This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkl...This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.展开更多
Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP),and nitrogen-use efficiency of crop production is also relatively low.Thus,it is imperative to improve the water-use effic...Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP),and nitrogen-use efficiency of crop production is also relatively low.Thus,it is imperative to improve the water-use efficiency (WUE) and nitrogen fertilizer productivity on the NCP.Here,we conducted a two-year field experiment to explore the effects of different irrigation amounts (S60,60 mm;S90,90 mm;S120,120 mm;S150,150 mm) and nitrogen application rates (150,195 and 240 kg ha^(–1);denoted as N1,N2 and N3,respectively) under micro-sprinkling with water and nitrogen combined on the grain yield(GY),yield components,leaf area index (LAI),flag leaf chlorophyll content,dry matter accumulation (DM),WUE,and nitrogen partial factor productivity (NPFP).The results indicated that the GY and NPFP increased significantly with increasing irrigation amount,but there was no significant difference between S120 and S150;WUE significantly increased first but then decreased with increasing irrigation and S120 achieved the highest WUE.The increase in nitrogen was beneficial to improving the GY and WUE in S60 and S90,while the excessive nitrogen application (N3) significantly reduced the GY and WUE in S120 and S150 compared with those in the N2 treatment.The NPFP significantly decreased with increasing nitrogen rate under the same irrigation treatments.The synchronous increase in spike number (SN) and 1 000-grain weight (TWG)was the main reason for the large increase in GY by micro-sprinkling with increasing irrigation,and the differences in SN and TGW between S120 and S150 were small.Under S60 and S90,the TGW increased with increasing nitrogen application,which enhanced the GY,while N2 achieved the highest TWG in S120 and S150.At the filling stage,the LAI increased with increasing irrigation,and greater amounts of irrigation significantly increased the chlorophyll content in the flag leaf,which was instrumental in increasing DM after anthesis and increasing the TGW.Micro-sprinkling with increased amounts of irrigation or excessive nitrogen application decreased the WUE mainly due to the increase in total water consumption (ET)and the small increase or decrease in GY.Moreover,the increase in irrigation increased the total nitrogen accumulation or contents (TNC) of plants at maturity and reduced the residual nitrate-nitrogen in the soil (SNC),which was conducive to the increase in NPFP,but there was no significant difference in TNC between S120 and S150.Under the same irrigation treatments,an increase in nitrogen application significantly increased the residual SNC and decreased the NPFP.Overall,micro-sprinkling with 120 mm of irrigation and a total nitrogen application of 195 kg ha^(–1) can lead to increases in GY,WUE and NPFP on the NCP.展开更多
The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain.Water-saving technologies and procedures are thus urgently required.To determine the water-saving ...The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain.Water-saving technologies and procedures are thus urgently required.To determine the water-saving potential of using micro-sprinkling irrigation(MSI)for winter wheat production,field experiments were conducted from 2012 to 2015.Compared to traditional flooding irrigation(TFI),micro-sprinkling thrice with 90 mm water(MSI1)and micro-sprinkling four times with 120 mm water(MSI2)increased the water use efficiency by 22.5 and 16.2%,respectively,while reducing evapotranspiration by 17.6 and 10.8%.Regardless of the rainfall pattern,MSI(i.e.,MSI1 or MSI2)either stabilized or significantly increased the grain yield,while reducing irrigation water volumes by 20–40%,compared to TFI.Applying the same volumes of irrigation water,MSI(i.e.,MSI3,micro-sprinkling five times with 150 mm water)increased the grain yield and water use efficiency of winter wheat by 4.6 and 11.7%,respectively,compared to TFI.Because MSI could supply irrigation water more frequently in smaller amounts each time,it reduced soil layer compaction,and may have also resulted in a soil water deficit that promoted the spread of roots into the deep soil layer,which is beneficial to photosynthetic production in the critical period.In conclusion,MSI1 or MSI2 either stabilized or significantly increased grain yield while reducing irrigation water volumes by 20–40%compared to TFI,and should provide water-saving technological support in winter wheat production for smallholders on the North China Plain.展开更多
The objective of this study was to investigate the contents and distribution of dissolved organic carbon (DOC) and microbial biomass carbon (MBC) at 0-100 cm soil depth under three irrigation treatments, viz., sub...The objective of this study was to investigate the contents and distribution of dissolved organic carbon (DOC) and microbial biomass carbon (MBC) at 0-100 cm soil depth under three irrigation treatments, viz., subsurface, drip and furrow irrigation in the greenhouse soil. The soil samples were collected at different depths (0-100 cm), and the contents of soil total organic carbon (TOC), DOC and MBC were analysed. The experiment was conducted for 10 yr, during which period the application of fertilizers and crop management practices were kept identical. The results showed that the contents of TOC, DOC and MBC were significantly affected by different irrigation regimes, decreased with the increase of soil depth. TOC at 0-10 and 80-100 cm soil depths followed the order of furrow irrigation 〉 subsurface irrigation 〉 drip irrigation, whereas at the depth of 10-80 cm followed the order of subsurface irrigation 〉 furrow irrigation 〉 drip irrigation. DOC and MBC contents at 0-100 cm soil depths followed the order of furrow irrigation 〉 drip irrigation 〉 subsurface irrigation, and drip irrigation 〉 furrow irrigation 〉 subsurface irrigation, respectively. The ratios of DOC and MBC to TOC accounted for 4.98-12.87% and 1.48-2.82%, respectively, which were the highest in the drip irrigation treatment, followed were in the furrow irrigation treatment, and the lowest in subsurface irrigation treatment. There were significant positive correlations among the contents of DOC, MBC and TOC in all irrigation treatments. The furrow irrigation facilitated the accumulation of TOC and DOC, while drip irrigation increased the MBC. The content of TOC and the ratios of DOC to TOC were the lowest in subsurface irrigation treatment.展开更多
Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Pe...Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Peanut Giza 5 variety (Arachishy pogaea L.) was planted in sandy soil during two successive growing seasons (2010-2011) in the 1st week of May and harvested after 130 days. Treatments used are: 1) two irrigation methods: surface drip irrigation and sub-surface drip irrigation (SDI;SSDI), 2) nitrogen source (NS):NH4NO3, (NH4)2SO4 and Ca(NO3)2 (NS1, NS2 and NS3) and 3) flushing number (FL) 0, 1 and 4 (FL1, FL2;FL3). The experiments design was split-split plot and three replicates were used. Data obtained were subjected to statistical analysis. The main effects of treatments used on clogging per cent could be written the following ascending orders: SDI 3 2 1, NS1 2 3. Concerning the 1st interaction the following ascending orders denote their effects on clogging percent: SDI × FL3 2 1, SDI × NS1 2 3, SSDI × FL3 2 1, SSDI × NS1 2 3, FL1 × NS1 1 × NS2 1 × NS3, FL2 × NS1 2 × NS2 2 × NS3 and FL3 × NS1 3 × NS2 3 × NS3. The differences between any two treatments and/or any two interactions in clogging percent were significant at the 5% level. The effect of the 2nd interaction on clogging percent was significant at the 5% level. The maximum value of clogging (20.18%) and the lowest one (3.9%) were archived in the interactions: SSDI × FL1 × NS3 and SDI × FL3 × NS1, respectively.展开更多
To achieve the greatest leaching efficiency,water movement must occur under unsaturated flow conditions.Accordingly,the water application intensity of irrigation must be chosen carefully.The aim of this study was to e...To achieve the greatest leaching efficiency,water movement must occur under unsaturated flow conditions.Accordingly,the water application intensity of irrigation must be chosen carefully.The aim of this study was to evaluate the impact of the water application intensity of micro-sprinkler irrigation on coastal saline soil with different salt contents.To achieve this objective,a laboratory experiment was conducted with three soil salinity treatments(2.26,10.13,and 22.29 dS/m)and three water application intensity treatments(3.05,5.19,and 7.23 mm/h).The results showed that the effect of soil salinity on soil water content,electrical conductivity,and pH was significant,and the effect of the water application intensity was insignificant.High soil water content was present in the 40e60 cm profile in all soil salinity treatments,and the content was higher in the medium and high water application intensity treatments than in the low-intensity treatment.Significant salt leaching occurred in all treatments,and the effect was stronger in the high soil salinity treatment and medium water application intensity treatment.In the medium and high soil salinity treatments,pH exhibited a decreasing trend,with no trend change in the low soil salinity treatment,and the pH value was higher in the medium water application intensity treatment than in the other two treatments.These results indicated that the three intensities evaluated had no statistically different effect on the electrical conductivity of saturated soil-paste extracts(EC)in the upper 20 cm of the soil profile,and it would be better to maintain a lower value of the water application intensity.展开更多
A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surfa...A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.展开更多
The sensor system is one of the modern and important methods of irrigation management in arid and semi-arid areas, which is water as the limiting factor for crop production. The study was applied for 2016 and 2017 sea...The sensor system is one of the modern and important methods of irrigation management in arid and semi-arid areas, which is water as the limiting factor for crop production. The study was applied for 2016 and 2017 seasons out in Al-Yousifya, 15 km Southwest of Baghdad. A study was conducted to evaluate coefficient uniformity, uniformity distribution and application efficiency for furrow, surface drip and subsurface drip irrigation methods and it was (98, 97 and 89)% and (97, 96 and 88)% for 2016 and 2017 seasons;respectively. And control the volumetric moisture content according to the rhizosphere depth for depths of 10, 20 and 30 cm by means of the sensor system. The results indicated that the height consumptive water use of furrow 707.91 and 689.69 mm<span style="white-space:nowrap;">·</span>season<sup>-1</sup> and the lowest for subsurface drip with emitter deep at 20 cm 313.93 and 293.50 mm<span style="white-space:nowrap;">·</span>season<sup>-1</sup> for 2016 and 2017 seasons;respectively. As well, the highest value of water use efficiency for subsurface in drip irrigation at a depth of 20 cm, was 2.71 and 2.99 kg<span style="white-space:nowrap;">·</span>m<sup>-3</sup> and the lowest value for furrow irrigation was 1.12 and 1.20 kg<span style="white-space:nowrap;">·</span>m<sup>-3</sup> for the 2016 and 2017 seasons;respectively.展开更多
[Objectives]This study was conducted to explore the most suitable irrigation integration mode for"Tinglin snow melon"in Jinshan District,Shanghai City.[Methods]With the field water holding capacity as the st...[Objectives]This study was conducted to explore the most suitable irrigation integration mode for"Tinglin snow melon"in Jinshan District,Shanghai City.[Methods]With the field water holding capacity as the standard,different upper limits of irrigation were set in the four growth stage of snow melon to investigate the effects of such three water-saving irrigation modes as single-row drip irrigation pipes,double-row drip irrigation pipes and drip arrows on the traits and yield of melon plants under the same growth conditions.[Results]The results showed that different irrigation modes had certain effects on the growth,comprehensive quality and yield of snow melon,and the drop arrow mode was better than other two modes.Under the drop arrow mode,the number of snow melons was the highest,7.34 per plant,and the yield was the highest,reaching 15463.35 kg/hm^(2),showing the best yield increasing effect.In addition,the contents of soluble solids and vitamin C in the drop arrow mode were higher than those in the drip irrigation pipe mode.[Conclusions]Compared with other irrigation methods,the drop arrow mode was more suitable for the production of snow melon.展开更多
Overhead aluminum sprinklers, which are used during the early stages of strawberry crop development to establish transplants and to leach out salts from the root zone, deliver significant volumes of water. Micro-sprin...Overhead aluminum sprinklers, which are used during the early stages of strawberry crop development to establish transplants and to leach out salts from the root zone, deliver significant volumes of water. Micro-sprinklers, which are typically used in orchard crops, were evaluated in a commercial strawberry field in California as an alternative to conventional aluminum sprinklers to conserve water without any negative impact on yields. In addition to the water consumption, data were collected from multiple plots within each treatment to determine the impact on plant growth, disease incidence, and seasonal yield. Micro-sprinklers used 32% less water than aluminum sprinklers during a three-week period without affecting fruit yield. They also appeared to lessen the severity of powdery mildew and botrytis fruit rot. This is the first study reporting the use of micro-sprinkler system, which can be a good alternative to the aluminum sprinklers to conserve irrigation water.展开更多
In Tunisia (36.5oN, 10.2oE, Alt.10 m), rainfall is the major factor govering olive production. Annual and seasonal falls are variable following years and regions, making yields of olive trees fluctuating consistently....In Tunisia (36.5oN, 10.2oE, Alt.10 m), rainfall is the major factor govering olive production. Annual and seasonal falls are variable following years and regions, making yields of olive trees fluctuating consistently. Irrigation was applied since the 70th in the intensive olive orchards to improve and stabilize olive production. This study aimed to determine the crop water needs of olive orchards and the rainfall frequencies at which they are covered following age and site of olive production. For this purpose, the rainfall distribution functions were established for different cities of Tunisia (Tunis, Bizerte, Béja, Nabeul, Sidi Bouzid, Gabes and Sousse). For all sites and growing periods, the reference evapotranspiration (ET0) was computed by using several methods. Their performance against the PM-ET0 (Penman-Monteith) estimates was evaluated graphically and statistically for a better adaptation them to the existing environmental conditions, particularly when data are missing to compute ET0-PM. Results show that ET0 estimates strongly correlate with ET0-PM with r values of up to 0.88. Particularly, the methods of Turc and Ivanov appropriately predict the ET0-PM in all climatic regions of Tunisia, constituing an appropriate alternative for determining ET0 when data are missing to compute ET0-PM. However, although the Turc method performs well with all climatic zones of Tunisia, the Ivanov method appears to be more appropriate to the northern areas (Béja and Bizerte), though a poorer agreement was found when using the Eagleman method. Estimates of ET0 by using the Hargreave-Samani (HS) formula for the east-southern area (Gabes, arid climate) show satisfactory agreement with ET0-PM estimates. It appears also that at a given site, the most appropriate method for ET0 estimation at annual scale may be different from that giving the best value of ET0 when considering the growing stages of the olive tree, for example, the method of Turc, although it was appropriate when estimating the annual ET0 value for Sousse, it wasn’t adequate at seasonal scale. In opposite, although the method of BC is suitable for stages 1, 2, 4 and 5 at Sousse, the appropriate method for the overall cycle is that of Turc. This indicates that there is no weather-based evapotranspiration equation that can be expected to predict evapotranspiration perfectly under every climatic situation due to simplification in formulation and errors in data measurement. However, we can say that when data are missing, ET0 can be estimated with a specific formula;that of Turc can be appropriately used for Tunis, Sidi Bouzid, Sousse and Béja at annual scale despite of their appartenance to different climatic regions, while the method of Ivanov is quite valuable for Bizerte and Nabeul. Results show also that values of P-ETc recorded during the irrigation period are negative even for young plantations, with lowest and highest deficits observed at Béja and Gabes cities, respectively. The driest period is that of July-August for all sites with F values exceeding 0.9 in most cases. Only 10% of water needs are supplied by rainfall during this period of fruit development. Therefore, irrigation is needed all time for adult trees even at the rainiest locations. For young plantations, irrigation becomes necessary beginning from the second period of tree development, i.e. April-June for Bizerte, Béja, Nabeul and Tunis and since the early spring period for both young and old plants for Gabes and Sidi-Bouzid. It appears from this analyze based on the seasonal rainfall frequencies and water needs computed with the PM-method, that there is a need for irrigating olive plantations aging more than 5 years in most case studies and especially when olive is cultivated in the western areas of Tunisia. Results indicate also that the use of no adequate method to estimate ET0 allowed overestimating or underestimating of irrigation water needs. So it is desirable to have for Tunisia a method that estimates ET consistently well and future research is needed to reconcile which should be the standard method of calculating the change in the crop coefficient over time. However, despite a quite good performance of the PM-equation in most applications, particularly when it is used for irrigation scheduling purposes, some problems may appear because of lack of local information on Kc-values and determination of the effective rainfall. Additional research is needed on developing crop coefficients that use the Penman-Monteith equation when calculating ET. In conclusion we can say that on the basis of the results produced, we can decide for each region and growing period if complementary irrigation is needed or not. Indicative amounts are given for each case study.展开更多
Mathematical-computational optimisation models of irrigation networks with a distributed flow that are capable of providing hydraulic data are important for understanding the behaviour of a system in relation to the d...Mathematical-computational optimisation models of irrigation networks with a distributed flow that are capable of providing hydraulic data are important for understanding the behaviour of a system in relation to the distribution of the hydraulic head (energy) and the pressure in the pipes of the network. The objective of this study was to examine the distribution of the parameters of hydraulic irrigation pipes, which were optimised using genetic algorithms. The degree of the optimisation was evaluated with the help of the genetic algorithms based on the diameters of stretch of the network: two for the lateral lines, four for the derivation lines, four for the secondary lines and one for the main line. A MatLab code was developed that considered all of the losses of energy, both distributed losses and those at specific locations between the beginning of the network and the pump system. The sensitivity analysis was based on the variations in the slope of the ground (0%, 2.5% and 5%). The results show that for pipes with a distributed flow, the influence of the behaviour of the kinetic energy in the pipe contributed to the distance between the energy lines and the piezometric lines at the beginning of each stretch after the decrease in the diameter of the pipes. At the end of the pipes, the values of the energy lines and the piezometric lines were very similar, and they were essentially the same for the final emitter.展开更多
This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of wat...This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of water and salt movement has been conducted through field test, laboratory simulation and numerical calculation. The dependence of desalination on irrigation water quantity, drainage quantity, leaching time and other parameters is obtained based on the field tests. The entire desalination process under the flood-irrigation and well-drainage operations was experimentally simulated in a vertical soil column. The water and salt movement has been numerically analysed for both the field and laboratory conditions. The present work indicates that this new technology can greatly improve the effects of desalination.展开更多
Rain-fed agriculture depends on the groundwater as a supplementary source of irrigation. The poor quality of water from the hard rock area is applied to the crops to save the crop. Continuous irrigation leads to degra...Rain-fed agriculture depends on the groundwater as a supplementary source of irrigation. The poor quality of water from the hard rock area is applied to the crops to save the crop. Continuous irrigation leads to degradation of soil, drip irrigation system as well plants. This study assessed the damages on the drip irrigation system and soil, inflicted by the use of low-quality irrigation water. The quality of water was improved with reference to raw water in terms of pH (1.57% - 5.88%), EC (3.08% - 10.08%), ions (0.96% - 46%) by using magnetization method, without disrupting the existing irrigation system in the basaltic aquifer in semi-arid to the arid condition. This was demonstrated before the farmers in central India.展开更多
In this study, irrigation modules calculated in planning and actualized operational stage of the irrigation networks are examined. Irrigation module used irrigation networks is a constant discharge parameter, meeting ...In this study, irrigation modules calculated in planning and actualized operational stage of the irrigation networks are examined. Irrigation module used irrigation networks is a constant discharge parameter, meeting the needs of irrigation water requirement smonthly of crops in one hectare of irrigation area and it is a constant discharge flowing continuously for a month. Extent of the overlapping between the irrigation planning module and the operation module actualized during the operational stage of the irrigation network depends on changes in the cropping patterns, differences in the effects of field irrigation methods used by farmers on the capacity of the constructed system, the increases or decreases in the water demands depending on the irrigation period, as well as the extent of sustainability according to the selected operation method. A2 irrigation area of Aydin plain irrigation network, locating in the Büyük Menderes basin, Turkey is selected as study area, with an area of 2500 ha. Irrigation planning module calculated for this network is q = 1.16 l/s/ha and it has been designed as per the supply demand operation method. For the study;actualized irrigation module in the operation stage has been compared with the planning irrigation module by using Excel software and taking parameters such as actual crop pattern and percentage distributions, actualized irrigated areas, irrigation networks and water distribution, water intake of irrigation networks which have been calculated without operation losses, as well as with 5%, 10%, and 15% operation losses. The July operation module calculated for the examined irrigation network generally conforms to the planning module, as it has received the values close to or below the value of irrigation planning modules.展开更多
基金supported by the China Scholarship Council(Grant No.201906715015)the Priority Academic Development Program of Jiangsu Higher Education Institutions.
文摘This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.
基金funded by the National Key Research and Development Program of China(2016YFD0300105 and 2016YFD0300401)the National Natural Science Foundation of China(31871563)the earmarked fund for China Agriculture Research System(CARS-3)。
文摘Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP),and nitrogen-use efficiency of crop production is also relatively low.Thus,it is imperative to improve the water-use efficiency (WUE) and nitrogen fertilizer productivity on the NCP.Here,we conducted a two-year field experiment to explore the effects of different irrigation amounts (S60,60 mm;S90,90 mm;S120,120 mm;S150,150 mm) and nitrogen application rates (150,195 and 240 kg ha^(–1);denoted as N1,N2 and N3,respectively) under micro-sprinkling with water and nitrogen combined on the grain yield(GY),yield components,leaf area index (LAI),flag leaf chlorophyll content,dry matter accumulation (DM),WUE,and nitrogen partial factor productivity (NPFP).The results indicated that the GY and NPFP increased significantly with increasing irrigation amount,but there was no significant difference between S120 and S150;WUE significantly increased first but then decreased with increasing irrigation and S120 achieved the highest WUE.The increase in nitrogen was beneficial to improving the GY and WUE in S60 and S90,while the excessive nitrogen application (N3) significantly reduced the GY and WUE in S120 and S150 compared with those in the N2 treatment.The NPFP significantly decreased with increasing nitrogen rate under the same irrigation treatments.The synchronous increase in spike number (SN) and 1 000-grain weight (TWG)was the main reason for the large increase in GY by micro-sprinkling with increasing irrigation,and the differences in SN and TGW between S120 and S150 were small.Under S60 and S90,the TGW increased with increasing nitrogen application,which enhanced the GY,while N2 achieved the highest TWG in S120 and S150.At the filling stage,the LAI increased with increasing irrigation,and greater amounts of irrigation significantly increased the chlorophyll content in the flag leaf,which was instrumental in increasing DM after anthesis and increasing the TGW.Micro-sprinkling with increased amounts of irrigation or excessive nitrogen application decreased the WUE mainly due to the increase in total water consumption (ET)and the small increase or decrease in GY.Moreover,the increase in irrigation increased the total nitrogen accumulation or contents (TNC) of plants at maturity and reduced the residual nitrate-nitrogen in the soil (SNC),which was conducive to the increase in NPFP,but there was no significant difference in TNC between S120 and S150.Under the same irrigation treatments,an increase in nitrogen application significantly increased the residual SNC and decreased the NPFP.Overall,micro-sprinkling with 120 mm of irrigation and a total nitrogen application of 195 kg ha^(–1) can lead to increases in GY,WUE and NPFP on the NCP.
基金the National Key Research and Development Program of China(2017YFD0300203 and 2016YFD0300105)。
文摘The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain.Water-saving technologies and procedures are thus urgently required.To determine the water-saving potential of using micro-sprinkling irrigation(MSI)for winter wheat production,field experiments were conducted from 2012 to 2015.Compared to traditional flooding irrigation(TFI),micro-sprinkling thrice with 90 mm water(MSI1)and micro-sprinkling four times with 120 mm water(MSI2)increased the water use efficiency by 22.5 and 16.2%,respectively,while reducing evapotranspiration by 17.6 and 10.8%.Regardless of the rainfall pattern,MSI(i.e.,MSI1 or MSI2)either stabilized or significantly increased the grain yield,while reducing irrigation water volumes by 20–40%,compared to TFI.Applying the same volumes of irrigation water,MSI(i.e.,MSI3,micro-sprinkling five times with 150 mm water)increased the grain yield and water use efficiency of winter wheat by 4.6 and 11.7%,respectively,compared to TFI.Because MSI could supply irrigation water more frequently in smaller amounts each time,it reduced soil layer compaction,and may have also resulted in a soil water deficit that promoted the spread of roots into the deep soil layer,which is beneficial to photosynthetic production in the critical period.In conclusion,MSI1 or MSI2 either stabilized or significantly increased grain yield while reducing irrigation water volumes by 20–40%compared to TFI,and should provide water-saving technological support in winter wheat production for smallholders on the North China Plain.
基金supported by the Agricultural Scientific Research Program,Liaoning Province,China(2008212003)the Provincial Innovative Team Program,Liaoning Province,China(2007T156)
文摘The objective of this study was to investigate the contents and distribution of dissolved organic carbon (DOC) and microbial biomass carbon (MBC) at 0-100 cm soil depth under three irrigation treatments, viz., subsurface, drip and furrow irrigation in the greenhouse soil. The soil samples were collected at different depths (0-100 cm), and the contents of soil total organic carbon (TOC), DOC and MBC were analysed. The experiment was conducted for 10 yr, during which period the application of fertilizers and crop management practices were kept identical. The results showed that the contents of TOC, DOC and MBC were significantly affected by different irrigation regimes, decreased with the increase of soil depth. TOC at 0-10 and 80-100 cm soil depths followed the order of furrow irrigation 〉 subsurface irrigation 〉 drip irrigation, whereas at the depth of 10-80 cm followed the order of subsurface irrigation 〉 furrow irrigation 〉 drip irrigation. DOC and MBC contents at 0-100 cm soil depths followed the order of furrow irrigation 〉 drip irrigation 〉 subsurface irrigation, and drip irrigation 〉 furrow irrigation 〉 subsurface irrigation, respectively. The ratios of DOC and MBC to TOC accounted for 4.98-12.87% and 1.48-2.82%, respectively, which were the highest in the drip irrigation treatment, followed were in the furrow irrigation treatment, and the lowest in subsurface irrigation treatment. There were significant positive correlations among the contents of DOC, MBC and TOC in all irrigation treatments. The furrow irrigation facilitated the accumulation of TOC and DOC, while drip irrigation increased the MBC. The content of TOC and the ratios of DOC to TOC were the lowest in subsurface irrigation treatment.
文摘Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Peanut Giza 5 variety (Arachishy pogaea L.) was planted in sandy soil during two successive growing seasons (2010-2011) in the 1st week of May and harvested after 130 days. Treatments used are: 1) two irrigation methods: surface drip irrigation and sub-surface drip irrigation (SDI;SSDI), 2) nitrogen source (NS):NH4NO3, (NH4)2SO4 and Ca(NO3)2 (NS1, NS2 and NS3) and 3) flushing number (FL) 0, 1 and 4 (FL1, FL2;FL3). The experiments design was split-split plot and three replicates were used. Data obtained were subjected to statistical analysis. The main effects of treatments used on clogging per cent could be written the following ascending orders: SDI 3 2 1, NS1 2 3. Concerning the 1st interaction the following ascending orders denote their effects on clogging percent: SDI × FL3 2 1, SDI × NS1 2 3, SSDI × FL3 2 1, SSDI × NS1 2 3, FL1 × NS1 1 × NS2 1 × NS3, FL2 × NS1 2 × NS2 2 × NS3 and FL3 × NS1 3 × NS2 3 × NS3. The differences between any two treatments and/or any two interactions in clogging percent were significant at the 5% level. The effect of the 2nd interaction on clogging percent was significant at the 5% level. The maximum value of clogging (20.18%) and the lowest one (3.9%) were archived in the interactions: SSDI × FL1 × NS3 and SDI × FL3 × NS1, respectively.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2016B14614)the Program of China Scholarship Council(Grant No.201906715015)+1 种基金the National Key Research and Development Program of China(Grant No.2017YFC040320502)a project funded by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘To achieve the greatest leaching efficiency,water movement must occur under unsaturated flow conditions.Accordingly,the water application intensity of irrigation must be chosen carefully.The aim of this study was to evaluate the impact of the water application intensity of micro-sprinkler irrigation on coastal saline soil with different salt contents.To achieve this objective,a laboratory experiment was conducted with three soil salinity treatments(2.26,10.13,and 22.29 dS/m)and three water application intensity treatments(3.05,5.19,and 7.23 mm/h).The results showed that the effect of soil salinity on soil water content,electrical conductivity,and pH was significant,and the effect of the water application intensity was insignificant.High soil water content was present in the 40e60 cm profile in all soil salinity treatments,and the content was higher in the medium and high water application intensity treatments than in the low-intensity treatment.Significant salt leaching occurred in all treatments,and the effect was stronger in the high soil salinity treatment and medium water application intensity treatment.In the medium and high soil salinity treatments,pH exhibited a decreasing trend,with no trend change in the low soil salinity treatment,and the pH value was higher in the medium water application intensity treatment than in the other two treatments.These results indicated that the three intensities evaluated had no statistically different effect on the electrical conductivity of saturated soil-paste extracts(EC)in the upper 20 cm of the soil profile,and it would be better to maintain a lower value of the water application intensity.
基金Project supported by the National Natural Science Foundation of China (Nos. 30230230 and 30370288)the NationalKey Laboratory for Soil Erosion and Dryland Farming on the Loess Plateau (No. 10501-116).
文摘A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.
文摘The sensor system is one of the modern and important methods of irrigation management in arid and semi-arid areas, which is water as the limiting factor for crop production. The study was applied for 2016 and 2017 seasons out in Al-Yousifya, 15 km Southwest of Baghdad. A study was conducted to evaluate coefficient uniformity, uniformity distribution and application efficiency for furrow, surface drip and subsurface drip irrigation methods and it was (98, 97 and 89)% and (97, 96 and 88)% for 2016 and 2017 seasons;respectively. And control the volumetric moisture content according to the rhizosphere depth for depths of 10, 20 and 30 cm by means of the sensor system. The results indicated that the height consumptive water use of furrow 707.91 and 689.69 mm<span style="white-space:nowrap;">·</span>season<sup>-1</sup> and the lowest for subsurface drip with emitter deep at 20 cm 313.93 and 293.50 mm<span style="white-space:nowrap;">·</span>season<sup>-1</sup> for 2016 and 2017 seasons;respectively. As well, the highest value of water use efficiency for subsurface in drip irrigation at a depth of 20 cm, was 2.71 and 2.99 kg<span style="white-space:nowrap;">·</span>m<sup>-3</sup> and the lowest value for furrow irrigation was 1.12 and 1.20 kg<span style="white-space:nowrap;">·</span>m<sup>-3</sup> for the 2016 and 2017 seasons;respectively.
基金Shanghai Agriculture Applied Technology Development Program,China(Grant No.T20180304)Jinshan District Science and Technology Innovation Fund Project(Grant No.T20200115).
文摘[Objectives]This study was conducted to explore the most suitable irrigation integration mode for"Tinglin snow melon"in Jinshan District,Shanghai City.[Methods]With the field water holding capacity as the standard,different upper limits of irrigation were set in the four growth stage of snow melon to investigate the effects of such three water-saving irrigation modes as single-row drip irrigation pipes,double-row drip irrigation pipes and drip arrows on the traits and yield of melon plants under the same growth conditions.[Results]The results showed that different irrigation modes had certain effects on the growth,comprehensive quality and yield of snow melon,and the drop arrow mode was better than other two modes.Under the drop arrow mode,the number of snow melons was the highest,7.34 per plant,and the yield was the highest,reaching 15463.35 kg/hm^(2),showing the best yield increasing effect.In addition,the contents of soluble solids and vitamin C in the drop arrow mode were higher than those in the drip irrigation pipe mode.[Conclusions]Compared with other irrigation methods,the drop arrow mode was more suitable for the production of snow melon.
文摘Overhead aluminum sprinklers, which are used during the early stages of strawberry crop development to establish transplants and to leach out salts from the root zone, deliver significant volumes of water. Micro-sprinklers, which are typically used in orchard crops, were evaluated in a commercial strawberry field in California as an alternative to conventional aluminum sprinklers to conserve water without any negative impact on yields. In addition to the water consumption, data were collected from multiple plots within each treatment to determine the impact on plant growth, disease incidence, and seasonal yield. Micro-sprinklers used 32% less water than aluminum sprinklers during a three-week period without affecting fruit yield. They also appeared to lessen the severity of powdery mildew and botrytis fruit rot. This is the first study reporting the use of micro-sprinkler system, which can be a good alternative to the aluminum sprinklers to conserve irrigation water.
文摘In Tunisia (36.5oN, 10.2oE, Alt.10 m), rainfall is the major factor govering olive production. Annual and seasonal falls are variable following years and regions, making yields of olive trees fluctuating consistently. Irrigation was applied since the 70th in the intensive olive orchards to improve and stabilize olive production. This study aimed to determine the crop water needs of olive orchards and the rainfall frequencies at which they are covered following age and site of olive production. For this purpose, the rainfall distribution functions were established for different cities of Tunisia (Tunis, Bizerte, Béja, Nabeul, Sidi Bouzid, Gabes and Sousse). For all sites and growing periods, the reference evapotranspiration (ET0) was computed by using several methods. Their performance against the PM-ET0 (Penman-Monteith) estimates was evaluated graphically and statistically for a better adaptation them to the existing environmental conditions, particularly when data are missing to compute ET0-PM. Results show that ET0 estimates strongly correlate with ET0-PM with r values of up to 0.88. Particularly, the methods of Turc and Ivanov appropriately predict the ET0-PM in all climatic regions of Tunisia, constituing an appropriate alternative for determining ET0 when data are missing to compute ET0-PM. However, although the Turc method performs well with all climatic zones of Tunisia, the Ivanov method appears to be more appropriate to the northern areas (Béja and Bizerte), though a poorer agreement was found when using the Eagleman method. Estimates of ET0 by using the Hargreave-Samani (HS) formula for the east-southern area (Gabes, arid climate) show satisfactory agreement with ET0-PM estimates. It appears also that at a given site, the most appropriate method for ET0 estimation at annual scale may be different from that giving the best value of ET0 when considering the growing stages of the olive tree, for example, the method of Turc, although it was appropriate when estimating the annual ET0 value for Sousse, it wasn’t adequate at seasonal scale. In opposite, although the method of BC is suitable for stages 1, 2, 4 and 5 at Sousse, the appropriate method for the overall cycle is that of Turc. This indicates that there is no weather-based evapotranspiration equation that can be expected to predict evapotranspiration perfectly under every climatic situation due to simplification in formulation and errors in data measurement. However, we can say that when data are missing, ET0 can be estimated with a specific formula;that of Turc can be appropriately used for Tunis, Sidi Bouzid, Sousse and Béja at annual scale despite of their appartenance to different climatic regions, while the method of Ivanov is quite valuable for Bizerte and Nabeul. Results show also that values of P-ETc recorded during the irrigation period are negative even for young plantations, with lowest and highest deficits observed at Béja and Gabes cities, respectively. The driest period is that of July-August for all sites with F values exceeding 0.9 in most cases. Only 10% of water needs are supplied by rainfall during this period of fruit development. Therefore, irrigation is needed all time for adult trees even at the rainiest locations. For young plantations, irrigation becomes necessary beginning from the second period of tree development, i.e. April-June for Bizerte, Béja, Nabeul and Tunis and since the early spring period for both young and old plants for Gabes and Sidi-Bouzid. It appears from this analyze based on the seasonal rainfall frequencies and water needs computed with the PM-method, that there is a need for irrigating olive plantations aging more than 5 years in most case studies and especially when olive is cultivated in the western areas of Tunisia. Results indicate also that the use of no adequate method to estimate ET0 allowed overestimating or underestimating of irrigation water needs. So it is desirable to have for Tunisia a method that estimates ET consistently well and future research is needed to reconcile which should be the standard method of calculating the change in the crop coefficient over time. However, despite a quite good performance of the PM-equation in most applications, particularly when it is used for irrigation scheduling purposes, some problems may appear because of lack of local information on Kc-values and determination of the effective rainfall. Additional research is needed on developing crop coefficients that use the Penman-Monteith equation when calculating ET. In conclusion we can say that on the basis of the results produced, we can decide for each region and growing period if complementary irrigation is needed or not. Indicative amounts are given for each case study.
文摘Mathematical-computational optimisation models of irrigation networks with a distributed flow that are capable of providing hydraulic data are important for understanding the behaviour of a system in relation to the distribution of the hydraulic head (energy) and the pressure in the pipes of the network. The objective of this study was to examine the distribution of the parameters of hydraulic irrigation pipes, which were optimised using genetic algorithms. The degree of the optimisation was evaluated with the help of the genetic algorithms based on the diameters of stretch of the network: two for the lateral lines, four for the derivation lines, four for the secondary lines and one for the main line. A MatLab code was developed that considered all of the losses of energy, both distributed losses and those at specific locations between the beginning of the network and the pump system. The sensitivity analysis was based on the variations in the slope of the ground (0%, 2.5% and 5%). The results show that for pipes with a distributed flow, the influence of the behaviour of the kinetic energy in the pipe contributed to the distance between the energy lines and the piezometric lines at the beginning of each stretch after the decrease in the diameter of the pipes. At the end of the pipes, the values of the energy lines and the piezometric lines were very similar, and they were essentially the same for the final emitter.
基金The project supported by the National Natural Science Foundation of China
文摘This paper describes a new technology for solonchak soil reclamation in which surface flood irrigation of fresh water and pumped wells drainage of salty groundwater are combined. The comprehensive investigation of water and salt movement has been conducted through field test, laboratory simulation and numerical calculation. The dependence of desalination on irrigation water quantity, drainage quantity, leaching time and other parameters is obtained based on the field tests. The entire desalination process under the flood-irrigation and well-drainage operations was experimentally simulated in a vertical soil column. The water and salt movement has been numerically analysed for both the field and laboratory conditions. The present work indicates that this new technology can greatly improve the effects of desalination.
文摘Rain-fed agriculture depends on the groundwater as a supplementary source of irrigation. The poor quality of water from the hard rock area is applied to the crops to save the crop. Continuous irrigation leads to degradation of soil, drip irrigation system as well plants. This study assessed the damages on the drip irrigation system and soil, inflicted by the use of low-quality irrigation water. The quality of water was improved with reference to raw water in terms of pH (1.57% - 5.88%), EC (3.08% - 10.08%), ions (0.96% - 46%) by using magnetization method, without disrupting the existing irrigation system in the basaltic aquifer in semi-arid to the arid condition. This was demonstrated before the farmers in central India.
文摘In this study, irrigation modules calculated in planning and actualized operational stage of the irrigation networks are examined. Irrigation module used irrigation networks is a constant discharge parameter, meeting the needs of irrigation water requirement smonthly of crops in one hectare of irrigation area and it is a constant discharge flowing continuously for a month. Extent of the overlapping between the irrigation planning module and the operation module actualized during the operational stage of the irrigation network depends on changes in the cropping patterns, differences in the effects of field irrigation methods used by farmers on the capacity of the constructed system, the increases or decreases in the water demands depending on the irrigation period, as well as the extent of sustainability according to the selected operation method. A2 irrigation area of Aydin plain irrigation network, locating in the Büyük Menderes basin, Turkey is selected as study area, with an area of 2500 ha. Irrigation planning module calculated for this network is q = 1.16 l/s/ha and it has been designed as per the supply demand operation method. For the study;actualized irrigation module in the operation stage has been compared with the planning irrigation module by using Excel software and taking parameters such as actual crop pattern and percentage distributions, actualized irrigated areas, irrigation networks and water distribution, water intake of irrigation networks which have been calculated without operation losses, as well as with 5%, 10%, and 15% operation losses. The July operation module calculated for the examined irrigation network generally conforms to the planning module, as it has received the values close to or below the value of irrigation planning modules.