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Effects of Subsoiling on Soil Moisture Under No-Tillage for Two Years 被引量:32
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作者 QIN Hong-ling GAO Wang-sheng +4 位作者 MA Yue-cun MA Li YIN Chun-mei CHEN Zhe CHEN Chun-lan 《Agricultural Sciences in China》 CAS CSCD 2008年第1期88-95,共8页
In order to improve the water use efficiency under conservation tillage, the effects of subsoiling on soil moisture under notillage were studied. An experiment of 40 cm subsoiling in a field kept under no-tillage for ... In order to improve the water use efficiency under conservation tillage, the effects of subsoiling on soil moisture under notillage were studied. An experiment of 40 cm subsoiling in a field kept under no-tillage for 2 years was operated from 2005 to 2006. Based on the data of the soil moisture and crop yield, the physical basis of subsoiling for water conservation and yield increase was analyzed. The results showed that the soil water storage under subsoiling, from the soil surface to a depth of 100 cm was more than that under no-tillage for the growth season. In the 0-100 cm soil depth, the soil moisture in 50-100 cm depth under subsoiling was more compared with no-tillage, which increased when it's drought and decreased when it's rainy with the increase in soil depth. Compared with no-tillage, subsoiling could reduce the water consumption of oats in the 0-50 cm depth and increase the water consumption in the 50-100 cm depth. Also, subsoiling increased the yield by 18.29% and the water use efficiency by 16.8% in a two-year average. The effects of subsoiling on water conservation and yield increase were affected by precipitation, and a well-proportioned rainfall was better to increase yield and water use efficiency. Meanwhile, subsoiling decreased bulk density, which increased with the available precipitation. Subsoiling under no-tillage is the effective rotation tillage to contain more soil moisture and improve water use efficiency in ecotone of North China. 展开更多
关键词 NO-TILLAGE subsoiling water conservation yield increasing
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Subsoiling and Ridge Tillage Alleviate the High Temperature Stress in Spring Maize in the North China Plain 被引量:20
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作者 TAO Zhi-qiang SUI Peng +5 位作者 CHEN Yuan-quan LI Chao NIE Zi-jin YUAN Shu-fen SHI Jiang-tao GAO Wang-sheng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第12期2179-2188,共10页
High temperature stress(HTS) on spring maize(Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain(NCP).Subsoiling(SS) and ridge tillage(R) were intr... High temperature stress(HTS) on spring maize(Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain(NCP).Subsoiling(SS) and ridge tillage(R) were introduced to enhance the ability of spring maize to resist HTS during the filling stage.The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County,Hebei Province,China.Compared with rotary tillage(RT),the net photosynthetic rate,stomatal conductance,transpiration rate,and chlorophyll relative content(SPAD) of maize leaves was increased by 40.0,42.6,12.8,and 29.7% under SS,and increased by 20.4,20.0,5.4,and 14.2% under R,repectively.However,the treatments reduce the intercellular CO 2 concentration under HTS.The SS and R treatments increased the relative water content(RWC) by 11.9 and 6.2%,and the water use efficiency(WUE) by 24.3 and 14.3%,respectively,compared with RT.The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile,whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment.Compared with 2011,the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012,whereas the plant yield decreased by 2.5,8.5 and 10.9%,the net photosynthetic rate reduced by 7.5,10.5 and 18.0%,the RWC reduced by 3.9,5.6 and 6.2%,and the WUE at leaf level reduced by 1.8,5.2 and 13.1% in the SS,R and RT treatments,respectively.Both the root length density and the soil moisture also decreased at different levels.The yield,photosynthetic rate,plant water status,root length density,and soil moisture under the SS and R treatments declined less than that under the RT treatment.The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage,and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status,photosynthesis and grain filling.The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP. 展开更多
关键词 high temperature stress spring maize filling stage subsoiling ridge tillage
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Effects of subsoiling depth,period interval and combined tillage practice on soil properties and yield in the Huang-Huai-Hai Plain,China 被引量:11
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作者 WANG Yun-xia CHEN Shu-ping +4 位作者 ZHANG Dong-xing YANG Li CUI Tao JING Hui-rong LI Yu-huan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第6期1596-1608,共13页
Compact!on layers are widely distributed in the Huang-Huai-Hai Plain,China,which restrict root growth and reduce yields.The adoption of subsoiling has been recommended to disrupt compacted soil layers and create a rea... Compact!on layers are widely distributed in the Huang-Huai-Hai Plain,China,which restrict root growth and reduce yields.The adoption of subsoiling has been recommended to disrupt compacted soil layers and create a reasonable soil structure for crop development.In this paper,the effects of subsoiling depth(30,35 and 40 cm),period interval(2 or 3 years)and combined pre-sowing tillage practice(rotary cultivation or ploughing)on soil condition improvement was studied on a tidal soil in the Huang-Huai-Hai Plain.Seve n tillage patter ns were desig ned by combini ng differe nt subsoili ng depths,period intervals and pre-sowing.The evaluation indicators for soil condition improvement were as follows:thickness of the plough layer and hard pan,soil bulk density,cone index,soil three-phase R values,alkali nitrogen content,crop yield,and economic ben efits.The results showed that subsoiling can sign ificantly improve the soil structure and physical properties.In all subsoiling treatments,the depth of 35 or 40 cm at a 2-year interval was the most significant.The thickness of the plough layer in creased from 13.67 cm before the test to 21.54-23.45 cm in 2018.The thick ness of the hard pan decreased from 17.68 cm before the test to 12.09-12.76 cm in 2018,a decrease of about 40.07%.However,the subsoiling combined presowing tillage practice,that is,rotary cultivation or ploughing,was not significant for soil structure and physical properties.For all subsoiling treatments,the soil bulk density,cone index and soil three-phase R values of the 15-25 cm soil layer were significantly lower compared to single rotary cultivation.Subsoiling was observed to increase the soil alkaline nitrogen and water conte nts.The tillage patter ns that had subsoiling at the depth of 35-40 cm at a 2-year in terval combi ned with rotary cultivation had the highest alkali nitrogen and water contents,which increased by 31.08-34.23%compared with that of the single rotary cultivati on.Subsoiling can sign ifica ntly in crease the yield both of wheat and corn,as well as the economic ben efits.The treatment of subsoili ng at the depth of 35 cm at an interval of 2 years com bined with rotary cultivation had the highest ann ual yield and economic benefits.For this treatme nt,the arinual yield and economic ben efits in creased by 14.55 and 62.87%in 2018,respectively.In con clusi on,the tillage patter ns that involved subsoili ng at a depth of 35 cm at a 2-year interval along with rotary cultivation are suitable for the Huang?Huai-Hai Plain. 展开更多
关键词 subsoiling PERIOD INTERVAL soil properties CROP YIELD Huang-Huai-Hai Plain
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Effects of Subsoiling on Some Soil Physical Properties and Wheat Yield in a Dry Land Ecological Condition
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作者 S. Afzalinia A. A. Solhjou I. Eskandari 《Journal of Agricultural Science and Technology(A)》 2011年第6期842-847,共6页
In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid dow... In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid down in the form of a complete block experimental design with four treatments and four replications for three years. Treatments included: (1) conventional tillage without using subsoiler which was control treatment (So); (2) using subsoiler with the shank space of 40 cm which was equal to the subsoiling depth (SO; (3) using subsoiler with the shank space of 60 cm which was 1.5 times of the subsoiling depth (S2); and (4) using subsoiler with the shank space of 80 cm which was 2 times of the subsoiling depth (S3). Subsoiling depth was set at 40 cm which was the lower limit of the hard pan depth in the soil. Soil cone index, soil bulk density, soil moisture content, wheat yield, and yield components were measured in this study and SAS software was used to analyze the collected data. Results showed that subsoiling decreased the soil bulk density and cone index, and increased water retention of the soil. Results also revealed that applying subsoiler increased wheat yield and yield components in our dry land conditions. Since subsoiling improved soil physical conditions and increases wheat yield, applying subsoiler in such a dry land conditions is therefore recommended. Results of this study also showed that subsoiling with the shank space of 40 cm and 60 cm had better performance compared to the shank space of 80 cm. On the other hand, shank space of 40 cm reduced the subsoiler effective working width and consequently effective field capacity. Therefore, subsoiler with a shank space of 60 cm is recommended for application in dry land soils of our type. 展开更多
关键词 subsoiling soil physical properties dry land conditions wheat yield.
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Parameter optimization and test of hydraulic soil insertion device of orchard gas explosion subsoiling and fertilizing machine
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作者 Congju Shen Lixin Zhang +5 位作者 Shouxing Jia Yan Zhou Fan Li Yameng Dai Jing Zhang Wenxiao Ma 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第2期132-141,共10页
Hydraulic soil insertion device is a key component of orchard gas explosion subsoiling and fertilizing machine to realize rod fixed point soil insertion and gas fertilizer injection into soil.In order to explore the i... Hydraulic soil insertion device is a key component of orchard gas explosion subsoiling and fertilizing machine to realize rod fixed point soil insertion and gas fertilizer injection into soil.In order to explore the influence of the main working parameters and structural parameters on the depth and cylinder pressure of the hydraulic insertion device during the insertion process,the working parameters were optimized to ensure the insertion quality and efficiency.In this paper,force analysis was performed on the rod insertion process,and key parameter equation of soil insertion resistance was established.LS-DYNA finite element simulation software was applied to analyze the force variation of the rod during the insertion process.Box-Behnken test optimization design method and Design-Expert V8.0.6.1 software were used to carry out parameter optimization test of hydraulic insertion device.A multivariate quadratic polynomial regression equation was established by setting the engine revolution,insertion rod diameter and insertion time as independent variables,and the operation parameters of the hydraulic insertion device were optimized based on the relationship between the independent variables and the response values.The results showed that the regression equation model based on the response values of insertion depth and cylinder pressure had a good fitting degree.The engine revolution,rod diameter and insertion time all had significant effects on the increase of insertion depth and decrease of cylinder pressure,with interaction between the engine speed and insertion time with the insertion depth,and interaction between any two factors of engine revolution,rod diameter and insertion time with the cylinder pressure.The influences of the test factors on the insertion depth showed a descending order as engine speed,insertion time,and rod diameter.The influences of the test factors on the cylinder pressure showed a descending order as engine speed,rod diameter,and insertion time.Based on the results of insertion depth and cylinder pressure,the optimal combination of parameters was as follows:engine revolution of 1450 r/min;rod diameter of 32 mm;and the insertion time of 8 s.Under this optimal combination,the insertion depth of the hydraulic insertion device was 44.43 cm,and the cylinder pressure was 23.09 MPa.The experimental results showed that the optimal combination of parameters could meet the agronomic requirements of fast and deep insertion,thus providing a theoretical support for the improvement and optimization of hydraulic soil insertion device of gas explosion subsoiling and fertilizing machine. 展开更多
关键词 orchard management machinery subsoiling gas explosion FERTILIZATION hydraulic insertion optimization
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Effects of subsoiling on working quality and total power consumption of high stubble straw returning machine 被引量:2
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作者 Hua Zhou Jumin Zhang +3 位作者 Junfang Xia H.M.Tahir Yinghao Zhu Chunling Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第4期56-62,共7页
Straw returning into field is a direct and effective measure to reduce the straw burning and improve the soil organic matter content.Straw returning directly to field needs higher performance machines,especially under... Straw returning into field is a direct and effective measure to reduce the straw burning and improve the soil organic matter content.Straw returning directly to field needs higher performance machines,especially under the condition of large amount of straw in the field is more difficult.Therefore,the model of conservation tillage by combination of subsoiling and straw returning was studied.Experiments on combined tillage machine for effect of subsoiling on working quality and total power consumption for high stubble straw returning were carried out.The high stubble rape field was used as the test field;forward speed and PTO speed of tractor were taken as the test factors.Straw coverage rate and straw proportion of the lower half burying layer were taken as the test indexes of the working quality.Subsoiling and rotary burying(SRB)returning operation was used as experimental group and direct rotary burying(DRB)returning operation was the control group.The results showed that under different working conditions,the mean value of straw coverage rate of SRB was 93.0%,straw proportion of the lower half burying layer was 52.8%,these values were better than DRB.The straw proportion of the lower half burying layer of SRB compared with DRB increased by 10.5%.Two factors all had a significant effect on it under the SRB and DRB conditions.Subsoiling could significantly reduce the PTO torque.Under low speed,the total power consumption of SRB was slightly smaller,while under high speed,the total power consumption of DRB was slightly smaller.Under the SRB and DRB conditions,two factors both had a significant effect on total power consumption.The optimal working combination(working quality as the primary index)was 1.5 km/h of forward speed and 720 r/min of PTO speed.Under this condition,the straw coverage rate was 94.1%,the straw proportion of the lower half burying layer was 59.0%,and the total power consumption was 35.62 kW.The research confirmed that subsoiling is beneficial to the working quality and total power consumption of high stubble straw returning machine.It could meet the working requirements,and provide a reference for optimizing straw returning machine and improving working quality. 展开更多
关键词 agricultural machinery CULTIVATION subsoiling straw returning working quality total power consumption
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Design and experiment of a subsoiling variable rate fertilization machine 被引量:1
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作者 Jiangtao Qi Xinliang Tian +4 位作者 Yang Li Xuhui Fan Hongfang Yuan Jiale Zhao Honglei Jia 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第4期118-124,共7页
In order to improve soil fertility and fertilizer utilization,a subsoiling variable rate fertilization machine based on conservation tillage and precision agriculture was designed and tested.The relationship between s... In order to improve soil fertility and fertilizer utilization,a subsoiling variable rate fertilization machine based on conservation tillage and precision agriculture was designed and tested.The relationship between suspension parameters and penetrating distance was analyzed,and a matching model between fertilizing quantity and penetrating distance was established.The variable rate fertilization control machine was developed based on an Advantech PCM-9363 industrial control mainboard.The machine operates under two patterns:DGPS-based positioning and straight-line path positioning based on a planar coordinate system.This machine can perform on-demand fertilization according to the spatial differences in soil nutrients and the prescription maps pre-set before the operation.Field experiments showed the machine has a subsoiling stability of 92.5%,a soil breaking rate of 61.1%,a maximum positioning relative error of 2.68%and a maximum variable rate fertilization error of 3.89%.The subsoiling performance and variable rate fertilization indices of this machine satisfy the requirements of GB/T24675.2-2009.The tested indices meet the national and industrial standards and satisfy the design requirements.The findings of the research can be used as the structural design of the subsoiling variable rate fertilization machine. 展开更多
关键词 agricultural machinery conservation tillage precision agriculture subsoiling variable rate fertilization
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Prospects and limitations of soil amendment and irrigation techniques for the water-saving public urban greenery and ephemeral weed management in the sandy soils of the United Arab Emirates
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作者 Ayesha ALAM Elke GABRIEL-NEUMANN 《Journal of Arid Land》 SCIE CSCD 2024年第9期1288-1302,共15页
Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Exist... Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture. 展开更多
关键词 native and exotic plant communities competitive strength soil improvers urban plantation subsoil amendment weed management
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HVSR analysis of pumice sands for sediment depth characterization:A case study for Guadalajara,Mexico
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作者 Hafid Salgado M. Alejandro Ramírez-Gaytan +1 位作者 Adolfo Preciado Christian R.Escudero 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期577-591,共15页
The horizontal to vertical spectral ratio(HVSR)methodology is used here to characterize pumice soils and to image the three-dimensional surface geometry of Guadalajara,Mexico.Similar to other Latin American cities,Gua... The horizontal to vertical spectral ratio(HVSR)methodology is used here to characterize pumice soils and to image the three-dimensional surface geometry of Guadalajara,Mexico.Similar to other Latin American cities,Guadalajara is exposed to high seismic risk,with the particularity of being the largest urban settlement in Latin America built on pumice soils.Methodology has not yet been tested to characterize subsoil depths in pumice sands.Due to the questionable use of traditional geotechnical tests for the analysis of pumice soils,HVSR provides an alternative for its characterization without altering its fragile and porous structure.In this work,resonance frequency(F0)and peak amplitude(A0)are used to constrain the depth of the major impedance contrast that represents the interface between bedrock and pumice soil.Results were compared with borehole depths and other available geotechnical and geophysical data and show good agreement.One of the profiles estimated on the riverbanks that cross the city,reveals different subsoil thickness that could have an impact on different site responses on riverine areas to an eventual earthquake.Government and academic efforts are combined in this work to characterize depth sediments,an important parameter that impacts the regulations for construction in the city. 展开更多
关键词 subsoil of Guadalajara shallow soil thickness bedrock depth pumice soil characterization
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Response of yield increase for dryland winter wheat to tillage practice during summer fallow and sowing method in the Loess Plateau of China 被引量:8
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作者 LI Hui XUE Jian-fu +2 位作者 GAO Zhi-qiang XUE Nai-wen YANG Zhen-ping 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第4期817-825,共9页
Soil moisture is the most critical limiting factor impacting yields of dryland winter wheat(Triticum aestivum L.) and it is strongly affected by tillage practice and sowing methods. This study was to assess the link b... Soil moisture is the most critical limiting factor impacting yields of dryland winter wheat(Triticum aestivum L.) and it is strongly affected by tillage practice and sowing methods. This study was to assess the link between sowing method and tillage practice during summer fallow and their subsequent effect on soil moisture and grain yield. Furthermore, we sought to identify a more appropriate farming management practice for winter wheat production in Loess Plateau region of China. The experiment was conducted from 2011 to 2013, using a two-factor split plot design, including subsoiling(SS) or no tillage(NT) during summer fallow for main plots, and conventional drill sowing(DS) or plastic film drill sowing(FM) for subplots. Results showed that the maximum soil water storage(SWS) was under SS×FM treatment with values of 649.1 mm(2011–2012) and 499.4 mm(2012–2013). The SWS during the 2011–2012 growing season were 149.7 mm higher than that in the 2012–2013 growing season. And adoption of SS×FM significantly increased precipitation use efficiency(PUE) and water use efficiency(WUE) compared to other treatments for both seasons. Moreover, adoption of SS×FM significantly increased yield by 13.1, 14.4, 47.3% and 25.9, 39.1, 35.7% than other three treatments during the two growing seasons, respectively. In summary, combining subsoiling during summer fallow with plastic film drill sowing(SS×FM) increased SWS at sowing and effectively improved WUE, thus representing a feasible technology to improve grain yield of dryland winter wheat in the Loess Plateau of China. 展开更多
关键词 dryland winter wheat subsoiling sowing method soil water storage YIELD
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Water Availability for Winter Wheat Affected by Summer Fallow Tillage Practices in Slope Dryland
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作者 WANGXiao-bin CAIDian-xiong +9 位作者 JINKe WUHui-jun BAIZhan-guo ZHANGCan-jun YAOYu-qing LUJun-jiez WANGYu-hong YANGBo RogerHartmann DonaldGabriels 《Agricultural Sciences in China》 CAS CSCD 2003年第7期773-778,共6页
The tillage experiments for winter wheat were conducted on the slope farmland in Luoyang, Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods including reduced tillage... The tillage experiments for winter wheat were conducted on the slope farmland in Luoyang, Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods including reduced tillage(RT), no-till(NT), 2 crops/year(2C), subsoiling(SS), and conventional tillage(CT)were compared to determine the effects of tillage methods on soil water conservation, water availability, and wheat yields in a search for better farming systems in the areas. The NT and SS showed good effects on water conservation. The soil water storage increased 12 - 33 mm with NT and 9-24 mm with SS at the end of summer fallow periods. The soil evaporation with NT and SS decreased 7-8 mm and 34 - 36 mm during the fallow periods of 1999 and 2001, respectively. Evapotranspiration(ET)with NT and SS increased about 47 mm during wheat growth periods of 2000 to 2001. Treatment RT and 2C had low water storage and high water losses during the fallow periods. The winter wheat yields with conservation tillage practices were improved in the 2nd year, increased by 3, 5 and 8% with RT, NT and SS, respectively, compared with CT. The highest wheat yields were obtained with subsoiling, and the maximum economic benefits from no-till. All conservation tillage practices provided great benefits to saving energy and labors, reducing operation inputs, and increasing economic returns. No-till and subsoiling have shown promise in increasing water storage, reducing water loss, enhancing water availability, and saving energy, as well as increasing wheat yield. 展开更多
关键词 DRYLAND Slope land Conservation tillage NO-TILL subsoiling Soil water
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Optimization of Specific Draft Requirement and Hitch Length for an Animal Drawn Sub-Soiler: A Case of Sandy Clay Loam Soils
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作者 Nicodemus K. Mwonga Ayub N. Gitau +1 位作者 Joackim M. Mutua Simon T. Mwangi 《Open Journal of Optimization》 2019年第3期83-99,共17页
This study aimed at optimizing tillage depth and hitching length for optimal draft requirement in sandy clay loam soils for animal drawn subsoiler. Field experiments were conducted to collect draft datasets using the ... This study aimed at optimizing tillage depth and hitching length for optimal draft requirement in sandy clay loam soils for animal drawn subsoiler. Field experiments were conducted to collect draft datasets using the MSI 7300 digital dynamometer communicating remotely with MSI-8000 RF data logger connected to a laptop through the serial port. To determine the numeric values of soil parameters pertinent to subsoiling, field experiments, laboratory tests and numerical analysis techniques were employed. For a specified speed, a combination of three hitch lengths of 2.5 m, 3.0 m and 3.5 m and three depths from 0 cm to 30 cm with a range of 10 cm interval was used. Soil bulk density was found to vary between 1.52 to 1.37 g/cm3 and 1.44 to 1.67 g/cm3 for Machakos and Kitui experimental plots respectively. Soil moisture content increased with an increase in depth ranging from 3.53% to 9.94% for Machakos site and from 4.15% to 9.61% for Kitui site. Soil shear strength parameters ranged between 21.71 and 29.6 kPa between depths of 0 - 20 cm and decreased to 28.07 kPa for depths beyond 20 cm at Machakos experimental plot;while for Kitui experimental plot, it ranged between 30.02 and 39.29 kPa between depths of 0 - 30 cm. A second-order quadratic expression of the form y = ax2 + bx + c was obtained for the relationship between specific draft and depth at given hitching length as well as specific draft against hitching length at a given depth. The optimal hitching length and tillage depth for Machakos experimental plot were obtained as 2.9 m (~3 m) and 16.5 cm respectively. In Kitui experimental site, the optimal hitching length was obtained as 2.9 m (~3 m) and the optimal tillage depth was 15.4 cm. 展开更多
关键词 Soil Resistance SPECIFIC DRAFT Hitching LENGTH subsoiling Depth ANIMAL Power
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Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize 被引量:44
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作者 Hongguang Cai Wei Ma +6 位作者 Xiuzhi Zhang Jieqing Ping Xiaogong Yan Jianzhao Liu Jingchao Yuan Lichun Wang Jun Ren 《The Crop Journal》 SCIE CAS 2014年第5期297-307,共11页
A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen(N), phosphorus(P), and potassium(K) uptake, and grain yield of spring maize. The results indicated ... A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen(N), phosphorus(P), and potassium(K) uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development,increased nutrient accumulation, and increased yield. Compared with conventional soil management(CK), root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm(T1) and subsoil tillage to 50 cm(T2) were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments. 展开更多
关键词 Spring MAIZE SUBSOIL TILLAGE Root morphology Grain yield NUTRIENT ACCUMULATION
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Effects of Soil Properties on Phosphorus Subsurface Migration in Sandy Soils 被引量:14
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作者 ZHANG Ming-Kui 《Pedosphere》 SCIE CAS CSCD 2008年第5期599-610,共12页
The soil factors influencing the potential migration of dissolved and particulate phosphorus(P) from structurally-weak sandy subsoils were evaluated by means of soil column leaching experiments. Soil colloids were ext... The soil factors influencing the potential migration of dissolved and particulate phosphorus(P) from structurally-weak sandy subsoils were evaluated by means of soil column leaching experiments. Soil colloids were extracted from two types of soils to make the colloid-bound forms of P solution. Eight sandy soils with diverse properties were collected for packing soil columns. The effects of influent solutions varying in concentrations of colloids,P,and electrolyte,on the transport of P and quality of leachates were characterized. P migration in the soils was soil property-dependent. High soil electrical conductivity values retarded the mobility of colloids and transportability of colloid-associated P(particulate P) . Soil electrical conductivity was negatively correlated with colloids and reactive particulate P(RPP) concentrations in the leachates,whereas,the total reactive P(TRP) and dissolved reactive P(DRP) concentrations in the leachates were mainly controlled by the P adsorption capacity and the P levels in the subsoil. The reactive particulate P in the leachates was positively correlated with the colloidal concentration. Increased colloidal concentration in the influent could significantly increase the colloidal concentration in the leachates. Elevated P concentration in the influent had little effect on P recovery in the leachates,but it resulted in significant increases in the absolute P concentration in the leachates. 展开更多
关键词 colloidal type electrical conductivity P adsorption capacity P subsoil migration sandy soil
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Stable response of axisymmetric two-phase water-saturated soil 被引量:6
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作者 蔡袁强 孟楷 徐长节 《Journal of Zhejiang University Science》 EI CSCD 2004年第9期1022-1027,共6页
Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacen... Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies. 展开更多
关键词 Biot's dynamic consolidation Lamb's problem Saturated subsoil
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Global buckling behavior of submarine unburied pipelines under thermal stress 被引量:2
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作者 郭林坪 刘润 闫澍旺 《Journal of Central South University》 SCIE EI CAS 2013年第7期2054-2065,共12页
Buckling of submarine pipelines under thermal stress is one of the most important problems to be considered in pipeline design. And pipeline with initial imperfections will easily undergo failure due to global bucklin... Buckling of submarine pipelines under thermal stress is one of the most important problems to be considered in pipeline design. And pipeline with initial imperfections will easily undergo failure due to global buckling under thermal stress and internal pressure. Therefore, it is vitally important to study the global buckling of the submarine pipeline with initial imperfections. On the basis of the characteristics of the initial imperfections, the global lateral buckling of submarine pipelines was analyzed. Based on the deduced analytical solutions for the global lateral buckling, effects of temperature difference and properties of foundation soil on pipeline buckling were analyzed. The results show that the snap buckling is predominantly governed by the amplitude value of initial imperfection; the triggering temperature difference of Mode I for pipelines with initial imperfections is higher than that of Mode I1; a pipeline with a larger friction coefficient is safer than that with a smaller one; pipelines with larger initial imperfections are safer than those with smaller ones. 展开更多
关键词 submarine pipeline lateral buckling analytical solution initial imperfection subsoil friction resistance
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Causes, effects and control of seasonal frost action in railways 被引量:2
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作者 Antti Nurmikolu Mika Silvast 《Research in Cold and Arid Regions》 CSCD 2013年第4期363-367,共5页
Seasonally cold climate and resulting frost action set great demands to railway track substructure in order to maintain Irack geomelry. Chal- lenges culminate on high-speed lines, where the tolerances for roughness ar... Seasonally cold climate and resulting frost action set great demands to railway track substructure in order to maintain Irack geomelry. Chal- lenges culminate on high-speed lines, where the tolerances for roughness are the tightest. Problems may result in highly increased Irack maintenance and need for temporary speed reslrictions. The causes of frost action can be associated with subsoil, subballast or ballast. The major concern in frost protection is to avoid the freezing of frost susceptible subsoil by using sufficient thickness of subballast and relying on non-fi'ost-susctible subballast material. This paper provides an overview of the main research findings on the role of ballast, subballast and subsoil in frost acedon. In new comlruclion the material specificalions, design procedures and construction methods have been developed to ensure adequate performance of Irack subscatt, but special challenges exist in managing existing Wacks that were not designed for modem requirements. In order to perform cost-effective and sustainable track maintenance, it is necessary to recognize the problem areas and define the root-causes of problems. For locating the problem sections and defining the causes of defects, a sophisticated analysis based on integration of track geometry and ground penetrating radar (GPR) data has been developed and is summarized in this paper, 展开更多
关键词 frost action railway Irack BALLAST subballast SUBSOIL frost susceptibility ground peneWating radar track geometry Irackmaintenance
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Alleviation of Subsoil Acidity of Red Soil in Southeast China with Lime and Gypsum *1 被引量:1
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作者 SUNBO R.MOREAU 《Pedosphere》 SCIE CAS CSCD 1998年第2期113-120,共8页
Application of lime or gypsum is a common agricultural practice to ameliorate soils with low pH which prohibits crop production. Its integrated effect on soil properties in a red soil derived from Quaternary red clay ... Application of lime or gypsum is a common agricultural practice to ameliorate soils with low pH which prohibits crop production. Its integrated effect on soil properties in a red soil derived from Quaternary red clay in Southeast China is discussed in this paper. Application of gypsum in the topsoil without leaching raised soil pH and promoted the production of soil NH 4, but lime addition had a contrary effect. Generally, application of lime and/or gypsum has little effect on soil electrical properties. Gypsum had a little effect on soil exchange complex and its effect went down to 30 cm in depth. The effect of lime reached only to 5 cm below its application layer. With leaching, Ca transferred from top soil to subsoil and decreased exchangeable Al in subsoil. Gypsum application led to a sharp decrease in soil exchangeable Mg but had no effect on K. 展开更多
关键词 alleviation GYPSUM LIME red soil subsoil acidity
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A ^(15)N-Labeling Study of the Capture of Deep Soil Nitrate from Different Plant Systems 被引量:1
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作者 YANG Zhi-xin WANG Jue +2 位作者 DI Hong-jie ZHANG Li-juan JU Xiao-tang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第1期167-176,共10页
The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate (NO3-) to reduce NO3- leaching in a field plot experiment using 15N labelling. The study was cond... The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate (NO3-) to reduce NO3- leaching in a field plot experiment using 15N labelling. The study was conducted on a calcareous alluvial soil on the North China Plains and the plant systems evaluated included alfalfa (Medicago sativa), American black poplar (Populus nigra) and cocksfoot (Dactylis). ^15N-labelled N fertilizer was injected to 90 cm depth to determine the recovery of ^15N by the plants. With conventional water and nutrient management, the total recovery of ^15N-labeled NO3--N was 23.4% by alfalfa after two consecutive growth years. The recovery was significantly higher than those by American black poplar (12.3%) and cocksfoot (11.4%). The highest proportion of soil residual ~SN from the labeled fertilizer N (%Ndff) was detected around 90 cm soil depth at the time of the 1st year harvest and at 110-130 cm soil depth at time of the 2nd year harvest. Soil %Ndff in 0-80 cm depth was significantly higher in the alfalfa treatment than those in all the other treatments. The soil %Ndff below 100 cm depth was much lower in the alfalfa than those in all the other treatments. These results indicated that ^15N leaching losses in the alfalfa treatment were significantly lower than by those in the black poplar and cocksfoot treatments, due to the higher root density located in nitrate labeling zone of soil profile. In conclusion, alfalfa may be used as a plant to capture deep soil NO3- left from previous crops to reduce NO3- leaching in high intensity crop cultivation systems of North China Plain. 展开更多
关键词 ^15N-labeled nitrate tree and forage grass ALFALFA COCKSFOOT black poplar residual nitrate in subsoil capture ability
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System of Combined Foundation for Tall Buildings 被引量:1
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作者 Janusz Rebielak 《Journal of Civil Engineering and Architecture》 2012年第12期1627-1634,共8页
Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its... Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its cost increases significantly when the building is located in earthquake area or in mining damage sector. The proposed structural system of the combined foundation makes possible to design and to construct a very stable and relative inexpensive foundation structure, which can obtain an extremely large horizontal surface and which can be placed not deeply beneath the terrain level. It can be a very solid support structure for a tall building placed on very weak subsoil and at the same time located in seismic area. This system can be applied not only for new buildings but it can be used for the existing buildings and moreover for straighten of the inclined objects. Due to special arrangement of component parts the combined foundation possesses inherent features of a vibration damper, what is highly desirable if buildings have to be located in earthquake areas. When the aboveground storeys structure has some similar patterns with structural form of the combined foundation then the structural system of the whole building obtains coherent structural characteristics and it is called the combined structural system of the tall building. Suitable application of this system makes possible to design high-rise buildings having interesting and unique architectonic forms, what is presented on a selected example. 展开更多
关键词 Foundation system tall building subsoil of small load capacity earthquake area.
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