The tangent resistance on the interface of the soil-moldboard is an important component of the resistance to moving soil . We developed simplified mechanical models to analyze this resistance. We found that it is comp...The tangent resistance on the interface of the soil-moldboard is an important component of the resistance to moving soil . We developed simplified mechanical models to analyze this resistance. We found that it is composed of two components, the frictional and adhesive resistances. These two components originate from the soil pore, which induced a capillary suction effect, and the soil-moldboard contact area produced tangent adhesive resistance. These two components varied differently with soil moisture. Thus we predicted that resistance reduction against soil exerted on the non-smooth bionic moldboard is mainly due to the elimination of capillary suction and the reduction of physical-chemical adsorption of soil.展开更多
Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice...Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.展开更多
A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part sur...A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part surface and lateral to the legs which are different in size, arrangement and shape. These setae have different lengths and many thorns on the whole seta. The top ends of these setae stand up without furcations which direct uprightly towards the surface of the touched soil. By the method of removing these setae, getting the insect weight before and after digging into the dung we affirm farther that the setae on the beetle body surface form the anti-stick and non-adherent gentle interface. The soil machines and components made by imitating the gentle body surface of beetles have favorable non-adherent results.展开更多
In order to solve the serious problem of soil adhering blade roller in the middle and lower reaches of Yangtze River,the anti-adhesion rototiller based on staggered double-roller scraping(ARSDS)was designed by mechani...In order to solve the serious problem of soil adhering blade roller in the middle and lower reaches of Yangtze River,the anti-adhesion rototiller based on staggered double-roller scraping(ARSDS)was designed by mechanical scraping methods.The volume equation for scraping the soil adhesion part with staggered rotary blades was constructed.The mechanical conditions for separation of soil adhesion part from blade roller were clarified,and the contact time between rotary blade and soil during rotary tillage was analyzed.By this way,the key parameters affecting soil adhering on and separating from the blade roller were determined,which were rotational speed,cutting pitch and tillage depth.The spatial and temporal trajectory changes for the sidelong section edge of staggered rotary blades were analyzed,so that the rotary blade arrangement was obtained.Combining the discrete element method,selecting the soil adhesion mass on the staggered blade rollers as the response value established prediction model by Box-Behnken design test.For example,taking the tillage depth of 14 cm for wheat cultivation in the middle and lower reaches of Yangtze River,the optimal combination of parameters was determined to be 230 r/min and 10 cm for rotational speed and cutting pitch,respectively.At this time,the soil adhesion mass was 4566.67 g.In the meantime,the process of soil particles adhering staggered blade rollers and rotary blades scraping off the adhering soil were clarified.Field experiments have shown that the operation quality of ARSDS met the requirements of rototiller performance indexes.In the rice stubble field of high water moisture,the soil adhesion mass was 13.455 kg and 38.215 kg for ARSDS and conventional rototiller,respectively,which indicated that ARSDS effectively reducing soil adhesion mass.The research results can provide technical support for the design of rototiller reducing soil adhesion in the agricultural areas of the middle and lower reaches of the Yangtze River.展开更多
In order to solve the serious problems of soil adhesion and blockage as well as high operating resistance for wheat seeders under the condition of sticky heavy loam clay in rice-wheat rotation area,a new concept of no...In order to solve the serious problems of soil adhesion and blockage as well as high operating resistance for wheat seeders under the condition of sticky heavy loam clay in rice-wheat rotation area,a new concept of non-contact pneumatic seeding technology that could rip wheat seed into the soil by high pressure accelerating airflow was proposed in this paper.A preliminary bench experiment was conducted and high-speed photography technology was used to study the parameters of wheat pneumatic seeding under five levels(30%,35%,40%,45%and 50%)of soil moisture content for loam clay.Experimental results showed that:wheat seeds could be ripped into soil without damage and acquired varying degrees of germination by way of pneumatic seeding;shooting depth shown a deepening tendency with the increase in shooting velocity,and the value of seeding depth and seeding velocity are closely related to the soil moisture level,which wheat seeds can achieve higher shooting depth with relative lower shooting velocity when the soil moisture content increases continuously;none of wheat seeds could be ripped into the soil with about 2.93 m/s shooting velocity that accelerated in the form of free fall,while the shooting velocity that wheat seeds needed in order to be completely ripped into soil with 3 mm shooting depth were 40-50 m/s(30%soil moisture content),30-40 m/s(35%soil moisture content),20-30 m/s(40%soil moisture content),10-20 m/s(45%soil moisture content)and 2.93-10 m/s(20%soil moisture content),respectively.The experimental results can provide basic data and technical support for the development of non-contact wheat seeding equipment in rice-wheat rotation area.展开更多
基金sup port provided by the Key Project of Ministry of Edu-cation of P.R.China(Grant No.02089)the National Key Grant Program of Basic Research De-velopment(Grant No.2002CCA01200).
文摘The tangent resistance on the interface of the soil-moldboard is an important component of the resistance to moving soil . We developed simplified mechanical models to analyze this resistance. We found that it is composed of two components, the frictional and adhesive resistances. These two components originate from the soil pore, which induced a capillary suction effect, and the soil-moldboard contact area produced tangent adhesive resistance. These two components varied differently with soil moisture. Thus we predicted that resistance reduction against soil exerted on the non-smooth bionic moldboard is mainly due to the elimination of capillary suction and the reduction of physical-chemical adsorption of soil.
基金financially supported by the National Natural Science Foundation of China(32071943,31872853,31871557)Jiangsu Provincial Department of Education and Yangzhou University(JS-2020-217)+3 种基金Zhejiang A&F University Research Development Fund(2023LFR003)ICD was in receipt of a Newton Advanced Fellowship(NA160430)the European Union SHui Project(773903)the GCRF RECIRCULATE(ES/P010857/1)Project.We thank Cameron Colclough for instruction in the soil adhesion assay,and Vasileios Giannakopoulos for determining the soil moisture release curve.
文摘Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.
文摘A scanning electron microscope was used to observe the structures of the setae on the surface of a dung beetle Copris ochus, Motschulsky. There are lots of setae on the body surface, especially on the ventral part surface and lateral to the legs which are different in size, arrangement and shape. These setae have different lengths and many thorns on the whole seta. The top ends of these setae stand up without furcations which direct uprightly towards the surface of the touched soil. By the method of removing these setae, getting the insect weight before and after digging into the dung we affirm farther that the setae on the beetle body surface form the anti-stick and non-adherent gentle interface. The soil machines and components made by imitating the gentle body surface of beetles have favorable non-adherent results.
基金supported by the National Natural Science Foundation of China(Grant No.32271994,31901412)Hubei Provincial Natural Science Foundation(Grant No.2024AFB696).
文摘In order to solve the serious problem of soil adhering blade roller in the middle and lower reaches of Yangtze River,the anti-adhesion rototiller based on staggered double-roller scraping(ARSDS)was designed by mechanical scraping methods.The volume equation for scraping the soil adhesion part with staggered rotary blades was constructed.The mechanical conditions for separation of soil adhesion part from blade roller were clarified,and the contact time between rotary blade and soil during rotary tillage was analyzed.By this way,the key parameters affecting soil adhering on and separating from the blade roller were determined,which were rotational speed,cutting pitch and tillage depth.The spatial and temporal trajectory changes for the sidelong section edge of staggered rotary blades were analyzed,so that the rotary blade arrangement was obtained.Combining the discrete element method,selecting the soil adhesion mass on the staggered blade rollers as the response value established prediction model by Box-Behnken design test.For example,taking the tillage depth of 14 cm for wheat cultivation in the middle and lower reaches of Yangtze River,the optimal combination of parameters was determined to be 230 r/min and 10 cm for rotational speed and cutting pitch,respectively.At this time,the soil adhesion mass was 4566.67 g.In the meantime,the process of soil particles adhering staggered blade rollers and rotary blades scraping off the adhering soil were clarified.Field experiments have shown that the operation quality of ARSDS met the requirements of rototiller performance indexes.In the rice stubble field of high water moisture,the soil adhesion mass was 13.455 kg and 38.215 kg for ARSDS and conventional rototiller,respectively,which indicated that ARSDS effectively reducing soil adhesion mass.The research results can provide technical support for the design of rototiller reducing soil adhesion in the agricultural areas of the middle and lower reaches of the Yangtze River.
基金This paper was funded by the Program for China Agriculture Research System(CARS-03)and Changjiang Scholars,Innovative Research Team in University of China(Grant No.IRT13039).Gratitude should be expressed to all the members of Conservation Tillage Research Centre.
文摘In order to solve the serious problems of soil adhesion and blockage as well as high operating resistance for wheat seeders under the condition of sticky heavy loam clay in rice-wheat rotation area,a new concept of non-contact pneumatic seeding technology that could rip wheat seed into the soil by high pressure accelerating airflow was proposed in this paper.A preliminary bench experiment was conducted and high-speed photography technology was used to study the parameters of wheat pneumatic seeding under five levels(30%,35%,40%,45%and 50%)of soil moisture content for loam clay.Experimental results showed that:wheat seeds could be ripped into soil without damage and acquired varying degrees of germination by way of pneumatic seeding;shooting depth shown a deepening tendency with the increase in shooting velocity,and the value of seeding depth and seeding velocity are closely related to the soil moisture level,which wheat seeds can achieve higher shooting depth with relative lower shooting velocity when the soil moisture content increases continuously;none of wheat seeds could be ripped into the soil with about 2.93 m/s shooting velocity that accelerated in the form of free fall,while the shooting velocity that wheat seeds needed in order to be completely ripped into soil with 3 mm shooting depth were 40-50 m/s(30%soil moisture content),30-40 m/s(35%soil moisture content),20-30 m/s(40%soil moisture content),10-20 m/s(45%soil moisture content)and 2.93-10 m/s(20%soil moisture content),respectively.The experimental results can provide basic data and technical support for the development of non-contact wheat seeding equipment in rice-wheat rotation area.
