplied to them from the external generator. At heating the heat pipe evaporator, starting from a certain thermal power threshold value, electromagnetic pulses became modulated. It is related with the formations of the boiling process in the capillary-porous evaporator and large amount of vapour over it. Boiling process results in rapid increase of the pressure under which the average temperature of the evaporator occurs to be less than the boiling temperature of the working fluid under increased pressure. Considering condensation of excess vapour, this leads to repeated initiation and extinction of the boiling process in the evaporator, which reflects in pressure pulsations in the vapour channel. Pressure pulsations cause modulating effect on electromagnetic impulses. Pulsations frequencies are measured as well as their dependence from overheating of the evaporator. Using the capacitive sensors and a special electronic equipment we measured the local thickness of the working fluid at the condensing surface inside the heat pipes. Time-averaged values of the condensate film thickness are measured, depending on the heat load on the capillary-porous evaporator. The measurement error does not exceed 2 × 10–3 mm. It is demonstrated that the condensate film thickness lessens sharply with the increase of the heat load on the evaporator of a Laval-like low-temperature heat pipe, while the heat resistance of the film on the condensing surface reaches 60% of the total heat resistance of heat pipe with the capillary-porous evaporator.展开更多
Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water in...Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.展开更多
Developing effective irrigation and drainage strategies to improve the quality of saline-alkali soil is vital for enhancing agricultural production and increasing economic returns. In this study, we explored how irrig...Developing effective irrigation and drainage strategies to improve the quality of saline-alkali soil is vital for enhancing agricultural production and increasing economic returns. In this study, we explored how irrigation and drainage modes (flood irrigation, drip irrigation, and sub-surface pipe drainage under drip irrigation) improve the saline-alkali soil in Xinjiang, China. We aimed to study the transport characteristics of soil water and salt under different irrigation and drainage modes, and analyze the effects of the combination of irrigation and drainage on soil salt leaching, as well as its impacts on the growth of oil sunflower. Our results show that sub-surface pipe drainage under drip irrigation significantly reduced the soil salt content and soil water content at the 0–200 cm soil depth. Under sub-surface pipe drainage combined with drip irrigation, the mean soil salt content was reduced to below 10 g/kg after the second irrigation, and the soil salt content decreased as sub-surface pipe distance decreased. The mean soil salt content of flood irrigation exceeded 25 g/kg, and the mean soil desalination efficiency was 3.28%, which was lower than that of drip irrigation. The mean soil desalination rate under drip irrigation and sub-surface pipe drainage under drip irrigation was 19.30% and 58.12%, respectively. After sub-surface drainage regulation under drip irrigation, the germination percentage of oil sunflower seedlings was increased to more than 50%, which further confirmed that combined drip irrigation and sub-surface pipe drainage is very effective in improving the quality of saline-alkali soil and increasing the productivity of agricultural crops.展开更多
A study was undertaken in Kenana Sugar Scheme, Sudan during 2009/2010 and 2010/2011 seasons. In this study, the gated pipe (hydro-flume) for ?furrow irrigation was compared with the conventional open field head ditch ...A study was undertaken in Kenana Sugar Scheme, Sudan during 2009/2010 and 2010/2011 seasons. In this study, the gated pipe (hydro-flume) for ?furrow irrigation was compared with the conventional open field head ditch irrigation system concerning the volume of irrigation water applied to the field, irrigation efficiencies, the time of cutoff, water and irrigation time saved and the irrigation production efficiency (IPE). To achieve these objectives, two commercial cane fields having the same furrow lengths (2100 m) and slopes were chosen. The study shows that in the open field head ditch irrigation, the irrigation water added was 69.1 mm in the top, 75.7 mm in the ?middle and 66.1 mm in the end of the furrow. Whereas, the irrigation water added in the gated pipe system was 132.7 mm, 46.1 mm and 101.9 mm, respectively. The present study indicates that the gated-pipe system has a high value of application efficiency (79% - 88%) compared with the open field head ditch (69% - 71%). The percent of deep percolation (PDP) for the gated-pipe system is greater than the PDP obtained under open field head ditch irrigation conditions. Also the percent of runoff (PRO) is higher under the open field head ditch system and the water conveyance efficiency for the open field head ditch is 88%. While the gated pipe needs more advance time but can save 20 to 65 m3 of water/irrigation cycle with better uniformity coefficient (CU) and irrigation production efficiency (IPE) compared with the open field head ditch. From the above mentioned results, it is concluded that under Kenana conditions the gated-pipe system is better than the open field head ditch irrigation system keeping in mind that for more uniform water distribution through irrigated furrows of the long fields of Kenana, increased pressure head at the inlet and/or larger openings of the hydro-flume gates may be necessary.展开更多
The results of the numerical studies of vortex formation inside short heat pipes (HP’s) with profiled vapour channel in the Laval-liked nozzle form are presented. For the first time, it was found that the vapour vort...The results of the numerical studies of vortex formation inside short heat pipes (HP’s) with profiled vapour channel in the Laval-liked nozzle form are presented. For the first time, it was found that the vapour vortex of moist compressible vapour flow in the cooled part of vapour channel changes its rotational motion direction. The rotation direction of the toroidal vapour vortex, obtained by solving the Navier Stokes equations is dependent on the heat power value, entering to the HP’s evaporator. With low heat power loads the rotational direction of the circular toroidal vapour ring due to the Coanda effect and sticking moving vapour jets to the channel’s walls occurs from the periphery to the longitudinal axis of the vapour channel. While the heat power load increasing, the direction of the circular toroidal vapour ring rotation changes to the opposite, from the longitudinal axis to the periphery of the vapour channel. The thickness of the formed working fluid condensate film located under the toroidal vapour vortex also related to the evaporator heat power load and the associated toroidal vapour vortex rotation direction. The numerical thickness calculation of the formed working fluid condensate film located under the toroidal vapour vortex was compared with experimental values, obtained by capacitive sensors. The thickness values of the calculated condensate film thickness and experimentally measured values using capacitive sensors are close in magnitude order.展开更多
This study was conducted to solve the problem of green weed control in wheat fields in Hetao irrigation area among the Yellow River.Based on the observation of the competition between wheat and weeds in areas where we...This study was conducted to solve the problem of green weed control in wheat fields in Hetao irrigation area among the Yellow River.Based on the observation of the competition between wheat and weeds in areas where weeds occurred seriously in wheat fields in Hetao irrigation area among the Yellow River,we measured the effects of green weed control measures and wheat yield using different wheat varieties,planting densities,different organic fertilizers,different ploughing times,and different mulching methods.The results showed that the emergence of weeds in wheat fields dominated by Chenopodiaceae weeds,grain amaranth and barnyard grass was more than 10 d later than wheat.Weeds were mainly distributed between rows(holes),and the number of plants accounted for 66.6%(drill seeding)and 97.6%(hole seeding),respectively.And the growth of weeds in rows(holes)was weaker,and the fresh weight of individual plants was 39.3%-41.9%lower than that between rows(holes).The ecological weed inhibitory effect was significant in the early stage of wheat growth;and among the green weed control measures,except that different varieties and planting densities caused no significant difference in weed control effect,other measures had obvious weed control effects.Comprehensive comparison showed that the control effects of plant number in black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 82.3%,71.7%,22.0%,and 8.6%,respectively;the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 98.0%,97.1%,23.9%,and 9.6%,respectively;and the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding and increasing ploughing times increased wheat yield by 69.4%,56.4%and 21.1%,respectively.The technologies in this study can realize the purposes of mechanized green weed control in organic wheat production and low-cost,high-yield,large-scale production.展开更多
Potato is one of the staple food crops in North China.However,potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.Increasing yield and water use effici...Potato is one of the staple food crops in North China.However,potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.Increasing yield and water use efficiency(WUE)of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.However,the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.Based on meta-analysis of field experiments from the literature and model simulation,this study quantified the potential yields of potatoes without water and fertilizer limitation,and yield under irrigated and rainfed conditions,and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains(DH),the Foothills of Yanshan hilly(YH),the North foot of the Yinshan Mountains(YM),and the Loess Plateau(LP)in North China.Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^(–1)for the YH region,11.4 t ha^(–1)for the YM region,11.2 t ha^(–1)for the DH region,and 10.7 t ha^(–1)for the LP region,respectively.Observed rainfed potato tuber dry weight yield accounted for 61,30,28 and 24%of the potential yield in the DH,YH,YM,and LP regions.The maximum WUE of 2.2 kg m^(–3)in the YH region,2.1 kg m^(–3)in the DH region,1.9 kg m^(–3)in the YM region and 1.9 kg m^(–3)in the LP region was achieved under the potential yield level.Ridge-furrow planting could boost yield by 8–49%and WUE by 2–36%while ridge-furrow planting with film mulching could boost yield by 35–89%and WUE by 7–57%across North China.Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.展开更多
基金funded by the National Natural Science Foundation of China (31000252, 31201681)the Science and Technology Supporting Project of the Department of Science and Technology of Xinjiang, China (200840102-08)
文摘High salinity in soil can prevent root growth of most plants. To investigate soil salinity dynamics under drip irrigation with mulch film (DI) and its effects on cotton root length, we conducted field experiments in saline soil based on a monolith method using flooding irrigation with mulch film (FI) as a control at the Korla Experimental Station of the Xinjiang Academy of Agricultural Sciences, China in 2009 and 2010. The results showed that the total root length decreased 120 days after sowing (DAS) under DI, and was mainly centered in the 0-30 cm soil layer and at distances of 30-70 cm from the drip-lines. There was almost complete overlap in the area of root length decline and salt accumulation. In the soil depth of 0-30 cm and at distances of 30-70 cm from the drip-lines at 110 to 160 DAS in 2009 and 171 DAS in 2010, the electrical conductivity (EC) in all soil samples was at least 3 mS/cm and in some cases exceeded 5 mS/cm under DI treatment. However, EC barely exceeded 3 mS/cm and no reduction in root length was observed under FI treatment. Correlation analysis of soil EC and root length density indicated that the root length declined when the soil EC exceeded 2.8 mS/cm. The main reason for the decrease of root length in cotton under DI was localized accumulation of salinity.
基金Supported by 973 Project(2009CB421302)Innovation Project of Chinese Academy of Sciences(KZCX2-YW-127)Youth Science Foundation of China(41401025)
文摘The primary purpose of this research was to give suitable irrigation program according to the growth period and water requirement.A cotton field experiment with mulched drip irrigation was conducted at the National Field Observation and Research Station for Oasis Farmland Ecosystem in Aksu of Xinjiang in 2008.Water balance method was adopted to study the water requirement and water consumption law of cotton under mulched drip irrigation in Tarim Irrigated Area.Statistical analysis of experimental data of irrigation indicates that the relationship between yield of cotton and irrigation presents a quadratic parabola.We fit the model of cotton water production on the basis of field experimental data of cotton.And the analysis on water saving benefit of cotton under mulched drip irrigation was done.Results indicate that water requirements for the irrigated cotton are 543 mm in Tarim Irrigated Area.The water requirements of seedling stage is 252 mm,budding stage is 186 mm,bolling stage is 316 mm and wadding stage is 139 mm.the irrigation amount determines the spatial distribution of soil moisture and water consumption during cotton life cycle.However,water consumption at different growth stages was inconsistent with irrigation.Quantitatively,the water consumed by cotton decreases upon the increase of irrigation amount.From the perspective of water saving,the maximal water use efficiency can reach 3 091 m3/ha.But the highest cotton yield needs 3464 m3/ha irrigation water.In summary,compared to the conventional drip irrigation,a number of benefits in water saving and yield increase were observed when using plastic mulch.At the same amount of irrigation,the cotton yield with plastic mulch was 30.2% higher than conventional approaches,and the efficiency of water utilization increased by30.2%.While at the same yield level,29.3% water was saved by using plastic mulch,and the efficiency increased by 41.5%.
基金supported by National Natural Science Foundation of China (NO. 41401036)China Postdoctoral Science Foundation (NO. 2015T81070, 2014M560818)West Light Foundation of the Chinese Academy of Sciences
文摘Furrow irrigation with film-mulched agricultural beds is being promoted in the arid region of northwest China because it improves water utilization. Two-dimensional infiltration patterns under film-mulched furrows can provide guidelines and criteria for irrigation design and operation. Our objective was to investigate soil water dynamics during ponding irrigation infiltration of mulched furrows in a cross-sectional ridge-furrow configuration, using laboratory experiments and mathematical simulations. Six experimental treatments, with two soil types (silt loam and sandy loam), were investigated to monitor the wetting patterns and soil water distribution in a cuboid soil chamber. Irrigation of mulched furrows clearly increased water lateral infiltration on ridge shoulders and ridges, due to enhancement of capillary driving force. Increases to both initial soil water content (SWC) and irrigation water level resulted in increased wetted soil volume. Empirical regression equations accurately estimated the wetted lateral distance (Rl) and downward distance (Rd) with elapsed time in a variably wetted soil medium. Optimization of model parameters followed by the Inverse approach resulted in satisfactory agreement between observed and predicted cumulative infiltration and SWC. On the basis of model calibration, HYDRUS-2D model can accurately simulate two-dimensional soil water dynamics under irrigation of mulched furrows. There were significant differences in wetting patterns between unmulched and mulched furrow irrigation using HYDRUS-2D simulation. The Rd under the mulched furrows was 32.14% less than the unmulched furrows. Therefore, film-mulched furrows are recommended in a furrow irrigation system.
基金National Key R&D Program of China(2016YFC0400204)National Natural Science Foundation of China(51479161,51279157,51779205)。
文摘Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation with muddy water and fertilizer.The relationship between the single-line interference infiltration parameters,the sand content,the wetting front movement distances,and the sand content were all established.The model of the cumulative infiltration volume of per unit film pore area,the vertical and horizontal wetting front movement distance of the free surface,and the wetting front movement distance of the interference center with sand content and infiltration time were proposed.Reveal the law of the change of soil water content and the distribution of NO_(3)^(-)-N content based on different muddy water sand content.The results indicate that at the same infiltration time,as the muddy water sand content increases,the cumulative infiltration volume per unit pore area decreases.The infiltration index of the free infiltration and the single-line interference vary little when the sand content increases,mainly are around 0.64 and 0.58.The relationship between infiltration parameters a,b and the sand content is linear function.At the same location,the more the sand content,the smaller the wetting front movement distance in free surface and the single-line interference surface,the less the NO_(3)^(-)-N content.
文摘The results of researches of condensation processes in the vapour channel similar to the Laval nozzle of short linear heat pipes are presented. Capacitive sensors are additionally installed in cooled top covers of the heat pipes, and electromagnetic pulses were supplied to them from the external generator. At heating the heat pipe evaporator, starting from a certain thermal power threshold value, electromagnetic pulses became modulated. It is related with the formations of the boiling process in the capillary-porous evaporator and large amount of vapour over it. Boiling process results in rapid increase of the pressure under which the average temperature of the evaporator occurs to be less than the boiling temperature of the working fluid under increased pressure. Considering condensation of excess vapour, this leads to repeated initiation and extinction of the boiling process in the evaporator, which reflects in pressure pulsations in the vapour channel. Pressure pulsations cause modulating effect on electromagnetic impulses. Pulsations frequencies are measured as well as their dependence from overheating of the evaporator. Using the capacitive sensors and a special electronic equipment we measured the local thickness of the working fluid at the condensing surface inside the heat pipes. Time-averaged values of the condensate film thickness are measured, depending on the heat load on the capillary-porous evaporator. The measurement error does not exceed 2 × 10–3 mm. It is demonstrated that the condensate film thickness lessens sharply with the increase of the heat load on the evaporator of a Laval-like low-temperature heat pipe, while the heat resistance of the film on the condensing surface reaches 60% of the total heat resistance of heat pipe with the capillary-porous evaporator.
文摘Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.
基金financially supported by the National Natural Science Foundation of China (51741908)
文摘Developing effective irrigation and drainage strategies to improve the quality of saline-alkali soil is vital for enhancing agricultural production and increasing economic returns. In this study, we explored how irrigation and drainage modes (flood irrigation, drip irrigation, and sub-surface pipe drainage under drip irrigation) improve the saline-alkali soil in Xinjiang, China. We aimed to study the transport characteristics of soil water and salt under different irrigation and drainage modes, and analyze the effects of the combination of irrigation and drainage on soil salt leaching, as well as its impacts on the growth of oil sunflower. Our results show that sub-surface pipe drainage under drip irrigation significantly reduced the soil salt content and soil water content at the 0–200 cm soil depth. Under sub-surface pipe drainage combined with drip irrigation, the mean soil salt content was reduced to below 10 g/kg after the second irrigation, and the soil salt content decreased as sub-surface pipe distance decreased. The mean soil salt content of flood irrigation exceeded 25 g/kg, and the mean soil desalination efficiency was 3.28%, which was lower than that of drip irrigation. The mean soil desalination rate under drip irrigation and sub-surface pipe drainage under drip irrigation was 19.30% and 58.12%, respectively. After sub-surface drainage regulation under drip irrigation, the germination percentage of oil sunflower seedlings was increased to more than 50%, which further confirmed that combined drip irrigation and sub-surface pipe drainage is very effective in improving the quality of saline-alkali soil and increasing the productivity of agricultural crops.
文摘A study was undertaken in Kenana Sugar Scheme, Sudan during 2009/2010 and 2010/2011 seasons. In this study, the gated pipe (hydro-flume) for ?furrow irrigation was compared with the conventional open field head ditch irrigation system concerning the volume of irrigation water applied to the field, irrigation efficiencies, the time of cutoff, water and irrigation time saved and the irrigation production efficiency (IPE). To achieve these objectives, two commercial cane fields having the same furrow lengths (2100 m) and slopes were chosen. The study shows that in the open field head ditch irrigation, the irrigation water added was 69.1 mm in the top, 75.7 mm in the ?middle and 66.1 mm in the end of the furrow. Whereas, the irrigation water added in the gated pipe system was 132.7 mm, 46.1 mm and 101.9 mm, respectively. The present study indicates that the gated-pipe system has a high value of application efficiency (79% - 88%) compared with the open field head ditch (69% - 71%). The percent of deep percolation (PDP) for the gated-pipe system is greater than the PDP obtained under open field head ditch irrigation conditions. Also the percent of runoff (PRO) is higher under the open field head ditch system and the water conveyance efficiency for the open field head ditch is 88%. While the gated pipe needs more advance time but can save 20 to 65 m3 of water/irrigation cycle with better uniformity coefficient (CU) and irrigation production efficiency (IPE) compared with the open field head ditch. From the above mentioned results, it is concluded that under Kenana conditions the gated-pipe system is better than the open field head ditch irrigation system keeping in mind that for more uniform water distribution through irrigated furrows of the long fields of Kenana, increased pressure head at the inlet and/or larger openings of the hydro-flume gates may be necessary.
文摘The results of the numerical studies of vortex formation inside short heat pipes (HP’s) with profiled vapour channel in the Laval-liked nozzle form are presented. For the first time, it was found that the vapour vortex of moist compressible vapour flow in the cooled part of vapour channel changes its rotational motion direction. The rotation direction of the toroidal vapour vortex, obtained by solving the Navier Stokes equations is dependent on the heat power value, entering to the HP’s evaporator. With low heat power loads the rotational direction of the circular toroidal vapour ring due to the Coanda effect and sticking moving vapour jets to the channel’s walls occurs from the periphery to the longitudinal axis of the vapour channel. While the heat power load increasing, the direction of the circular toroidal vapour ring rotation changes to the opposite, from the longitudinal axis to the periphery of the vapour channel. The thickness of the formed working fluid condensate film located under the toroidal vapour vortex also related to the evaporator heat power load and the associated toroidal vapour vortex rotation direction. The numerical thickness calculation of the formed working fluid condensate film located under the toroidal vapour vortex was compared with experimental values, obtained by capacitive sensors. The thickness values of the calculated condensate film thickness and experimentally measured values using capacitive sensors are close in magnitude order.
基金Supported by Science and Technology Cooperation Project between Bayannaoer Academy of Agricultural and Animal Sciences and Bayannaoer Municipal Government(2020BCN886)2020 Science and Technology Major Special Project of Inner Mongolia Autonomous Region(NMKJXM202013)Inner Mongolia"Grassland Talents"Engineering Team(CYYC2019-2-50).
文摘This study was conducted to solve the problem of green weed control in wheat fields in Hetao irrigation area among the Yellow River.Based on the observation of the competition between wheat and weeds in areas where weeds occurred seriously in wheat fields in Hetao irrigation area among the Yellow River,we measured the effects of green weed control measures and wheat yield using different wheat varieties,planting densities,different organic fertilizers,different ploughing times,and different mulching methods.The results showed that the emergence of weeds in wheat fields dominated by Chenopodiaceae weeds,grain amaranth and barnyard grass was more than 10 d later than wheat.Weeds were mainly distributed between rows(holes),and the number of plants accounted for 66.6%(drill seeding)and 97.6%(hole seeding),respectively.And the growth of weeds in rows(holes)was weaker,and the fresh weight of individual plants was 39.3%-41.9%lower than that between rows(holes).The ecological weed inhibitory effect was significant in the early stage of wheat growth;and among the green weed control measures,except that different varieties and planting densities caused no significant difference in weed control effect,other measures had obvious weed control effects.Comprehensive comparison showed that the control effects of plant number in black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 82.3%,71.7%,22.0%,and 8.6%,respectively;the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 98.0%,97.1%,23.9%,and 9.6%,respectively;and the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding and increasing ploughing times increased wheat yield by 69.4%,56.4%and 21.1%,respectively.The technologies in this study can realize the purposes of mechanized green weed control in organic wheat production and low-cost,high-yield,large-scale production.
基金the National Key Research and Development Program of China(2021YFD1901104)the 2115 Talent Development Program of China Agricultural University(00109016)。
文摘Potato is one of the staple food crops in North China.However,potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.Increasing yield and water use efficiency(WUE)of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.However,the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.Based on meta-analysis of field experiments from the literature and model simulation,this study quantified the potential yields of potatoes without water and fertilizer limitation,and yield under irrigated and rainfed conditions,and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains(DH),the Foothills of Yanshan hilly(YH),the North foot of the Yinshan Mountains(YM),and the Loess Plateau(LP)in North China.Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^(–1)for the YH region,11.4 t ha^(–1)for the YM region,11.2 t ha^(–1)for the DH region,and 10.7 t ha^(–1)for the LP region,respectively.Observed rainfed potato tuber dry weight yield accounted for 61,30,28 and 24%of the potential yield in the DH,YH,YM,and LP regions.The maximum WUE of 2.2 kg m^(–3)in the YH region,2.1 kg m^(–3)in the DH region,1.9 kg m^(–3)in the YM region and 1.9 kg m^(–3)in the LP region was achieved under the potential yield level.Ridge-furrow planting could boost yield by 8–49%and WUE by 2–36%while ridge-furrow planting with film mulching could boost yield by 35–89%and WUE by 7–57%across North China.Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.