Dissertations / Theses: 'Soil conservation'

1

Stenberg, Maria. "Soil tillage influences on nitrogen conservation /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5468-9.gif.

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2

Hoshino, Mitsuo, and 光雄星野. "Soil erosion and conservation in Western Kenya." Graduate School of Environmental Studies, Nagoya University, 2006. http://hdl.handle.net/2237/7323.

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3

Hwang, Sang Won. "Sustainable use of soil resource base in the Dominican Republic : a farm level economic analysis of soil conservation practices /." This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-01122010-020205/.

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Piccoli, Ilaria. "CHALLENGES OF CONSERVATION AGRICULTURE ON SILTY SOILS. DISENTANGLING THE EFFECTS OF CONSERVATION PRACTICES ON SOIL ORGANIC CARBON CYCLE AND SOIL PORE NETWORK IN NORTH-EASTERN ITALY." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3424845.

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Soil organic matter loss is a widely recognized European soil threat and intensive and repeated tillage operations are known to negatively affect numerous soil properties and ecosystem services. In this view, the study on more sustainable agronomic managements is a pressing need for research community. Between sustainable techniques, conservation agriculture (CA) is nowadays a spread technique based on three main pivotal points: 1) minimum soil disturbance, 2) permanent soil covering and 3) crop diversification. CA is often associated with numerous soil functions such as increasing of soil biodiversity, organic matter stocks and aggregate stability and decreasing of runoff, erosion and P losses and dioxide carbon emissions. Despite the first estimates, CA practices are recently not recognized as a win-win solution for climate mitigation and agro-ecosystem improvement because the absence of tillage operations may impact the crop root growth through an increase in soil strength and bulk density, and reduce soil porosity and gas exchanges and lastly, the overall benefits of CA have been strictly related to soil type and climate. Within this viewpoint of not consistent results, more research is needed to understand and optimize the potential of sustainable agronomic practices. For these reasons, in this work, a field experiment was conducted including four farms on the low-lying plain of Veneto Region characterized by silty soils, in which conservation agriculture practices (no-tillage, cover crops and residues retention) were applied and compared to conventional tillage system. The first objective of the thesis was to evaluate the effects of CA practices on C cycle. The soil organic carbon (SOC) evolution in terms of both stock quantity and quality was monitored over a 3-yr transition period. The SOC stock was quantified through an equivalent soil mass approach up to 50 cm depth while the influence of each CA component was disentangled considering crop, cover crop and root biomasses, and tillage type as separate factors. The SOC quality was evaluated through humic carbon, its molecular weight distribution and microbial biomass analyses. The study showed that after short period, CA adoption did not increase C stock but rather its distribution within the soil profile while a positive effect was observed on humic carbon with the production of more polycondensed humic substances. The second objective regarded the evaluation of the soil gas exchange properties in the poorly structured silty soils of the low-lying plain. The effect of conservation agriculture practices on soil pore and gas transport characteristics was studied through the analyses of air permeability, gas diffusivity and air-filled porosity, and the derivation of soil structure indices on 144 undisturbed 100 cm3 soil cores. Gas transport measurements highlighted low transmission properties of the silty soils independently from agronomic management leading to critical value for both soil aeration and microbial aerobic activity. The third objective focused on the characterisation of the soil structure evolution after 5-yr of conservation agriculture management adoption. The soil pore network was quantified coupling mercury intrusion porosimetry and x-ray micro-tomography to study the total porosity and size distribution, from the macro- to the ultramicro- scale, and its architecture, on 96 undisturbed soil samples collected in the field experiment. Results suggested that silty soils of Veneto plain are micro-structured since much of the porosity is in the 0.0074-30 μm range and CA practices showed a positive influence on the ultramicroporosity range (0.1-5 μm) which are strictly linked to SOC stabilization. Concluding, silty soils of the Veneto region low-lying plain showed a slow reaction to conservation agriculture practices, as demonstrated by the poor effect on C sequestration, gas-transport characteristics and soil structure improvements. The limited amount of non-complexed organic carbon available for interaction with the soil fines prevented the formation of a more resilient soil structure leading to soil compaction that negated the exploitation of CA-related benefits. Despite such mechanisms, CA practices positively influenced C quality and ultramicroporosity range suggesting that a virtuous cycle between SOC and soil structure has been initiated. Longer transition period will be needed to reach a favourable equilibrium in the CA systems and more studies elucidating the mechanisms of structure improving conditions for silty soils, such as those examined in this study, are also required.
La perdita di sostanza organica è una delle minacce del suolo riconosciute a livello europeo e le ripetute lavorazioni del terreno sono state connesse con alcuni effetti negativi sulle proprietà del suolo e con i relativi servizi ecosistemici. Per questo, lo studio di pratiche agronomiche più sostenibili rappresenta una sfida per l’intera comunità scientifica. Tra le tecniche agronomiche sostenibili, l’agricoltura conservativa (AC) è una pratica ampiamente diffusa che è basata su tre principi cardine: 1) minimo disturbo del suolo, 2) copertura permanente del terreo e 3) diversificazione delle colture. AC è spesso associata a numerose funzioni del suolo quali l’aumento della biodiversità, dello stock di carbonio organico e della stabilità degli aggregati e la riduzione del runoff, dell’erosione, delle lisciviazioni di P e delle emissioni di anidride carbonica. Nonostante ciò, recentemente AC non è sempre considerata come una soluzione vincente per la mitigazione del clima e per il miglioramento dell’agroecosistema in quanto l’assenza delle lavorazioni del terreno possono influenzare negativamente lo sviluppo radicale mediante un aumento della densità e della resistenza del suolo e mediante una diminuzione della porosità e degli scambi gassosi. Per di più, i benefici delle pratiche conservative sono riconosciuti essere strettamente legati al tipo di clima e suolo. In quest’ottica di risultati contrastanti, maggiori studi sono necessari per studiare e ottimizzare le potenzialità di pratiche agronomiche più sostenibili. Per questi motivi, in questa tesi, è stata condotta una prova di campo comprendente quattro aziende agricole della bassa pianura Veneta caratterizzate da suoli limosi nei quali le pratiche conservative (non lavorazione, cover-crop e ritenzione dei residui) sono state adottate e confrontate con quelle tradizionali. Il primo obiettivo di questa tesi è stato quello di valutare gli effetti di AC sul ciclo del C. In particolare è stata valutata l’evoluzione del carbonio organico del suolo (COS) sia in termini quantitativi che qualitativi durante un periodo di transizione di tre anni. Lo stock di COS è stato quantificato mediante l’applicazione della massa equivalente fino a 50 cm di profondità mentre l’effetto delle diverse componenti del trattamento conservativo è stato studiato considerando le biomasse delle colture, delle cover-crop e degli apparati radicali e il tipo di lavorazione come fattori separati. La qualità del COS è stata invece caratterizzata analizzando il carbonio umico, le sue frazioni in peso e la biomassa microbica. Questo studio ha mostrato come dopo un breve periodo di applicazione di tali pratiche, lo stock di COS nel suolo non sia aumentato mostrando piuttosto una diversa ripartizione lungo il profilo. La qualità del carbonio organico ha invece beneficiato delle pratiche conservative con la produzione di sostanze umiche più policondensate. Il secondo obiettivo ha riguardato lo studio dell’influenza di AC sugli scambi gassosi del suolo mediante l’analisi della permeabilità all’aria, della diffusione, della air-filled porosity e mediante la derivazione di indici di struttura su 144 campioni indisturbati di suolo di 100 cm3. Le analisi hanno evidenziato le scarse proprietà di trasmissione dei suoli limosi indipendentemente dalla pratica agronomica adottata che hanno portato al raggiungimento di valori critici sia per l’aerazione del terreno che per le attività microbiche aerobiche. Il terzo obiettivo si è focalizzato sulla caratterizzazione dell’evoluzione della struttura del suolo dopo cinque anni dall’adozione delle pratiche di AC. La porosità del suolo è stata analizzata sia mediante l’utilizzo di microtomografie a raggi-x che di porosimetrie a intrusione di mercurio. La porosità totale, la distribuzione dei pori (dalla macro- alla micro-scala) e l’architettura dei pori sono state quantificate su 96 campioni indisturbati raccolti nelle quattro aziende sperimentali. I risultati hanno mostrato come i suoli limosi del Veneto siano “microstrutturati” in quanto la maggior parte della porosità ricade nel range 0.0074-30 μm e come le pratiche conservative abbiano positivamente influenzato la ultramicroporosità (0.1-5 μm) che è strettamente legata alla protezione della sostanza organica. Concludendo, come evidenziato dallo scarso effetto sul sequestro del C, sugli scambi gassosi e sulla struttura del terreno, i suoli limosi della bassa pianura Veneta hanno mostrato una lenta reazione alle pratiche conservative. Lo scarso contenuto di COS non complessato disponibile all’interazione con le particelle fini del terreno ha ostacolato la formazione di una struttura stabile portando al compattamento del suolo. Nonostante ciò, le pratiche conservative hanno però positivamente influenzato la qualità del C e la ultramicroporosità suggerendo che un ciclo virtuoso tra sostanza organica e struttura del suolo è stato inizializzato. Un periodo di transizione di più lunga durata sembra essere indispensabile per il raggiungimento di un nuovo equilibrio in sistemi conservativi e più studi sui meccanismi che regolano la struttura in suoli limosi risultano inoltre necessari.

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Dinel, H. (Henri) 1950. "The influence of soil organic matter components on the aggregation and structural stability of a lacustrine silty clay /." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74306.

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Under intensive farming, soil structure degradation and soil erosion are primarily associated with losses of organic matter. Restoration of soil structure may depend on the amount and nature of the organic amendment added. The effect of the addition of humic and fibric materials, and beeswax, a naturally occurring source of long-chain aliphatics comparable to those present in humic materials, on microbial activity and the structural properties of a waterlogged silty clay low in organic carbon was investigated. The incorporation of the fibric material increased the microbial activity in proportion to the amount of material added, whereas the humic and beeswax materials had the opposite effect. All organic materials added increased the cohesion of aggregates due to non water-dispersible cements. The fibric material was predominantly composed of polysaccharides and large quantities were required to produce a positive effect. The humic material was mainly lipids and the effect was associated with the time of incubation rather than the amount of material added. Principal-component analysis showed that the humic material was more effective at stabilizing soil aggregates than the fibric material, although the fibric material had a greater effect on the resistance of aggregates to slaking forces. Further testing with beeswax showed that the clay-associated lipids increased by 3.5-4.0 times the resistance of soil aggregates to the slaking forces, whereas the effect of hydrophobic "free" lipids was transient and accessory by coating and embedding soil aggregates.

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Alemu, Tekie. "Land tenure and soil conservation : evidence from Ethiopia /." Göteborg, 1999. http://www.loc.gov/catdir/toc/fy041/00309493.html.

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Montas, Hubert J. "A decision support system for soil conservation planning /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59831.

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A Decision Support System for the design and planning of soil conservation systems on a watershed scale was conceived and applied to southwestern Quebec. The system integrated Geographical Information System, distributed parameter hydrologic modeling and Expert System technologies. Maps of appropriate soil conservation practices were produced for two small rural basins representative of the study region. The effect of the selected practices on runoff and sediment was assessed using the ANSWERS model. Erosion sites were targeted using a once-in-25 year design storm. It was observed that small portions of the study basins produced large amounts of eroded sediment. The expert system was designed to select appropriate conservation practices for the 1-ha cells which had more than one ton of erosion as a result of the design storm. The results demonstrated that the selected conservation practices would reduce sediment yield and average erosion rates by 50% in each of the study basins.

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8

Goshu, Kassaye. "Biological soil conservation techniques for Maybar area, Ethiopia /." [S.l : s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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9

Barrak, Khalid Mohamed 1956. "Effects of various mulches on soil moisture conservation." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/191944.

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The purpose of this work was to study and evaluate the effect of various mulches on the soil moisture content for sandy loam soil under high temperatures. The straw, wood shavings, and rock fragments were used with different rates of application for covering soil. Treatments were compared to bare soil. The moisture content was significantly higher for mulched treatments. However, the effectiveness of wood shavings and rock fragments mulches did not seem different in soil moisture content, while straw mulch did. The soil moisture content for the straw had the highest value at the end of the experiment. The straw mulch apparently conserved soil moisture over the other treatments. The conservation of soil moisture under 10, 15, 20 gm of straw mulch was occasioned by less direct contact soil surface with air surface and less possibility of heat transfer. The greatest savings in water was under 2.7 tons/ha of straw mulch.

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Kelsey, Kurt L. "Use of the Revised Universal Soil Loss Equation (Rusle) to predict event soil loss /." Link to abstract, 2002. http://epapers.uwsp.edu/abstracts/2002/Kelsey.pdf.

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Wigley, Georgina M. "Constraints on soil conservation in the Pindars River and Two Meetings Watersheds, Jamaica." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64098.

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12

Newman, James Kenneth. "Soil erosion prediction for shaping conservation policy and practice." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3403858.

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13

Nyangena, Wilfred. "Essays on soil conservation, social capital and technology adoption /." Göteborg : Deptartment of Economics, School of Economics and Commercial Law [Nationalekonomiska institutionen, Handelshögskolan], Göteborg University, 2006. http://www.handels.gu.se/epc/archive/00004619/01/Nyangena%5Ffull.pdf.

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Pradhan, Lal Chand. "DESIGN, CONSTRUCTION AND EVALUATION OF SMALL SCALE STRUCTURES FOR CONTROLLING CONCENTRATED FLOW EROSION." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275415.

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Kagwanja, Joan Cuka. "Determinants of farm level soil conservation technology adoption : lessons from the high rainfall, high populated, steep sloped Mt. Kenya highlands, Embu, Kenya /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025628.

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Cooper, Sophie E. "The role of conservation soil management on soil and water protection at different spatial scales." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1775.

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Agriculture has a direct impact on the soil environment, altering soil properties, surface characteristics and erosion risk. This has led to a move away from conventional tillage to the adoption of conservation practices, aiming to minimise soil disturbance and reduce erosion. The effectiveness of this has been shown in studies from the USA, but equivalent research in Europe is limited. The present study investigated losses of soil, water, nutrients and carbon from different tillage regimes. Two UK sites were used – Loddington (Leicestershire, on heavy clay) and Tivington (Somerset on sandy clay loam). Three cultivations were applied - conventional (deep, inversion ploughing), and two forms of conservation tillage - SOWAP (non-inversion, shallow tillage), and Farmer Preference (non-inversion, deep tillage). Treatment effects were investigated at three spatial scales, ranging from field based erosion plots (0.05 ha), to micro-plots (1.5 m2), to soil aggregate tests. Results from 2004 to 2006 showed that adoption of conservation tillage did not consistently reduce losses of soil, water, nutrient and carbon, due to high temporal variability. Notable differences were found between sites. Runoff coefficients ranged from 0.39-0.46% at Loddington, and 2.43-3.82% at Tivington. Soil losses at Loddington were below 2 t ha-1 y-1, but higher at Tivington (3.47 t ha-1 y-1). Conservation tillage led to notable changes in soil properties and surface characteristics, including a decrease in bulk density and increases in organic matter, micro-topography and residue cover. Absolute values of erosion from small scale investigations could not be extrapolated directly to field scale results. Relative treatment ranks gave better comparisons, although results were not consistent for all small scale methods, due to high levels of variability. Caution should be used when extrapolating between spatial scales. Further work is required to understand the links between temporal and spatial fluctuations in soil, surface and rainfall characteristics and erosion processes.

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Bhattacharyya, Ranjan. "Using palm-mat geotextiles for soil conservation on arable loamy sands in the United Kingdom." Thesis, University of Wolverhampton, 2009. http://hdl.handle.net/2436/88536.

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To date, most studies on the effectiveness of geotextiles on soil erosion rates were conducted in laboratory experiments for <1 h. Hence, at Hilton, East Shropshire, UK, this study investigated the effectiveness of palm-mat geotextiles (Borassus and Buriti mats) in reducing rainsplash erosion, runoff and soil loss and changing selected soil properties under field conditions over two years (January 2007-January 2009). Mat-cover effects on rainsplash erosion were studied in two sets on a loamy sand soil (0o slope). In both sets, six randomly-selected plots (each 1 m2) were completely matcovered and six were bare. Unlike Buriti mats, Borassus mat-cover on bare soil significantly (P<0.001) decreased rainsplash erosion (by ~89%). Duplicate runoff plots (10 x 1 m on a 15o slope) had five treatments (bare, permanent grass, Borassus completely-cover, Borassus buffer strip and Buriti buffer strip). Using Borassus buffer strips (area coverage ~10%) on bare soil decreased runoff by ~71% (P>0.05) and soil erosion by ~92% (P<0.001). Borassus buffer strip, Buriti buffer strip and Borassus completely-covered plots had similar effects in decreasing runoff and soil loss. However, the longevity of Borassus mats was ~twice that of Buriti mats. Despite physical protection, runoff control and sediment entrapment, biomat buffer zones may considerably alter and protect flow direction by presenting barriers and creating several cross-drains. Except Borassus completely-covered plots, all plots had significant (P<0.05) increases in topsoil (0-5 cm) bulk density and decreased aggregate stability. However, buffer strips were more effective in trapping fine particles than Borassus completely-covered plots. No treatments had significant (P>0.05) effects on changes in pH, soil organic matter, total soil carbon or N. Plots with Borassus mats significantly (P<0.05) increased total P and decreased total Ca. Treatments had no significant effects on changes in total S, Mg, Zn, Cu, Fe, Mn, Mo or Cl concentrations. Borassus buffer strips can effectively conserve soil and water and improve and maintain selected soil properties, with results similar to Borassus completely-covered plots. The mechanisms explaining the effectiveness of buffer zones require further studies under varied pedo-climatic conditions.

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Mei, Xiaodong. "Soil conservation and sustainable land use in Inner Mongolia, China." Weikersheim Margraf, 2005. http://deposit.ddb.de/cgi-bin/dokserv?id=2795672&prov=M&dok_var=1&dok_ext=htm.

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19

Hellin, Jonathan. "Soil and water conservation in Honduras : a land husbandry approach." Thesis, Oxford Brookes University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325265.

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Cárcamo, Julio Antonio. "Sustainable development in Honduras: economic evaluation of soil conservation practices." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/42613.

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Costs and benefits associated with erosion reduction and adoption of soil conservation practices for a representative farm in a watershed in Honduras are examined in a linear programming framework. Special attention is paid to income-soil loss tradeoffs, income-risk tradeoffs, and on the effect of different farmers' planning horizons on net farm income. A representative farm model for the area was constructed to achieve the objectives of the study. Twelve farmers in the region were surveyed, crop budgets were prepared, and soil loss values were calculated to provide the information required to construct this representative farm. A linear programming model that maximizes net farm income is used to examine the effect of different soil loss levels on farm income. A MOTAD model that minimizes deviation in income (risk) is used to determine risk levels while income and/or soil loss levels restrictions are imposed. Results indicate that considerable reductions in the amount of soil loss can be achieved in the study area. Erosion is reduced from 328.24 ton./mn./year to 6.56 ton./mn./year1 when constraints are imposed on the model. The reduced erosion lowers income from L.5929.24/year for high erosion rates to L.2825.8l/year for low erosion rates. Low levels of soil erosion are achieved at the expense of higher levels of risk. High levels of income are associated with high levels of risk regardless of whether soil loss constraints exist or not. Small differences in income exist among the four planning horizons analyzed. The best soil conservation practices for this region turned out to be the cultivation of coffee on the highest slopes, the use of live barriers and terraces, and the use of conventional and minimum tillage.
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Milne, Eleanor. "Soil conservation in relation to maize productivity on sub-tropical red soils in Yunnan Province, China." Thesis, University of Wolverhampton, 2001. http://hdl.handle.net/2436/93882.

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Agricultural land in China is being degraded, with soil erosion becoming an increasing problem. In Yunnan Province, south-west China, there is a long history of soil erosion due to soil type, climate, anthropogenic influence and because 95% of the Province is mountainous. Population pressure and lack of flat land necessitate cultivation of steep slopes. The Yunnan Government prohibits cultivation of slopes >25°, however policy enforcement would result in food shortages in the Province, due to a lack of suitable land <25°. Therefore, the most appropriate way to curb soil erosion in Yunnan is to devise affordable agronomic means of reducing soil loss, which do not decrease crop productivity on sloping land currently under cultivation. At present, very little research has addressed these issues. A research project, building on existing work from 1993-1996, was initiated in 1998. The aim was to test the hypothesis that contour cultivation and contour cultivation plus straw mulch decrease runoff and soil erosion rates on sloping land in Yunnan Province under maize cultivation and to assess the impact of these conservation measures on maize productivity and soil nutrient status. Thirty runoff plots, located on three different slope angles (I 3°, II 10° and III 27°), in three groups of 10, were used to examine three cropping treatments in a replicated plot design in 1998 and 1999. Treatments were downslope cultivation (control), contour cultivation and contour cultivation plus straw mulch. In addition, there was an unreplicated bare plot in each group. Runoff and soil loss were measured on a storm-by-storm basis. Soil nutrient status was measured at the beginning and end of each cropping season. Crop growth parameters and soil physical properties were measured throughout the cropping seasons (21/05–7/10 in 1998 and 22/05–2/10 in 1999). In 1998, seasonal rainfall was 1024 mm, ~28% greater than the 30-year mean. Soil loss was significantly reduced by contour cultivation on Slopes I and II. On Slope I, downslope cultivation produced 3.07 t ha-1 soil loss and contour cultivation reduced this by 81.4 %. On Slope II, downslope cultivation produced 19.11 t ha-1 and contour cultivation reduced this by 58.0%. The addition of straw mulch gave a further, nonsignificant, reduction on both slopes. On Slope III, downslope cultivation and contour cultivation produced 6.92 and 6.29 t ha-1 of soil loss, respectively, with contour cultivation plus straw mulch having 99.4% less erosion than downslope cultivation. In the much drier 1999 season, no treatment significantly reduced soil loss on Slope I. Contour cultivation significantly reduced soil loss on Slopes II and III. On Slope II, downslope and contour cultivation produced 11.52 t ha-1 of soil loss and contour cultivation reduced this by 85.8%. On Slope III, downslope and contour cultivation produced 8.62 and 0.23 t ha-1, respectively; a reduction of 97.3% by contour cultivation. The addition of straw mulch did not further decrease soil loss. Treatment effects on soil nutrient status varied between the two years. At the end of the 1998 season, there was significantly higher soil available N under contour cultivation plus straw mulch on all three slopes (Slopes I and II P <0.001, Slope III P <0.05), an effect that was not found in 1999. At the end of the 1999 season, soil available K was significantly (P <0.001) higher under contour cultivation plus straw mulch on Slope III. In both years, contour cultivation plus straw mulch significantly reduced soil temperature. However, this did not result in yield reductions in comparison with the control. There was an increase in soil moisture content under contour cultivation plus straw mulch during dry periods, which was particularly noticeable in 1999. In 1998, there were no significant treatment effects on grain or shoot yield. In 1999, on Slope II, contour cultivation plus straw mulch significantly increased grain yield by 50.3% compared with the downslope treatment (P <0.05). In 1999, contour cultivation plus straw mulch also significantly increased leaf plus stem yield on Slopes I and II by 12.4 and 36.8%, respectively. It is concluded that on ≤10° slopes, contour cultivation alone is a suitable soil conservation measure. However, use of straw mulch would benefit soil moisture and nutrient status and could, therefore, increase crop yield. On ≥27° slopes, it is recommended that contour cultivation plus straw mulch be used as a soil conservation measure to ensure maximum soil conservation, even in extreme rainfall conditions.

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Tizale, Chilot Yirga. "The dynamics of soil degradation and incentives for optimal management in the Central Highlands of Ethiopia." Thesis, Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-06082007-094341.

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23

Moehansyah, Haji. "Soil erosion, population pressure and conservation strategies in the Riam Kanan catchment, Indonesia /." [Richmond, N.S.W.] : Faculty of Environmental Management and Agriculture, University of Western Sydney, Hawkesbury, 1998. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030623.113640/index.html.

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24

Norris, Patricia E. "Factors influencing the adoption of soil conservation practices in Virginia's Piedmont Bright Leaf Erosion Control Area." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/104521.

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25

Yau, Fung-yee Caroline. "Soil and afforestation in the Shing Mun Country Park, Hong Kong." Click to view the E-thesis via HKUTO, 1997. http://sunzi.lib.hku.hk/hkuto/record/B42128420.

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Negim, Osama. "New Technique for Soil Reclamation and Conservation: In Situ Stabilization of Trace Elements in Contaminated Soils." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2009. http://tel.archives-ouvertes.fr/tel-00408020.

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L'accumulation de métaux toxiques dans le sol est principalement héritée de matériaux parents ou d'éléments résultant de l'activité humaine. Par conséquent, de nouvelles techniques sont en cours d'élaboration pour remédier à ces contaminations dans les sols pollués, telles que la phytoremédiation et la stabilisation in situ. La stabilisation in situ est une technique commune de réduction des effets négatifs des métaux et métalloïdes, tels que As, Cr, Cu, Cd et Zn dans les sols contaminés par l'ajout d'amendements. L'application de matières alcalines telles que les laitiers d'aciéries et un laitier modifié enrichie en phosphates dans le sol constitue un outil prometteur pour la réduction de la mobilité et la biodisponibilité des éléments traces dans les sols contaminés ainsi que pour l'assainissement du sol et l'amélioration de ses propriétés physique, chimique et minéralogique, ainsi que la production végétale.

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Negim, Osama. "New technique for soil reclamation and conservation : in situ stabilisation of trace elements in contaminated soils." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13821/document.

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Les sols sous contraintes que ce soit du point de vue charges polluantes comme avec les Métaux Traces (MT) ou bien du point de vue stress hydrique (perte des capacités de rétention menant à la désertification des sols) concernent de nombreux espaces du territoire national, de même que la région du pourtour Méditerranéen. Le nombre de sites pollués par des substances inorganiques affectant de larges espaces est en constante augmentation. Les stratégies pour leur rémédiation sont variées mais très peu envisagent la dépollution tout en restaurant les propriétés pédologiques des sols concernés. La rémédiation comme la restauration des capacités fertilisantes de sols pollués sont un enjeu international. Pour cela, la stratégie de cette étude porte sur le développement d’outils technologiques innovants basée sur la phytorémédiation assistée par des matrices duales de sols contaminés par des MT (Cuivre, Chrome, Arsenic). Ces matrices duales ont une action double concomitante en permettant une immobilisation ou un piégeage des MT tout en favorisant la repousse végétale ou la catalyse de la croissance végétale. Le piégeage peut se faire par l’apport d’amendement ayant des capacités d’échanges (généralement liées à l’existence de phase allophane et/ou d’un réseau poral important) et de rétention (liées au réseau porale et à l’existence de phases minérales type phosphates, silice amorphe, oxydes hydroxydes de fer-manganèse). L’élaboration, à partir de laitiers d’aciéries, d’une matrice susceptible d’adsorber des MT (aspect dépollution) tout en favorisant la pousse végétale (aspect amendement) nous a permis de tester ce produit de synthèse. La seconde originalité de cette étude est d’analyser le potentiel de ces matrices, non seulement à différentes échelles (du pot en passant par le stade mésocosme et jusqu’au champ), du point de vue impact écotoxique – dépollution de sols associé à une re-végétalisation. Cette dernière participe également au transfert des charges polluantes (MT) depuis l’amendement de synthèse ou du sol vers, et dans le réseau racinaire des radicelles et ainsi favoriser la réhabilitation des propriétés hydriques des sols par le développement d’un couvert végétale pérenne. On conjugue ainsi un apport dépolluant à celui de maintient de la potentielle anti-désertification grâce au développement de solutions innovantes respectueuses de l’environnement sur la base de technologie douce valorisant les co produits de l’industrie
Soil contamination by trace elements is a widespread problem in many parts of the world. The accumulation of toxic metals in soil is mainly inherited from parent materials or inputs through human activities. In fact, one of the sources of soil contaminations is very important resulting from chemical widely used wood preservative industries in aquatic environments and storing the wood after treatment by chromated copper arsenate (CCA). Elements such as As, Cu, Cr, and Zn can be found in excess in contaminated soils at wood treatment facilities, especially when Cu sulphates and chromated copper arsenate (CCA) were used as a preservative against insects and fungi, which may result in soil phytotoxicity as well as toxic to plants, animals and humans. New techniques are being developed to remediate trace elements in contaminated soils such as phytoremediation and in situ stabilization. In situ stabilization technique or in situ immobilisation is one of the common practices for reducing negative effects of metals and metalloids such as As, Cr, Cu, Pb, Cd and Zn in contaminated soils by adding amendments. Alkaline materials are usually added to acidic soils to improve soil chemical and physical properties and also to reduce the mobility and bioavailability of contaminant. Slag, which consists of calcium oxide, phosphorus oxide, silicon oxide, iron oxide, and other metal oxides, is an alkaline by-product of metallurgical processes or a residue of incineration processes. Slags have been successfully used to soil reclamation and soil fertiliser. It has been used as a soil additive to reduce various metals contaminated soil by precipitation and adsorption on the surface of metal oxide. The objectives of this Ph.D study were to evaluate the physical, chemical soil properties and the distribution of trace elements in contaminated soil. Also to evaluate the characteristics of two different slags samples, a basic slag (BS) and a basic slag phosphate (BSP) which are alkaline by-products of the French steel industry and which used as a soil amendments to improve soil properties and for the in situ immobilisation of copper and metals in chromated copper arsenate (CCA) contaminated soil

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Negim, Osama Le Coustumer Philippe Mench Michel. "New technique for soil reclamation and conservation in situ stabilisation of trace elements in contaminated soils /." S. l. : S. n, 2009. http://ori-oai.u-bordeaux1.fr/pdf/2009/NEGIM_OSAMA_2009.pdf.

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Shouse, Bennett Scott. "Implementation costs of Kentucky's erosion control best management practices for skid trails." Lexington, Ky. : [University of Kentucky Libraries], 2002. http://lib.uky.edu/ETD/ukyfore2001t00015/Shouse.pdf.

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Thesis (M.S.)--University of Kentucky, 2001.
Title from document title page. Document formatted into pages; contains vi, 75p : ill., maps. Includes abstract. Includes bibliographical references (p. 74).

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Moehansyah, Haji. "Soil erosion, population pressure and conservation strategies in the Riam Kanan Catchment, Indonesia." Thesis, [Richmond, N.S.W.] : Faculty of Environmental Management and Agriculture, University of Western Sydney, Hawkesbury, 1998. http://handle.uws.edu.au:8081/1959.7/394.

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This thesis studies the Riam Kanan Catchment (RKC), located in Indonesia, in order to: evaluate the effect of land use on runoff, erosion and soil properties; examine rainfall-runoff-erosion relationships under different land use types; evaluate the suitability of runoff and soil erosion models; develop an understanding of the interaction between physical, demographic, socio-economic and political aspects in relation to soil erosion; evaluate population pressure and its impacts; develop a suitable methodology for identifying potential erosion hazard areas; and develop suitable soil conservation strategies. Rainfall pattern and water level fluctuation; changes in runoff, erosion and soil properties under different land use types; relationships between soil properties as well as between rainfall and runoff-erosion; population pressure; and potential hazard areas were all analysed. Selected runoff and erosion models were evaluated for their suitability, and soil conservation strategies were developed, considering physical, demographic, socio-economic and political aspects. Results show that changes in inflow patterns are most likely due to changes in volumes of surface and subsurface runoff values; erosion in RKC is occurring at various levels depending on the land use types; there is a relationship between rainfall-runoff and erosion parameters; population pressure is above the critical limit and can be reduced by various methods; and RKC has a moderate to high erosion hazard. The soil conservation strategies outlined in this study appear promising.

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Castonguay, Stéphane. "Managing scientific change in agricultural policies : soil productivity, resource conservation and the legitimation of agrobiology /." This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09052009-040708/.

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Norville, Peter. "The design and evaluation of soil conservation systems in St. Lucia /." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59576.

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Three soil conservation systems: contour drainage, strip cropping, and terracing, were designed and established within separate plots on hillside farmlands in St. Lucia. A control plot with no form of soil conservation was also established. Topographic and soils surveys of these plots were conducted. Rainfall, runoff and soil loss were measured over one wet season. Crop yields and construction and maintenance costs were also determined.
For rainfall amounts between 14.2 and 211.2 mm, runoff depths varied from 0.6 to 203.6 mm in the control plot, 2.1 to 199.2 mm in the contour drained plot, 3.2 to 155.1 mm in the strip cropped plot and 1.3 to 94.7 mm in the terraced plot. The largest amounts of runoff were most often recorded in the strip cropped plot, while on most occasions, the terraced plot produced the least runoff.
Soil loss rates varied from 0.01 to 1.77 kg/ha in the control plot, 0.07 to 16.88 kg/ha in the contour drained plot, 0.2 to 28.86 kg/ha in the strip cropped plot and 0.01 to 6.62 kg/ha in the terraced plot.
Construction costs per hectare were EC$5565 for the contour drainage system, EC $5425 for the strip cropped system and EC$6350 for the terraced system.
Further monitoring of the conservation systems is required for prediction of their long-term effectiveness in runoff and soil erosion control.

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Ahiale, Evelyn Dalali. "Economic valuation of soil and water conservation technologies in northern Ghana." Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578024.

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Land degradation resulting largely from the environmentally unsustainable agricultural practices of smallholder farmers is a serious problem in Ghana. It is most serious in northern Ghana, where in spite of past efforts to solve it, persists because farmers' adoption of soil and water conservation technologies has not been encouraging. Farmers' inability to adopt soil and water conservation measures is mainly as a result of constraints resulting from market failures which lead to externalities like degradation. In the presence of externalities, government intervention is justified, and payment for environmental services, whereby incentive payments are made to resource managers, is one such intervention. The current study uses the choice experiment and contingent valuation methods to estimate farmers' WTA for soil and water conservation technologies, specifically soil and stone bunds, and examine the effect of collective action and other factors on farm households' willingness-to-accept. Based on data collected from 305 smallholder farm households in northern Ghana, and using the Bayesian approach, the mixed logit and interval-data probit models were employed to analyze choice experiment and contingent valuation data respectively. Results from both the choice experiment and the contingent valuation methods revealed that farmers like collective action and are prepared to receive less when they act collectively. From the choice experiment, farmers were willing to accept ¢49.40/acre (or ¢125.30/hectare) less in order to act collectively under a compensation scheme for the adoption of SWC technologies. Farmers were willing to accept ¢182.00/acre (¢455.00/hectare) to adopt a SWC technology in order to maintain landscape quality and ¢66.20/acre (¢165.50/hectare) to improve landscape quality. Results from the contingent valuation revealed that farm households would accept from ¢913.46 - 922.08/hectare for stone bund and ¢705.34-714.92/hectare for soil bund. Farmers belonging to farmers' groups were willing to accept from ¢23.55 - 62.54/hectare less than non-group members depending on the technology and type of participation. Willingness of farm households to accept compensation were positively correlated with education, wealth status, farm households with adequate labour supply, the severity of erosion of their farms, and whether the household has already adopted either stone or soil bunds. Age, farm size, and previous participation in soil and water conservation projects are some variables found to be negatively correlated to willingness-to-accept. It is recommended that collective action/contracting be designed into payment schemes to reduce their transaction costs to make them more successful.

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Arevalo-Mendez, Ignacio. "Soil conservation with leguminous cover crops following deforestation of tropical steepland." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/33228.

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The steeplands of Central America are being systematically deforested as population pressure dictates a need for an increase in subsistence agriculture. The combined effect of high rainfall and lack of conservation measures leads to high levels of soil erosion. In order to assess sustainable soil conservation technology, research was conducted in the mountainous agricultural area of Guinope, Honduras. Runoff and soil loss from a number of plots that were established on various ground slopes and under different land uses were measured during the 1994 and 1995 seasons. Natural and fired woodland were assessed to provide an indication of both baseline conditions and those associated with the initial stage of deforestation. Against these, the impacts of agriculture involving maize - Zea mays L.- with and without two leguminous cover crops - Mucuna sp. and Canavalia ensiformis (l)DC. - were assessed on ground sloping at 6, 11 and 18 degrees. Seasonal runoff under natural pine forest is shown to be 10 % that of maize agriculture on similar slopes while fired forest is 49 %. Of the cover crops, after a second year Mucuna is the most protective when intercropped with maize, giving runoff on 18 degree slopes which is 47 % that of maize grown by itself, compared with 51 % for Canavalia. On 11 degree slopes, Canavalia offers greater protection but here the difference between the two cover crops is marginal Soil erosion can be shown to be a function of ground slope. For maize grown by itself, soil losses from 6 and 11degree slopes are 13 % and 23 % those from 18 degree slopes. On two years of research Canavalia is more stable in giving protection. On 18 degree slopes, soil loss where Mucuna is intercropped is 43 % that under maize alone while for Canavalia it is 47 %. By comparison, the natural forest loses much less than 1 % that of the maize fields. This study clearly shows the vulnerability of steep lands that are being clear-felled. It also demonstrates the considerable advantages of using extensive green soil conservation technology in reducing soil erosion and prolonging the usefulness of land. This extends to relieving the pressure on virgin forest in a situation where population growth discourages long periods fallow as part of a form of shifting cultivation.

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Schuler, Johannes. "An economic analysis of the implementation options of soil conservation policies." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-3186.

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Elliott, Jennifer A. "Soil erosion and conservation in Zimbabwe : political economy and the environment." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/6945.

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This thesis concerns soil erosion and conservation in Zimbabwe. It is framed in the light of the contemporary heightened concern for the environment generally in Africa and the recent publication of the National Conservation Strategy for Zimbabwe (1987). Soil erosion is an archetypal interdisciplinary problem. This thesis complements and extends understanding of soil erosion and conservation in Zimbabwe via a methodological approach and a scale of analysis which have been under-represented in the literature to date. The research adopts a pluralist, regional political ecology approach (after Blaikie and Brookfield 1987) to soil erosion and conservation in Svosve communal area, combining political-economic understanding with case study analysis of changing social-environmental relationships. Plural problem definitions are constructed through interview and survey techniques, historical analysiso f archival sourcesa nd oral testimonies,a ssessmenot f contemporary policy and planning documents and via sequential air photograph analysis. The researchc hallengesa spectso f the colonial conservationislti terature to date for southernA frica andn ational level modelling of human-environmenrte lationshipsi n Zimbabwe. It presentsa quantitativea ssessmenotf the changei n symptomso f deterioration and in the nature and extent of soil erosion for the case study area. It operationalisesth e concepto f multiple problem definitions with implications for the contemporary model for conservation extension and for improving the role of local development institutions.

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Troyee, Anupoma Niloya. "Impact of soil treatments in the conservation of native rhizobia populations." Master's thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/22076.

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Sustainable agriculture aims to achieve highcrop production, reducing the use of chemical fertilizers and herbicides. Rhizobia-legume symbioses are importantN2-fixing systems that can improvethe productivity ofsoils.The aim of this work was toevaluate the diversity of rhizobia on nodules of chickpeaplants grown in soil treated with a glyphosate, nitrate and Mesorhizobiuminoculation. The impact of glyphosate and nitrate on mesorhizobia growth and on the early stages of infection was also evaluated. The phylogenetic analysis of the 16S rRNA gene sequences showed a low diversity of rhizobia nodulating chickpea, regardless of the treatments applied. The detection of Mesorhizobiummuleiense as predominant species may be related to the high competitiveness of this species. Smallerroot hairsand less curling was observed for the highestconcentrations ofnitrate tested. This work hascontributed to clarifythe impact of chemical fertilizers and herbicide application onthe legume-rhizobia symbiosis; Impacto de tratamentos do solo na conservação das populações nativasde rizóbio Sumário: A agricultura sustentável tem como objetivo atingir elevadas produções, reduzindo o uso de fertilizantes químicos e herbicidas. As simbioses rizóbio-leguminosa são importantes sistemas de fixação de N2,que podem melhorar a produtividade dos solos. O objetivo deste trabalho foi avaliar a diversidade de rizóbios nos nódulos de grão-de-bico plantado em solo tratado com glifosato, nitrato e inoculação de Mesorhizobium. Um outro objetivo foi a avaliação do impacto do glifosato e nitrato no crescimento de rizóbios e nas fases iniciais da infeção. A análise filogenética das sequências do gene 16S rRNA mostrou uma baixa diversidade de rizóbios em nódulos de grão-de-bico, independentemente do tratamento. A deteção de Mesorhizobium muleiensecomo espécie predominante poderá estar relacionada com elevada competitividade desta espécie. Pêlos radiculares mais pequenos e menos “curling” foram observados para as concentrações mais elevadas de nitrato testadas. Este trabalho contribuiu para clarificar o impacto de fertilizantes e herbicidas nesta simbiose.

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Smith, Jennifer Lynn. "The use of rolled erosion control products (RECPs) for minimizing soil erosion." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available, full text:, 2007. http://wwwlib.umi.com/cr/syr/main.

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Moehansyah, Haji, of Western Sydney Hawkesbury University, and Faculty of Environmental Management and Agriculture. "Soil erosion, population pressure and conservation strategies in the Riam Kanan Catchment, Indonesia." THESIS_FEMA_XXX_Moehansyah_H.xml, 1998. http://handle.uws.edu.au:8081/1959.7/394.

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This thesis studies the Riam Kanan Catchment (RKC), located in Indonesia, in order to: evaluate the effect of land use on runoff, erosion and soil properties; examine rainfall-runoff-erosion relationships under different land use types; evaluate the suitability of runoff and soil erosion models; develop an understanding of the interaction between physical, demographic, socio-economic and political aspects in relation to soil erosion; evaluate population pressure and its impacts; develop a suitable methodology for identifying potential erosion hazard areas; and develop suitable soil conservation strategies. Rainfall pattern and water level fluctuation; changes in runoff, erosion and soil properties under different land use types; relationships between soil properties as well as between rainfall and runoff-erosion; population pressure; and potential hazard areas were all analysed. Selected runoff and erosion models were evaluated for their suitability, and soil conservation strategies were developed, considering physical, demographic, socio-economic and political aspects. Results show that changes in inflow patterns are most likely due to changes in volumes of surface and subsurface runoff values; erosion in RKC is occurring at various levels depending on the land use types; there is a relationship between rainfall-runoff and erosion parameters; population pressure is above the critical limit and can be reduced by various methods; and RKC has a moderate to high erosion hazard. The soil conservation strategies outlined in this study appear promising.
Doctor of Philosophy (PhD)

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Rachman, Achmad. "Influence of grass hedges on soil hydraulic properties, runoff and soil erosion in a small watershed /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115583.

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Moopayak, Sumitra. "Local polysaccharide-producing soil cyanobacteria as potential soil conditioners in Nakhonsawan Province, Thailand." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/235.

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This study describes the successful cultivation of an indigenous (from Nakhonsawan) extrapolysaccharide-producing algal strain, and demonstrates its soil-conditioning potential in a greenhouse environment. The results show that local algal resources have potential as soil conditioners. The process involved surveying soil algae to identify potential candidates, selection of the most suitable candidate followed by optimisation for biomass production. mass cultivation and soil inoculation.

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Dijk, Paulus Maria van. "Soil erosion and associated sediment supply to rivers seasonal dynamics, soil conservation measures and impacts of climate change /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/60698.

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Mulengera, Matthew Kagorobha. "Soil loss prediction in the semi-arid tropical savanna zone : a tool for soil conservation planning in Tanzania." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318175.

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Hwang, Sang Won. "Sustainable use of soil resource base in the Dominican Republic:a farm level economic analysis of soil conservation practices." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/40618.

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Income effects associated with specific levels of erosion reduction for a representative farm in the Bao watershed area in the Dominican Republic are examined in a linear programming framework. Estimation of costs expected in response to specific levels of erosion reduction and the income effects of changes in agricultural policies on the farmer's ability to conserve soil are examined.

Results indicate that income losses will be substantial when complying with soil loss standards without introducing soil conservation practices. Net income reduction of 36% can be expected with a reduction in soil loss by 50%. With the introduction of soil conservation practices, substantial reductions in erosion can be obtained with only a minor reduction in net income. For example, with grass strips, 50% reduction in soil loss can be expected with only a 7% reduction in income.

Analysis of the effects of changes in agricultural policies indicates that restricting access to credit and changes in tenure from secure land holdings to lack of land titles does not affect the incentive to conserve soil in the short run. Furthermore, analysis of effects of changes in agricultural pricing policies indicates that the promotions of coffee, sweet potatoes, and beans represent the least-costly means of meeting the twin goals of erosion reduction and income maintenance.
Master of Science

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Yau, Fung-yee Caroline, and 邱鳳儀. "Soil and afforestation in the Shing Mun Country Park, Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B42128420.

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Zaikin, Andrey. "Economics of soil and water conservation in irrigated and dry lands agriculture." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/a%5Fzaikin%5F072606.pdf.

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Tabot, Helen, Muluken Elias Adamseged, and Mohammed Nasir Uddin. "Analysis of Soil Conservation Policies : A Case Study of Germany and Bangladesh." 名古屋大学大学院教育発達科学研究科技術・職業教育学研究室, 2012. http://hdl.handle.net/2237/17033.

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Dzuda, Lorraine Nyaradzo. "Analysis of soil and water conservation techniques in Zimbabwe, a duration analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60424.pdf.

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Krois, Joachim [Verfasser]. "Soil and Water Conservation in the Northern Andes of Peru / Joachim Krois." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1115722476/34.

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Kawa, Ibrahim Hussein. "The Dodoma Region Soil Conservation Project (HADO), Tanzania : is it institutionally sustainable?" Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357243.

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Dissertations / Theses on the topic 'Soil conservation'

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