Compared with conventional full irrigation,the existing water-saving irrigation method achieves the purpose of water saving by actively controlling soil moisture.High-frequency irrigation can make the ideal conditions...Compared with conventional full irrigation,the existing water-saving irrigation method achieves the purpose of water saving by actively controlling soil moisture.High-frequency irrigation can make the ideal conditions for soil water movement and root absorption of water and nutrients.This research used a plot experiment in a greenhouse and set up different fertilization amounts and frequencies during the growth stage to study the effects of small-amount and continuous subsurface drip irrigation on the dry matter,yield,and quality of tomato and celery.The results showed that the frequency of topdressing had a great influence on the dry matter accumulation of tomatoes,and the amount of topdressing had little effect on the fresh weight of the upper part of a tomato plant.The application of high-frequency fertilizer increased the dry matter accumulation in the underground part of the tomato.Under the premise given amount of total fertilization,the growth rate and yield of tomatoes were positively correlated with the amount of topdressing.The optimum fertilization frequency was 1 time during the first fruit stage,3 times for the second fruit stage,and 5 times for the third fruit stage,the yield during the fourth stage was increased with higher frequency,and the topdressing was started ahead of the fourth fruit stage when the diameter of fruit was 40 mm.The lower fertilization frequency during the early stage and higher fertilization frequency during the later stage can increase the yield of celery.The higher ratio of topdressing,the higher frequency during the early growth stage,and the lower frequency during the later stage can achieve the best quality of celery.展开更多
For different texture of soils,the grain composition is different with significant changes.Since the emitter of subsurface drip irrigation(SDI)is buried in the soil,emitter discharge is influenced by soil properties.A...For different texture of soils,the grain composition is different with significant changes.Since the emitter of subsurface drip irrigation(SDI)is buried in the soil,emitter discharge is influenced by soil properties.An experiment was conducted to investigate the relationship between the soil properties with emitter working pressure and emitter discharge of SDI.Selecting three different grain composition soils,and emitter working pressure,as well as soil clay content,soil bulk density and initial soil moisture content respectively as influence factors of emitter discharge of SDI,the experimental scheme was gained by uniform design.A calculation model for determination of the SDI emitter discharge was established by regression analysis with the first two kinds of soil test data,and its reliability was verified by the third kind of soil test data.The model is simple with high accuracy,easy to use,and lays the foundation to study hydraulic elements of SDI field network,especially taking the soil clay content as an influencing factor has widened the scope of application of the model.The achievement is of great significance for design and management of SDI.展开更多
<span style="font-family:Verdana;">Modeling of irrigation methods </span><span style="font-family:Verdana;">is</span><span style="font-family:""><spa...<span style="font-family:Verdana;">Modeling of irrigation methods </span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> one of the most important techniques that contribute to the future of modern agriculture. This will conserve water as water scarcity is a major threat for agriculture. In this study, AquaCrop model was used to model different irrigation methods of maize in field trails in Al-Yousifya, 15 km Southwest of Baghdad. Field experiments were conducted for two seasons during 2016 and 2017 using five irrigation methods including furrow, surface drip and subsurface drip with three patterns of emitter depth (10, 20 and 30 cm) irrigation. AquaCrop simulations of biomass, grain yield, harvest index and water productivity were validated using different statistical parameters under the natural conditions obtained in the study area. For 2016 and 2017 seasons, results of R</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> were 0.98 and 0.99, 0.99 and 0.99, 0.99 and 0.97, and 0.8 and 0.73 for biomass, grain yield, harvest index and water productivity, respectively. The study has conducted that simulation using AquaCrop is considered very efficient tool for modeling of different irrigation applications</span><span style="font-family:Verdana;"> for maize production under the existing conditions</span><span style="font-family:Verdana;"> in the central region of Iraq.展开更多
Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygati...Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygation improves water use efficiency(WUE),producing more yield and,and therefore,optimizes the use of drip and SDI.But the efficiency of oxygation is quite possibly dependent on a number of factors.The primary objective of this study was,therefore,to quantify the effects of oxygation,emitter depths and soil type on crop root zone oxygen content,soil respiration,plant physiological response,biomass yield,quality and WUE of three crop species.Methods This study investigated the potential of oxygation to enhance soil respiration,plant growth,yield and water use efficiencies(WUE)of cotton and wheat in experiments in enclosed heavy-duty concrete troughs(tubs)and pineapple and cotton in field experiments.Experimental treatments in tubs for wheat included comparisons between two soil types(vertisol and ferrosol)and superimposed were two oxygation methods(Mazzei air injector and Seair Diffusion System)compared to a control,and for cotton,emitters at two depths using Mazzei air injectors were compared to a control.The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon,both in central Queensland,Australia.Important findings In all experiments,soil oxygen content and soil respiration markedly increased in response to the oxygation treatments.The O2 concentration in the crop root zone increased by 2.4–32.6%,for oxygation compared to control at the same depth.The soil respiration increased by 42–100%.The number of wheat ears,leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control.Fresh biomass of wheat increased by 11 and 8%,and dry weight of wheat increased by 8 and 3%in Mazzei and Seair oxygation treatments compared to the control,respectively.Likewise,the irrigation water use efficiency increased with oxygation compared to the control in wheat.The yield,WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol.The seed cotton yield in the tub experiment increased with oxygation by 14%,and significant differences for fresh biomass,dry matter and yield were also noted between oxygation and the control in the field.Lint yield and WUE both increased by 7%using Mazzei in the cotton field trial during 2008–09.There were significant effects of oxygation on pineapple fresh biomass,and dry matter weight,industry yield and a number of quality parameters were significantly improved.The total fruit yield and marketable increased by 17 and 4%and marketable WUE increased by 3%using Mazzei.Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO_(2) fixation pathways.展开更多
基金This work was funded by the National Science and Technology Planning Project(Grant No.2014BAD12B06)the National Natural Science Fund(Grant No.51621061).
文摘Compared with conventional full irrigation,the existing water-saving irrigation method achieves the purpose of water saving by actively controlling soil moisture.High-frequency irrigation can make the ideal conditions for soil water movement and root absorption of water and nutrients.This research used a plot experiment in a greenhouse and set up different fertilization amounts and frequencies during the growth stage to study the effects of small-amount and continuous subsurface drip irrigation on the dry matter,yield,and quality of tomato and celery.The results showed that the frequency of topdressing had a great influence on the dry matter accumulation of tomatoes,and the amount of topdressing had little effect on the fresh weight of the upper part of a tomato plant.The application of high-frequency fertilizer increased the dry matter accumulation in the underground part of the tomato.Under the premise given amount of total fertilization,the growth rate and yield of tomatoes were positively correlated with the amount of topdressing.The optimum fertilization frequency was 1 time during the first fruit stage,3 times for the second fruit stage,and 5 times for the third fruit stage,the yield during the fourth stage was increased with higher frequency,and the topdressing was started ahead of the fourth fruit stage when the diameter of fruit was 40 mm.The lower fertilization frequency during the early stage and higher fertilization frequency during the later stage can increase the yield of celery.The higher ratio of topdressing,the higher frequency during the early growth stage,and the lower frequency during the later stage can achieve the best quality of celery.
基金primarily funded by the National Natural Science Foundation of China(No.50979089,51279156,51209225)Technology Planning Project Foundation of Shaanxi Provincial Department of Water Resources of China(No.2011slkj-04).
文摘For different texture of soils,the grain composition is different with significant changes.Since the emitter of subsurface drip irrigation(SDI)is buried in the soil,emitter discharge is influenced by soil properties.An experiment was conducted to investigate the relationship between the soil properties with emitter working pressure and emitter discharge of SDI.Selecting three different grain composition soils,and emitter working pressure,as well as soil clay content,soil bulk density and initial soil moisture content respectively as influence factors of emitter discharge of SDI,the experimental scheme was gained by uniform design.A calculation model for determination of the SDI emitter discharge was established by regression analysis with the first two kinds of soil test data,and its reliability was verified by the third kind of soil test data.The model is simple with high accuracy,easy to use,and lays the foundation to study hydraulic elements of SDI field network,especially taking the soil clay content as an influencing factor has widened the scope of application of the model.The achievement is of great significance for design and management of SDI.
文摘<span style="font-family:Verdana;">Modeling of irrigation methods </span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> one of the most important techniques that contribute to the future of modern agriculture. This will conserve water as water scarcity is a major threat for agriculture. In this study, AquaCrop model was used to model different irrigation methods of maize in field trails in Al-Yousifya, 15 km Southwest of Baghdad. Field experiments were conducted for two seasons during 2016 and 2017 using five irrigation methods including furrow, surface drip and subsurface drip with three patterns of emitter depth (10, 20 and 30 cm) irrigation. AquaCrop simulations of biomass, grain yield, harvest index and water productivity were validated using different statistical parameters under the natural conditions obtained in the study area. For 2016 and 2017 seasons, results of R</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> were 0.98 and 0.99, 0.99 and 0.99, 0.99 and 0.97, and 0.8 and 0.73 for biomass, grain yield, harvest index and water productivity, respectively. The study has conducted that simulation using AquaCrop is considered very efficient tool for modeling of different irrigation applications</span><span style="font-family:Verdana;"> for maize production under the existing conditions</span><span style="font-family:Verdana;"> in the central region of Iraq.
基金Horticulture Australia LimitedNational Program for Sustainable Irrigation,AustraliaNational Natural Science Foundation of China(no.50779059).
文摘Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygation improves water use efficiency(WUE),producing more yield and,and therefore,optimizes the use of drip and SDI.But the efficiency of oxygation is quite possibly dependent on a number of factors.The primary objective of this study was,therefore,to quantify the effects of oxygation,emitter depths and soil type on crop root zone oxygen content,soil respiration,plant physiological response,biomass yield,quality and WUE of three crop species.Methods This study investigated the potential of oxygation to enhance soil respiration,plant growth,yield and water use efficiencies(WUE)of cotton and wheat in experiments in enclosed heavy-duty concrete troughs(tubs)and pineapple and cotton in field experiments.Experimental treatments in tubs for wheat included comparisons between two soil types(vertisol and ferrosol)and superimposed were two oxygation methods(Mazzei air injector and Seair Diffusion System)compared to a control,and for cotton,emitters at two depths using Mazzei air injectors were compared to a control.The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon,both in central Queensland,Australia.Important findings In all experiments,soil oxygen content and soil respiration markedly increased in response to the oxygation treatments.The O2 concentration in the crop root zone increased by 2.4–32.6%,for oxygation compared to control at the same depth.The soil respiration increased by 42–100%.The number of wheat ears,leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control.Fresh biomass of wheat increased by 11 and 8%,and dry weight of wheat increased by 8 and 3%in Mazzei and Seair oxygation treatments compared to the control,respectively.Likewise,the irrigation water use efficiency increased with oxygation compared to the control in wheat.The yield,WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol.The seed cotton yield in the tub experiment increased with oxygation by 14%,and significant differences for fresh biomass,dry matter and yield were also noted between oxygation and the control in the field.Lint yield and WUE both increased by 7%using Mazzei in the cotton field trial during 2008–09.There were significant effects of oxygation on pineapple fresh biomass,and dry matter weight,industry yield and a number of quality parameters were significantly improved.The total fruit yield and marketable increased by 17 and 4%and marketable WUE increased by 3%using Mazzei.Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO_(2) fixation pathways.
