135 research outputs found

    The impact of agricultural irrigation on land surface characteristics and near surface climate in China

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    It is well known that land cover and land use change can significantly influence the climate system by modulating surface-atmosphere exchanges. Land management, such as irrigation, also has a profound influence on the climate system. Irrigation can alter the water and energy flux from ground surface to the atmosphere and further influence near surface climate. Considering its dramatic expansion during the last century, the widespread use of irrigation has had an ongoing impact on our climate system. However, until now, this relationship between increased irrigation and its effect on climate system has not been well examined. The main objective of this dissertation is to quantify the irrigation impacts on land surface characteristics and near surface climate over China by using both observational (remote sensing and meteorological observation) and modeling studies with four specific questions: Where are the irrigated areas in China? What might have happened in the past? What will happen as a result of irrigation expansion in the future? And what is the relationship between the land cover land use change (LCLUC) impact and the irrigation impact on near surface climate in China? To answer these questions, I 1) developed three irrigation potential indices and produced a high resolution irrigation map of China; 2)analyzed and compared meteorological and remote sensing observations in irrigated and non-irrigated agriculture areas of China; 3) simulated both irrigation and LCLUC impact on land surface energy balance components (i.e., land surface temperature, latent flux, and sensible flux) and near surface climate (i.e., air temperature, water vapor, relative humidity) of China in the past (1978-2004) and also in two future time periods (2050 and 2100) by using the Community Land Model and compared the impact of irrigation with that of LUCC. Meteorological observations in Jilin Province show that the temperature differences between highly and lightly irrigated areas are statistically significant. The differences are highly correlated with the effective irrigation area (EIA) and sown area of crop (CSA). Results from satellite observations show that highly irrigated areas corresponded to lower albedo and daytime land surface temperature (LST), and higher normalized difference vegetation index (NDVI) and evapotranspiration (ET). The difference between highly and lightly irrigated areas is bigger in drier areas and in drier years. The modeling studies show that the irrigation impact on temperature is much less in the future than in the 20th century and that irrigation impacts more on the maximum air temperature than on the minimum air temperature. Both contemporary and future irrigation simulations show, nationally, irrigation decreases daily maximum temperature (Tmax) but increase daily minimum temperature (Tmin). Daily mean temperature (Tmean) decreases in contemporary irrigation simulations but increases in most of the cases in future irrigation simulations. In the 20th century, nationally, the spray irrigation leads to a decrease in Tmax of 0.079K and an increase in Tmin of 0.022K. Nationally, the spray irrigation leads to a decrease in Tmax between 0.022K and 0.045K and an increase in Tmin between 0.019K and 0.057K under future scenarios. This study demonstrates that the irrigation patterns (flood irrigation and spray irrigation) have statistically significant impacts on local climate. Moreover, this study suggests that, in the national respective, the impacts of changes in land management on climate are not comparable to the impacts of changes in land cover land use. This dissertation on irrigation and its impact is the first study which focuses solely on China using observational and modeling methods. The results from this dissertation contribute to a better understanding of the irrigation impact on near-surface climate which can improve our knowledge of how human activities influence climate, guide future policies aimed at mitigating or adapting to climate change, and help design a precise model to project the impact of irrigation on the climate system and irrigation requirements in the future. It can also be useful in assessing future food and water security issues

    Advanced Soil Moisture Predictive Methodology in the Maize Cultivation Region using Hybrid Machine Learning Algorithms

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    The moisture level in the soil in which maize is grown is crucial to the plant's health and production. And over 60% of India's maize cultivation comes from the states of South India. Therefore, forecasting the soil moisture of maize will emerge as a crucial factor for regulating the cultivation of maize crops with optimal irrigation. In light of this, this research provides a unique Improved Hybridized Machine Learning (IHML) model, which combines and optimizes several ML models (base learners-BL). The convergence rate of all the considered BL approaches and the preciseness of the proposed approach significantly enhances the process of determining the appropriate parameters to attain the desirable outcome. Consequently, IHML contributes to an improvement in the accuracy of the overall forecast. This research collects data from districts in South India that are primarily committed to maize agriculture to develop a model. The correlation evaluations served as the basis for the model's framework and the parameter selection. This research compares the outcomes of BL models to the IHML model in depth to ensure the model's accuracy. Results reveal that the IHML performs exceptionally well in forecasting soil moisture, comprising Correlation Coefficient (R2) of 0.9762, Root Mean Square Error (RMSE) of 0.293, and Mean Absolute Error (MAE) of 0.731 at a depth of 10 cm. Conceptual IHML models could be used to make smart farming and precise irrigation much better

    Sustainable Use of Soils and Water: The Role of Environmental Land Use Conflicts

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    This book on the sustainable use of soils and water addressed a variety of issues related to the utopian desire for environmental sustainability and the deviations from this scene observed in the real world. Competing interests for land are frequently a factor in land degradation, especially where the adopted land uses do not conform with the land capability (the natural use of soil). The concerns of researchers about these matters are presented in the articles comprising this Special Issue book. Various approaches were used to assess the (im)balance between economic profit and environmental conservation in various regions, in addition to potential routes to bring landscapes back to a sustainable status being disclosed

    Millions fed: Proven successes in agricultural development

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    Learning from successes in agricultural development is now more urgent than ever. Progress in feeding the world’s billions has slowed, while the challenge of meeting future food needs remains enormous and is subject to new uncertainties in the global food and agricultural systems. In the late 1950s around a billion people were estimated to go hungry every day. Scientists, policymakers, farmers, and ordinary people initiated a concerted push to boost agricultural production and productivity in developing countries. Great strides were also made in improving the quality of food and the ability of vulnerable people to access food needed for survival. All these efforts have done more than just feed millions. They have also demonstrated that agriculture can be a key driver of growth and development for many of the world’s poorest countries.Developing countries, Food prices, Poverty reduction, Hunger, malnutrition, Agricultural research, Agricultural technology, food security, Agricultural development, Climate change, Agricultural markets, Agricultural policies, Science and technology,

    Mapping Spatio-Temporal Cropland Changes Due To Water Stress In Krishna River Basin Using Temporal Satellite Data

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    Natural hazards namely droughts, floods, cyclones, hailstorms, volcanic eruptions, earth quakes, landslides, forest fire, locust outbreak etc, are common on the earth’s surface. Most of them are of climatic origin. Incidence of these hazards causes loss of human life, failure of crops and destruction of ecosystems. Consequently, the social as well as economic conditions of any region is disoriented. Natural hazards cannot be prevented but the loss can be minimized to some extent by taking appropriate disaster mitigation strategies. These strategies can be achieved by developing early warning systems and developing effective communication systems to take immediate action during the incidence of disasters, improving medical services and training to the people individually; how to react when disaster warning announced in a region, on their own without waiting for the help. Thus, disaster management includes warning, prevention, planning, preparedness, monitoring, and assessment and relief activity

    Earth Resources, A Continuing Bibliography with Indexes

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    This bibliography lists 460 reports, articles and other documents introduced into the NASA scientific and technical information system between July 1 and September 30, 1984. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economical analysis

    City regions of the People's Republic of China 1949-1959.

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    In contrast with the stagnation in city planning and development during the Nationalist regime, industrial urbanization began to accelerate soon after the Chinese Communist Party came to power in 1949. The central authorities promulgated the Suburban Agrarian Reform Law for acquiring and reserving land in designated suburban areas for future development. This law laid the foundation for China's long-term urban and suburban planning. However, throughout the First Five Year Plan period (1953-1957), many "key-point" industrial centres spread chaotically into the surrounding countryside. This was mainly attributed to legislative weaknesses in land allocation for capital construction and unplanned, or at best, improperly planned urban development, arising from indiscriminate emulation of Soviet model of city planning and development. One of the most serious consequences of urban sprawl was the extensive displacement of urban fringe agriculture, leading to acute shortage of vegetable supply in many large cities. To limit excessive expansion of cities in order to conserve valuable suburban farm land and to promote self-sufficiency in vegetable supply in the cities, a variety of remedial measures was introduced. The beginning of 1958 witnessed the institutionalisation of the urban-centred planning unit - the city region. Under this unified planning agency, the functions of the municipal authorities of the central city were centralized. The agricultural land use in the suburban districts was restructured. The urban population and economic activities were dispersed to the self-contained industrial satellites. Since 1959 all large urban centres in China have been encircled by an intensively cultivated horticultural zone, resembling the innermost circle of von Thunen's model. A case study of the suburban development in Shanghai is presented. The findings reveal that China's city region strategy has successfully accomplished socialist urban transformation of the city
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