Soil erosion is a hazard that is adversely affecting agricultural production in the Eastern Cape province. The climatic conditions ad parent material (natural resources) are not conducive for the development of stable soil. This situation is, however, aggravated by amongst other things, poor planning, bad agricultural practices, land tenure, population pressures, overgrazing, etc. Soil reclamation has become one of the Government’s priorities. However, all their attempts have failed. On the other hand the interventions by NGO’s have been successful. This study has found that the most effective way to address the soil reclamation problems and ensure that the soil conservation initiatives are successful and sustainable, is to: 1. Involve the natural resource users (the local community). Community involvement entails the following: -- The community taking ownership and the lead in the initiative -- Where there is a need they must be empowered to make informed decisions. -- For the participation to be effective, there must be technology transfer. -- The immediate beneficiaries must be the active participants. 2. Prevent soil degradation through development of sustainable farming systems for the poor soils. This is a process that needs detailed study of the natural resources as a first step. In this study it was learnt that poor planning as a result of lack of understanding or knowledge of the natural resource of the province, particularly the soil, is one of the key causes of soil erosion. A detailed study of the soils or soil survey of the Eastern Cape has become critically important in order to ensure that planning is based on facts rather than assumptions. This will pave the way for the development of sustainable farming systems. However, without addressing the land tenure system in the Eastern Cape province (communal), by giving ownership of land to the people it becomes difficult to ensure that farmers will invest in the land through soil reclamation and soil conservation practices. / Dissertation (M Inst Agrar (Land-use planning))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

No description available.

No description available.

A field experiment was conducted to evaluate the possibility of using shallow reservoirs containing aquatic plants to reduce excess nutrient levels of agricultural drainage effluent from organic soils. The reservoir systems consisted of three small reservoirs in series, containing separate stands of Eichhornia crassipes, Egeria densa and Typha sp., and a single large reservoir containing equal areas of all three aquatic plants. A control reservoir without plants was included. Drainage water from organic soils was pumped through each reservoir at 39.6 l/sec., 6 hours per day, 6 days per week. the major nutrients monitored in theses flow-through systems included nitrate-N, ammonium-N, total-N, ortho-P (soluble reactive phosphorus) and total-P. Temperature, pH, alkalinity, dissolved oxygen, carbon dioxide and turbidity were also monitored at the inflow and outflow of each reservoir system. Standing crop measurements and plant tissue analysis for nitrogen and phosphorus were conducted every 21 days. When a single large reservoir was used, effluent nitrate-N, ammonium-N, ortho-P and total-P concentrations decreased by 65%, 57.9%, 70.3% and 51% respectively, while organic-N concentrations increased by 7.2%. In the a series of small reservoirs the concentrations of nutrients decreased by 80%, 73%, 33%, 74%, and 70% for nitrate-N, ammonium-N organic-N, ortho-P and total-P respectively. The dissolved oxygen increased and turbidity was reduced in both reservoir systems. The bicarbonate and carbonate equilibrium in the series of reservoirs and control reservoir shifted to the carbonate sides as carbon dioxide was reduced. The carbon dioxide in the large reservoir remained at the same concentration throughout the study. The standing crop in both reservoir systems was similar with an average of 11.6 mt/ha grown in R-1 and 11.2 mt/ha grown in the series of reservoirs. The nitrogen retained during the study was 1017 kg/ha and 750 kg/ha in the series and the large reservoir respectively. Phosphorus retained in the series was 249 kg/ha while the large reservoir retained 211 kg/ha of phosphorus. The series of reservoirs was more effective in reducing the nutrient levels of the drainage effluent than the large single reservoir. The results obtained from this study indicated that reservoirs in series can be used to reduce excess nutrient levels of agricultural drainage waters. However, further studies are necessary to increase the efficiency of the system and to accelerate plant removal. The physical, chemical, and biological processes involved in removal of the nitrogen and phosphate should be optimized in future applications.

No description available.

published_or_final_version / Geography and Geology / Master / Master of Philosophy

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1986. / Bibliography: leaves 442-469. / Photocopy. / xv. 469 leaves, bound ill. 29 cm

Typescript (photocopy). / Digitized by Kansas Correctional Industries

This study investigates the potential impacts on soils from development practices associated with new single-family residential home construction in the extra territorial jurisdiction (ETJ) of Pflugerville, Texas. My research question is: Are regulations that directly focus on soil conservation advisable within Pflugerville’s ETJ, and what areas of development ought to be primarily targeted by these regulations in order to better ensure the long-term stability of soil health and the minimization of soil loss? The rationale for this question is based on the city’s projected future population growth, the projected future demand for single-family residences, as well as the development and management practices typically associated with new single-family residential development in the ETJ of Pflugerville. I hypothesize that due to Pflugerville’s proximity to Austin and Round Rock, in addition to the relative abundance of available land to the east of the city of Pflugerville, that it is likely to continue experiencing sustained population and residential development growth, particularly in the form of new single-family residences in the ETJ. A population projection was conducted up to the year 2030, which in conjunction with average persons-per-household and single-family home permitting data, estimates potential consumer demand for single-family residences. The imperative to prevent soil loss is conceptually linked to ecosystem service benefits resulting from healthy and intact soils, such as improved water quality and the regulation of peak flow rates during storm events. Single-family residential development is evaluated in terms of conventional on-the-ground construction practices gathered from interviews with developers of single-family homes in the Pflugerville ETJ, as well as planning and regulatory specialists. These analyses are intended to inform regulatory and decision making processes regarding the importance and potential integration of soil preservation and conservation at the individual construction site level. / text

In Mexico, corn (Zea mays L.) is the most important crop (59% of its agriculture land) and the primary source of sediment yield. This study looks for alternatives to maintain corn productivity by means of sustainable soil and water conservation practices at central Mexico. In order to understand broad tendencies between soil erosion and crop productivity in the region, the EPIC (Erosion Productivity Impact Calculator) model was applied in the Texcoco's district as follows:1) Calibrate the model using 352 experimental corn plots established between 1972 and 1992 in 36 rural communities.2) Validate the model on a spatial basis, using GIS tools, by means of historic corn yields.3) Identify the most vulnerable areas where corn productivity is being affected by soil erosion.4) Analyze the relationship between soil erosion and crop productivity, over a 100 years of simulation, comparing the Current Management (CM) and the Recommended Management (RM) by governmental institutions.5) Evaluate the most feasible soil and water conservation practices for the region.From the calibration process, it was concluded that the EPIC model, under a wide range of environmental conditions, simulates very good corn yield (r2 between 0.88 and 0.90), annual runoff (r2=0.98), and annual sediment production (r2=0.96).Base on the official environmental inputs available in the region, the EPIC model can assess only a moderately strong relationship (r2=0.58) between the official historical crop records and the simulated ones.Comparison between CM and RM shows that the average crop yield in the region can be increased by 32.6% if RM were followed. Under the CM, the loss of soil fertility in the district reduces corn productivity by 3% over a hundred years. At least 50.0% of the region's agricultural area needs soil conservation practices, mainly on areas with slopes over 5%. If it is decided to grow corn under conventional till in such areas it is recommended to construct bench terraces in order to maintain soil erosion below 20 t/ha/yr. Corn under no till, besides control erosion, can also increase grain productivity by at least 40% (0.6 t/ha) by combining contouring, mulching, and manures.