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1.
Hawai‘i's agricultural landscape was previously dominated by large monocrop plantations of sugar cane and pineapple, but following a sweeping series of plantation closures beginning at the end of the twentieth century, that era has concluded. The last spatial assessment of Hawai‘i's agricultural footprint was completed in 1980, during the active plantation period. Here we present the results of a 2015 statewide assessment of the commercial crop footprint for Hawai‘i, based on World-View 2 satellite imagery and supporting datasets. We analyzed changes relative to the 1980 baseline on both a statewide and regional basis, to better understand how Hawai‘i's agricultural system has evolved in the post-plantation era. Sugar cane and pineapple saw dramatic reductions during this period, collectively losing more acres (257,000) than were planted for all crops combined (152,000) in 2015. Idle plantation lands and past plantation-era investments in irrigation and other infrastructure have created opportunities for other types of agriculture, despite rising land values, new and existing tropical diseases, and other challenges. Seed crops, primarily for genetically modified corn trials, were the second largest crop in 2015 (24,000 acres) despite having no mapped footprint in 1980. Commercial forestry, also absent in 1980, covered 23,000 acres in 2015. Macadamia nut, coffee, and diversified agriculture also all saw significant gains in their footprints, with coffee plantings increasing >250% during this period. Despite these gains, the Hawaiian Islands continue to have an extremely low degree of self-reliance for food production. The Oahu plain, adjacent to the major population center of Honolulu, has the most potential for considerably increasing the production of local produce, but without changes in consumption patterns and significant efforts to protect agricultural land from development, any increases in local food production will continue to be incremental. The post-plantation agricultural landscape in Hawaii is smaller, more diversified, and more nimble than it was in 1980, reflecting inter-island geographic differences in land use, history, and ownership. Mapping and assessing spatial changes in agricultural activity over time can provide valuable insights for decision-makers and communities as they continue to define what agriculture should look like in the post-plantation era. Our results suggest that Hawai‘i's agricultural landscape and overall production capability will continue to contract without substantial changes in policy and practice. 相似文献
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In this paper we aimed to explain differences in agricultural labour productivity at microregional level. We tested the effects of three major independent variables – farmland fragmentation, urbanization economies and farm size structure with particular emphasis on the relationship between land-use fragmentation and microregional differences in agricultural labour productivity. Our principal question therefore was if higher agricultural labour productivity at microregional level is associated with internal scale economies resulting from large average farm size (in terms of employment), proximity to large cities as a proxy for urbanization economies and lower levels of land-use fragmentation. We also asked if productivity gains from large average size of plots is higher than potential losses resulting from land tenure (tenants are generally less productive than farmland owners). Drawing on a case study of Czechia – a country with extremely fragmented farmland ownership, but the largest average size of plots in the EU and a strong role of farmland rental market – we confirmed our initial expectation that land-use fragmentation affects negatively microregional agricultural labour productivity. Larger average size of plots is positively related to microregional agricultural labour productivity despite potentially negative effects of land tenure. At the same time, no significant effects of urbanization economies and farm size structure were documented. 相似文献
3.
Impact of the shrinking winter wheat sown area on agricultural water consumption in the Hebei Plain简 总被引：6，自引：2，他引：4
This study firstly analyzed the shrinkage of winter wheat and the changes of crop- ping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calcu- lated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are as follows. 1） The sown areas of winter wheat in the 11 cities in the Hebei Plain all shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×10^4 ha. The shrinkage was most serious in the Bei- jing-Tianjin-Tangshan metropolitan agglomerate, with a shrinkage rate of 47.23%. 2） The precipitation fill rate of winter wheat was only 20%-30%, while those of spring maize and summer maize both exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged only from 160 mm to 210 ram. 3） The water resources conserved as a result of the winter wheat sown area shrinkage during the study period were about 15.96×10^8 m^3/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Mid-Route of the South-to-North Water Diversion Project. 相似文献
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The causes and environmental effects of land use conversion during agricultural restructuring in Northeast China 总被引：1，自引：0，他引：1
1IntroductionLand use change has received lots of attention internationally (Turner etal., 1994). Understanding of the mechanism of land use change and its adverse effect on the environment is conducive to understanding of population, resources, environment and sustainable economic development on the global, national and regional scales. With the rapid rise in human population, human-induced changes in land use form an important component of regional environmental change. In China, to emphasi… 相似文献
6.
An analysis is made of the oil pollution of the Ob river waters using a long-term (1993–2013) hydrochemical monitoring of oil fields in Khanty-Mansi Autonomous Okrug. Contents of oil hydrocarbons (OHC) were determined in 4277 samples from the main Ob channel, and in 7076 samples from its anabranches by using infrared spectrometry. An increase in MAC (0.05 mg/dm3) was observed in 28% of the samples from the main channel, and in 32% from the anabranches. The total percentage of samples with an extremely high (> 50 MAC) and high (30–50 MAC) pollution level made up 0.3% of the samples for the anabranches, and 0.1% for the main channel. Maximum pollution was revealed in the eastern part of Okrug, from its eastern boundary to the mouth of the Trom’egan river which is associated with a considerable number of accidents on the pipelines within the Nizhnevartovskii district. The upper and lower quantiles in the most polluted anabranches, Pasl and Bagras, are 0.03–01.7 and 0.032–0.16 mg/dm3, respectively, whereas in the main Ob channel they vary from 0.022 to 0.065 mg/dm3 (0.4–1.2 MAC). The methods of geoinformatics and mathematical statistics were used to assess a dependence of OHC on the number of pollution sources (well clusters, and the area of oil spills) in zones at different distances from the river channels. By calculating the Spearman correlation coefficients, it was shown that OHC contents are dependent mainly on the number of wells, and on the area of oil spills located at less than 2 km from the channels. 相似文献
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I. Yu. Savin 《Geography and Natural Resources》2014,35(3):284-292
The specific character of soil cover in the territory of the Democratic People’s Republic of Korea (DPRK) is revealed, and the soil interpretation schemes in the key areas are compiled. It is established that the main soil resource for agriculture within the region’s low and middle mountains is provided by areas of weakly developed brown forest soils in the lower parts of slopes as well as by alluvial soils along the valleys of large and medium-sized rivers. Specifically, brown forest soils of slopes are used largely in dry farming and forestry, while soils along river valleys are utilized in rice cultivation. Soils of terraced slopes and rice fields have been transformed anthropogenically to the greatest extent. 相似文献
9.
ZHAO Xiaoyuan ZHANG Zhongwei LIU Xiaojie ZHANG Qian WANG Lingqing CHEN Hao XIONG Guangcheng LIU Yuru TANG Qiang RUAN Huada Daniel 《地理学报(英文版)》2023,(10):2094-2116
There is a great uncertainty in generation and formation of non-point source(NPS)pollutants, which leads to difficulties in the investigation of monitoring and control. However,accurate calculation of these pollutant loads is closely correlated to control NPS pollutants in agriculture. In addition, the relationships between pollutant load and human activity and physiographic factor remain elusive. In this study, a modified model with the whole process of agricultural NPS pollutant migration was ... 相似文献
10.
An analysis is made of the karst geomorphosystems of the Yucatán Peninsula. It is found that the main factors influencing its formation were climate and ocean level oscillations, tectonic movements, and impact effects. It is established that as a result of an active influence of the Maya civilization on the karst landscape of the peninsula, the geomorphosystems was transformed to the karst-anthropogenic system. The karstic landforms, and also the underground caverns experienced the anthropogenic impact, and the subsurface waters were particularly heavily influenced, which, on the one hand, determined the places of concentration of settlements and were actively consumed by the population, and, on the other, their reserves were replenished at regular intervals as a result of the creation of artificial subsurface water storages. In a further transformation of the karst-anthropogenic system, two stages were additionally identified: dominated by natural karstic processes (after the decline of the Maya civilization), and with a renewed intensification of anthropogenic pressure (1980s–current period). The last transformation stage is distinguished by an extension of the impact to the surface karst as well as to the underground caverns: they are subjected to mechanical destruction with an enhancement in the chemical impact as a result of inputs of polluted runoffs to encompass ever deeper horizons of subsurface waters. It is established that the rates of transformation processes of anthropogenic objects created of limestone are, in general, comparable with the mean rates of natural karstic processes on the neighboring territories: the formation of karrens on Maya steles is generally proceeding at the rate of 0.04 mm/year, while the growth rates of flowstones within urban structures of limestone vary from 0.03 to 0.6 mm/year. 相似文献
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Anette Reenberg Peter Oksen Jannick Svendsen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):57-69
The paper deals with land use changes in semi arid Burkina Faso, specifically the issue of field encroachment on extensively used land. Some theoretical perspectives of field expansions in agricultural production systems characterised by crop-livestock interaction are discussed with reference to Boserup's theories on intensification. The empirical part provides documentation for the land use patterns and practices, based on aerial photos from 1978 and 1994 and village surveys. Answers are sought to some of the key questions presented by the ‘land use land cover change community’, i.e.: how has ‘land cover been changed by human land use?’—how do immediate human and biophysical dynamics affect the sustainability of specific types of land uses?—and how do land uses and land covers affect the vulnerability of land users in the face of change? Based on the findings, the paper proposes the notion of the expansion dilemma which questions the theory that agricultural expansion should always be perceived as a forerunner of intensification. 相似文献
13.
《Geography and Natural Resources》2008,29(3):256-262
An analysis is made of the geographical circumstances and factors of formation of a large urban agglomeration to unite the cities of Irkutsk, Angarsk and Shelekhov in the south of the Irkutsk region. The principles of delineating the agglomeration are formulated, which are used to single out different variants of the urban “Greater Irkutsk” agglomeration. A comparison is made of the characteristics of the agglomeration obtained in the different variants. 相似文献
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《地理学报(英文版)》1999,(4)
ThefoundingoftheChinaEarthScienceSociety(PredecessoroftheGeographicalSocietyofChina)in1909markedthegeographyinChinafromtheclassicalstagetothemodernstage.TheGeographicalSocietyofChinaisplayinganimportantroleinthedevelopmentofgeographyinChina.ThenewstageofthedevelopmentofgeographyhasbeenstartedinChinasincethe1950s.ItischaracterizedbytheestablishmentofinstitutesanddepartmentsofgeographyundertheChineseAcademyofSciencesandProvincialAcademies,attheuniversities,thegrowingupofnumerousyounggeog… 相似文献
15.
A. S. Zavadskii A. K. Il’yasov S. N. Ruleva V. V. Surkov L. A. Turykin R. S. Chalov 《Geography and Natural Resources》2013,34(1):26-33
We examine the transformation of a gentle segmental to a meander loop with the result that the city, founded in the 17th century, found itself on the caving bank. Comparison of cartographic materials from different times showed the occurrence of secondary bends on elongated rectilinear wings. Not only did such an evolution of the meanders lead to the caving of the terraced urban bank, but also it involved a likely emergency situation on the underwater crossing of the pipeline, and on other engineering facilities. We ascertained the causes of the ongoing channel deformations; modeling data were used in developing recommendations on meander straightening in order to divert the river away from the city. 相似文献
16.
We assessed the level of geomorphological risk associated with the occurrence of erosion processes on the western slope of the Tom’-Yaya interfluve (West-Siberian Plain). We suggest the technique for points-based risk assessment in technogenically modified and naturally occurring geomorphological systems. Using the Luchanovskii area as an example, we identified the zones of increased, moderate and low risk levels. 相似文献
17.
Runoff in the source region of a river makes up most of water resources in the whole basin in arid and semi-arid areas. It is very important for water resources management to timely master the latest dynamic changes of the runoff and quantitatively reveal its main driving factors. This paper aims to discover the variation heterogeneity of runoff and the impacts of climatic factors on this runoff in the source region of the Yellow River(SRYR) in China from 1961 to 2016. We divided SRYR into four sub-regions, and analyzed changes of their contributions to total runoff in SRYR. We also revealed the impacts of precipitation, temperature and potential evapotranspiration on runoff in each sub-region by constructing the regression relationships between them at multiple temporal scales. The changes of runoff in the four sub-regions and their contributions to the total runoff were not exactly consistent. The climatic variables’ changes also have heterogeneity, and runoff was mainly affected by precipitation compared to influences of temperature or potential evapotranspiration. Their impacts on runoff have spatiotemporal heterogeneity and can be reflected by very significant-linear regression equations.It provided a simple method to predict headwater runoff for better water management in the whole basin. 相似文献
18.
?ngstr?m-Prescott equation (AP) is the algorithm recommended by the Food and Agriculture Organization (FAO) of the United Nations for calculating the surface solar radiation (R_s) to support the estimation of crop evapotranspiration.Thus,the a_s and b_s coefficients in the AP are vital.This study aims to obtain coefficients a_s and b_s in the AP,which are optimized for China’s comprehensive agricultural divisions.The average monthly solar radiation and relative sunshine duration data at 121 stations from 1957–2016 were collected.Using data from 1957 to 2010,we calculated the monthly a_s and b_s coefficients for each subregion by least-squares regression.Then,taking the observation values of R_s from 2011 to 2016 as the true values,we estimated and compared the relative accuracy of R_s calculated using the regression values of coefficients a_s and b_s and that calculated with the FAO recommended coefficients.The monthly coefficients,a_s and b_s,of each subregion are significantly different,both temporally and spatially,from the FAO recommended coefficients.The relative error range (0–54%) of R_s calculated via the regression values of the a_s and b_s coefficients is better than the relative error range (0–77%) of R_s calculated using the FAO suggested coefficients.The station-mean relative error was reduced by 1%to 6%.However,the regression values of the a_s and b_s coefficients performed worse in certain months and agricultural subregions during verification.Therefore,we selected the a_s and b_s coefficients with the minimum R_(s )estimation error as the final coefficients and constructed a coefficient recommendation table for 36 agricultural production and management subregions in China.These coefficient recommendations enrich the case study of coefficient calibration for the AP in China and can improve the accuracy of calculating R_s and crop evapotranspiration based on existing data. 相似文献
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A. D. Kalikhman T. P. Kalikhman B. D. Sharastepanov 《Geography and Natural Resources》2011,32(2):172-178
Presented are the results from expedition-based investigations made by the Institute of Geography SB RAS, and an analysis
is made of the economic indices of development of the Okinsky district (Republic of Buryatia), which made it possible to draw
a preliminary conclusion about the formation of the ecological tourism structure on the territory of Gornaya Oka and provide
a rationale for the establishment of the “Gornaya Oka” natural park as a necessary and legislatively supported territory designed
for rational and controlled utilization of tourist and recreational resources. 相似文献
20.
James B. Elsner 《The Professional geographer》2013,65(4):559-560
Books reviewed: Bassin, Mark, Imperial Visions: Nationalist Imagination and Geographical Expansion in the Russian Far East, 1840 – 1865 Shortridge, James R., Our Town on the Plains: J. J. Pennell's Photographs of Junction City, Kansas, 1893 – 1922 Jakle, John A. and Sculle, Keith A., Fast Food: Roadside Restaurants in the Automobile Age Boeschenstein, Walter, Historic American Towns along the Atlantic Coast McKee, Jesse O., Ethnicity in Contemporary America: A Geographical Appraisal Luciuk, Lubomyr Y., Searching for Place: Ukrainian Displaced Persons, Ottawa, and the Migration of Memory Hausladen, Gary, Places for Dead Bodies Phillips, Richard, Watt, Diane and Shuttleton, David, De-Centering Sexualities: Politics and Representations beyond the Metropolis Goldin, Liliana R., Identities on the Move, Transnational Processes in North America and the Caribbean Basin McDonald, David A., On Borders: Perspectives on International Migration in Southern Africa Fox, Roddy and Rowntree, Kate, The Geography of South Africa in a Changing World Takeuchi, Keiichi, Modern Japanese Geography: An Intellectual History Amery, Hussein A., and Wolf, Aaron T., Water in the Middle East: A Geography of Peace Karl, Thomas R., Nicholls, Neville and Ghazi, Anver, Weather and Climate Extremes: Changes, Variations, and a Perspective from the Insurance Industry Pittman, Blair, Texas Caves 相似文献