Rural land use and agricultural production in Dinokana Village,Bophuthatswana

In recent years geographers have researched the problems of many rural areas of the third world. However, analysis of rural and agricultural development in the Bantustans of South Africa has been conspicuously absent. Although mythically independent, the Bantustans have their own Departments of Agriculture, as well as parastatal bodies, which develop and implement agricultural policies. This paper examines agricultural policy in the Bophuthatswana Bantustans, which is largely based on increasing food production for national self-sufficiency through the establishment of agricultural development projects. The effects of the implementation of this programme on a specific rural community, the village of Dinokana, are discussed. Two irrigation based projects were implemented in Dinokana in the early 1980's. The project planners did not seem to be concerned about the existence of an indigenous irrigation system which had been the foundation for agricultural development at Dinokana for several decades, and which could have been revived and upgraded. This suggests that there is a need for agricultural planners to have a detailed historial knowledge of local African agriculture. Geographers could play a valuable role here, by uncovering the dynamics of past systems of African agricultural production, in particular focusing on patterns of rural resource management.     

Human population growth and over-utilization of the biotic resources of the Murray — Darling River system, Australia

Imbalances in aquatic ecosystems of the Murray-Darling Basin reflect 180 years of inappropriate land use practices. Regulation of most rivers in the Basin has reduced frequency or duration of inundation of floodplains, with profound effects on a species-rich, highly specialized aquatic biota. Exotic introductions (e.g. trout, carp) have further modified aquatic ecosystems. Floodplain billabongs (= ox-bow lakes) are critical to maintenance of floodplain biodiversity, yet with isolation of floodplains from the parent rivers, billabongs are being lost or severely degraded. Consideration is given to the apparent carrying-capacity of the Basin, the present over-commitment of its most valuable resource, water, and the prospects for amelioration in view of present conflicting land use and water abstraction requirements.     

Source and flux of POC in two subtropical karstic tributaries with contrasting land use practice in the Yangtze River Basin

Elemental (C/N ratio) and C isotope composition (δ¹³C) of particulate organic C (POC) and organic C content (OC) of total suspended solids (TSS) were determined for two subtropical karstic tributaries of the Yangtze River, the Wujiang (the eighth largest tributary) and Yuanjiang (the third largest tributary). For the latter, two headwaters, the karstic Wuyanghe and non-karstic Qingshuijiang were studied. The Wujiang catchment is subject to intensive land use, has low forest coverage and high soil erosion rate. The δ¹³C of POC covered a range from −30.6‰ to −24.9‰, from −27.6‰ to −24.7‰, and from −26.2‰ to −23.3‰ at the low-water stage, while at the high-water stage varied in a span between −28.6‰ and −24.4‰, between −27.7‰ and −24.5‰, and between −27.6‰ and −24.2‰ for the Wujiang, Wuyanghe, and Qingshuijiang, respectively. The combined application of C isotopes, C/N ratio, OC, and TSS analyses indicated that catchment soil was the predominant source of POC for the Wujiang while for the Wuyanghe and Qingshuijiang, in-stream processes supplied the main part of POC in winter and summer. A significant increase in δ¹³C value (1.4‰) of POC was found in the Wujiang during summer, and was attributed to the enhanced soil erosion of the dry arable uplands close to the riverbanks of the main channel. Based on a conservative estimate, POC fluxes were 3.123 × 10¹⁰, 0.084 × 10¹⁰, and 0.372 × 10¹⁰ g a⁻¹ while export rates of POC were 466, 129, and 218 mg m⁻² a⁻¹ for the Wujiang, Wuyanghe, and Qingshuijiang, respectively. The POC export rate for the karstic Wujiang, with intensive land use, was 2–3 higher than that of the karstic Wuyanghe or of the non-karstic Qingshuijiang where soil erosion was minor. Such high values imply rapid degradation of related karstic ecosystems impacted by intensive land use activities, and pose a potential threat to the health of the Three Gorges Reservoir.     

Exploring the effects of urban and agricultural land use on surface water chemistry,across a regional watershed,using multivariate statistics

In this paper, the influence of anthropogenic activity on surface water chemistry is investigated. Base flow samples from dominant land use streams in the Muskegon River Watershed, Michigan, USA, were analyzed for nutrients, major ions, and trace elements. Principal component and hierarchical cluster analysis were used to investigate the processes controlling the effects of land use on the biogeochemistry of streams in this Watershed. Biogeochemical fingerprints of land use were developed based on the results of the cluster analysis. Spider diagrams which referenced the natural environment aided the identification of the individual contributions of urban and agricultural land uses to surface water chemistry. The biogeochemical fingerprints quantified support previous findings (Urb: Na, K, Cl/Ag: Ca, Mg) and produced new insights into the effects of land use on the behavior of nutrients (Ag: N and Urb: N, P) and trace elements (Urb: V, Cr, Co, Cu, Se, Rb, Mo, Sr, Cd, Pb and Ba/Ag: U and As). The higher correlations of urban than agricultural land uses with nutrients, specifically P, were not expected and may reflect the effects of fertilization and wastewater or the season the samples were taken. More study in different geologic and urban settings is needed to help refine these fingerprints, but it is becoming apparent that despite obscuring factors, land use produces consistent, quantifiable associations between biogeochemical analytes.     

Aspects of agricultural land use in Ireland

Ireland's soil regions consist largely of Luvisols, Cambisols, and Gleysols. Approximately 60% of Ireland's land area is subject to varying degrees of soil limitations. Twenty-five percent of the land area comprises wet lowland mineral soils. Ninety percent of Ireland's agricultural area comprises pasture, hay, and silage. Approximately 30% of the agricultural area is devoted to dairying, and 55% to cattle production. is devoted to dairying, and 55% to cattle production. Trends in agricultural land use indicate that tillage declined substantially while livestock showed a substantial increase particularly in the decade 1965–1975. Research concludes that over 2.8 million ha has a capacity to carry at least 100 LU/40 ha (100 acres). Levels of fertilizer use in Ireland are below EEC levels. The highest fertilizer use levels are associated with the eastern and southern areas of Ireland. Tillage crops occupy only 10% of the agricultural area, while they account for 26% of tertilizer and lime use.     

Seasonal agricultural land use patterns in China's Pearl River Delta from multi-date landsat images

Landsat images of the Pearl River delta region of SE China were interpreted manually in combination with other data sources to identify, measure and to map agricultural land use in a 25,775 km² study area during three growing seasons of 1978. Areal measurements for different land uses were compiled. Paddy lands, which accounted for 6,340 km², were evaluated and classified on the basis of quality, yield and production. Rice production for the study area was then estimated at 5.9 million metric tons based on average yields for the different grades of paddy land.     

Hydrogeochemistry of the Winder River and adjoining tributaries, Balochistan, Pakistan

Quantitative estimation of ground and stream waters draining through sedimentary rocks of the Pab and Mor ranges (Jurassic-Cretaceous) and the Bela ophiolite has been made. The degree of correspondence among cations and anions has been estimated in order to evaluate their mutual relationships. The abundance of major ions is interpreted to be related to bedrocks and climatic conditions, which may contribute to the genetic affiliation. The log TDS and Na/Na Ca ratio reflected supremacy of weathering of rocks with some influence of evaporation. Ionic relationship is exhibited in the form of Stiff diagrams. Patterns of ionic composition revealed high NaCl, medium Ca(HCO3)2 and low MgSO4. Piper diagram has been used to classify the hydrofacies. The important hydrogeochemical parameters have been estimated for assessment of groundwater quality for domestic purposes in accordance to WHO. Irrigation water qualities have been evaluated in terms of EC, SAR, RSC, ESP and pH.     

西澳Darling Range地区红土型铝土矿地球化学特征及源区研究

Darling Range位于西澳大利亚地区,红土型铝土矿资源丰富。本文对Darling Range地区红土型铝土矿及相关岩石开展了元素地球化学分析,并对铝土矿中的碎屑锆石和其下伏的花岗岩开展了LA-ICP-MS锆石U-Pb测年,目的是探讨西澳地区红土型铝土矿的成矿作用及其源区。结果表明,西澳地区红土型铝土矿的主量元素以Al2O3、Fe2O3、SiO2和TiO2为主,Al2O3与SiO2呈显著的负相关关系,与TiO2则呈现显著的正相关关系,表明铝土矿的形成过程是一个去Si富Al、Ti的过程。铝土矿微量元素富集Th、U、Nb、Ta、Zr、Hf、Ti,相对亏损Ba、K、Sr、P、Sm;稀土总量较低,为1.36×10~(-6)~65.58×10~(-6),稀土元素球粒陨石标准化分布曲线略微向右倾斜,富集轻稀土。铝土矿碎屑锆石U-Pb年龄分布于1167Ma和1267Ma与2539~2696Ma(16颗)两个年龄段,分析锆石来源前者可能来自Albany-Fraser造山带;后者加权平均年龄为2579±15Ma(MSWD=1.16),与研究区本次获得的太古宙花岗岩加权平均年龄2585±12Ma(MSWD=0.83)在误差范围内一致,表明铝土矿中的锆石除了来自本区太古宙花岗岩,还有少量的锆石来自Albany-Fraser造山带。结合元素地球化学钛率(Al2O3/TiO2)、lgCr-lgNi、微量元素比值、稀土元素配分模式对铝土矿源区进行示踪表明,Darling Range地区的太古宙花岗岩为红土型铝土矿的主要物质来源。     

The effect of land tenure systems on agricultural production: a case study of the land tenancy system in the Okun Area of Kwara State,Nigeria

Since all agricultural systems depend on land, the ownership of, or access to, agricultural land becomes crucial in the consideration of factors which determine agricultural land-use systems. The land tenure system affects agricultural land use and prospects for improvement. This paper examines the structure of the land tenure system in the Okun Area of Kwara State, Nigeria, and its influence on the farming system in that area. It reveals that despite the fact that this is a predominantly agricultural rural community, the operation of the land tenure system is exceptionally liberal and only marginally affects both the size of individual farm holdings and the way the land is cropped. This situation results mainly from two factors. First, the Okun people perceive land as a God-given entity and therefore it is held in trust for Him and second, the population density is very low, with plenty of land to go round. In the present circumstances, large-scale agricultural projects developed in the Okun area over the last decade have been offered land freely by the people rather than finding the land tenure system a hinderance.     

西澳Darling Range地区铝土矿特征及成矿控制因素

我国铝土矿资源相对匮乏,但需求量大。澳大利亚铝土矿资源丰富,是我国铝土矿进口主要国家之一。Darling Range地区为澳大利亚铝土矿主产地之一,了解该区的铝土矿成矿特征将有助于我国企业走出去在该地区或相似地区找矿提供依据。Darling Range位于西澳大利亚的伊尔岗克拉通,该区铝土矿以红土型为主,铝土矿的显著特点是品位较低,铁、硅含量高,但对铝土矿冶炼有害的可溶性硅含量低,资源潜力巨大。铝土矿产于红土层中,厚度受后期剥蚀作用控制。红土剖面从上到下依次分为覆盖层、硬壳、碎屑层和底部粘土层。覆盖层以砂砾为主,具有经济意义的铝土矿主要集中在碎屑层和硬壳中,底部粘土层则阻止铝土矿继续向下运移。铝土矿中的矿石矿物主要是三水铝石,也有少量一水软铝石,主要由花岗岩或基性岩(如辉绿岩、绿岩)中的长石经过风化淋滤形成。Darling Range地区铝土矿根据基岩的种类可分为花岗岩类铝土矿和镁铁质类铝土矿,分别以Jarrahdale铝土矿矿床和Mount Saddleback铝土矿矿床为代表。铝土矿的成矿主要受气候、母岩、地貌、排水和植被等因素控制。气候主要通过控制气温和降水影响红土化作用的进行;母岩通过自身的物理化学性质和矿物组成控制铝土矿的形成;地貌和排水影响铝土矿的风化速度;植被的作用既保证了土壤风化淋滤所需的渗透性,又降低了外部因素对土壤的侵蚀速率。在各种成矿因素的综合作用下,经过漫长的时间演化最终形成了红土型铝土矿。     

Effect of agricultural land use on the chemistry of groundwater from basaltic aquifers, Jeju Island, South Korea

Geochemical processes were identified as controlling factors of groundwater chemistry, including chemical weathering, salinization from seawater and dry sea-salt deposition, nitrate contamination, and rainfall recharge. These geochemical processes were identified using principal component analysis of major element chemistry of groundwater from basaltic aquifers in Jeju Island, South Korea, a volcanic island with intense agricultural activities. The contribution of the geochemical processes to groundwater chemistry was quantified by a simple mass-balance approach. The geochemical effects due to seawater were considered based on Cl contributions, whereas the effects due to natural chemical weathering were based on alkalinity. Nitrogenous fertilizers, and especially the associated nitrification processes, appear to significantly affect groundwater chemistry. A strong correlation was observed between Na, Mg, Ca, SO₄ and Cl, and nitrate concentrations in groundwater. Correspondingly, the total major cations, Cl, and SO₄ in groundwater were assessed to estimate relative effect of N-fertilizer use on groundwater chemistry. Cl originates more from nitrate sources than from seawater, whereas SO₄ originates mostly from rainwater. N-fertilizer use has shown the greatest effect on groundwater chemistry, particularly when nitrate concentrations exceed 6–7 mg/L NO₃–N. Nitrate contamination significantly affects groundwater quality and 18% of groundwater samples have contamination-dominated chemistry.     

A multi-scale study on land use and land cover quality change: The case of the Yellow River Delta in China

This paper presents a case study of the Yellow River Delta in China, to trace land use and land cover changes during the past 20 years, with an emphasis on land quality changes. Three sets of data are used in this case study: remote sensing data derived from satellite images; crop yield data from statistics; and soil data collected by the researchers in the field. Our study reveals that at the regional scale, LUCC has taken place in a positive direction: vegetation cover has been expanding and crop yields per hectare have been on rise. However, while the overall eco-environment has improved, the improvement is uneven across the Delta region. At local levels, some areas show signs of increased salinization and declining organic content. Both natural forces and human activities are responsible for the LUCC, but human activities play a more important role. While some impacts of human activities are positive, the damages are often long-lasting and irreversible. We also conclude that it is necessary to use both macro data (such as remote sensing data) and micro data (data collected in the field) to study land quality change. The former are efficient in examining land quality changes at the regional scale, the latter can serve to verify ground patterns revealed from macro data and help to identify local variations, so as to get a comprehensive understanding of LUCC and promote sustainable land use and land management. This revised version was published online in July 2006 with corrections to the Cover Date.     

Use of SWAT to determine the effects of climate and land use changes on streamflow and sediment concentration in the Purna River basin,India

A semi-distributed, physically based, basin-scale Soil and Water Assessment Tool (SWAT) model was developed to determine the key factors that influence streamflow and sediment concentration in Purna river basin in India and to determine the potential impacts of future climate and land use changes on these factors. A SWAT domain with a Geographical Information System (GIS) was utilized for simulating and determining monthly streamflow and sediment concentration for the period 1980–2005 with a calibration period of 1980–1994 and validation period of 1995 to 2005. Additionally, a sequential uncertainty fitting (SUFI-2) method within SWAT-CUP was used for calibration and validation purpose. The overall performance of the SWAT model was assessed using the coefficient of determination (R²) and Nash–Sutcliffe efficiency parameter (E_NS) for both calibration and validation. For the calibration period, the R² and E_NS values were determined to be 0.91 and 0.91, respectively. For the validation period, the R² and E_NS were determined to be 0.83 and 0.82, respectively. The model performed equally well with observed sediment data in the basin, with the R² and E_NS determined to be 0.80 and 0.75 for the calibration period and 0.75 and 0.65 for the validation, respectively. The projected precipitation and temperature show an increasing trend compared to the baseline condition. The study indicates that SWAT is capable of simulating long-term hydrological processes in the Purna river basin.     

The Salt River Indian Reservation: land use conflicts and aspects of socioeconomic change on the outskirts of Metro-Phoenix, Arizona

Several North American metropolitan areas including Albuquerque, El Paso and Seattle in the U.S., and the Canadian urban areas of Montreal and Vancouver, are characterized by Indian reservations situated either within or on the outskirts of these cities. This type of Indian reservation or reserve within metropolitan areas has been the subject of limited geographical research, and is nowhere as manifest as in Metro-Phoenix. Three reservations obstruct the otherwise unlimited growth of Arizona??s capital. This phenomenon is most striking in the eastern regions of Phoenix where, until the end of the 1980s, the almost exclusively rural, agrarian Salt River Indian Reservation formed a physical and cultural barrier to urban development, preventing metropolitan sprawl beyond a clearly marked boundary. Continued urban pressures have led to changing land uses, effectively hollowing out this embankment or barrier, which has caused a profound change in the reservation. Both the Salt River and Gila River Indian reservations maintain large tracts of irrigated agricultural land, but the transformation that converted farms to suburbs off the reservation is now changing the reservation itself. In fact, this change actually began more than a hundred years ago with the Anglo-American colonization of what is today Arizona??s central region.     

Urbanization and agricultural intensification in the Lower Fraser River valley,: Impacts on water use and quality

The Fraser River drains a quarter of the province of British Columbia and is renown as one of the greatest salmon rivers in the world. The Fraser watershed is under threat from rapid urbanization in its lower reaches as pollutants generated from domestic and industrial wastes, and stormwater runoff threaten the health of the aquatic ecosystem. Plans for secondary sewage treatment in the metropolitan area will reduce waste loadings of some contaminants, but rapid growth will soon offset these benefits. Intensive urbanization, spreading up the Lower Fraser valley, with a network of impervious roads and increased traffic volumes contribute pollutants in surface runoff that are difficult to control. Rapid growth in agrobusiness to provide fresh produce to the nearby markets has resulted in very high densities of farm animals and excessive use of fertilizers and pesticides on the land. These pollutants threaten the groundwater and many of the remaining salmonid streams in the lower valley. The Fraser Basin Management Program, the Fraser River Estuary Management Program, and a variety of government agencies are coordinating studies and analyzing issues and conflicts to develop a strategy for sustainable development in the region.     

Nature and origins of granitic regolith in bauxite mine floors in the Darling Range,Western Australia

Chemical and physical weathering of primary minerals during the formation of laterite profiles in the Darling Range has formed distinct secondary mineral and morphological zones in the regolith. Erosion and human activity such as mining have exposed large areas of lateritic regolith, and its classification is important for land management, especially for mine rehabilitation. Preserved rock fabrics within regolith may enable the identification of parent rock type and degree of weathering, thus providing explanations for variations in important physical properties such as the strength and water retention of regolith. Feldspar, quartz, biotite and muscovite in porphyritic and fine-grained monzogranite in lateritic profiles have weathered via a series of gradational changes to form saprolite and pedolith consisting of kaolin, quartz, iron oxides, muscovite and gibbsite. Local reorganisation in the upper regolith or pedoplasmation zone has included illuviation of kaolin, which may be iron oxide-stained and which has disrupted the preserved rock fabric of saprock and saprolite. Quartz grain- or matrix-supported fabrics have developed, with greater pedoplasmation resulting in a quartz-grain-supported fabric. The recognition of these processes enables the use of gibbsite grainsize and distribution in regolith to infer original feldspar grainsize. Muscovite-rich or muscovite-deficient kaolin matrix indicates where plagioclase or alkali feldspar, respectively, was present in the parent rock. In some regolith, cementing by iron oxides has faithfully preserved rock fabric. The recognition of these various regolith types provides a basis for identifying the parent materials of lateritic regolith developed from granitic and doleritic rocks. Rock fabric is sometimes preserved in iron oxide-cemented bauxite mine floor regolith (Zh) due to the pseudomorphic gibbsite grains and iron oxide cement which forms a porous, rigid fabric. Plagioclase-rich granitoid is more likely to have weathered to dense clay-rich regolith (Zp), whereas albite and alkali feldspar have weathered to quartz-rich regolith (Zm) with the random orientation of quartz grains indicating that substantial reorganisation of rock fabric has occurred. It is possible to predict the response of regolith materials exposed in mine floors to management practices including ripping and re-vegetation, thus allowing targeted use of deep-ripping and planting density based on regolith type.     

A North American perspective on land use and mineral aggregate production

Land use conflicts involving natural aggregate producers often result in the sterilization of aggregate resources like crushed stone, sand and gravel when land management policies render potential resources inaccessible. Transport plays a major role in the cost structure of aggregates. Limiting the sources of aggregate, thereby increasing transport costs, will translate into unnecessary social costs. Sequential land use is examined for conventional aggregate and multiple land use for marine and recycled aggregates. The integration of aggregate production within the land management planning process would preserve the natural resource stock of aggregate and also be economically efficient.     

Effects of land use change on landscape pattern of the Manas River watershed in Xinjiang, China

The mechanism of interaction between land use change and landscape pattern is pivotal in research concerning global environmental change. Quantitative evaluation of land use change that has resulted from excessive land development and its impact on landscape pattern are important for sustainable utilization of local land resources. The study area was the Manas River watershed, a typical watershed in an arid area. The present study evaluated the influence of long-term land use change on the landscape pattern; the findings are valuable for economic development and environmental protection. The processes for land use change and changes in landscape pattern were reconstructed and analyzed for data in topographic maps dated 1962 and in remote sensing images taken in 1976, 1989, 1999 and 2008 using mathematical models and landscape metrics. The results indicate significant changes in land use over the past 50 years, with increases in the areas of cultivated land and construction land, and a significant decrease in unused land and woodland areas; grassland and water resources first increased and then tended to decrease over this time. The comprehensive index of land use change is 0.55, indicating an unbalanced, one-way transition in the study area. Landscape fragmentation and diversity increased and landscape dominance decreased; in other words, differences between landscapes decreased. The changes resulted in a significant tendency toward diversity and fragmentation of the landscape. Therefore, large-scale intensive agricultural development can reduce the negative influence of land use change on the landscape pattern.     

The late Wisconsinan Savanna Terrace in tributaries to the upper Mississippi River

The Savanna Terrace, composed of alternating red and gray clayey sediments of late Wisconsinan age, can be found in five states along the upper Mississippi valley from Pepin County, Wisconsin, to Jackson County, Illinois. The terrace is the highest glaciofluvial-lacustrine deposit without a loess cover in the upper Mississippi valley. Chemical, physical, and mineralogical data show that two different sources provided sediment. The red clay is believed to have come from Lake Superior sources, while the gray clay is believed to have come from sources farther west. Large-scale flood events from glacial Lakes Agassiz, Grantsburg, and Superior were probably the main contributors of the sediments. The red clay in the terrace is similar in composition to red glaciolacustrine sediment found in eastern and northern Wisconsin. It also is mineralogically similar to the Hinckley Sandstone and the Fond du Lac Formation, which occur under and around Lake Superior. Radiocarbon dates obtained from the lower Illinois valley indicate that the terrace sediments were deposited sometime between about 13,100 and 9500 yr ago. Soils developed on the terrace are variable in their physical, chemical, and mineralogical properties, which reflect the composition of the clayey sediments.     

Vegetation change,erosion risk and land management on the Nullarbor Plain,Australia

 Arid karst landscapes that have been degraded by human activities provide a challenge for rehabilitation and an opportunity to test ideas about the stability and resilience of limestone ecosystems. The Nullarbor Plain is the largest arid karst area in Australia (220 000 km²) and is divided into extensive closed karstic depressions separated by low rocky ridges, while the dominant vegetation is chenopod shrubland. Since European settlement there has been considerable change in the vegetation, with significant reduction in shrub and grass cover over large areas of the plain. These changes are related to a state and transition model of vegetation dynamics which incorporates climatic variability, fire history and grazing pressure from sheep, kangaroos and rabbits. A partial sediment budget using ¹³⁷Cs inventories reveals local and regional patterns of soil redistribution within this arid karst landscape. Rehabilitation of eroded soil in pastoral lands has been accomplished at several sites but is labour intensive and vulnerable to climatic fluctuations. Given the low stock numbers, limited number of people involved, and poor economic returns, it would be sensible to make pastoral activities on the Nullarbor secondary to conservation priorities. This would necessitate a change in land ethic to stewardship, with emphasis on rehabilitation and control of feral animals. Management of increased numbers of visitors to the caves and karst also requires that resource inventories and management plans for each area be drawn up and used. Received: 1 June 1995 · Accepted: 4 December 1995