Modern subsoiling technology is a little ploughing measure in dry land protective farming technology system.The subsoiler can scarify soil,deepen the arable layer,break the plough layer,improve the soil permeability,i...Modern subsoiling technology is a little ploughing measure in dry land protective farming technology system.The subsoiler can scarify soil,deepen the arable layer,break the plough layer,improve the soil permeability,increase soil infiltration speed and amount,and create an arable layer structure with coexistence of fictional and real situation.Also,it can effectively promote development and growth of crop root system and play a favorable role in drought resistance and yield increase of crops.This paper made a simple overview of the subsoiling technology,current development situation of subsoiler both at home and abroad,and classification of subsoilers.展开更多
Multi-subsoiler collaboration plays a significant role in improving the efficiency of subsoiling.High tillage resistance during subsoiling seriously affects consumption,and the excessive soil disturbance may result in...Multi-subsoiler collaboration plays a significant role in improving the efficiency of subsoiling.High tillage resistance during subsoiling seriously affects consumption,and the excessive soil disturbance may result in an increase in the amount of water that evaporates from the soil,which is unfavorable for water conservation.However,the space arrangement and types of subsoiler are key parameters for design of a set of subsoilers and have a major effect on tillage resistance and soil disturbance,which is a critical performance indicator of subsoiling.In this paper,a set of subsoiler models were developed using DEM.A field experiment was conducted in the sowing season in an experimental field of 1 hm2 with black soil of Juliangtun Village,Liaoning Province.In both the simulation and experiment,six types of subsoilers(TC-SM,TC-SC,TA-SM,TA-SC,TDW-SM,and TDW-SC)were investigated at three different spacing arrangements(500,600,and 700 mm),a constant vertical distance between the front and back subsoilers(500 mm),a constant working speed(3 km/h),and a constant working depth(400 mm).The mechanism of resistance was analyzed.The results showed that the tillage resistances of the six types of subsoilers were in the descending order of F_(TDW-SC)>F_(TA-SC)>F_(TC-SC)>F_(TDW-SM)>F_(TA-SM)>F_(TC-SM).The field test showed that TC-SM with 600 mm spacing produced stable fluctuations with less tillage resistance.The variance analysis and regression equation testing of the experimental results were analyzed to enhance their scientific rigor.The analysis showed that the significances of each factor on the results were in the descending order of shank,space,and tine.The optimal configuration may be with spacing of 600 mm,tine of TC,and shank of SM,which is consistent with the field test and theoretical analysis.Tillage resistance of the DEM simulation was less than that of the field experiment,with an error of less than 10%,due to ignoring the effect of crop roots,straw residue,stones,or blunt tine and shank,which confirms the authenticity of simulation.The effect of spacing on soil disturbance behavior indicates that a mixed soil structure with moderate soil disturbance and soil porosity ratio and a spacing of 600 mm would be a good choice.This study provides an important foundation in selecting spacing for subsoiling to achieve an optimal soil tillage condition.展开更多
Subsoiling is an effective tillage technique for alleviating soil compaction,but the high traction resistance encountered at deeper working depths constrains its widespread application.To address this issue,a self-exc...Subsoiling is an effective tillage technique for alleviating soil compaction,but the high traction resistance encountered at deeper working depths constrains its widespread application.To address this issue,a self-excited and forced intelligent vibrating subsoiler was developed.The subsoiler is equipped with a compound vibration mechanism that can adaptively switch between self-excited vibration and forced vibration modes based on real-time monitoring of soil resistance.Field experiments were conducted to evaluate the performance of the self-excited and forced vibrating subsoiling(SEFV).These experiments compared its performance with conventional subsoiling(CS)and self-excited vibrating subsoiling(SEV)at different working depths(35-45 cm)and forward speeds(2 and 4 km/h).The results showed that at 2 km/h,SEFV operated in self-excited vibration mode and reduced traction resistance by 12.4%-13.1%compared to CS,with no significant difference from SEV.At 4 km/h,the resistance reduction effect of SEFV became more pronounced with increasing depth.At 45 cm depth,SEFV reduced traction resistance by 9.9%and 18.9%compared to SEV and CS,respectively,as it switched to forced vibration mode to overcome the high soil resistance.SEFV also maintained high subsoiling depth stability(>90%)at both speeds and all depths tested,demonstrating its advantage over SEV under high resistance conditions.The intelligent control system based on resistance feedback enabled the SEFV to automatically adapt to variable soil conditions and optimize its vibration behavior for improved subsoiling performance and energy efficiency.This study provides new insights into the design of adaptive vibrating subsoilers for enhanced tillage operations.展开更多
Since the design of the subsoiler is a complex work,the interaction between the subsoiler and soil was investigated by using Distinct Element Method(DEM)in this study.Based on the traditional discrete element theory,t...Since the design of the subsoiler is a complex work,the interaction between the subsoiler and soil was investigated by using Distinct Element Method(DEM)in this study.Based on the traditional discrete element theory,the 3D model of soil particles and the subsoiler were established after considering the liquid bridge force between soil particles.The operating resistance curves of the subsoiler were achieved after the DEM simulation at a speed of 1 m/s,and three depths of 180 mm,220 mm and 260 mm,respectively.The simulation curves agreed well with the field experimental results based on relative errors of 2.96%,14.95%and 7.15%,respectively,at three depths.All these data proved that it was feasible and favorable to analyze the performance of the subsoiler by using the DEM and it is of important significance for studying and further optimizing the structure of the subsoiler.展开更多
Generally,a subsoiler is comprised of a shank and a point.The point shape has a significant effect on the draft force of a subsoiler.In this study,the draft force of subsoilers with four different points were compared...Generally,a subsoiler is comprised of a shank and a point.The point shape has a significant effect on the draft force of a subsoiler.In this study,the draft force of subsoilers with four different points were compared under the speed of 0.8 m/s and the depth of 350 mm in the soil bin.Discrete Element Method(DEM)was applied in simulating the working process of the subsoiler.The stiffness of soil particles used in DEM was calibrated by comparing the simulated draft force of a standard arc-shaped subsoiler with the experiment.The calibrated soil particle stiffness was 1.1×104 N/m.The validated model was then used to compare the draft force of subsoilers with four different points under the same condition in the test.Results showed that different points would cause different draft forces.The subsoiler with short chisel point caused the smallest draft force(2885 N)while the point with short face and wings had the largest force(4474 N).The relative errors of the simulated results were less than 4%,which proved that DEM was an effective way for predicting the draft force of subsilers.The velocity field and contact force filed could show the movement of soil around the subsoiler.展开更多
Subsoiling is essential in the tillage of banana planting,as banana plants have a fairly sturdy pseudostem and wide row spacing while soil tends to be compacted.In this study,a bionic vibrating subsoiler for banana fi...Subsoiling is essential in the tillage of banana planting,as banana plants have a fairly sturdy pseudostem and wide row spacing while soil tends to be compacted.In this study,a bionic vibrating subsoiler for banana fields was developed,verified,and evaluated.The vibrator was designed based on crank-rocker mechanism while the bionics design was used for subsoiler development.The forces on the susboiler were analyzed to verify the strength of the subsoiler tine.To test the performance of the subsoiler,field tests were conducted to measure the draft force and fuel consumption.There was approximately 14%reduction in the draft force and 22%increase in the fuel consumption in vibrating mode compared with that in non-vibrating mode.In conclusion,the study results could be applied in China’s tropical agricultural regions.展开更多
Soil compaction is a common problem facing conservation fields that restricts crop root growth and causes yield decrease.Subsoil techniques have been developed to break up the compaction layer.However,subsoil implemen...Soil compaction is a common problem facing conservation fields that restricts crop root growth and causes yield decrease.Subsoil techniques have been developed to break up the compaction layer.However,subsoil implement requires large draft power that hampered the development of subsoil techniques for most of developing countries due to lack of large scale tractors.Aiming to optimize the penetration resistance of the subsoiler and create a good working environment for the operators,a staggered vibrating subsoiler was developed.A new staggered vibrating mechanism was designed to generate the staggered vibration of the shanks meanwhile the V-shape shanks arrangement was adopted to keep relative balance for the subsoiler.In order to obtain optimum working parameters of the vibration frequency and forward speed,the trajectory of shanks was simulated by using the MATLAB software.The forward speed of 2-3 km/h with vibration frequency of 12 Hz was recommended to acquire an effective decrease in draft force.Field performance of this subsoiler was evaluated in terms of the draft force,power requirement and tractor wheel slippage.By comparing the two operation modes,staggered vibrating(SV)and rigid(NV)of shanks,the decrease ratios of draft force for SV were determined by 16.97%,12.12%and 9.02%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.This is better than the research for the 1SZ-460 vibratory subsoiler that was decreased by 9.09%in draft force.The power requirement for SV was not significantly greater than that for NV.The obviously decreased wheel slippage was observed for SV by decrease of 12.47%,17.96%and 21.79%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.In conclusion,the staggered vibrating subsoiler presents preferable working performance and is recommended to be applied in subsoil tillage process for developing countries.展开更多
Understanding soil disturbance behaviors under the impact of the winged subsoiler is critical for designing or optimizing the winged subsoiler(a primary subsoiling tool).In this study,a soil-winged subsoiler interacti...Understanding soil disturbance behaviors under the impact of the winged subsoiler is critical for designing or optimizing the winged subsoiler(a primary subsoiling tool).In this study,a soil-winged subsoiler interaction model was developed and the effects of winged subsoiler on soil disturbance behaviors were investigated using the discrete element method(DEM)simulations and lab soil-bin tests.The results showed that wings mainly affected the disturbance range and fragmentation degree of soil above them.The draught forces of share section(SS),arc section in the hardpan(ASHP),arc section in the top layer(ASTL)and line section(LS)were accounted for 69.53%,25.22%,4.73%and 0.52%of the total draught force of winged subsoiler;the lateral disturbance range from high to low of the soil at different depths followed the ranking:top layer(TL),hardpan disturbed by arc section(HDAS)and hardpan disturbed by share section(HDSS).Wings had the greatest influence on the draught force of ASHP.Adding wings to an arc-shaped subsoiler increased the disturbance areas of HDAS,TL and HDSS by 47.52%,7.74%and 4.59%,respectively,but meanwhile increased the total draught force by 36%.Compared with a non-winged subsoiler,winged subsoiler had higher soil looseness(15.83%),soil disturbance coefficient(58.59%),furrow width(448.65 mm)and soil disturbance area ratio(0.3835),but poorer soil surface flatness(19.79 mm)and lower soil loosening efficiency(39.35 mm²/N).This study provided critical information for optimizing winged subsoilers on aspects of improving soil loosening effectiveness and reducing draught force.展开更多
A new subsoiler with placoid scale microstructure bionic surface was proposed which mimicked shark skin to reduce tillage resistance and soil adhesion during subsoiling cultivation.The contour curves of placoid scale ...A new subsoiler with placoid scale microstructure bionic surface was proposed which mimicked shark skin to reduce tillage resistance and soil adhesion during subsoiling cultivation.The contour curves of placoid scale microstructure on shark skin were fitted,and two kinds of bionic subsoiler with continuous and discontinuous microstructures were designed and fabricated,respectively.The effects of different bionic surfaces on tillage resistance were investigated by finite element simulation and experiment.The results indicated that the bionic subsoiler with discontinuous microstructure reduced the horizontal and vertical force by 21.3%and 24.8%,respectively.The subsoiler with discontinuous microstructure surface can prevent the adhesion between the soil and subsoiler surface more efficiently.展开更多
The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity...The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.展开更多
The commonly used subsoiling cum rotary tiller machine(SRT)in Northern China is a combination of subsoiler and horizontal rotary tiller,however backfilling of the subsoiling slot,excessive vibration and plant residue ...The commonly used subsoiling cum rotary tiller machine(SRT)in Northern China is a combination of subsoiler and horizontal rotary tiller,however backfilling of the subsoiling slot,excessive vibration and plant residue wrapping on rotary components has been rarely considered.Therefore,the rotary components and assembly were redesigned to address these issues and to an SRT fitted with IT225 short curve rotary blades behind the V-shape subsoiling slots and IIT245 long curve rotary blades between the tines.Long and short blades were fitted on a rotor in a double helix,with optimal spiral angles of 65° and 90°,and phase angle of 147°and 180°,respectively.Compared with the commonly used SRT(CSRT),the additional anti-wrapping cutting blades in the circumferential and axial direction of ASRT could remove hanging residue on the blade holders,wrapping on the rotor and formation of an isolation layer.Moreover,the cutting edge curve of anti-wrapping cutting blades was an exponential curve.Field tests demonstrated that the redesigned SRT with anti-vibrating and anti-wrapping rotary components(ASRT)had was a significant advancement over the CSRT.Moreover,the working depth of rotary tillage was more stable,while other observations confirmed that backfilling of the subsoiling slot was also improved.展开更多
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
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
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
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
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
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
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
Denitrification in subsoil(to a depth of 12 m) is an important mechanism to reduce nitrate(NO3^-) leaching into groundwater.However, regulating mechanisms of subsoil denitrification, especially those in the deep subso...Denitrification in subsoil(to a depth of 12 m) is an important mechanism to reduce nitrate(NO3^-) leaching into groundwater.However, regulating mechanisms of subsoil denitrification, especially those in the deep subsoil beneath the crop root zone, have not been well documented. In this study, soil columns of 0–12 m depth were collected from intensively farmed fields in the North China Plain. The fields had received long-term nitrogen(N) fertilizer inputs at 0(N0), 200(N200) and 600(N600) kg N ha^-1 year^-1. Main soil properties related to denitrification, i.e., soil water content, NO3^-, dissolved organic carbon(DOC), soil organic carbon(SOC),pH, denitrifying enzyme activity(DEA), and anaerobic denitrification rate(ADR), were determined. Statistical comparisons among the treatments were performed. The results showed that NO3^- was more heavily accumulated in the entire soil profile of the N600 treatment, compared to the N0 and N200 treatments. The SOC, DOC, and ADR decreased with increasing soil depth in all treatments,whereas considerable DEA was observed throughout the subsoil. The long-term fertilizer rates affected ADR only in the upper 4 m soil layers. The ADRs in the N200 and N600 treatments were significantly correlated with DOC. Multiple regression analysis indicated that DOC rather than DEA was the key factor regulating denitrification beneath the root zone. Additional research is required to determine if carbon addition into subsoil can be a promising approach to enhance NO3^- denitrification in the subsoil and consequently to mitigate groundwater NO3^- contamination in the intensive farmlands.展开更多
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
基金Supported by Project of National Natural Science Foundation(51105123)Key Science and Technology Program of Hainan Province(ZDXM20120074)
文摘Modern subsoiling technology is a little ploughing measure in dry land protective farming technology system.The subsoiler can scarify soil,deepen the arable layer,break the plough layer,improve the soil permeability,increase soil infiltration speed and amount,and create an arable layer structure with coexistence of fictional and real situation.Also,it can effectively promote development and growth of crop root system and play a favorable role in drought resistance and yield increase of crops.This paper made a simple overview of the subsoiling technology,current development situation of subsoiler both at home and abroad,and classification of subsoilers.
基金supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ23E050007)Huzhou Key Research and Development Project(Grant No.2022ZD2068)+1 种基金Huzhou Science and Technology Special Commissioner Project(Grant No.2023KT75)National Key R&D Program of China(Grant No.2022YFD1500600).
文摘Multi-subsoiler collaboration plays a significant role in improving the efficiency of subsoiling.High tillage resistance during subsoiling seriously affects consumption,and the excessive soil disturbance may result in an increase in the amount of water that evaporates from the soil,which is unfavorable for water conservation.However,the space arrangement and types of subsoiler are key parameters for design of a set of subsoilers and have a major effect on tillage resistance and soil disturbance,which is a critical performance indicator of subsoiling.In this paper,a set of subsoiler models were developed using DEM.A field experiment was conducted in the sowing season in an experimental field of 1 hm2 with black soil of Juliangtun Village,Liaoning Province.In both the simulation and experiment,six types of subsoilers(TC-SM,TC-SC,TA-SM,TA-SC,TDW-SM,and TDW-SC)were investigated at three different spacing arrangements(500,600,and 700 mm),a constant vertical distance between the front and back subsoilers(500 mm),a constant working speed(3 km/h),and a constant working depth(400 mm).The mechanism of resistance was analyzed.The results showed that the tillage resistances of the six types of subsoilers were in the descending order of F_(TDW-SC)>F_(TA-SC)>F_(TC-SC)>F_(TDW-SM)>F_(TA-SM)>F_(TC-SM).The field test showed that TC-SM with 600 mm spacing produced stable fluctuations with less tillage resistance.The variance analysis and regression equation testing of the experimental results were analyzed to enhance their scientific rigor.The analysis showed that the significances of each factor on the results were in the descending order of shank,space,and tine.The optimal configuration may be with spacing of 600 mm,tine of TC,and shank of SM,which is consistent with the field test and theoretical analysis.Tillage resistance of the DEM simulation was less than that of the field experiment,with an error of less than 10%,due to ignoring the effect of crop roots,straw residue,stones,or blunt tine and shank,which confirms the authenticity of simulation.The effect of spacing on soil disturbance behavior indicates that a mixed soil structure with moderate soil disturbance and soil porosity ratio and a spacing of 600 mm would be a good choice.This study provides an important foundation in selecting spacing for subsoiling to achieve an optimal soil tillage condition.
基金supported by the National Key Research and Development Program of China(Grant No.2024YFD2000100)the National Natural Science Foundation of China(Grant No.52105300 and 52075215)the Science and Technology Research Project of Jilin Provincial Education Department(Grant No.JJKH20250136KJ).
文摘Subsoiling is an effective tillage technique for alleviating soil compaction,but the high traction resistance encountered at deeper working depths constrains its widespread application.To address this issue,a self-excited and forced intelligent vibrating subsoiler was developed.The subsoiler is equipped with a compound vibration mechanism that can adaptively switch between self-excited vibration and forced vibration modes based on real-time monitoring of soil resistance.Field experiments were conducted to evaluate the performance of the self-excited and forced vibrating subsoiling(SEFV).These experiments compared its performance with conventional subsoiling(CS)and self-excited vibrating subsoiling(SEV)at different working depths(35-45 cm)and forward speeds(2 and 4 km/h).The results showed that at 2 km/h,SEFV operated in self-excited vibration mode and reduced traction resistance by 12.4%-13.1%compared to CS,with no significant difference from SEV.At 4 km/h,the resistance reduction effect of SEFV became more pronounced with increasing depth.At 45 cm depth,SEFV reduced traction resistance by 9.9%and 18.9%compared to SEV and CS,respectively,as it switched to forced vibration mode to overcome the high soil resistance.SEFV also maintained high subsoiling depth stability(>90%)at both speeds and all depths tested,demonstrating its advantage over SEV under high resistance conditions.The intelligent control system based on resistance feedback enabled the SEFV to automatically adapt to variable soil conditions and optimize its vibration behavior for improved subsoiling performance and energy efficiency.This study provides new insights into the design of adaptive vibrating subsoilers for enhanced tillage operations.
基金This study was funded by the National Science and Technology Supporting Plan(No.2011BAD29B08)the“111”Project(No.B12007).
文摘Since the design of the subsoiler is a complex work,the interaction between the subsoiler and soil was investigated by using Distinct Element Method(DEM)in this study.Based on the traditional discrete element theory,the 3D model of soil particles and the subsoiler were established after considering the liquid bridge force between soil particles.The operating resistance curves of the subsoiler were achieved after the DEM simulation at a speed of 1 m/s,and three depths of 180 mm,220 mm and 260 mm,respectively.The simulation curves agreed well with the field experimental results based on relative errors of 2.96%,14.95%and 7.15%,respectively,at three depths.All these data proved that it was feasible and favorable to analyze the performance of the subsoiler by using the DEM and it is of important significance for studying and further optimizing the structure of the subsoiler.
基金the National Science and Technology Supporting Plan of China(2011BAD29B08).
文摘Generally,a subsoiler is comprised of a shank and a point.The point shape has a significant effect on the draft force of a subsoiler.In this study,the draft force of subsoilers with four different points were compared under the speed of 0.8 m/s and the depth of 350 mm in the soil bin.Discrete Element Method(DEM)was applied in simulating the working process of the subsoiler.The stiffness of soil particles used in DEM was calibrated by comparing the simulated draft force of a standard arc-shaped subsoiler with the experiment.The calibrated soil particle stiffness was 1.1×104 N/m.The validated model was then used to compare the draft force of subsoilers with four different points under the same condition in the test.Results showed that different points would cause different draft forces.The subsoiler with short chisel point caused the smallest draft force(2885 N)while the point with short face and wings had the largest force(4474 N).The relative errors of the simulated results were less than 4%,which proved that DEM was an effective way for predicting the draft force of subsilers.The velocity field and contact force filed could show the movement of soil around the subsoiler.
基金the Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(Grant No.201503136)the National Natural Science Foundation of China(Grant No.51565010)the National Natural Science Foundation of Hainan Province(Grant No.20163038)。
文摘Subsoiling is essential in the tillage of banana planting,as banana plants have a fairly sturdy pseudostem and wide row spacing while soil tends to be compacted.In this study,a bionic vibrating subsoiler for banana fields was developed,verified,and evaluated.The vibrator was designed based on crank-rocker mechanism while the bionics design was used for subsoiler development.The forces on the susboiler were analyzed to verify the strength of the subsoiler tine.To test the performance of the subsoiler,field tests were conducted to measure the draft force and fuel consumption.There was approximately 14%reduction in the draft force and 22%increase in the fuel consumption in vibrating mode compared with that in non-vibrating mode.In conclusion,the study results could be applied in China’s tropical agricultural regions.
基金This work was supported by China’s Ministry of Agriculture,Agricultural Public Welfare Industry Research(201503117)China’s Ministry of Agriculture,Agricultural Public Welfare Industry Research(201503116-16)the Soil-Machine-Plant Key Laboratory of the Ministry of Agriculture of China.
文摘Soil compaction is a common problem facing conservation fields that restricts crop root growth and causes yield decrease.Subsoil techniques have been developed to break up the compaction layer.However,subsoil implement requires large draft power that hampered the development of subsoil techniques for most of developing countries due to lack of large scale tractors.Aiming to optimize the penetration resistance of the subsoiler and create a good working environment for the operators,a staggered vibrating subsoiler was developed.A new staggered vibrating mechanism was designed to generate the staggered vibration of the shanks meanwhile the V-shape shanks arrangement was adopted to keep relative balance for the subsoiler.In order to obtain optimum working parameters of the vibration frequency and forward speed,the trajectory of shanks was simulated by using the MATLAB software.The forward speed of 2-3 km/h with vibration frequency of 12 Hz was recommended to acquire an effective decrease in draft force.Field performance of this subsoiler was evaluated in terms of the draft force,power requirement and tractor wheel slippage.By comparing the two operation modes,staggered vibrating(SV)and rigid(NV)of shanks,the decrease ratios of draft force for SV were determined by 16.97%,12.12%and 9.02%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.This is better than the research for the 1SZ-460 vibratory subsoiler that was decreased by 9.09%in draft force.The power requirement for SV was not significantly greater than that for NV.The obviously decreased wheel slippage was observed for SV by decrease of 12.47%,17.96%and 21.79%at forward speeds of 2.2 km/h,2.6 km/h and 3.1 km/h,respectively.In conclusion,the staggered vibrating subsoiler presents preferable working performance and is recommended to be applied in subsoil tillage process for developing countries.
基金The authors gratefully acknowledge the financial assistance received from the National Key Research and Development Program of China(Grant No.2016YFD0200601,2016YFD020060101)and the Key Industry Chain Innovation Project of Shaanxi Province(Grant No.2018ZDCXL-NY-03-06).
文摘Understanding soil disturbance behaviors under the impact of the winged subsoiler is critical for designing or optimizing the winged subsoiler(a primary subsoiling tool).In this study,a soil-winged subsoiler interaction model was developed and the effects of winged subsoiler on soil disturbance behaviors were investigated using the discrete element method(DEM)simulations and lab soil-bin tests.The results showed that wings mainly affected the disturbance range and fragmentation degree of soil above them.The draught forces of share section(SS),arc section in the hardpan(ASHP),arc section in the top layer(ASTL)and line section(LS)were accounted for 69.53%,25.22%,4.73%and 0.52%of the total draught force of winged subsoiler;the lateral disturbance range from high to low of the soil at different depths followed the ranking:top layer(TL),hardpan disturbed by arc section(HDAS)and hardpan disturbed by share section(HDSS).Wings had the greatest influence on the draught force of ASHP.Adding wings to an arc-shaped subsoiler increased the disturbance areas of HDAS,TL and HDSS by 47.52%,7.74%and 4.59%,respectively,but meanwhile increased the total draught force by 36%.Compared with a non-winged subsoiler,winged subsoiler had higher soil looseness(15.83%),soil disturbance coefficient(58.59%),furrow width(448.65 mm)and soil disturbance area ratio(0.3835),but poorer soil surface flatness(19.79 mm)and lower soil loosening efficiency(39.35 mm²/N).This study provided critical information for optimizing winged subsoilers on aspects of improving soil loosening effectiveness and reducing draught force.
基金This work was financially supported by Natural Science Basic Research Program of Shaanxi(Program No.2021JQ-173)Innovation and Entrepreneurship Training Program of Northwest A&F University(Program No.201910712134).
文摘A new subsoiler with placoid scale microstructure bionic surface was proposed which mimicked shark skin to reduce tillage resistance and soil adhesion during subsoiling cultivation.The contour curves of placoid scale microstructure on shark skin were fitted,and two kinds of bionic subsoiler with continuous and discontinuous microstructures were designed and fabricated,respectively.The effects of different bionic surfaces on tillage resistance were investigated by finite element simulation and experiment.The results indicated that the bionic subsoiler with discontinuous microstructure reduced the horizontal and vertical force by 21.3%and 24.8%,respectively.The subsoiler with discontinuous microstructure surface can prevent the adhesion between the soil and subsoiler surface more efficiently.
基金fnancially supported by the Natural Science Foundation of Hebei Province,China(C2021301004)the State Key Laboratory of North China Crop Improvement and Regulation,China(NCCIR2023KF-10)the HAAFS Science and Technology Innovation Special Project,China(2022KJCXZX-LYS-9)。
文摘The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.
基金The authors gratefully acknowledge that this research was financially supported by the Modern Agricultural Industry Technology System(Grant No.CARS-03)Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(Grant No.201503136)Innovative Research Team in University of China(Grant No.IRT13039).
文摘The commonly used subsoiling cum rotary tiller machine(SRT)in Northern China is a combination of subsoiler and horizontal rotary tiller,however backfilling of the subsoiling slot,excessive vibration and plant residue wrapping on rotary components has been rarely considered.Therefore,the rotary components and assembly were redesigned to address these issues and to an SRT fitted with IT225 short curve rotary blades behind the V-shape subsoiling slots and IIT245 long curve rotary blades between the tines.Long and short blades were fitted on a rotor in a double helix,with optimal spiral angles of 65° and 90°,and phase angle of 147°and 180°,respectively.Compared with the commonly used SRT(CSRT),the additional anti-wrapping cutting blades in the circumferential and axial direction of ASRT could remove hanging residue on the blade holders,wrapping on the rotor and formation of an isolation layer.Moreover,the cutting edge curve of anti-wrapping cutting blades was an exponential curve.Field tests demonstrated that the redesigned SRT with anti-vibrating and anti-wrapping rotary components(ASRT)had was a significant advancement over the CSRT.Moreover,the working depth of rotary tillage was more stable,while other observations confirmed that backfilling of the subsoiling slot was also improved.
基金partly funded by the Al Ain MunicipalityNational Water and Energy Center, United Arab Emirates University。
文摘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.
基金Consejo Nacional de Ciencia y Tecnología of Mexico(CONACyT)under Grant No.1000473。
文摘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.
基金supported by the National Key Technology R&D Program of China(2012BAD04B02,2013BAD07B02,and2011BAD16B10)the Special Fund for Agro-Scientific Research in the Public Interest(201103003 and 201303126-4)the Key Technology R&D Program of Jilin province,China(20126026)
文摘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.
基金the National Key Technologies R&D Program of China during the 1 lth Five-Year Plan Period(2006BAD02A15,2007BAD89B01)the National Natural Science Foundation of China(30471010).
文摘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.
基金This work was supported by the Agricultural Public Welfare Industry Research,Ministry of Agriculture,China(201503117)and the earmarked fund for China Agriculture Research System(CARS-02).
文摘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.
基金supported by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD16B15)
文摘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.
基金the Natural Science Foundation of Zhejiang Province, China (No.R306011).
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.31270554 and41301323)the Key Program of National Natural Science Foundation of China(No.41530859)
文摘Denitrification in subsoil(to a depth of 12 m) is an important mechanism to reduce nitrate(NO3^-) leaching into groundwater.However, regulating mechanisms of subsoil denitrification, especially those in the deep subsoil beneath the crop root zone, have not been well documented. In this study, soil columns of 0–12 m depth were collected from intensively farmed fields in the North China Plain. The fields had received long-term nitrogen(N) fertilizer inputs at 0(N0), 200(N200) and 600(N600) kg N ha^-1 year^-1. Main soil properties related to denitrification, i.e., soil water content, NO3^-, dissolved organic carbon(DOC), soil organic carbon(SOC),pH, denitrifying enzyme activity(DEA), and anaerobic denitrification rate(ADR), were determined. Statistical comparisons among the treatments were performed. The results showed that NO3^- was more heavily accumulated in the entire soil profile of the N600 treatment, compared to the N0 and N200 treatments. The SOC, DOC, and ADR decreased with increasing soil depth in all treatments,whereas considerable DEA was observed throughout the subsoil. The long-term fertilizer rates affected ADR only in the upper 4 m soil layers. The ADRs in the N200 and N600 treatments were significantly correlated with DOC. Multiple regression analysis indicated that DOC rather than DEA was the key factor regulating denitrification beneath the root zone. Additional research is required to determine if carbon addition into subsoil can be a promising approach to enhance NO3^- denitrification in the subsoil and consequently to mitigate groundwater NO3^- contamination in the intensive farmlands.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest,China(201303104)the earmarked fund for China Agriculture Research System(CARS-03-01-24)the Project Funded by China Postdoctoral Science Foundation(K461501024)
文摘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.
