Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch dr...Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch drip irrigation emitters,focusing on the anti-clogging performance through the experiment,were investigated.The dynamic variations in the clogging characteristics of emitters,specifically were subjected to statistical analysis.The movement mechanism of emitter clogging and discharging sediment was studied.The effects of emitter structure and position factors on emitter clogging were analyzed.The results show that the pressure-compensated emitter exhibits superior anti-clogging perfor-mance,with a service life that is 227.8%greater than that of the labyrinth channel emitter.A single structural factor cannot completely evaluate the anti-clogging performance of emitters.All factors causing emitter clogging should be considered comprehensively.Emitters contain sensitive sediment prone to clogging,however,significant blockage occurs primarily when the sediment content is elevated.The discharge of sediment,denoted as V90,from the emitter is affected by the accumulative effect of clogged sediment.These results may offer valuable insights for the application and advancement of drip irrigation technology.展开更多
Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.How...Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.However,delayed sowing is unavoidable in mulch-free cultivation in ecological regions with a short frost-free period.Intercropping with cumin,which has a shorter growth period,served as an effective strategy to improve land use efficiency during the early growth stages of cotton.Therefore,a two-year field experiment was conducted to study the effects of intercropping cumin at the seeding rate of 2.5(ID1),3.85(ID2),and 5.2(ID3)kg・hm−2 on cotton growth,interspecies competition,fiber quality,and water use efficiency(WUE),as well as system economic benefits under subsurface drip irrigation.Monocropping cotton was used as the control(CK)treatment.Results At the initial flowering(IF)stage(the end of the co-growth period of cotton and cumin),cotton plant height in ID2 and ID3 treatments decreased by 5.93%–16.53%and 10.87%–31.11%,respectively,cotton stem diameter by 11.41%–14.25%and 3.37%–26.49%,respectively,and vegetative biomass by 14.46%–30.65%and 22.59%–49.91%,respectively,compared with CK treatment.With the increase in cumin density,the crop growth rate(CGR)and compensation effect in cotton tended to significantly decrease at the IF stage regardless of organs considered.For the non-co-growth period(after harvesting cumin),cotton reproductive organ biomass in ID2 and ID3 treatments increased by 4.09%‒14.61%at the boll opening stage,crop growth rate in reproductive organs by 20.74%and 74.26%from peak boll to boll opening stages compared with CK treatment,due to an enhancement of 19.09%and 49.30%in the compensation effect.Compared with ID1,the aggressivity treated by ID2 and ID3 decreased by 12.82%–46.34%and 17.95%–31.71%,respectively.However,owing to a greater number of green bolls in the upper canopy at the harvest stages in the ID3 treatment,the system production value(closely related to yield)treated by ID2 was 11.69%–16.89%,6.56%–20.02%,and 16.48%–59.83%greater than that of the ID1,ID3,and CK treatments,respectively.This also led to the highest WUE and net profit under the ID2 treatment.Conclusion Intercropping cumin with medium density improved the cotton biomass accumulation characteristics and increased resources such as land and water utilization efficiency and economic benefits through a stronger compensation effect after harvesting cumin under subsurface drip irrigation without mulch.This study not only provides alternatives to residual film pollution in arid cotton fields but also establishes a sustainable agro-ecological-economic planting paradigm by reducing plastic use and enhancing water and fertilizer use efficiency,holding significant implications for advancing resource-efficient agricultural systems.展开更多
Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considere...Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.展开更多
The rapid identification of planting patterns for major crops in a large irrigated district has vital importance for irrigation management,water fee collection,and crop yield estimation.In this study,the OTSU algorith...The rapid identification of planting patterns for major crops in a large irrigated district has vital importance for irrigation management,water fee collection,and crop yield estimation.In this study,the OTSU algorithm and Mean-Shift algorithm were employed to automatically determine threshold values for mapping two main rotated crop patterns at the pixel scale.A time series analysis was conducted to extract the spatial distribution of rice-wheat and wheat-maize rotations in the Chuanhang irrigation district from 2016 to 2020.The results demonstrate that both threshold segmentation algorithms are reliable in extracting the spatial distribution of the crops,with an overall accuracy exceeding 80%.Additionally,both Kappa coefficients surpass 0.7,indicating better performance by OTSU method.Over the period from 2016 to 2020,the area occupied by rice-wheat rotation cropping ranged from 12500 to 14400 hm 2;whereas wheat-maize rotation cropping exhibited smaller and more variable areas ranging from 19730 to 34070 hm 2.These findings highlight how remote sensing-based approaches can provide reliable support for rapidly and accurately identifying the spatial distribution of main crop rotation patterns within a large irrigation district.展开更多
The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI)...The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI) and fixed drip irrigation( FDI) on growth,photosynthetic characteristics,biomass accumulation and irrigation water use efficiency of Arabica coffee were investigated under three nitrogen levels,high nitrogen( NH),middle nitrogen( NM) and low nitrogen( NL). The results show that there was a significant Logistic curve between the plant height,the stem diameter of Arabica coffee and growth days. Compared with CDI,ADI had no significant effects on leaf net photosynthetic rate,stomatal conductance,instantaneous water use efficiency and biomass accumulation above ground of Arabica coffee,while FDI decreased significantly,ADI and FDI increased irrigation water use efficiency by 50. 59% and 32. 85%,respectively. Compared with NH,with the reduction of N application rate,net photosynthetic rate,stomatal conductance,biomass accumulation above ground and irrigation water use efficiency decreased by 6. 81%-12. 30%,13. 70%-22. 69%,9. 61%-16. 67% and 9. 78%-15. 64%,respectively. Compared with CDINH,ADINHdecreased net photosynthesis rate and the stomatal conductance not significantly,other treatments decreased by 9. 16%-19. 22%,14. 49%-32. 91%,and decreased biomass accumulation above ground by 8. 26%-27. 34% except ADINH,and increased irrigation water use efficiency by 16. 46%-60. 95% except CDINMand CDINL. Therefore,alternate drip irrigation under high N level( ADINH) is the best water and nitrogen coupling mode of young Arabica coffee tree for water efficiency.展开更多
Six-year old apple trees were selected for field experiment.The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards.There were three factors:the buried ...Six-year old apple trees were selected for field experiment.The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards.There were three factors:the buried depth H(25,40,55 cm),the horizontal distance L(30,40,60 cm)between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N(1,2,4).The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency(IWUE)of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75%of the field water capacity.The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28388.17 kg/hm2 and 16.83 kg/m3 in treatment T3,respectively.At the same L and N levels(T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22%and 31.48%,while IWUE is reduced by14.02%and 18.12%compared with T3,respectively.At the same H and N levels(T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level.Especially,when L was 30 cm(T3),the yield and IWUE were the highest.The same L and H levels(T3,T6,and T7)could promote the growth of apple trees when N was 2(T3).Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%.Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.展开更多
Owing to overcoming the characteristics that there are many economic and technical indexes which are fuzzy and incompatibility to each other in evaluating investment project,a new method is proposed.The method is base...Owing to overcoming the characteristics that there are many economic and technical indexes which are fuzzy and incompatibility to each other in evaluating investment project,a new method is proposed.The method is based on the matter-element analysis and combined with the concepts of fuzzy mathematics,which is called the method of fuzzy matter-element analysis.It constructs the compound fuzzy matter element with the investment projects,evaluation factors and their fuzzy value.Through establishing the best subjection degree (fuzzy value),complex fuzzy matter element of relational coefficient and weight aggregation of fuzzy matter-element model,the writer achieves on optimum order of the investment projects according to the calculated relational degree and finds the best project.In this paper,the calculation of weight adopts the analytical hierarchy process method(AHP).Through the actual example,it shows that the model is simple and its calculation is reliable.It is very significant for the engineering evaluated bid and investment decision.展开更多
The author considered the influences of several weather factors, such as air temperature, sunlight, saturation deficiency, wind speed and so on to forecasting the water requirement of well irrigation rice based on Art...The author considered the influences of several weather factors, such as air temperature, sunlight, saturation deficiency, wind speed and so on to forecasting the water requirement of well irrigation rice based on Artificial Neutron Network. Through dealing with the time series of water requirement and its influence factors, the author applied the multi-dimension data correlation analysis to ensure the net structure. Thus, the ANN model to forecast the water requirement of well irrigation rice has been built. By means of the ANN model, uncertainty relation between water requirement and many influence factors among the interior and exterior can be discovered. The results of ANN model is good, and can provide some references for establishing the water saving irrigation system.展开更多
Background:Cotton production in China is challenged by high labor input including manual topping(MT).Recently,to replace MT in the Xinjiang cotton region of China,mepiquat chloride(MC)was applied once more than the tr...Background:Cotton production in China is challenged by high labor input including manual topping(MT).Recently,to replace MT in the Xinjiang cotton region of China,mepiquat chloride(MC)was applied once more than the traditional multiple-application;this was designated as chemical topping(CT),but it is unclear whether the amount of irrigation needs to be adjusted to accommodate CT.Results:The main plots were assigned to three drip irrigation amounts[300(I_(1))480(I_(2)), and 660(I_(3))mm],and the subplots were assigned to the CT treatments[450(MC)750(MC_(2)),and 1050(MC_(3))mL·hm^(-2)25%MC]with MT as a control that was performed after early bloom.The optimum drip irrigation amount for CT was explored based on leaf photosynthesis,chlorophyll fluorescence,biomass accumulation,and yield.There were significant influe nces of drip irrigation,topping treatme nts and their interaction on chlorophyll fluorescence characteristics,gas exchange parameters and biomass accumulation characteristics as well as yield.The combination of I_(2) and MC_(2)(I_(2)MC_(2))performed best.Compared with I_(2)MC_(2)the net photosynthetic rate(Pn),stomatai conductance(Gs),transpiration rate(Tr),and photochemical quenching coefficient(qP)of I_(2)MC_(2)significantly increased by 4.0%~7.2%,6.8%〜17.1%,5.2%~17.6%,and 4.8%~9.6%,respectively,from the peak flowering to boll opening stages.Moreover,I_(2)MC_(2) showed fast reproductive organ biomass accumulation and the highest seed cotton yield;the latter was 6.6%~12.8%higher than that of I_(2)MT.Further analysis revealed that a 25%MC emulsion in water(MCEW)application resulted in yield improvement by increasing Pn,φPSⅡ,and qP to promote biomass accumulation and transport to reproductive organs.Conclusion:The results showed that the 480 mm drip irrigation combined with 750 mL·hm^(-2)MC increased the rate of dry matter accumulation in reproductive organs by increasing Pn,φPSⅡ and qP to improve photosynthetic performance,thus achieving higher yield.展开更多
In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experime...In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experiments were carried out with different apple trees. Three irrigation levels were applied: 85%-100%(H1), 70%-85%(H2) and 55%-70%(H3) of the field water capacity, respectively, and three nitrogen levels were N1(360 g/plant), N2(240 g/plant) and N3(120 g/plant). The results show that irrigation and nitrogen application has significant effects on new shoot length, flowering and fruit setting, fruit diameter, fruit volume and yield of apple. The leaf area index(LAI) shows a single trend during the growth period, and the peak value appears in the middle of July. Under the same irrigation level, compared with N3, N1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 17.91%, 28.31%, 18.75%, 11.38%, 10.13%, 36.60%, 20.92% and 5.19%, respectively, while N2 also increases by 12.40%, 15.63%, 4.86%, 5.40%, 5.11%, 17.01%, 26.17% and 13.74%, respectively. The rate of flowering and fruit setting decreases with the increase of nitrogen application. Under the same nitrogen level, compared with H3, H1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 34.65%, 15.49%, 30.77%, 3.93%, 4.95%, 12.86%, 33.15% and 28.62%, respectively, while H2 also increases by 33.67%, 16.42%, 67.52%, 3.81%, 2.97%, 11.57%, 43.45% and 27.26%, respectively. The rate of flowering and fruit setting decreases first and then increases with the increase of irrigation amount. Compared with H3N3, the yield of other treatments increases by 2.69%-52.20%, while H2N1 treatment has the highest yield(26 852.55 kg/ha). Considering from the point of view of promoting growth and increasing yield, the best water and nitrogen combination mode of mountain apple in northern Shaanxi is medium water deficit irrigation and high nitrogen(H2N1) treatment. The results from this study can provide a theoretical basis for apple water and nitrogen management in mountainous areas of northern Shaanxi.展开更多
The paper builds up the forecasting model of air temperature according to the data (1994～1998) of Fu Jin area.At the same time,the writer inquires into the relation of water requirement of well irrigation rice (ET) a...The paper builds up the forecasting model of air temperature according to the data (1994～1998) of Fu Jin area.At the same time,the writer inquires into the relation of water requirement of well irrigation rice (ET) and average air temperature (T).Furthermore,the rice irrigation water requirement (ET) of Fu Jin area has been forecast in 1999.Thus,we can apply the model in irrigation management.展开更多
Aiming at less and un-uniform distribution rainfall problems, the serious draught in spring, low crop production and water efficiency in sandy soil area of Heilongjiang Province, the experiment of alternative furrow i...Aiming at less and un-uniform distribution rainfall problems, the serious draught in spring, low crop production and water efficiency in sandy soil area of Heilongjiang Province, the experiment of alternative furrow irrigation was conducted in Dumeng County in 2009. The purpose of the experiment was to find the water consumption law and its influence on maize yield. The results showed that the highest water consumption was during the heading stage and the highest daily consumption of water was during the filling stage. The stimulation effect of alternative furrow irrigation on yield was obvious in the appropriate irrigation level. The best irrigation pattern for the highest yield was as follows： the seedling stage was 325 m3. hm^-2; the jointing stage was 400 m3-hm^-2; and the filling stage was 288 m3- hm-2. The water consumption during each growing period was that the seedling was 38.85 mm; the jointing was 108.11 mm; the heading was 124.39 ram; the filling was 88.96 ram; the milk was 60.21 ram; and the harvesting was 47.89 mm.展开更多
Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilizatio...Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilization of agricultural production and waste water resources.The results demonstrated that the difference of crop energy capture mainly depended on the development stage.Waste water with a certain concentration was able to promote crop growth,while excessive concentration inhibited crop growth.The correlation between water absorption rate and leaf area index was close(R=0.9498,p<0.01).The amount of bad seeds increased at a speed of 34.7·d^-1,when system irrigated randomly in the seedling stage,while it tended to remain stable at a speed of 0.3·d^-1 after plants entering the mature stage which impacted the total yields of crops.展开更多
An analytical approach was developed to design a single uniformly sloping lateral in the micro-irrigation systems.Emission uniformity was used as the water application uniformity criterion.Energy relations based on th...An analytical approach was developed to design a single uniformly sloping lateral in the micro-irrigation systems.Emission uniformity was used as the water application uniformity criterion.Energy relations based on the energy-gradient-line approach were revamped to account for the spatial variance of emitter outflow and the emitter connections local energy losses.Four pressure head grade line profiles were distinguished:uphill,horizontal,gentle downhill and steep downhill.Analytical expressions of emission uniformity by hydraulic variation for each pressure profile were developed based on the design variables:length and diameter of lateral,emitter spacing,emitter flow equation parameters,equivalent length characterizing local losses and ground slope.The design conditions for selecting emitter type,the number of emitters per plant and designing the diameter of the uphill and steep downhill laterals were also developed.The nonlinear equations for determining lateral diameter and lateral length were solved iteratively by using the built-in root-finding function of(Tools>Goal Seek…)in the calculation spreadsheet of Microsoft Excel.The procedures also provide the options to fix the design lateral diameter with the commercial standard size or fix the design lateral length based on the field size.The operating inlet pressure and maximum amplitude of the pressure head throughout the lateral could also be determined easily by the procedure.Two numerical applications with various slope combinations indicate that the proposed analytical approach produces results close to the accurate stepwise numerical solutions.In comparison with Keller method,the proposed approach could produce more appropriate designs.展开更多
A field experiment was conducted to elucidate the regulation mechanism of different irrigation schedules on population photosynthetic of winter wheat. The experiment included five irrigation schedules, such as no irri...A field experiment was conducted to elucidate the regulation mechanism of different irrigation schedules on population photosynthetic of winter wheat. The experiment included five irrigation schedules, such as no irrigation （W0）, irrigation once at jointing （W1j） or at booting （W1b）, irrigation twice at jointing and booting （W2）, and irrigation three times at jointing, booting and grain-filling （W3） and three planting densities, such as 180 （D1）, 300 （D2） and 450 （D3） seedlings per square meter. The results indicated that irrigation significantly improved population photosynthesis. The relationship between population photosynthesis and irrigation time/volume was to some extent parabolic. Improvements in population photosynthesis （resulting from more irrigation time/volume） were mainly related to increase in leaf area index and population light interception. Population photosynthesis exhibited a significantly negative correlation with canopy light transmittance. Population photosynthesis at grain filling stage was significantly positively correlated with dry matter accumulation at post-anthesis and grain yield. Main effects and partial correlation analysis showed that population photosynthesis of W0, W1j, W1b and W3 were regulated by canopy light transmittance and leaf area. On the other hand, population photosynthesis of W2 was mainly influenced by flag leaf photosynthetic rate. On this basis, planting 300 seedlings per square meter was the optimum combination. The combination of W2D2 increased population photosynthesis during mid-late growth stages and extended high population photosynthesis duration, which ultimately increased grain yield.展开更多
To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil w...To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil water content, and tube diameter on the emitter discharge of the vertical tube were studied. The results show that quantitative relationship between the time and cumulative infiltration and emitter discharge of the vertical tube is obtained, and R 2 is more than 0.98. Emitter discharge exhibits a positive and negative correlation with the pressure head and soil water content, respectively. Tube dia- meter has a nonsignificant effect on the emitter discharge. Changes of the soil water content around the emitter water outlet are the main causes of emitter discharge variations. In the experiments, the range of vertical tube emitter discharge is 0.056-1.102 L/h. The emitter of vertical tube irrigation automatically adjusts the soil water content and maintains the root zone soil water content within an appropriate range, which achieves continuous irrigation, and further achieves the effect of water-saving.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
Background:This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential(ΨPD)irrigation thresholds to increase agricultural water use efficiency(WUE)in cotton....Background:This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential(ΨPD)irrigation thresholds to increase agricultural water use efficiency(WUE)in cotton.To this end,a study was conducted near Tifton,Georgia under a manually-controlled,variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season.ΨPDthresholds were-0.4 MPa(T1),-0.5 MPa(T2),and-0.7 MPa(T3).A winter rye cover crop or conventional tillage were utilized for T1-T3 as well.Results:Reductions in irrigation of up to 10%were noted in this study for the driest threshold(-0.7 MPa)with no reduction in lint yield relative to the-0.4 MPa and-0.5 MPa thresholds.Drier conditions during flowering(2014)limited plant growth and node production,hastened cutout,and decreased yield and WUE relative to 2015.Conclusions:We conclude thatΨPDirrigation thresholds between-0.5 MPa and-0.7 MPa appear to be viable for use in aΨPDscheduling system with adequate yield and WUE for cotton production in the southeastern U.S.Rye cover positively impacted water potential at certain points throughout the growing season but not yield or WUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.展开更多
基金National Natural Science Foundation of China(52269011,52469008)。
文摘Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch drip irrigation emitters,focusing on the anti-clogging performance through the experiment,were investigated.The dynamic variations in the clogging characteristics of emitters,specifically were subjected to statistical analysis.The movement mechanism of emitter clogging and discharging sediment was studied.The effects of emitter structure and position factors on emitter clogging were analyzed.The results show that the pressure-compensated emitter exhibits superior anti-clogging perfor-mance,with a service life that is 227.8%greater than that of the labyrinth channel emitter.A single structural factor cannot completely evaluate the anti-clogging performance of emitters.All factors causing emitter clogging should be considered comprehensively.Emitters contain sensitive sediment prone to clogging,however,significant blockage occurs primarily when the sediment content is elevated.The discharge of sediment,denoted as V90,from the emitter is affected by the accumulative effect of clogged sediment.These results may offer valuable insights for the application and advancement of drip irrigation technology.
基金supported by the National Natural Science Foundation of China(31250512).
文摘Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.However,delayed sowing is unavoidable in mulch-free cultivation in ecological regions with a short frost-free period.Intercropping with cumin,which has a shorter growth period,served as an effective strategy to improve land use efficiency during the early growth stages of cotton.Therefore,a two-year field experiment was conducted to study the effects of intercropping cumin at the seeding rate of 2.5(ID1),3.85(ID2),and 5.2(ID3)kg・hm−2 on cotton growth,interspecies competition,fiber quality,and water use efficiency(WUE),as well as system economic benefits under subsurface drip irrigation.Monocropping cotton was used as the control(CK)treatment.Results At the initial flowering(IF)stage(the end of the co-growth period of cotton and cumin),cotton plant height in ID2 and ID3 treatments decreased by 5.93%–16.53%and 10.87%–31.11%,respectively,cotton stem diameter by 11.41%–14.25%and 3.37%–26.49%,respectively,and vegetative biomass by 14.46%–30.65%and 22.59%–49.91%,respectively,compared with CK treatment.With the increase in cumin density,the crop growth rate(CGR)and compensation effect in cotton tended to significantly decrease at the IF stage regardless of organs considered.For the non-co-growth period(after harvesting cumin),cotton reproductive organ biomass in ID2 and ID3 treatments increased by 4.09%‒14.61%at the boll opening stage,crop growth rate in reproductive organs by 20.74%and 74.26%from peak boll to boll opening stages compared with CK treatment,due to an enhancement of 19.09%and 49.30%in the compensation effect.Compared with ID1,the aggressivity treated by ID2 and ID3 decreased by 12.82%–46.34%and 17.95%–31.71%,respectively.However,owing to a greater number of green bolls in the upper canopy at the harvest stages in the ID3 treatment,the system production value(closely related to yield)treated by ID2 was 11.69%–16.89%,6.56%–20.02%,and 16.48%–59.83%greater than that of the ID1,ID3,and CK treatments,respectively.This also led to the highest WUE and net profit under the ID2 treatment.Conclusion Intercropping cumin with medium density improved the cotton biomass accumulation characteristics and increased resources such as land and water utilization efficiency and economic benefits through a stronger compensation effect after harvesting cumin under subsurface drip irrigation without mulch.This study not only provides alternatives to residual film pollution in arid cotton fields but also establishes a sustainable agro-ecological-economic planting paradigm by reducing plastic use and enhancing water and fertilizer use efficiency,holding significant implications for advancing resource-efficient agricultural systems.
文摘Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.
基金Jiangsu Water Science and Technology Project(2021081)。
文摘The rapid identification of planting patterns for major crops in a large irrigated district has vital importance for irrigation management,water fee collection,and crop yield estimation.In this study,the OTSU algorithm and Mean-Shift algorithm were employed to automatically determine threshold values for mapping two main rotated crop patterns at the pixel scale.A time series analysis was conducted to extract the spatial distribution of rice-wheat and wheat-maize rotations in the Chuanhang irrigation district from 2016 to 2020.The results demonstrate that both threshold segmentation algorithms are reliable in extracting the spatial distribution of the crops,with an overall accuracy exceeding 80%.Additionally,both Kappa coefficients surpass 0.7,indicating better performance by OTSU method.Over the period from 2016 to 2020,the area occupied by rice-wheat rotation cropping ranged from 12500 to 14400 hm 2;whereas wheat-maize rotation cropping exhibited smaller and more variable areas ranging from 19730 to 34070 hm 2.These findings highlight how remote sensing-based approaches can provide reliable support for rapidly and accurately identifying the spatial distribution of main crop rotation patterns within a large irrigation district.
基金National Natural Science Foundation of China(51109102,51469010,51769010)the basic research project of Yunnan Province(2014FB130)key project of education department in Yunnan Province(2011Z035)
文摘The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI) and fixed drip irrigation( FDI) on growth,photosynthetic characteristics,biomass accumulation and irrigation water use efficiency of Arabica coffee were investigated under three nitrogen levels,high nitrogen( NH),middle nitrogen( NM) and low nitrogen( NL). The results show that there was a significant Logistic curve between the plant height,the stem diameter of Arabica coffee and growth days. Compared with CDI,ADI had no significant effects on leaf net photosynthetic rate,stomatal conductance,instantaneous water use efficiency and biomass accumulation above ground of Arabica coffee,while FDI decreased significantly,ADI and FDI increased irrigation water use efficiency by 50. 59% and 32. 85%,respectively. Compared with NH,with the reduction of N application rate,net photosynthetic rate,stomatal conductance,biomass accumulation above ground and irrigation water use efficiency decreased by 6. 81%-12. 30%,13. 70%-22. 69%,9. 61%-16. 67% and 9. 78%-15. 64%,respectively. Compared with CDINH,ADINHdecreased net photosynthesis rate and the stomatal conductance not significantly,other treatments decreased by 9. 16%-19. 22%,14. 49%-32. 91%,and decreased biomass accumulation above ground by 8. 26%-27. 34% except ADINH,and increased irrigation water use efficiency by 16. 46%-60. 95% except CDINMand CDINL. Therefore,alternate drip irrigation under high N level( ADINH) is the best water and nitrogen coupling mode of young Arabica coffee tree for water efficiency.
基金Supporting founds:National Key R&D Program(2016YFC0400204)Natural Science Foundation of China(51479161,51279157,51779205)。
文摘Six-year old apple trees were selected for field experiment.The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards.There were three factors:the buried depth H(25,40,55 cm),the horizontal distance L(30,40,60 cm)between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N(1,2,4).The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency(IWUE)of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75%of the field water capacity.The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28388.17 kg/hm2 and 16.83 kg/m3 in treatment T3,respectively.At the same L and N levels(T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22%and 31.48%,while IWUE is reduced by14.02%and 18.12%compared with T3,respectively.At the same H and N levels(T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level.Especially,when L was 30 cm(T3),the yield and IWUE were the highest.The same L and H levels(T3,T6,and T7)could promote the growth of apple trees when N was 2(T3).Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%.Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.
基金Project supported by the National High-Tech Research and Development program of China (863 Program ) (No.2 0 0 2 AA2 Z42 5 1-2 10 0 41) Postdoctoral Scientific Foundation of Northeast Agricultural U niversity. (No. 2 40 0 0 9) and postdoctoral Scien
文摘Owing to overcoming the characteristics that there are many economic and technical indexes which are fuzzy and incompatibility to each other in evaluating investment project,a new method is proposed.The method is based on the matter-element analysis and combined with the concepts of fuzzy mathematics,which is called the method of fuzzy matter-element analysis.It constructs the compound fuzzy matter element with the investment projects,evaluation factors and their fuzzy value.Through establishing the best subjection degree (fuzzy value),complex fuzzy matter element of relational coefficient and weight aggregation of fuzzy matter-element model,the writer achieves on optimum order of the investment projects according to the calculated relational degree and finds the best project.In this paper,the calculation of weight adopts the analytical hierarchy process method(AHP).Through the actual example,it shows that the model is simple and its calculation is reliable.It is very significant for the engineering evaluated bid and investment decision.
文摘The author considered the influences of several weather factors, such as air temperature, sunlight, saturation deficiency, wind speed and so on to forecasting the water requirement of well irrigation rice based on Artificial Neutron Network. Through dealing with the time series of water requirement and its influence factors, the author applied the multi-dimension data correlation analysis to ensure the net structure. Thus, the ANN model to forecast the water requirement of well irrigation rice has been built. By means of the ANN model, uncertainty relation between water requirement and many influence factors among the interior and exterior can be discovered. The results of ANN model is good, and can provide some references for establishing the water saving irrigation system.
基金financially supported by the Research Fund for the National Natural Science Foundation of China (31760369)Xinjiang Corps Science and Technology Innovation Talent Program (2020CB014)Major projects of the eighth Division (2020ZD01)
文摘Background:Cotton production in China is challenged by high labor input including manual topping(MT).Recently,to replace MT in the Xinjiang cotton region of China,mepiquat chloride(MC)was applied once more than the traditional multiple-application;this was designated as chemical topping(CT),but it is unclear whether the amount of irrigation needs to be adjusted to accommodate CT.Results:The main plots were assigned to three drip irrigation amounts[300(I_(1))480(I_(2)), and 660(I_(3))mm],and the subplots were assigned to the CT treatments[450(MC)750(MC_(2)),and 1050(MC_(3))mL·hm^(-2)25%MC]with MT as a control that was performed after early bloom.The optimum drip irrigation amount for CT was explored based on leaf photosynthesis,chlorophyll fluorescence,biomass accumulation,and yield.There were significant influe nces of drip irrigation,topping treatme nts and their interaction on chlorophyll fluorescence characteristics,gas exchange parameters and biomass accumulation characteristics as well as yield.The combination of I_(2) and MC_(2)(I_(2)MC_(2))performed best.Compared with I_(2)MC_(2)the net photosynthetic rate(Pn),stomatai conductance(Gs),transpiration rate(Tr),and photochemical quenching coefficient(qP)of I_(2)MC_(2)significantly increased by 4.0%~7.2%,6.8%〜17.1%,5.2%~17.6%,and 4.8%~9.6%,respectively,from the peak flowering to boll opening stages.Moreover,I_(2)MC_(2) showed fast reproductive organ biomass accumulation and the highest seed cotton yield;the latter was 6.6%~12.8%higher than that of I_(2)MT.Further analysis revealed that a 25%MC emulsion in water(MCEW)application resulted in yield improvement by increasing Pn,φPSⅡ,and qP to promote biomass accumulation and transport to reproductive organs.Conclusion:The results showed that the 480 mm drip irrigation combined with 750 mL·hm^(-2)MC increased the rate of dry matter accumulation in reproductive organs by increasing Pn,φPSⅡ and qP to improve photosynthetic performance,thus achieving higher yield.
基金National Natural Science Foundation of China(52079105,51779205)。
文摘In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experiments were carried out with different apple trees. Three irrigation levels were applied: 85%-100%(H1), 70%-85%(H2) and 55%-70%(H3) of the field water capacity, respectively, and three nitrogen levels were N1(360 g/plant), N2(240 g/plant) and N3(120 g/plant). The results show that irrigation and nitrogen application has significant effects on new shoot length, flowering and fruit setting, fruit diameter, fruit volume and yield of apple. The leaf area index(LAI) shows a single trend during the growth period, and the peak value appears in the middle of July. Under the same irrigation level, compared with N3, N1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 17.91%, 28.31%, 18.75%, 11.38%, 10.13%, 36.60%, 20.92% and 5.19%, respectively, while N2 also increases by 12.40%, 15.63%, 4.86%, 5.40%, 5.11%, 17.01%, 26.17% and 13.74%, respectively. The rate of flowering and fruit setting decreases with the increase of nitrogen application. Under the same nitrogen level, compared with H3, H1 increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 34.65%, 15.49%, 30.77%, 3.93%, 4.95%, 12.86%, 33.15% and 28.62%, respectively, while H2 also increases by 33.67%, 16.42%, 67.52%, 3.81%, 2.97%, 11.57%, 43.45% and 27.26%, respectively. The rate of flowering and fruit setting decreases first and then increases with the increase of irrigation amount. Compared with H3N3, the yield of other treatments increases by 2.69%-52.20%, while H2N1 treatment has the highest yield(26 852.55 kg/ha). Considering from the point of view of promoting growth and increasing yield, the best water and nitrogen combination mode of mountain apple in northern Shaanxi is medium water deficit irrigation and high nitrogen(H2N1) treatment. The results from this study can provide a theoretical basis for apple water and nitrogen management in mountainous areas of northern Shaanxi.
基金Funditem:China Postdoctoral Science Fund(2 0 0 0 ).The Youth Fund of Sichuan U niversity.(43 2 0 2 8)
文摘The paper builds up the forecasting model of air temperature according to the data (1994～1998) of Fu Jin area.At the same time,the writer inquires into the relation of water requirement of well irrigation rice (ET) and average air temperature (T).Furthermore,the rice irrigation water requirement (ET) of Fu Jin area has been forecast in 1999.Thus,we can apply the model in irrigation management.
基金Supported by Construction Found of Key Laboratory for Water-saving Agriculture in Universities of Heilongjiang Province (2006BAD29B01)National Science and Technology Program of China (2007BAD88B01)
文摘Aiming at less and un-uniform distribution rainfall problems, the serious draught in spring, low crop production and water efficiency in sandy soil area of Heilongjiang Province, the experiment of alternative furrow irrigation was conducted in Dumeng County in 2009. The purpose of the experiment was to find the water consumption law and its influence on maize yield. The results showed that the highest water consumption was during the heading stage and the highest daily consumption of water was during the filling stage. The stimulation effect of alternative furrow irrigation on yield was obvious in the appropriate irrigation level. The best irrigation pattern for the highest yield was as follows： the seedling stage was 325 m3. hm^-2; the jointing stage was 400 m3-hm^-2; and the filling stage was 288 m3- hm-2. The water consumption during each growing period was that the seedling was 38.85 mm; the jointing was 108.11 mm; the heading was 124.39 ram; the filling was 88.96 ram; the milk was 60.21 ram; and the harvesting was 47.89 mm.
基金Supported by the Science and Technology Research Project of the Ministry of Education(14YJCZH017)the Major State Basic Research Development Program of China(973 Program)(2017YFC0404503)+1 种基金Key Cultivation Project of Lingnan Normal University in 2019(LZ1903)Lingnan Normal University Special Talent Program(ZL2007)
文摘Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilization of agricultural production and waste water resources.The results demonstrated that the difference of crop energy capture mainly depended on the development stage.Waste water with a certain concentration was able to promote crop growth,while excessive concentration inhibited crop growth.The correlation between water absorption rate and leaf area index was close(R=0.9498,p<0.01).The amount of bad seeds increased at a speed of 34.7·d^-1,when system irrigated randomly in the seedling stage,while it tended to remain stable at a speed of 0.3·d^-1 after plants entering the mature stage which impacted the total yields of crops.
基金supported by the Special Foundation of National Science & Technology Supporting Plan( 2011BAD29B02)the "111" Project (B12007)
文摘An analytical approach was developed to design a single uniformly sloping lateral in the micro-irrigation systems.Emission uniformity was used as the water application uniformity criterion.Energy relations based on the energy-gradient-line approach were revamped to account for the spatial variance of emitter outflow and the emitter connections local energy losses.Four pressure head grade line profiles were distinguished:uphill,horizontal,gentle downhill and steep downhill.Analytical expressions of emission uniformity by hydraulic variation for each pressure profile were developed based on the design variables:length and diameter of lateral,emitter spacing,emitter flow equation parameters,equivalent length characterizing local losses and ground slope.The design conditions for selecting emitter type,the number of emitters per plant and designing the diameter of the uphill and steep downhill laterals were also developed.The nonlinear equations for determining lateral diameter and lateral length were solved iteratively by using the built-in root-finding function of(Tools>Goal Seek…)in the calculation spreadsheet of Microsoft Excel.The procedures also provide the options to fix the design lateral diameter with the commercial standard size or fix the design lateral length based on the field size.The operating inlet pressure and maximum amplitude of the pressure head throughout the lateral could also be determined easily by the procedure.Two numerical applications with various slope combinations indicate that the proposed analytical approach produces results close to the accurate stepwise numerical solutions.In comparison with Keller method,the proposed approach could produce more appropriate designs.
基金Supported by China and CAS Main Direction Program of Knowledge Innovation (KSCX2-EW-B-1)China and CAS Knowledge Innovation Project(KSCX1-YW-09-06)
文摘A field experiment was conducted to elucidate the regulation mechanism of different irrigation schedules on population photosynthetic of winter wheat. The experiment included five irrigation schedules, such as no irrigation （W0）, irrigation once at jointing （W1j） or at booting （W1b）, irrigation twice at jointing and booting （W2）, and irrigation three times at jointing, booting and grain-filling （W3） and three planting densities, such as 180 （D1）, 300 （D2） and 450 （D3） seedlings per square meter. The results indicated that irrigation significantly improved population photosynthesis. The relationship between population photosynthesis and irrigation time/volume was to some extent parabolic. Improvements in population photosynthesis （resulting from more irrigation time/volume） were mainly related to increase in leaf area index and population light interception. Population photosynthesis exhibited a significantly negative correlation with canopy light transmittance. Population photosynthesis at grain filling stage was significantly positively correlated with dry matter accumulation at post-anthesis and grain yield. Main effects and partial correlation analysis showed that population photosynthesis of W0, W1j, W1b and W3 were regulated by canopy light transmittance and leaf area. On the other hand, population photosynthesis of W2 was mainly influenced by flag leaf photosynthetic rate. On this basis, planting 300 seedlings per square meter was the optimum combination. The combination of W2D2 increased population photosynthesis during mid-late growth stages and extended high population photosynthesis duration, which ultimately increased grain yield.
基金National Natural Science Foundation of China (41571222)。
文摘To examine the working principle of vertical tube irrigation, variations in vertical tube emitter discharge and their causes were analyzed in the laboratory experiment. The effects of the pressure head, initial soil water content, and tube diameter on the emitter discharge of the vertical tube were studied. The results show that quantitative relationship between the time and cumulative infiltration and emitter discharge of the vertical tube is obtained, and R 2 is more than 0.98. Emitter discharge exhibits a positive and negative correlation with the pressure head and soil water content, respectively. Tube dia- meter has a nonsignificant effect on the emitter discharge. Changes of the soil water content around the emitter water outlet are the main causes of emitter discharge variations. In the experiments, the range of vertical tube emitter discharge is 0.056-1.102 L/h. The emitter of vertical tube irrigation automatically adjusts the soil water content and maintains the root zone soil water content within an appropriate range, which achieves continuous irrigation, and further achieves the effect of water-saving.
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.
基金Funding was made available through the Georgia Cotton Commission and was funded with producer checkoff funds to improve cotton production within the state of Georgia。
文摘Background:This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential(ΨPD)irrigation thresholds to increase agricultural water use efficiency(WUE)in cotton.To this end,a study was conducted near Tifton,Georgia under a manually-controlled,variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season.ΨPDthresholds were-0.4 MPa(T1),-0.5 MPa(T2),and-0.7 MPa(T3).A winter rye cover crop or conventional tillage were utilized for T1-T3 as well.Results:Reductions in irrigation of up to 10%were noted in this study for the driest threshold(-0.7 MPa)with no reduction in lint yield relative to the-0.4 MPa and-0.5 MPa thresholds.Drier conditions during flowering(2014)limited plant growth and node production,hastened cutout,and decreased yield and WUE relative to 2015.Conclusions:We conclude thatΨPDirrigation thresholds between-0.5 MPa and-0.7 MPa appear to be viable for use in aΨPDscheduling system with adequate yield and WUE for cotton production in the southeastern U.S.Rye cover positively impacted water potential at certain points throughout the growing season but not yield or WUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.
