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A simplified dynamic method for field capacity estimation and its parameter analysis

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Water Science and Engineering 2014年第4期7卷 351-362页

作者： Zhen-tao CONG Hua-fang Lü Guang-heng NI Department of Hydraulic Engineering Tsinghua University

This paper presents a simplified dynamic method based on the definition of field capacity. Two soil hydraulic characteristics models, the Brooks-Corey （BC） model and the van Genuchten （vG） model, and four soil data groups were used in this study. The relative drainage rate, which is a unique parameter and independent of the soil type in the simplified dynamic method, was analyzed using the pressure-based method with a matric potential of -1/3 bar and the flux-based method with a drainage flux of 0.005 cm/d. As a result, the relative drainage rate of the simplified dynamic method was determined to be 3% per day. This was verified by the similar field capacity results estimated with the three methods for most soils suitable for cultivating plants. In addition, the drainage time calculated with the simplified dynamic method was two to three days, which agrees with the classical definition of field capacity. We recommend the simplified dynamic method with a relative drainage rate of 3% per day due to its simple application and clearly physically-based concept.

关键词： field capacity simplified dynamic method pressure-based method flux-basedmethod soil water HYDRUS

Variation of soil organic carbon and bulk density during afforestation regulates soil hydraulic properties

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Journal of Mountain Science 2022年第8期19卷 2322-2332页

作者： GU Feng CHEN Xue-jiao SU Zheng-an ZHANG Xin-bao ZHOU Ming-hua Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Sichuan Academy of Environmental Policy and Planning Chengdu 610093China School of Food and Bioengineering Xihua UniversityChengdu 610039China

Grain to Green program on arable land has been conducted for decades in semi-arid regions of North ***,it remains uncertain how afforestation practices affect soil hydraulic properties(SHP).Two afforestation types,***(SL)and woodland(WL),and the adjacent cropland(CL)were investigated to determine afforestation effects on SHP in this *** and undisturbed soil cores were collected in three experimental *** field capacity(FC),wilting point(WP),and available water capacity(AWC)increased in SL compared to the *** saturated water content,however,decreased significantly in both SL and *** and redundancy analysis identified that bulk density(BD)and soil organic carbon(SOC)were the main factors regulating SHP across different land *** saturated water contents in afforestation sites were likely driven by the higher BD,compared to the adjacent ***,WP,and AWC were positively correlated to SOC *** afforestation may not increase the saturated water content of a landscape,our results indicate that it can improve soil water retention and could be an effective practice for soil and water conservation.

关键词： Afforestation Bulk density field capacity Soil hydraulic properties Soil organic carbon Soil water retention curve

Cadmium speciation as influenced by soil water content and zinc and the studies of kinetic modeling in two soils textural classes

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International Soil and Water Conservation Research 2020年第3期8卷 286-294页

作者： Farzad Rassaei Mehran Hoodaji Seyed Ali Abtahi Department of Soil Science Isfahan(Khorasgan)BranchIslamic Azad UniversityIsfahanIran Department of Soil Science Shiraz UniversityShirazIran

Background and aims:Since few studies have existed in the literature about the effect of zinc(Zn)on cadmium(Cd)chemical forms in ***,this study has been performed to determine the impact of Zn on cadmium Cd chemical forms in two soil textural classes in Fars province-Iran at two soil water content(SWC)(flooded soil water content(FSWC)and field capacity soil water content(FCSWC))and study the kinetic modeling of *** and materials:Variables were three levels of Cd(0,30 and 60 mg kg-1 of soil as CdSO4·8H2O),three levels of Zn(0,5 and 10 mg kg-1 of soil as Zn-EDTA)three level Incubation times(2,4 and eight weeks),two soil textural classes(clay and sandy clay loam)and two *** randomized completed block design(RCBD)was used for this *** Tessier sequential extraction method was used to determine the Cd concentration in(WsEx),(Fe-MnOx),(Car),(Om)and(Res)chemical ***:In the FSWC,Zn reduced the Cd concentration in Fe-MnOx,Car and Om forms and increased the WsEx but had no significant effect on the Res *** in the Cd chemical forms under the in-fluence of Zn in both soils followed a similar *** the FCSWC,Zn reduced the Cd concentration Car and Om forms and increased the Cd concentration in the Fe-MnOx and WsEx forms while had no sig-nificant effect on Res form in the sandy clay loam *** the clay soil adding Zn reduced the Cd con-centration in Car and Om fractions and increased the Fe-MnOx and Res forms while has no significant effect on WsEx *** competitive transport and adsorption Interactions between these two ions caused the changing in the Cd concentration in its chemical *** reduces the Cd concentration in the forms which are easily released into the soil solution from where they can be absorbed by *** power function kinetic mode is the best fitted model which can describe the Cd adsorption in our soil *** clay and organic compounds control the Cd adsorption in *** higher rate of C

关键词： Cadmium Chemical forms field capacity Flooding condition Kinetic model Sequential technique Soil water content Zinc

Effects of biological soil crusts and drought on emergence and survival of a Patagonian perennial grass in the Monte of Argentina

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Journal of Arid Land 2014年第6期6卷 735-741页

作者： Flavia Alejra FUNK Alejro LOYDI Guadalupe PETER Center for Renewable Natural Resources of the Semi-arid Zone National Scientific and Technical Research Council (CONICET)Bahía Blanca 8000Argentina Río Negro National University Viedma 8500Argentina

Biological soil crusts are widely distributed in arid and semiarid regions. They have an important eco- logical role, especially by modifying physical and chemical properties of soils. Biological crusts may also modify seed germination and seedling establishment. The effects vary widely according to the type of crust and the vas- cular plant species. The objective of this study was to determine the effect of moss-dominated biological soil crusts on the emergence, biomass and survival of Poa ligularis Nees ex Steud. under different irrigation regimes. We col- lected seeds of P. ligularis and biological soil crusts composed of two species of mosses： Syntrichia princeps （De Not.） Mitt and Ceratodon purpureus （Hedw.） Brid. from an area in the Monte of Argentina. The result showed that seedling emergence of P. ligularis was higher in treatments with bare soil than in soil covered by crusts, and also in those with watering to field capacity. Mean emergence time was higher in treatments with bare soil and watering to field capacity. Seedling biomass also showed significant differences between treatments. These results suggest that biological soil crusts dominated by mosses do not promote P. ligularis emergence, although they would not affect its survival.

关键词： drought field capacity recruitment microsites mosses semiarid region Poa ligularis

Effects of metal oxide nanoparticles on soil water retention curve and tensile strength

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Pedosphere 2024年第6期34卷 1136-1145页

作者： Elahe DARAEI Hossein BAYAT Pouya ZAMANI Department of Soil Science and Engineering Faculty of Agriculture Bu-Ali Sina University Department of Animal Science Faculty of Agriculture Bu-Ali Sina University

Generally,nanotechnology plays an very important role in various applied scientific *** and magnesium nanoparticles （NPs） can cause positive or negative changes in soil physical and mechanical properties,especially in long *** aim of this study was to investigate the multi-year effects of NPs on soil water retention and aggregate tensile strength.A wheat farm loamy soil was amended with 1%,3%,and 5%（weight/weight） of magnesium oxide（Mg O） and iron oxide （Fe3O4） NPs in three replications and incubated for three *** contents were measured at different matric suctions of 0,10,20,40,60,100,300,1 000,and 15 000 *** van Genuchten model was fitted to the moisture *** strength was measured on the 2–4 mm aggregates at matric suctions of 300 （i.e.,field capacity） and 15 000 （i.e.,permanent wilting point） *** results showed that the levels of 1%and 3%Fe3O4NPs significantly increased water retention,compared to the no NP application control and 5%Mg O NPs,which is probably due to the increase of adsorption surfaces in the treated *** contents at field capacity and permanent wilting point in the 5%Mg O NP treatment decreased compared to those of the other treatments,due to the increased soil vulnerability and reduced soil fine *** application of Fe3O4NPs did not have any significant effect on soil tensile *** on the results of this study,soil physical and mechanical properties could be affected by NP application.

关键词： field capacity iron oxide nanoparticles magnesium oxide nanoparticles matric suction permanent wilting point soil water content surface morphology van Genuchten model

Monitoring and predicting the soil water content in the deeper soil profile of Loess Plateau,China

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International Soil and Water Conservation Research 2016年第1期4卷 6-11页

作者： Aijuan Wang Baoyuan Liu Zhiqiang Wang Gang Liu Center of Soil and Water Conservation Monitoring Ministry of Water ResourcesFloor 10Block AGuidu International CenterNo.27Guang’anmen Nanbinhe RoadXicheng DistrictBeijing 100055PR China School of Geography Beijing Normal UniversityNo.19Xinjiekouwai StreetHaidian DistrictBeijing 100875PR China

Estimation of soil water content(SWC)in deep soil profiles is of crucial importance for strategic management of water resource for sustainable land use in arid and semi-arid zones,as well as for soil and water *** properties have a very important effect on *** study aimed to analyze the influence of soil particle size on SWC,for the first time using soil particle size to estimate SWC in deep soil *** was measured mainly in farmland,natural grasslands and plantations of Caragana from the surface to more than 20 m *** same soil samples were also tested for particle *** results show that the soil desiccation is formed in the caragana forest in 3–18 m soil layers,but almost no formation in 18–24 m layers;water content of farmland and grassland is different in all soil profiles although they are both shallow rooted *** analysis indicated that SWC could be well predicted by clay content and the close correlation between SWC and clay content yielded a coefficient of determination(R^(2))of 0.82 and 0.72,respectively,for farmland and *** multiple regression analysis,a regression model was built using SWC,clay content and sand content data,giving R^(2)=*** model provided reliable estimates of SWC profile based on textural *** can assist in estimating water depletion by vegetation,by comparing moisture of farmland and grassland soils with that of plantation forests,and in selecting sustainable land use of arid land.

关键词： Clay content field capacity Sand content Soil water content(SWC) Soil particle size

Development and Evaluation of Self-propelled Cabbage/Cauliflower Harvester

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NASS Journal of Agricultural Sciences 2022年第1期4卷 56-63页

作者： Jagvir Dixit Naieam Jan Rawat Division of Farm Machinery and Power Engineering College of Agricultural Engineering&TechnologySKUAST-KSrinagar(J&K)India

In the present study,self-propelled cabbage/cauliflower harvester was designed,developed and *** machine consisted of different components like engine,frame,shearing(cutting)unit and power transmission *** power transmission unit consisted of main clutch,shearing blade operating clutch,belt drive unit,chain and sprocket drive,universal joint and cutter blade *** main working principle of harvester is based on shearing of crop stem against high-speed rotating *** power from the engine is transmitted by belt-pulley drive unit to transmission shaft on which chain and sprocket is mounted on one side and then power is transmitted to shearing blade coupling with the help of a stationary pulley and fixed *** mean head diameter of the selected cabbage and cauliflower was 89.5±15.24 mm and 107.5±15.24 mm,*** mean stem(plant)diameter of the selected cabbage and cauliflower was 18±4.85 mm and 21.5±3.08 mm,*** shearing force increased with increase in diameter of *** optimum performance of the machine was achieved when it was operated at 1.5 km/h forward speed and the shearing blade moving at speed of 147 *** mean field capacity for developed prototype was observed as 0.063 ha/h and 0.053 in case of cabbage and cauliflower,respectively with field efficiency of 91.97 and 90.48%.The average head damage was negligible(0.15%)for both the *** average untrimmed percentage with developed harvester was 3.2 and 3.0%in case of cabbage and cauliflower crop,*** developed machine helps to increase the field capacity in cabbage/cauliflower harvesting due to 7-times more capacity and 50%cheaper compared to traditional method of cabbage/cauliflower *** the operating condition of forward speed(1.5 km/h)and shearing blade speed(147 rpm),the machine could harvest 0.5 ha of cabbage and 0.42 ha of cauliflower farm per day of *** same task would have required between 15 labour per day if

关键词： Self-propelled Harvester Cabbage/cauliflower field capacity field efficiency Untrimmed percentage

Development and Fabrication of Manually Push-Pull Type Conical Weeder for Bangladesh Condition

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Agricultural Sciences 2023年第5期14卷 685-709页

作者： Subrata Paul Bidhan Chandra Nath Anwar Hossen Kamruzzaman Pintu Haimonti Paul Sharmin Islam Arafat Ullah Khan Moudud Ahmmed Farm Machinery and Postharvest Technology Division Bangladesh Rice Research Institute Gazipur Bangladesh School of Civil Engineering and Surveying University of Southern Queensland Queensland Australia Workshop Machinery & Maintenance Division Bangladesh Rice Research Institute Gazipur Bangladesh

In Bangladesh, the use of machinery in agriculture production is fast rising. Researchers are developing technology to replace traditional hand weeding to manage weeds in rice fields. The present study has been taken to increase weeding efficiency and reduce the drudgery in weeding and mulching. A line-to-line distance of 20 cm, the operation is push-pull, and field operating condition at 2 - 4 cm standing water (for softening the field) was the designed hypothesis. The weeder consists of a skid/float, float holder, float adjuster, main body frame, rotor, axel, bush, rotor holder, rotor holder adjuster, handle, handle griper, handle holder, handle height adjuster, nut, bolt, etc. The designed weeder was fabricated using MS sheet, MS pipe, MS flat bar, MS nut-bolt, etc. When the rotors perform back and forth, the weeder’s two conical rotors with six plain blades and six serrated blades work together to uproot and bury the weeds. It also contains a 2 mm thick float assembly with a precise angle of 22 degrees. Weeds are uprooted by the weeder’s blades and buried in the muddy soil. It causes topsoil disturbance and enhances aeration. The weeding efficiency and capacity of the conical weeder were 81.92% and 0.0203 ha/h respectively. With a push-pull operation, the weeder can uproot and bury the weeds in a single row at a time. The pushing force and weight of weeder were 43.42 N and 5.6 kg respectively. Farmers can use this weeder to increase their comfort and reduce the drudgery associated with weeding and mulching in their fields.

关键词： Conical Weeder field capacity Weeding Efficiency Weed Paddy

Effect of SHAKTI and KUBOTA power tillers on physical properties of soil and rice yield under Sawah production system in Nigeria

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Journal of Agricultural Science and Technology 2009年第8期3卷 43-48页

作者： Segun Yinka Ademiluyi Oladimeji Idowu Oladele Toshiyuki Wakatsuki National Center for Agricultural Mechanization Ilorin Nigeria Department of Agricultural Economics Education and Extension Botswana College of 4griculture University of Botswana Gaborone P/bag 0027 Botswana. Faculty of Agriculture Kinki University Nara 631-8505 Japan

The use of the power tillers （walking tractors） are increasingly popular in Nigeria among farmers adopting Sawah rice production technology. This study compares the effects of two types of power tillers on physical properties of soil and rice yield. because soil properties determine to a large extents rice yield. Data on soil properties and rice yield were collected and subjected to t-test statistics. The results show that, significant differences exit for all the physical properties of soils rice yields from fields where the two power tiller were used with yields from rice field where SHAKTI was used was higher than KUBOTA. It is important that farmers using these models of power tillers for rice production should not only focus on the purchase cost of these power tillers but their overall efficiency in order to achieve the desired high level of yield.

关键词： power tillers field capacity field efficiency:draught fuel consumption: soil moisture bulk density coneindex shear strength