Irrigation in lowland rice production systems in Sub-Saharan Africa (SSA) is mainly based on traditional surface irrigation methods with continuous flooding practices. This irrigation method ends up using a lot more w...Irrigation in lowland rice production systems in Sub-Saharan Africa (SSA) is mainly based on traditional surface irrigation methods with continuous flooding practices. This irrigation method ends up using a lot more water that would have otherwise been used to open more land and be used in other water-requiring sectors. Various studies suggest Alternate Wetting and Drying (AWD) as an alternative practice for water management that reduces water use without significantly affecting yield. However, this practice has not been well adopted by the farmers despite its significant benefits of reduced total water use. Improving the adoption of AWD using irrigation Decision Support Systems (DSSs) helps the farmer on two fronts;to know “how much water to apply” and “when to irrigate”, which is very critical in maximizing productivity. This paper reviews the applicability of DSSs using AWD in lowland rice production systems in Sub-Saharan Africa.展开更多
This study has investigated the suitable drip irrigation scheduling for tomato grown in solar greenhouse based on 20-cm pan evaporation (Epan) in North China Plain. Irrigation treatments included three irrigation fr...This study has investigated the suitable drip irrigation scheduling for tomato grown in solar greenhouse based on 20-cm pan evaporation (Epan) in North China Plain. Irrigation treatments included three irrigation frequencies (11 10, 12 20 and 13 30 mm, and irrigation interval of 2-6 d for 11, 4-9 d for 12 and 8-12 d for 13) based on accumulated pan evaporation (Epan), and four plant-pan coefficients (Kcp1 0.5, Kcp2 0.7, Kcp3 0.9 and Kcp4 1.1). Results indicate that total irrigation amount, seasonal crop evapotranspiration (ET) and tomato yield (Y) were 185.1-365.8 mm, 249.1-388.0 mm and 99.6-151.8 t ha^-1, respectively. Irrigation frequency and amount increased the yield, and second-degree polynomial relationship was found between Y and ET (R2=0.8671). Irrigation frequency did not increase mean fruit weight, diameter and length significantly but increased fruit number, total soluble solids content (TSS), TSS yield, fruit firmness and water use efficiency (WUE) and irrigation WUE (IWUE) significantly. Irrigation amount increased external quality of tomato but reduced TSS content, TSS yield, fruit firmness, WUE and IWUE significantly. Kep3 and gep4 treatments had the highest fruit yield, but Kep2 and Kep3 treatments had the highest WUE. 11Kcp3 treatment (irrigation interval of 2-6 d, and Kop=0.9) had higher IWUE, WUE, external quality, yield, and TSS yield, so it is recommended as the suitable irrigation scheduling for tomato grown in solar greenhouse in North China Plain.展开更多
This study is aimed to assess the usefulness of weather forecasts for irrigation scheduling in crops to economize water use. The short-term gains for the farmers come from reducing costs of irrigation with the help of...This study is aimed to assess the usefulness of weather forecasts for irrigation scheduling in crops to economize water use. The short-term gains for the farmers come from reducing costs of irrigation with the help of advisory for when not to irrigate because rain is predicted (risk-free because the wrong forecast only delays irrigation within tolerance). Here, a quantitative assessment of saving (indirect income) if irrigation is avoided as rain is imminent (as per forecast), using a five-year archived forecast data over Karnataka state at hobli (a cluster of small villages) level is presented. Estimates showed that the economic benefits to the farmers from such advisories were significant. The potential gain in annual income from such forecast-based irrigation scheduling was of the order of 10% - 15%. Our analysis also indicated that the use of advisory by a small percentage of more than 10 million marginal farmers (landholding < 3 acres) in Karnataka could lead to huge cumulative savings of the order of many crores.展开更多
In an irrigation management problem, decisions are made at various levels for assessment of water availability and requirements, proposing the type of irrigation scheduling, and deriving an actual operational policy f...In an irrigation management problem, decisions are made at various levels for assessment of water availability and requirements, proposing the type of irrigation scheduling, and deriving an actual operational policy for various crop scenarios. In this study, a plan was developed for water management. A general strategy for planning and application of irrigation management was proposed. Since the Penman method was used, the focus was on a synthetic study involving basic project situations, relevant data, water requirement calculation, irrigation scheduling, and discussion on optimizing water use efficiency in the steppe and irrigated crop production ecosystems. Effective use of tabular displays made interpreting and analyzing results easier. Based on the statistical analysis between spring wheat water availability and water requirement, a new type of index called water niche suitability was proposed. The particular type of irrigation scheduling was based on this index together with concrete situation of irrigated areas. The research showed that there are great potentiality of water resources in optimizing Ningxia irrigation management. The irrigation scheduling in this paper was found to be reasonable and demonstrated that results could be used to assist in improving water management decisions in the northwestern China.展开更多
Due to varying crop responses to water stress at different growth stages, scheduling irrigation is a challenge for farmers, especially when water availability varies on a monthly, seasonal and yearly basis. The object...Due to varying crop responses to water stress at different growth stages, scheduling irrigation is a challenge for farmers, especially when water availability varies on a monthly, seasonal and yearly basis. The objective of this study was to optimize irrigation between the vegetative(V) and reproductive(R) phases of maize under different available water levels in Colorado. Longterm(1992–2013) scenarios simulated with the calibrated Root Zone Water Quality Model were designed to meet40%–100% of crop evapotranspiration(ET) requirements at V and R phases, subject to seasonal water availabilities(300, 400, 500 mm, and no water limit), with and without monthly limits(total of 112 scenarios). The most suitable irrigation between V and R phases of maize was identified as 60/100, 80/100, and 100/100 of crop ET requirement for the 300, 400, 500 mm water available, respectively, based on the simulations from 1992 to 2013. When a monthly water limit was imposed, the corresponding suitable irrigation targets between V and R stages were 60/100,100/100, and 100/100 of crop ET requirement for the above three seasonal water availabilities, respectively.Irrigation targets for producing higher crop yield with reduced risk of poor yield were discussed for projected five-year water availabilities.展开更多
Camelina(Camelina sativa)has emerged as a potential biofuel crop globally with its suitability even as a jet fuel source with 75–80%less greenhouse gas emissions compared to common petroleum fuels.The crop has origin...Camelina(Camelina sativa)has emerged as a potential biofuel crop globally with its suitability even as a jet fuel source with 75–80%less greenhouse gas emissions compared to common petroleum fuels.The crop has originated from Mediterranean region and belongs to Brassicaceae family.DIBER,DRDO has made initial and pioneer efforts in successful introduction of this crop to India and its agro-technology standardization.Being a short duration crop with lesser input requirement,it fits well in the cropping pattern of hilly states of Indian Himalaya.These areas experience fallow land due to shortage of irrigation water for growing other crops.The present study revealed that irrigation at flowering stage is more beneficial.Irrigation at this stage(if only one irrigation is available)exhibited grain yield of 1.004 kg·m^(-2)which was 21 and 80%higher over pod setting and rosette stage irrigation,respectively.The maximum seed yield was observed under treatment where irrigation was provided at all three crop growth stages(2.044 kg·m^(-2)).It was 50%higher over T6 treatment(where two irrigations were given at rosette and flowering stage)and 104%higher over T3(where only one irrigation was given at flowering stage).展开更多
Furrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in wat...Furrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in water-limited regions. The objectives of this study are to analyze root length density distribution and to explore soil water dynamics by simulating soil water content using a HYDRUS-2D model with consideration of root water uptake for furrow irrigated tomato plants in a solar greenhouse in Northwest China. Soil water contents were also in-situ observed by the ECH_2O sensors from 4 June to 19 June and from 21 June to 4 July, 2012. Results showed that the root length density of tomato plants was concentrated in the 0–50 cm soil layers, and radiated 0–18 cm toward the furrow and 0–30 cm along the bed axis. Soil water content values simulated by the HYDRUS-2D model agreed well with those observed by the ECH_2O sensors, with regression coefficient of 0.988, coefficient of determination of 0.89, and index of agreement of 0.97. The HYDRUS-2D model with the calibrated parameters was then applied to explore the optimal irrigation scheduling. Infrequent irrigation with a large amount of water for each irrigation event could result in 10%–18% of the irrigation water losses. Thus we recommend high irrigation frequency with a low amount of water for each irrigation event in greenhouses for arid region. The maximum high irrigation amount and the suitable irrigation interval required to avoid plant water stress and drainage water were 34 mm and 6 days, respectively, for given daily average transpiration rate of 4.0 mm/d. To sum up, the HYDRUS-2D model with consideration of root water uptake can be used to improve irrigation scheduling for furrow irrigated tomato plants in greenhouses in arid regions.展开更多
The efficient use of irrigation water requires several kinds of information. One element of efficient irrigation scheduling is monitoring the soil moisture to assure that the crop irrigation goals are being met. Vario...The efficient use of irrigation water requires several kinds of information. One element of efficient irrigation scheduling is monitoring the soil moisture to assure that the crop irrigation goals are being met. Various soil moisture sensing devices were tested for irrigation scheduling in silt loam at the Malheur Agricultural Experiment Station, Oregon State University between 2001 and 2004. Neutron probes, frequency domain probes, tensiometers, granular matrix sensors, and Irrigas were compared as to their performance under field conditions at Ontario, Oregon, USA. Granular matrix sensors were tested as read automatically by a datalogger and read manually with a hand-held meter. Practical suggestions are provided to use soil moisture sensors to the benefit of crop production and water conservation.展开更多
Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and furth...Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated. Key words drip irrigation - linear cumulative frequency curve - optimal irrigation schedule - water saving - production increment CLC number TV 139.1 Foundation item: Supported by the National Natural Science Foundation of China (59379407)Biography: QIU Yuan-feng (1973-), male, Ph. D, research direction: water saving irrigation theory and techniques.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
Agriculture in southeastern Oregon and southwestern Idaho known collectively as the Treasure Valley has depended on furrow irrigation using heavy inputs of water and nitrogen (N) fertilizer. Crop rotations include o...Agriculture in southeastern Oregon and southwestern Idaho known collectively as the Treasure Valley has depended on furrow irrigation using heavy inputs of water and nitrogen (N) fertilizer. Crop rotations include onion, corn, wheat, sugar beet, potato, bean, and other crops. By 1986 groundwater had become contaminated with nitrate and residues of the herbicide chlorthal-dimethyl (DCPA); an official groundwater management area was established by the Oregon Department of Environmental Quality along with an action plan and well monitoring network. The action plan allowed for a trial period to see whether voluntary changes would improve trends. Researchers, producers, and agencies cooperated to develop production options that had the possibility of being both environmentally protective and cost effective. Options were tested to improve irrigation practices, increase N fertilizer use efficiency on several rotation crops, and find a cost effective replacement for DCPA. Research demonstrated the opportunity for increased productivity through both irrigation scheduling and the adoption of drip and sprinkler systems. Fertilizer research demonstrated that smaller, more frequent N applications were more efficient than a single large application. Effective, lower cost herbicides replaced DCPA. Research results were effectively delivered through many means and voluntarily adopted. Both groundwater nitrate and DCPA residues are declining. Productivity has increased.展开更多
To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Acer rubrum L. (red maple) trees are endemic to Cent...To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Acer rubrum L. (red maple) trees are endemic to Central Florida and native to the eastern portion of the United States. Urban and suburban expansion has increased use of A. rubrum in landscape plantings and their production in nurseries. In Florida A. rubrum is planted around stormwater retention areas, but also in urban landscapes. To provide a basis for irrigation allocations both during production and in landscapes, daily actual evapotranspiration (ET<sub>A</sub>) for three red maple trees were measured with weighing lysimeters, beginning with rooted cuttings and continuing until trees averaged 8 m in height. Empirical models were derived to calculate ET<sub>A</sub> based on crown horizontal projected area or trunk caliper, adjusted daily by changes in reference evapotranspiration (ETo). Water use efficiency, based on carbon sequestered in above ground wood mass, was calculated at the end of five growing seasons. Average ET<sub>A</sub> to produce these maples was 29,107 L over 4.75 years, with an average water use efficiency of 1 kg dry mass of wood per 709 L of water lost by transpiration.展开更多
Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The o...Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.展开更多
The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by plants.SIS was implemented and tested under sprinkler irrigation system to irri...The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by plants.SIS was implemented and tested under sprinkler irrigation system to irrigate wheat crops(YecoraRojo).Results obtained from this system were compared with the control irrigation system(CIS),whose scheduling method was based on data from an automatic weather station.Results indicated significant savings in applied water using the SIS.In addition,the use of the SIS conserved 12%of irrigation water compared to CIS and obtained an economical yield.The water use efficiency(WUE)under SIS had generally higher values(1.64 kg/m^(3))compared to CIS(1.46 kg/m^(3)).Hence,the application of SIS technology provides significant advantages on WUE and irrigation water use efficiency(IWUE).Relatively high WUE and IWUE were found for the irrigation treatment(80%of evapotranspiration under SIS).Results showed that the irrigation requirements of wheat increased(100%of ETc under CIS)with increasing evapotranspiration(ETc)but excessive irrigation could decrease WUE and IWUE.These results indicated that extreme irrigation might not produce higher yield or optimal economic benefit,thus,suitable irrigation schedules by using SIS must be established and extendable to other agricultural crops.展开更多
The brackish water is an important potential water source and has frequently been utilized to drip-irrigate cotton due to the water shortage in the arid region of Xinjiang,northwestern of China.The brackish water is u...The brackish water is an important potential water source and has frequently been utilized to drip-irrigate cotton due to the water shortage in the arid region of Xinjiang,northwestern of China.The brackish water is usually saline water with salinity ranging from 1 g/L to 5 g/L,which is widely distributed in this area,so the reasonable use of that brackish water may not only play a vital role in the local agricultural production,but also save plenty of freshwater.However,irrigation with brackish water usually causes the reduction of crop yield and soil salinization which can negatively impact plants through three major components:osmotic,nutritious and toxic stresses.Therefore,a field experiment,with eight different time-series irrigation modes using brackish water(3.5±0.2)g/L and freshwater(<1 g/L),beneath a combined film and drip-irrigation system was carried out to study the changes of soil salt content and cotton yield aiming to search for a balanced method during the 2 cotton growing seasons in 2012 and 2013.The results indicated that the time-series irrigation modes determined the soil salinity and moisture distribution based on observed spatio-temporal distribution of water content and electric conductivity,and soil salinity generally gathered at the depth of 0-10 cm and 60 cm of soil with the increase of irrigation quota.Moreover,the results demonstrated that the yields of cotton which was grown using brackish water and freshwater were better than those only using freshwater and the soil salinity with reasonable irrigation timing was not accumulated obviously.展开更多
Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP), A 2-year experiment was conducted to investigate the e...Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP), A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system, Soil water depletion (~SWS) by crop generally decreased with the increase of irrigation and rainfall, while ASWS for the whole rotation was relatively stable among these irrigation treatments, High irrigations in wheat season increased initial soil moisture and ASWS for subsequent maize especially in the drought season, Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems, Grain yield decreased prior to evapotranspiraUon (ET) when ET reached about 300mm for wheat, while maize showed various WUEs with similar seasonal ET, For whole rotation, WUE declined when ET exceeded about 650 mm, These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP, Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.展开更多
In order to explore the appropriate irrigation schedule for summer maize,a field experiment was conducted in 2013 in Lubotan of Shaanxi Province.Soil water content,soil salinity,soil hydraulic parameters,crop growth p...In order to explore the appropriate irrigation schedule for summer maize,a field experiment was conducted in 2013 in Lubotan of Shaanxi Province.Soil water content,soil salinity,soil hydraulic parameters,crop growth parameters and summer maize yield were measured in the experiment.The SWAP model was calibrated based on field experiment observation data in 2013.The SWAP model was used to simulate and optimize irrigation schedule for summer maize after calibration.The results showed that model simulation results of soil water content,soil salinity and summer maize yield agreed well with the measured values.The Root Mean Square Error(RMSE)and Mean Relative Error(MRE)were within the allowable error ranges.The RMSE values were all lower than 0.05 cm3/cm3 and the MRE values were lower than 15%in soil water content calibration.The RMSE values were all lower than 0.1 mg/cm3 and the MRE values were lower than 20%in soil salinity calibration.The RMSE and MRE values were 1299.6 kg/hm2 and 15.26%in summer maize yield calibration.The model parameters suitable for the study area were obtained in calibration.The SWAP model could be used to simulate and optimize irrigation schedule for summer maize after calibration.The SWAP model was used to simulate soil water-salt balance,summer maize yield and water use efficiency under different irrigation schedules.The model simulation results for different irrigation schedules indicated that the optimal irrigation schedules of summer maize were three times each for jointing stage(July 5),heading stage(August 5)and grain filling stage(August 30)with irrigation amount of 128 mm,128 mm and 96 mm,respectively.The optimal irrigation quota was 352.0 mm for summer maize in the study area.展开更多
Rice response to water application is necessary for increased productivity;hence,this study was aimed at establishing the agronomic responses of rice crop to differential water supplies.A two-year dry season experimen...Rice response to water application is necessary for increased productivity;hence,this study was aimed at establishing the agronomic responses of rice crop to differential water supplies.A two-year dry season experiment was conducted on the research farm of International Institute of Tropical Agriculture(IITA),Ibadan,Nigeria.Two upland rice varieties(NERICA 2 and NERICA 4)were planted on a 5 m×5 m plot in a randomized complete block design with four treatments and two replicates based on different water application.Irrigation scheduling was designed as 100%ET,75%ET,50%ET and 25%ET for the treatments weekly.Agronomic parameters such as plant height,root depth,canopy shading(CS),leaf area index(LAI),panicle and tiller configuration,biomass and grain yield in relation to crop water use were obtained and the results were subjected to statistical analysis.Average values of highest plant height(89.0 and 100.3 cm),deepest root depth(22.1 and 23.8 cm),panicle diameter(3.9 and 4.5 cm),panicle length(26.1 and 25.7 cm),LAI,3.27 and 3.95,CS,0.22 and 0.99 were obtained for both NERICA 2 and NERICA 4 respectively.Leaf width(1.3 and 1.4 cm),total tillers(14 and 12)and leaf length(36.9 and 38 cm)were also observed for the two varieties respectively.The highest total grain and biomass yields of 1.94 t/ha and 1.95 t/ha were observed in 100%ET treatment for NERICA 2 while the least values of 0.29 t/ha and 1.09 t/ha were observed in 25%ET treatment.As for NERICA 4,the highest values(1.90 t/ha and 2.27 t/ha)were from 100%ET and the least(0.38 t/ha and 2.29 t/ha)in 25%ET.The result of ANOVA showed significant differences in biomass and grain yield,LAI,CS,plant height and root depth among treatments(P<0.05)stressing the domineering influence of water in agronomic response of rice.展开更多
文摘Irrigation in lowland rice production systems in Sub-Saharan Africa (SSA) is mainly based on traditional surface irrigation methods with continuous flooding practices. This irrigation method ends up using a lot more water that would have otherwise been used to open more land and be used in other water-requiring sectors. Various studies suggest Alternate Wetting and Drying (AWD) as an alternative practice for water management that reduces water use without significantly affecting yield. However, this practice has not been well adopted by the farmers despite its significant benefits of reduced total water use. Improving the adoption of AWD using irrigation Decision Support Systems (DSSs) helps the farmer on two fronts;to know “how much water to apply” and “when to irrigate”, which is very critical in maximizing productivity. This paper reviews the applicability of DSSs using AWD in lowland rice production systems in Sub-Saharan Africa.
基金financial supports from the National Natural Science Foundation of China (51009140)the National High-Tech Program of China (2011AA100502 and 2011AA100509)
文摘This study has investigated the suitable drip irrigation scheduling for tomato grown in solar greenhouse based on 20-cm pan evaporation (Epan) in North China Plain. Irrigation treatments included three irrigation frequencies (11 10, 12 20 and 13 30 mm, and irrigation interval of 2-6 d for 11, 4-9 d for 12 and 8-12 d for 13) based on accumulated pan evaporation (Epan), and four plant-pan coefficients (Kcp1 0.5, Kcp2 0.7, Kcp3 0.9 and Kcp4 1.1). Results indicate that total irrigation amount, seasonal crop evapotranspiration (ET) and tomato yield (Y) were 185.1-365.8 mm, 249.1-388.0 mm and 99.6-151.8 t ha^-1, respectively. Irrigation frequency and amount increased the yield, and second-degree polynomial relationship was found between Y and ET (R2=0.8671). Irrigation frequency did not increase mean fruit weight, diameter and length significantly but increased fruit number, total soluble solids content (TSS), TSS yield, fruit firmness and water use efficiency (WUE) and irrigation WUE (IWUE) significantly. Irrigation amount increased external quality of tomato but reduced TSS content, TSS yield, fruit firmness, WUE and IWUE significantly. Kep3 and gep4 treatments had the highest fruit yield, but Kep2 and Kep3 treatments had the highest WUE. 11Kcp3 treatment (irrigation interval of 2-6 d, and Kop=0.9) had higher IWUE, WUE, external quality, yield, and TSS yield, so it is recommended as the suitable irrigation scheduling for tomato grown in solar greenhouse in North China Plain.
文摘This study is aimed to assess the usefulness of weather forecasts for irrigation scheduling in crops to economize water use. The short-term gains for the farmers come from reducing costs of irrigation with the help of advisory for when not to irrigate because rain is predicted (risk-free because the wrong forecast only delays irrigation within tolerance). Here, a quantitative assessment of saving (indirect income) if irrigation is avoided as rain is imminent (as per forecast), using a five-year archived forecast data over Karnataka state at hobli (a cluster of small villages) level is presented. Estimates showed that the economic benefits to the farmers from such advisories were significant. The potential gain in annual income from such forecast-based irrigation scheduling was of the order of 10% - 15%. Our analysis also indicated that the use of advisory by a small percentage of more than 10 million marginal farmers (landholding < 3 acres) in Karnataka could lead to huge cumulative savings of the order of many crores.
文摘In an irrigation management problem, decisions are made at various levels for assessment of water availability and requirements, proposing the type of irrigation scheduling, and deriving an actual operational policy for various crop scenarios. In this study, a plan was developed for water management. A general strategy for planning and application of irrigation management was proposed. Since the Penman method was used, the focus was on a synthetic study involving basic project situations, relevant data, water requirement calculation, irrigation scheduling, and discussion on optimizing water use efficiency in the steppe and irrigated crop production ecosystems. Effective use of tabular displays made interpreting and analyzing results easier. Based on the statistical analysis between spring wheat water availability and water requirement, a new type of index called water niche suitability was proposed. The particular type of irrigation scheduling was based on this index together with concrete situation of irrigated areas. The research showed that there are great potentiality of water resources in optimizing Ningxia irrigation management. The irrigation scheduling in this paper was found to be reasonable and demonstrated that results could be used to assist in improving water management decisions in the northwestern China.
基金supported by the National Natural Science Foundation of China (31671627)the 2016 Agricultural international exchange and cooperation project
文摘Due to varying crop responses to water stress at different growth stages, scheduling irrigation is a challenge for farmers, especially when water availability varies on a monthly, seasonal and yearly basis. The objective of this study was to optimize irrigation between the vegetative(V) and reproductive(R) phases of maize under different available water levels in Colorado. Longterm(1992–2013) scenarios simulated with the calibrated Root Zone Water Quality Model were designed to meet40%–100% of crop evapotranspiration(ET) requirements at V and R phases, subject to seasonal water availabilities(300, 400, 500 mm, and no water limit), with and without monthly limits(total of 112 scenarios). The most suitable irrigation between V and R phases of maize was identified as 60/100, 80/100, and 100/100 of crop ET requirement for the 300, 400, 500 mm water available, respectively, based on the simulations from 1992 to 2013. When a monthly water limit was imposed, the corresponding suitable irrigation targets between V and R stages were 60/100,100/100, and 100/100 of crop ET requirement for the above three seasonal water availabilities, respectively.Irrigation targets for producing higher crop yield with reduced risk of poor yield were discussed for projected five-year water availabilities.
基金This research was funded by the Defence Research&Development Organisation,Ministry of Defence,Govt of India.Contribution of all contributors has been acknowledged.
文摘Camelina(Camelina sativa)has emerged as a potential biofuel crop globally with its suitability even as a jet fuel source with 75–80%less greenhouse gas emissions compared to common petroleum fuels.The crop has originated from Mediterranean region and belongs to Brassicaceae family.DIBER,DRDO has made initial and pioneer efforts in successful introduction of this crop to India and its agro-technology standardization.Being a short duration crop with lesser input requirement,it fits well in the cropping pattern of hilly states of Indian Himalaya.These areas experience fallow land due to shortage of irrigation water for growing other crops.The present study revealed that irrigation at flowering stage is more beneficial.Irrigation at this stage(if only one irrigation is available)exhibited grain yield of 1.004 kg·m^(-2)which was 21 and 80%higher over pod setting and rosette stage irrigation,respectively.The maximum seed yield was observed under treatment where irrigation was provided at all three crop growth stages(2.044 kg·m^(-2)).It was 50%higher over T6 treatment(where two irrigations were given at rosette and flowering stage)and 104%higher over T3(where only one irrigation was given at flowering stage).
基金supported by the National Key Research and Development Program of China (2016YFC0400207)the National Natural Science Foundation of China (51222905, 51621061, 51509130)+2 种基金the Natural Science Foundation of Jiangsu Province, China (BK20150908)the Discipline Innovative Engineering Plan (111 Program, B14002)the Jiangsu Key Laboratory of Agricultural Meteorology Foundation (JKLAM1601)
文摘Furrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in water-limited regions. The objectives of this study are to analyze root length density distribution and to explore soil water dynamics by simulating soil water content using a HYDRUS-2D model with consideration of root water uptake for furrow irrigated tomato plants in a solar greenhouse in Northwest China. Soil water contents were also in-situ observed by the ECH_2O sensors from 4 June to 19 June and from 21 June to 4 July, 2012. Results showed that the root length density of tomato plants was concentrated in the 0–50 cm soil layers, and radiated 0–18 cm toward the furrow and 0–30 cm along the bed axis. Soil water content values simulated by the HYDRUS-2D model agreed well with those observed by the ECH_2O sensors, with regression coefficient of 0.988, coefficient of determination of 0.89, and index of agreement of 0.97. The HYDRUS-2D model with the calibrated parameters was then applied to explore the optimal irrigation scheduling. Infrequent irrigation with a large amount of water for each irrigation event could result in 10%–18% of the irrigation water losses. Thus we recommend high irrigation frequency with a low amount of water for each irrigation event in greenhouses for arid region. The maximum high irrigation amount and the suitable irrigation interval required to avoid plant water stress and drainage water were 34 mm and 6 days, respectively, for given daily average transpiration rate of 4.0 mm/d. To sum up, the HYDRUS-2D model with consideration of root water uptake can be used to improve irrigation scheduling for furrow irrigated tomato plants in greenhouses in arid regions.
文摘The efficient use of irrigation water requires several kinds of information. One element of efficient irrigation scheduling is monitoring the soil moisture to assure that the crop irrigation goals are being met. Various soil moisture sensing devices were tested for irrigation scheduling in silt loam at the Malheur Agricultural Experiment Station, Oregon State University between 2001 and 2004. Neutron probes, frequency domain probes, tensiometers, granular matrix sensors, and Irrigas were compared as to their performance under field conditions at Ontario, Oregon, USA. Granular matrix sensors were tested as read automatically by a datalogger and read manually with a hand-held meter. Practical suggestions are provided to use soil moisture sensors to the benefit of crop production and water conservation.
文摘Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated. Key words drip irrigation - linear cumulative frequency curve - optimal irrigation schedule - water saving - production increment CLC number TV 139.1 Foundation item: Supported by the National Natural Science Foundation of China (59379407)Biography: QIU Yuan-feng (1973-), male, Ph. D, research direction: water saving irrigation theory and techniques.
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The development of this paper was aided by previous writing of the Lower Owyhee Watershed Assessment for the Owyhee Watershed Council with financial support from the Oregon Watershed Enhancement Board
文摘Agriculture in southeastern Oregon and southwestern Idaho known collectively as the Treasure Valley has depended on furrow irrigation using heavy inputs of water and nitrogen (N) fertilizer. Crop rotations include onion, corn, wheat, sugar beet, potato, bean, and other crops. By 1986 groundwater had become contaminated with nitrate and residues of the herbicide chlorthal-dimethyl (DCPA); an official groundwater management area was established by the Oregon Department of Environmental Quality along with an action plan and well monitoring network. The action plan allowed for a trial period to see whether voluntary changes would improve trends. Researchers, producers, and agencies cooperated to develop production options that had the possibility of being both environmentally protective and cost effective. Options were tested to improve irrigation practices, increase N fertilizer use efficiency on several rotation crops, and find a cost effective replacement for DCPA. Research demonstrated the opportunity for increased productivity through both irrigation scheduling and the adoption of drip and sprinkler systems. Fertilizer research demonstrated that smaller, more frequent N applications were more efficient than a single large application. Effective, lower cost herbicides replaced DCPA. Research results were effectively delivered through many means and voluntarily adopted. Both groundwater nitrate and DCPA residues are declining. Productivity has increased.
文摘To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Acer rubrum L. (red maple) trees are endemic to Central Florida and native to the eastern portion of the United States. Urban and suburban expansion has increased use of A. rubrum in landscape plantings and their production in nurseries. In Florida A. rubrum is planted around stormwater retention areas, but also in urban landscapes. To provide a basis for irrigation allocations both during production and in landscapes, daily actual evapotranspiration (ET<sub>A</sub>) for three red maple trees were measured with weighing lysimeters, beginning with rooted cuttings and continuing until trees averaged 8 m in height. Empirical models were derived to calculate ET<sub>A</sub> based on crown horizontal projected area or trunk caliper, adjusted daily by changes in reference evapotranspiration (ETo). Water use efficiency, based on carbon sequestered in above ground wood mass, was calculated at the end of five growing seasons. Average ET<sub>A</sub> to produce these maples was 29,107 L over 4.75 years, with an average water use efficiency of 1 kg dry mass of wood per 709 L of water lost by transpiration.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB100140)National Natural Science Foundation of China(Grant No.51975136)+4 种基金Natural Science Foundation of Guangdong Province(Grant No.2023A1515011723)Industry-University-research Collaborative Innovation Base of Ministry of Education(Grant No.230703950183536,220903950010408)Special Research Projects in the Key Fields of Guangdong Higher Educational Universities(Grant No.2023ZDZX3016,2019KZDZX1009)Tertiary Education Scientific research project of Guangzhou Municipal Education Bureau(Grant No.202235139)Guangzhou University Research Project(Grant No.YJ2023034,YJ2021002).
文摘Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.
基金This project was supported by King Saud University,Deanship of Scientific Research,College of Food&Agriculture Sciences,Research Center.
文摘The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by plants.SIS was implemented and tested under sprinkler irrigation system to irrigate wheat crops(YecoraRojo).Results obtained from this system were compared with the control irrigation system(CIS),whose scheduling method was based on data from an automatic weather station.Results indicated significant savings in applied water using the SIS.In addition,the use of the SIS conserved 12%of irrigation water compared to CIS and obtained an economical yield.The water use efficiency(WUE)under SIS had generally higher values(1.64 kg/m^(3))compared to CIS(1.46 kg/m^(3)).Hence,the application of SIS technology provides significant advantages on WUE and irrigation water use efficiency(IWUE).Relatively high WUE and IWUE were found for the irrigation treatment(80%of evapotranspiration under SIS).Results showed that the irrigation requirements of wheat increased(100%of ETc under CIS)with increasing evapotranspiration(ETc)but excessive irrigation could decrease WUE and IWUE.These results indicated that extreme irrigation might not produce higher yield or optimal economic benefit,thus,suitable irrigation schedules by using SIS must be established and extendable to other agricultural crops.
基金We appreciate the financial support of National Key Development Program(2017YFC0404304,2017YFC0404303)the National Natural Science Fund Project(41601579)+2 种基金the application foundation research project of Bingtuan(2016AG003)Excellent Youth Teachers Program of Xinjiang Production&Construction Corps(CZ027204)National Science&Technology Program(2014BAC14B01).
文摘The brackish water is an important potential water source and has frequently been utilized to drip-irrigate cotton due to the water shortage in the arid region of Xinjiang,northwestern of China.The brackish water is usually saline water with salinity ranging from 1 g/L to 5 g/L,which is widely distributed in this area,so the reasonable use of that brackish water may not only play a vital role in the local agricultural production,but also save plenty of freshwater.However,irrigation with brackish water usually causes the reduction of crop yield and soil salinization which can negatively impact plants through three major components:osmotic,nutritious and toxic stresses.Therefore,a field experiment,with eight different time-series irrigation modes using brackish water(3.5±0.2)g/L and freshwater(<1 g/L),beneath a combined film and drip-irrigation system was carried out to study the changes of soil salt content and cotton yield aiming to search for a balanced method during the 2 cotton growing seasons in 2012 and 2013.The results indicated that the time-series irrigation modes determined the soil salinity and moisture distribution based on observed spatio-temporal distribution of water content and electric conductivity,and soil salinity generally gathered at the depth of 0-10 cm and 60 cm of soil with the increase of irrigation quota.Moreover,the results demonstrated that the yields of cotton which was grown using brackish water and freshwater were better than those only using freshwater and the soil salinity with reasonable irrigation timing was not accumulated obviously.
文摘Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP), A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system, Soil water depletion (~SWS) by crop generally decreased with the increase of irrigation and rainfall, while ASWS for the whole rotation was relatively stable among these irrigation treatments, High irrigations in wheat season increased initial soil moisture and ASWS for subsequent maize especially in the drought season, Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems, Grain yield decreased prior to evapotranspiraUon (ET) when ET reached about 300mm for wheat, while maize showed various WUEs with similar seasonal ET, For whole rotation, WUE declined when ET exceeded about 650 mm, These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP, Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.
基金This research was financially supported by Jiangxi Educational Bureau Science-Technology Research Program(GJJ170981)National Natural Science Foundation of China(51709144)and Farmland Irrigation Research Institute,Chinese Academy of Agricultural Sciences(FIRI2017-22-01).
文摘In order to explore the appropriate irrigation schedule for summer maize,a field experiment was conducted in 2013 in Lubotan of Shaanxi Province.Soil water content,soil salinity,soil hydraulic parameters,crop growth parameters and summer maize yield were measured in the experiment.The SWAP model was calibrated based on field experiment observation data in 2013.The SWAP model was used to simulate and optimize irrigation schedule for summer maize after calibration.The results showed that model simulation results of soil water content,soil salinity and summer maize yield agreed well with the measured values.The Root Mean Square Error(RMSE)and Mean Relative Error(MRE)were within the allowable error ranges.The RMSE values were all lower than 0.05 cm3/cm3 and the MRE values were lower than 15%in soil water content calibration.The RMSE values were all lower than 0.1 mg/cm3 and the MRE values were lower than 20%in soil salinity calibration.The RMSE and MRE values were 1299.6 kg/hm2 and 15.26%in summer maize yield calibration.The model parameters suitable for the study area were obtained in calibration.The SWAP model could be used to simulate and optimize irrigation schedule for summer maize after calibration.The SWAP model was used to simulate soil water-salt balance,summer maize yield and water use efficiency under different irrigation schedules.The model simulation results for different irrigation schedules indicated that the optimal irrigation schedules of summer maize were three times each for jointing stage(July 5),heading stage(August 5)and grain filling stage(August 30)with irrigation amount of 128 mm,128 mm and 96 mm,respectively.The optimal irrigation quota was 352.0 mm for summer maize in the study area.
文摘Rice response to water application is necessary for increased productivity;hence,this study was aimed at establishing the agronomic responses of rice crop to differential water supplies.A two-year dry season experiment was conducted on the research farm of International Institute of Tropical Agriculture(IITA),Ibadan,Nigeria.Two upland rice varieties(NERICA 2 and NERICA 4)were planted on a 5 m×5 m plot in a randomized complete block design with four treatments and two replicates based on different water application.Irrigation scheduling was designed as 100%ET,75%ET,50%ET and 25%ET for the treatments weekly.Agronomic parameters such as plant height,root depth,canopy shading(CS),leaf area index(LAI),panicle and tiller configuration,biomass and grain yield in relation to crop water use were obtained and the results were subjected to statistical analysis.Average values of highest plant height(89.0 and 100.3 cm),deepest root depth(22.1 and 23.8 cm),panicle diameter(3.9 and 4.5 cm),panicle length(26.1 and 25.7 cm),LAI,3.27 and 3.95,CS,0.22 and 0.99 were obtained for both NERICA 2 and NERICA 4 respectively.Leaf width(1.3 and 1.4 cm),total tillers(14 and 12)and leaf length(36.9 and 38 cm)were also observed for the two varieties respectively.The highest total grain and biomass yields of 1.94 t/ha and 1.95 t/ha were observed in 100%ET treatment for NERICA 2 while the least values of 0.29 t/ha and 1.09 t/ha were observed in 25%ET treatment.As for NERICA 4,the highest values(1.90 t/ha and 2.27 t/ha)were from 100%ET and the least(0.38 t/ha and 2.29 t/ha)in 25%ET.The result of ANOVA showed significant differences in biomass and grain yield,LAI,CS,plant height and root depth among treatments(P<0.05)stressing the domineering influence of water in agronomic response of rice.