Made available in DSpace on 2014-06-11T19:31:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-24Bitstream added on 2014-06-13T21:01:56Z : No. of bitstreams: 1 nascimento_jm_dr_jabo.pdf: 470384 bytes, checksum: f204b878182346a08975c166192d44c4 (MD5) / Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT) / O sistema plantio direto como prática conservacionista associado a técnicas como a integração lavoura-pecuária, tem como foco principal otimizar o uso das áreas agrícolas. Nessa condição, a opção do consórcio de milho com forrageiras constitui uma alternativa para suprir o aporte anual de palha e tornar o sistema sustentável. O presente trabalho teve como objetivo, em dois anos agrícolas, avaliar, no primeiro, três forrageiras (Brachiaria brizantha, B. decumbens e B. ruzizienses) em consórcio com duas populações de plantas de milho e, no segundo, verificar o efeito da palhada dos tratamentos do ano anterior na semeadura do milho em duas velocidades do conjunto trator-semeadora. O experimento foi conduzido na área da Fazenda de Ensino, Pesquisa e Produção da UNESP/Jaboticabal, SP, o solo da área experimental é classificado como LATOSSOLO VERMELHO Eutroférrico típico, A moderado, textura argilosa. Foi utilizado o delineamento em blocos ao acaso, no esquema fatorial (2x3), com quatro repetições. No ano agrícola 2008/2009, os tratamentos foram constituídos por duas populações de plantas de milho (55 e 75 mil plantas ha-1) consorciado com três forrageiras semeadas na entrelinha 30 dias após a semeadura do milho, totalizando 24 parcelas. Para o ano agrícola 2009/2010, a semeadura do milho foi realizada nas mesmas parcelas do ano anterior, com palhada proporcionada pelo consórcio das três forrageiras com milho e duas velocidades de deslocamento do conjunto trator-semeadora (6,0 e 7,7 km h-1). A população de 75 mil plantas ha-1 em consórcio com B. brizantha e B. ruzizienses, promoveu maiores valores de produtividade de grãos e as forrageiras promoveram maior quantidade de massa seca residual, com maior porcentagem de cobertura do solo para brizantha (2008/2009). Para o segundo ano agrícola, a variação da... / No tillage system as a conservation practice associated with techniques such as crop-livestock integration focuses primarily to optimize the use of agricultural areas. Given this condition, the option of corn intercropped with forage constitutes an alternative to supply the annual intake of straw and make the system sustainable. The study aimed, in two growing seasons, to evaluate in the first year three forages (Brachiaria brizantha, B. decumbens and B. ruzizienses) intercropped with two populations of corn plants, and in the second year to determine the effect of the straw treatment from previous year in two speeds of the tractor-seed drill. The experiment was conducted in the experimental area of the Laboratory of Agricultural Machinery and Mechanization of UNESP / Jaboticabal County, São Paulo State, Brazil. The soil is classified as typiceutroferric Red Latossol, clayey. Randomized blocks design was used for the experimental layout forming a factorial arrangement of 2x3 with 4 replications. In the crop year of 2008/2009, treatments consisted of two corn plants populations (55 and 75 000 plants ha-1) sown intercropped with three forages 30 days after sowing of corn, totaling 24 plots. For crop year of 2009/2010 corn sowing was performed on the same plots as in the previous year but with two forward speeds of the tractor-seeder (6.0 and 7.7 km h-1), over the straw provided by the consortium of the corn and three forages. The population of 75,000 plants ha-1 in association with B. brizantha and B. ruziziensis promoted the highest values for grain productivity, and the forages promoted greater amount of residual dry matter, being B brizantha (2008/2009) with the highest percentage of soil cover. For the second crop season, speed variation of seeding affected the operational performance of the... (Complete abstract click electronic access below)

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)

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 128-134). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 128-134). Also available on the Internet.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Soil erosion is a long standing problem in the Scotland District of Barbados. Many workers, including pedologists, geologists, hydrologists and soil conservationists have recently undertaken investigation into the causes of soil erosion and the possible means of its control. These studies have focussed on a problem in a restricted field. As accelerated soil erosion is an important ecological process, it was felt that an investigation into the problems of erosion from an ecological viewpoint was necessary. [...]

Public concern for the intergenerational transfer of natural resources has generated an interest in sustainable development and sustainable agriculture. Policy makers have a new mandate to insure the promotion of sustainable agriculture. At the same time these policy makers must also reduce public expenditures in agriculture. These two conflicting mandates can only be accomplished when private market values for various soil conservation investments are known. Once this market information is known, policy makers can formulate appropriate policies to achieve both goals. / The focus of this research is to measure the significant factors affecting land values in the study area. The sample farm sales data used were drawn from four of Quebec's twelve agricultural regions. Two of these regions are among Quebec's most productive. These data were used in conjunction with a Hedonic Pricing Model for the analysis. / This research seeks to quantify the implied price paid for land characteristics, soil conservation and capital improvement investments. The research should determine whether the studied land market provides adequate price incentives for private market implementation of soil conservation and capital improvement investments. These investments are necessary to achieve a sustainable agriculture scheme.

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.

Soil water erosion is recognized as the principal mechanisms behind soil organic carbon (SOC) losses from soils, a soil constituent essential for ecosystem functions. SOC erosion can thus be far-reaching, affecting the future human welfare and the sustainability of ecosystems. Little research has yet been done to investigate the main mechanisms involved in the lateral translocation of SOC on the landscape. Understanding the effects of the different water erosion mechanisms, which control SOC losses (SOCL) at the hillslope level, creates scope for further scientific studies. Empirical data from 357 plots, with a range in slope length from 1 (n=117) to 22.1m (n=240) were analysed to estimate the global variations of particulate organic carbon content (POCC), POC losses (POCL) and sediment POC enrichment ratio (ER). The global average POCL rate was calculated to be 12.1 g C m-2 y-1. Tropical clayey soil environments revealed the highest POCL (POCL=18.0 g C m-2 y-1), followed by semi-arid sandy (POCL=16.2 g C m-2 y-1) and temperate clayey soil environments (POCL=2.9 g C m-2 y-1). The global net amount of SOC displaced from its original bulk soil on an annual basis was calculated to be 0.59±0.09 Gt C, making up an approximated 6.5% of the net annual fossil fuel induced C emissions (9 Gt C). POCL data for different spatial scales revealed that up to 83% of the eroded POC re-deposits near its origin in hillslopes, and is not exported out of the catchment. The low organic carbon sediment ER obtained from the data of clayey soils (ER of 1.1) suggests that most of the eroded POC remains protected within soil aggregates. Consequently, erosion-induced carbon dioxide (CO2) emissions in tropical areas with clayey soils are likely to be limited (less than 10%), as the process of POC re-burial in hillslopes is likely to decrease the rate of organic matter (OM) decomposition and thus serve as a potential carbon sink. Water erosion in sandy and silty soils revealed organic carbon sediment ER as high as 3.0 and 5.0, suggesting that in these soils the eroded POC is not re-buried, but is made vulnerable to micro-decomposers, thus adding to the atmospheric CO2 influx. The results obtained in the review study only reaffirm that large variations of POCL are evident across the different pedo-climatic regions of the world, making it a scientific imperative to conduct further studies investigating the link between SOC erosion by water and the global carbon cycle. A field study was designed to quantify the POC exported in the eroded sediments from 1x1m2 and 2x5m2 erosion plots, installed at different hillslope aspects, and to further identify the main erosion mechanisms involved in SOC erosion and the pertaining factors of control. The erosion plots were installed on five topographic positions under different soil types, varying vegetation cover, and geology in the foothills of the Drakensberg mountain range of South Africa. Soil loss (SL), sediment concentration (SC), runoff water (R) and POCL data were obtained for every rainfall event from November 2010 up to February 2013. Scale ratios were calculated to determine which erosion mechanism, rain-impacted flow versus raindrop erosion, dominates R, SL and POCL. Averaged out across the 32 rainfall events, there were no significant differences in R and POCL between the two plot sizes but SL were markedly higher on the 5m compared to the 1m erosion plots (174.5 vs 27g m-1). This demonstrates that the sheet erosion mechanism has a greater efficiency on longer as opposed to shorter slopes. Rain-impacted flow was least effective where soils displayed high vegetation coverage (P < 0.05) and most efficient on steep slopes with a high prevalence of soil surface crusting. By investigating the role of scale in erosion, it was possible to single out the controlling in situ (soil surface related conditions) and ex situ (rainfall characteristics) involved in the export of SOC from soils. This information will in future contribute toward generating SOC specific models and thus further inform erosion mitigation. / M. Sc. University of KwaZulu-Natal, Durban 2013.

The disturbed soil from a stream channelization project at Cooper Woods was used to evaluate the feasibility of establishing native grasses and forbs and their effectiveness in preventing soil erosion. Treatments included; 1- plots seeded, no application of herbicide, 2-plots seeded, herbicide applied, 3-unseeded and untreated control plots. The effect of variation in slope was assessed for each treatment. Cover and density were significantly different (Ps0.05) during the first and second year of sampling. No significant differences in mean total cover or mean density were attributed to slope variation. There was not a significant interaction between treatment variables in 1994 and 1995. Mean erosion was insignificant (Pz0.05) in 1994. Mean erosion was significantly different (Ps0.001) between slope categories in 1995. Bulk density was insignificant within vegetative treatments in 994, however in 1995, bulk density was significantly different(P=0.002). Plant cover and density were generally negatively associated with soil erosion and bulk density. However, there were a number of anomalies in the results. Four of the native species seeded in treatment plots became well established during the study period. Additional time is necessary to determine the establishment success of the remaining species and their effects on soil erosion. / Department of Biology