To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistan...To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistance rice （WDR） variety and a double low rapeseed variety as materials was conducted under no-tillage direct seeding （NTDS） mode and conventional tillage direct seeding （CTDS） mode for four years, using the CTDS mode as the control. Compared with the CTDS mode, the actual rice yield of WDR decreased by 8.10% at the first year, whereas the plant height, spikelet number per panicle, spikelet fertility, 1000-grain weight, grain yield, actual yield, and harvest index increased with no-tillage years, which led to the actual yield increase by 6.49% at the fourth year. Correlation analysis showed that the panicle length was significantly related to the actual yield of WDR. Compared with the CTDS mode in terms of the soil properties, the pH value of the NTDS mode decreased every year, whereas the contents of soil organic matter and total N of the NTDS mode increased. In the 0-5 cm layer of the NTDS mode, the soil bulk decreased, whereas the contents of soil organic matter, total N, and available N increased. In the 5-20 cm layer of the NTDS mode, the available N and K decreased, whereas the soil bulk, contents of soil organic matter, and total N increased. In summary, the NTDS mode increased the rice yield, and could improve the paddy soil fertility of the top layer.展开更多
The present study investigated whether an irrigation system could be established to save water and increase grain yield to enhance water productivity by proper water management at the field level in irrigated lowland ...The present study investigated whether an irrigation system could be established to save water and increase grain yield to enhance water productivity by proper water management at the field level in irrigated lowland rice （Oryza sativa L.）. Using two field-grown rice cultivars, two irrigation systems; conventional irrigation and water-saving irrigation, were conducted. In the water-saving irrigation system, limiting values of soil water potential related to specific growth stages were proposed as irrigation indices. Compared with conventional irrigation where drainage was in mid-season and flooded at other times, the water-saving irrigation increased grain yield by 7.4% to 11.3%, reduced irrigation water by 24.5% to 29.2%, and increased water productivity （grain yield per cubic meter of irrigation water） by 43.1% to 50.3%. The water-saving irrigation significantly increased harvest index, improved milling and appearance qualities, elevated zeatin-I-zeaUn riboside concentrations in root bleedings and enhanced activities of sucrose synthase, adenosine diphosphate glucose pyrophosphorylase, starch synthase and starch branching enzyme in grains. Our results indicate that water-saving irrigation by controlling limiting values of soil water potential related to specific growth stages can enhance physiological activities of roots and grains, reduce water input, and increase grain yield.展开更多
Droplet shear stress is considered as an important indicator that reflects soil erosion in sprinkler irrigation more accurately than kinetic energy,and the effect of droplet impact angle on the shear stress cannot be ...Droplet shear stress is considered as an important indicator that reflects soil erosion in sprinkler irrigation more accurately than kinetic energy,and the effect of droplet impact angle on the shear stress cannot be ignored.In this study,radial distribution of droplet impact angles,velocities,and shear stresses were investigated using a two-dimensional video disdrometer with three types of low-pressure sprinkler(Nelson D3000,R3000,and Komet KPT)under two operating pressures(103 and 138 kPa)and three nozzle diameters(3.97,5.95,and 7.94 mm).Furthermore,the relationships among these characteristical parameters of droplet were analyzed,and their influencing factors were comprehensively evaluated.For various types of sprinkler,operating pressures,and nozzle diameters,the smaller impact angles and larger velocities of droplets were found to occur closer to the sprinkler,resulting in relatively low droplet shear stresses.The increase in distance from the sprinkler caused the droplet impact angle to decrease and velocity to increase,which contributed to a significant increase in the shear stress that reached the peak value at the end of the jet.Therefore,the end of the jet was the most prone to soil erosion in the radial direction,and the soil erosion in sprinkler irrigation could not only be attributed to the droplet kinetic energy,but also needed to be combined with the analysis of its shear stress.Through comparing the radial distributions of average droplet shear stresses among the three types of sprinklers,D3000 exhibited the largest value(26.94-3313.51 N/m^(2)),followed by R3000(33.34-2650.80 N/m^(2)),and KPT(16.15-2485.69 N/m^(2)).From the perspective of minimizing the risk of soil erosion,KPT sprinkler was more suitable for low-pressure sprinkler irrigation than D3000 and R3000 sprinklers.In addition to selecting the appropriate sprinkler type to reduce the droplet shear stress,a suitable sprinkler spacing could also provide acceptable results,because the distance from the sprinkler exhibited a highly significant(P<0.01)effect on the shear stress.This study results provide a new reference for the design of low-pressure sprinkler irrigation system.展开更多
This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies de...This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies dealing with water shortage in the Yellow River.展开更多
Alternate moistube-irrigation is a new type of water-saving irrigation,and research on water infiltration with alternate moistube-irrigation is important for the design of irrigation schemes and helpful to understand ...Alternate moistube-irrigation is a new type of water-saving irrigation,and research on water infiltration with alternate moistube-irrigation is important for the design of irrigation schemes and helpful to understand and apply this technology.The effects of the pressure head(1.0 m and 1.5 m)and tube spacing(10 cm,20 cm,and 30 cm between two moistubes respectively)on soil water infiltration in alternate moistube-irrigation were studied in laboratory experiments,and the cumulative infiltration,discharge of the moistube,and shape and water distribution of the cross-section of the wetting front were determined.The cumulative infiltration increased quickly and linearly with the infiltration time at 0-96 h(R^(2)>0.99),and changed smoothly at 96-192 h with a basically steady infiltration rate.The discharge of the moistube increased rapidly at the beginning of irrigation,then decreased before stabilizing.The cumulative infiltrations and discharges of moistube under the 1.5 m pressure head were more than those under the 1.0 m pressure head.The shape of the cross-section of the wetting front for a single moistube was similar to a concentric circle.With the increase of tube spacing,the interaction between water infiltrations of two moistubes decreased.The soil water distributions around two moistubes were similar to each other under the 1.0 m pressure head and large tube spacing.When the tube spacing was 20 cm,the soil water distribution was more uniform around two moistubes.展开更多
基金supported by the Key Project of Developing Agriculture through Science and Technology of Shanghai Municipal Agricultural Commission,China(Grant No.2010-1-1)Shanghai Science and Technology Development Funds,China(Grant No.11QA1405900)the National High-Tech Research and Development Program of China(Grant No.2012AA101102)
文摘To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistance rice （WDR） variety and a double low rapeseed variety as materials was conducted under no-tillage direct seeding （NTDS） mode and conventional tillage direct seeding （CTDS） mode for four years, using the CTDS mode as the control. Compared with the CTDS mode, the actual rice yield of WDR decreased by 8.10% at the first year, whereas the plant height, spikelet number per panicle, spikelet fertility, 1000-grain weight, grain yield, actual yield, and harvest index increased with no-tillage years, which led to the actual yield increase by 6.49% at the fourth year. Correlation analysis showed that the panicle length was significantly related to the actual yield of WDR. Compared with the CTDS mode in terms of the soil properties, the pH value of the NTDS mode decreased every year, whereas the contents of soil organic matter and total N of the NTDS mode increased. In the 0-5 cm layer of the NTDS mode, the soil bulk decreased, whereas the contents of soil organic matter, total N, and available N increased. In the 5-20 cm layer of the NTDS mode, the available N and K decreased, whereas the soil bulk, contents of soil organic matter, and total N increased. In summary, the NTDS mode increased the rice yield, and could improve the paddy soil fertility of the top layer.
基金Supported by the National Natural Science Foundation of China(30671225)the State Key Project(2004-BA520A12-5)+1 种基金the Natural Science Foundation of Jiangsu Province(BK2006069)Hong Kong Research Grants Council(Project HKBU 2465/05M).
文摘The present study investigated whether an irrigation system could be established to save water and increase grain yield to enhance water productivity by proper water management at the field level in irrigated lowland rice （Oryza sativa L.）. Using two field-grown rice cultivars, two irrigation systems; conventional irrigation and water-saving irrigation, were conducted. In the water-saving irrigation system, limiting values of soil water potential related to specific growth stages were proposed as irrigation indices. Compared with conventional irrigation where drainage was in mid-season and flooded at other times, the water-saving irrigation increased grain yield by 7.4% to 11.3%, reduced irrigation water by 24.5% to 29.2%, and increased water productivity （grain yield per cubic meter of irrigation water） by 43.1% to 50.3%. The water-saving irrigation significantly increased harvest index, improved milling and appearance qualities, elevated zeatin-I-zeaUn riboside concentrations in root bleedings and enhanced activities of sucrose synthase, adenosine diphosphate glucose pyrophosphorylase, starch synthase and starch branching enzyme in grains. Our results indicate that water-saving irrigation by controlling limiting values of soil water potential related to specific growth stages can enhance physiological activities of roots and grains, reduce water input, and increase grain yield.
基金the National Natural Science Foundation of China(51939005)the Key Research and Development Program of Hebei Province,China(21327002D)+2 种基金the Hebei Forage Industry Innovation Team of Modern Agro-industry Technology Research System of China(HBCT2018160202)the Regional Collaborative Innovation Project of Xinjiang Uygur Autonomous Region of China(2021E02056)the China Agriculture Research System of Ministry of Finance and Ministry of Agriculture and Rural Affairs(CARS-34).
文摘Droplet shear stress is considered as an important indicator that reflects soil erosion in sprinkler irrigation more accurately than kinetic energy,and the effect of droplet impact angle on the shear stress cannot be ignored.In this study,radial distribution of droplet impact angles,velocities,and shear stresses were investigated using a two-dimensional video disdrometer with three types of low-pressure sprinkler(Nelson D3000,R3000,and Komet KPT)under two operating pressures(103 and 138 kPa)and three nozzle diameters(3.97,5.95,and 7.94 mm).Furthermore,the relationships among these characteristical parameters of droplet were analyzed,and their influencing factors were comprehensively evaluated.For various types of sprinkler,operating pressures,and nozzle diameters,the smaller impact angles and larger velocities of droplets were found to occur closer to the sprinkler,resulting in relatively low droplet shear stresses.The increase in distance from the sprinkler caused the droplet impact angle to decrease and velocity to increase,which contributed to a significant increase in the shear stress that reached the peak value at the end of the jet.Therefore,the end of the jet was the most prone to soil erosion in the radial direction,and the soil erosion in sprinkler irrigation could not only be attributed to the droplet kinetic energy,but also needed to be combined with the analysis of its shear stress.Through comparing the radial distributions of average droplet shear stresses among the three types of sprinklers,D3000 exhibited the largest value(26.94-3313.51 N/m^(2)),followed by R3000(33.34-2650.80 N/m^(2)),and KPT(16.15-2485.69 N/m^(2)).From the perspective of minimizing the risk of soil erosion,KPT sprinkler was more suitable for low-pressure sprinkler irrigation than D3000 and R3000 sprinklers.In addition to selecting the appropriate sprinkler type to reduce the droplet shear stress,a suitable sprinkler spacing could also provide acceptable results,because the distance from the sprinkler exhibited a highly significant(P<0.01)effect on the shear stress.This study results provide a new reference for the design of low-pressure sprinkler irrigation system.
基金funded in part by National Natural Science Fund (No. 30671722)
文摘This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies dealing with water shortage in the Yellow River.
基金This work was supported by the National Natural Science Foundation for Young Scientists of China(51809189)the Natural Science Foundation(201701D121109,201801D121266)the Key Research and Development Plan(201703D211020-2)of Shanxi Province,China.
文摘Alternate moistube-irrigation is a new type of water-saving irrigation,and research on water infiltration with alternate moistube-irrigation is important for the design of irrigation schemes and helpful to understand and apply this technology.The effects of the pressure head(1.0 m and 1.5 m)and tube spacing(10 cm,20 cm,and 30 cm between two moistubes respectively)on soil water infiltration in alternate moistube-irrigation were studied in laboratory experiments,and the cumulative infiltration,discharge of the moistube,and shape and water distribution of the cross-section of the wetting front were determined.The cumulative infiltration increased quickly and linearly with the infiltration time at 0-96 h(R^(2)>0.99),and changed smoothly at 96-192 h with a basically steady infiltration rate.The discharge of the moistube increased rapidly at the beginning of irrigation,then decreased before stabilizing.The cumulative infiltrations and discharges of moistube under the 1.5 m pressure head were more than those under the 1.0 m pressure head.The shape of the cross-section of the wetting front for a single moistube was similar to a concentric circle.With the increase of tube spacing,the interaction between water infiltrations of two moistubes decreased.The soil water distributions around two moistubes were similar to each other under the 1.0 m pressure head and large tube spacing.When the tube spacing was 20 cm,the soil water distribution was more uniform around two moistubes.
