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

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

Land Quality and Landscape Processes

This monograph contains a selection of scientific papers presented on the conference on Land Quality and Landscape Processes, hold in Keszthely, Hungary. It covers topics related to various aspects of land quality including : concepts of assessment; evaluation of biomass productivity ; bioindicators of land quality ; quality assessment of degraded land ; land use related data processingJRC.H.5-Land Resources Managemen

Presence and Dispersion of Organic and Inorganic Contaminants in Groundwater

This paper offers an extensive examination of studies published in the recent past and highlights the documented issues surrounding groundwater pollution, its sources, and distribution worldwide. The depletion of groundwater resources and the deteriorating overall quality present a significant cause for concern, particularly as a large human population relies on groundwater as a drinking water source. The review focuses on various factors contributing to groundwater pollution, including anthropogenic activities, hydro climatological influences, and natural processes. Special attention is given to organic contaminants such as pesticides, herbicides, and emerging pollutants, which have been found to have a substantial impact on groundwater quality. Additionally, the review covers pollution caused by inorganic pollutants like arsenic and other heavy metals, with a particular emphasis on regions experiencing a higher incidence of these contaminants in groundwater. Furthermore, the paper includes a compilation of studies that highlight the increased occurrence of waterborne illnesses resulting from fecal and microbial contamination, often caused by inadequate sanitary practices. To provide a comprehensive understanding of the global groundwater pollution problem, the review also encompasses an examination of contaminants like fluoride and nitrate

Spatio-temporal Analysis of Agriculture in the Vietnamese Mekong Delta using MODIS Imagery

New methodologies using MODIS time‒series imagery were developed for revealing spatio‒temporal changes of agricultural environments and land use patterns in the Vietnamese Mekong Delta. The following methodologies were proposed:a Wavelet based Filter for Crop Phenology (WFCP), a Wavelet‒based fi lter for evaluating the spatial distribution of Cropping Systems (WFCS), and a Wavelet‒based fi lter for detecting spatio‒temporal changes in Flood Inundation(WFFI). The WFCP algorithm involves smoothing the temporal profi le of the Enhanced Vegetation Index (EVI) using the wavelet transform approach. As a result of validation using the agricultural statistical data in Japan, it was shown that the WFCP was able to estimate rice growing stages, including transplanting date, heading date and harvesting date from the smoothed EVI data, with 9‒12 days accuracy(RMSE). The WFCS algorithm was developed for detecting rice‒cropping patterns in the Vietnamese Mekong delta based on WFCP. It was revealed that the spatial distribution of rice cropping seasons was characterized by both annual fl ood inundation around the upper region in the rainy season and salinity intrusion around the coastal region in the dry season. The WFFI algorithm was developed for estimating start and end dates of fl ood inundation by using time‒series Land Surface Water Index and EVI. Annual intensity of Mekong fl oods was evaluated from 2000 to 2004, at a regional scale. Applying a series of wavelet‒based methodologies to the MODIS data acquired from 2000 to 2006, it was confi rmed that the cropping season for the winter‒spring rice in the fl ood‒prone area fl uctuated depending on the annual change of fl ood scale. It was also confi rmed that the triple rice‒cropped area in the An Giang province expanded from 2000 to 2005, because the construction of a ring‒dike system and water‒resource infrastructure made it possible to sustain a third rice cropping season during the fl ood season. The proposed methodologies(WFCP, WFCS, WFFI) based on MODIS time‒series imagery made it clear that while the rice cropping in the Vietnamese Mekong Delta was quantitatively(annual fl ooding) and qualitatively(salinity intrusion) affected by water‒resource changes, there were some regions where the cultivation system was changed from double rice cropping to triple rice cropping because of the implementation of measures against fl ooding.日本の食料自給率 (2005年時の供給熱量ベース) は、40% と先進7カ国の中で最も低い。日本は、その食料海外依存度の高さから、世界的な食料価格の変動の影響を最も受け易い国と言える。近年の経済発展に伴う中国の大豆輸入量の増加や世界的なエネルギー政策の転換 (バイオエタノール政策) は、世界の穀物需給バランスを不安定にさせつつあり、世界的な問題となっている。さらに、地球温暖化による農業生産影響、増加し続ける世界人口、鈍化する穀物生産性を考えれば、世界の食料需給バランスが将来にわたって安定し続けると言うことはできないだろう。他方、食料増産・生産性向上を目的とした集約的農業の展開は、発展途上国の農業環境にさらなる負荷を与えるかもしれない。世界の食料生産と密接な関係にある日本は、自国の食料安全保障を議論する前提として、急速に変わり行く世界の農業生産現場やそれを取り巻く農業環境を客観的に理解し、世界の農業環境情報を独自の手法によって収集・整理する必要がある。そこで、筆者は、衛星リモートセンシング技術を活用することによって、地球規模の視点で、時間的・空間的な広がりを持って変わり行く農業生産活動とそれを取り巻く農業環境情報を把握・理解するための時系列衛星データ解析手法の確立を目指すこととした。本研究では、インドシナ半島南端に位置するベトナム・メコンデルタを調査対象領域とした。ベトナムは、タイに次ぐ世界第2位のコメ輸出国であり、その輸出米の9割近くが、ベトナム・メコンデルタで生産されたものである。筆者は、ベトナム・メコンデルタを世界の食料安全保障を考える上で重要な食料生産地帯の一つであると考え、本地域における農業環境及び土地利用パターンの時空間変化を明らかにするためのMODIS データを用いた新たな時系列解析手法の開発を行った。　本研究において提案する時系列解析手法は、次の三つである。1. Wavelet‒based Filter for Crop Phenology (WFCP) ,2. Wavelet‒based Filter for evaluating the spatial distribution of Cropping System (WFCS) , 3. Wavelet‒based Filterfor detecting spatio‒temporal changes in Flood Inundation (WFFI) . WFCP は、時系列植生指数 (EVI) を平滑化するためにウェーブレット変換手法を利用しており、日本の農業統計データを用いた検証結果から、水稲生育ステージ (田植日、出穂日、収獲日) を約9－12日 (RMSE) の精度で推定可能であることが示された。WFCP を基に改良されたWFCS は、水稲作付パターンの年次把握を可能にし、ベトナムメコンデルタにおける水稲作付時期の空間分布が、上流部において毎年雨期に発生する洪水と沿岸部において乾季に発生する塩水遡上によって特徴づけられていることを明らかにした。WFFI は、時系列水指数 (LSWI) と植生指数 (EVI) から、湛水期間、湛水開始日・湛水終息日を広域把握し、メコン川洪水強度の年次変化を地域スケールで評価することを可能にする。そして、ウェーブレット変換を利用した一連の手法を、2000～2006年までのMODIS 時系列画像に適用することによって、メコンデルタ上流部の洪水常襲地帯において、冬春米の作付時期が、年次変化する洪水規模に依存していることを明らかにした。また、An Giang 省において、堤防建設 (輪中) や水利施設の建設によって、洪水期における水稲三期作が可能になった地域が、2000～2005年にかけて拡大していることを明らかにした。本研究で提案したMODIS 時系列画像を利用した時系列解析手法 (WFCP、WFCS、WFFI) によって、ベトナムメコンデルタにおける水稲生産が水資源の量的 (洪水) ・質的 (塩水遡上) 変動影響を受ける一方、洪水対策の実施によって、栽培体系を二期作から三期作に変更している地域があることを明らかにした

Environmental assessment of imported organic products - focusing on orange juice from Brazil and soybeans from China

The import of organic products to Denmark has seen a four to five fold increase during the last seven years, due to a growing demand for organic products. Globally, the market for organic food and drinks has also more than doubled during the same period. The global organic agricultural land has concurrently expanded from 26 to 35 million hectares, mostly due to major conversions in Argentina, China, India, Australia, USA and Brazil. While Europe and North America still makes up the major markets for organic food and drink, the extraordinary growth in the organic markets offers export opportunities for both developed and developing countries. The production and export of organic products in developing countries might offer both economic and environmental benefits, though this has mainly been investigated in Europe and North America. However, long-distance trade with organic products has also given rise to a debate on the sustainability of this development especially with regard to global warming. Consumers of organic products might ask themselves what are the environmental benefits of buying organic products from e.g. South America or Asia as compared to conventional production and is this outweighed by the long-distance trade? The overall aim of the present PhD study was to assess the environmental impacts of selected imported organic products from developing countries based on impacts during both production (as compared to conventional) and during processing and transport to Denmark. Firstly, the global trade, development and overall environmental impacts of organic agriculture and food systems were investigated to form the foundation for the further analysis. Organic soybeans from China and orange juice from Brazil were selected as relevant case studies. Secondly, environmental life cycle assessments (LCA) were conducted for the case studies in China and Brazil focusing on comparing organic with conventional cultivation and on identifying environmental hotspots of the imported organic product during production, processing and transport to Denmark. Thirdly, LCA was evaluated as a tool for evaluating the environmental soundness of organic agricultural products and a new methodology on including of soil carbon sequestration in LCA was suggested. The PhD study shows that the increasing globalization affects both conventional and organic agriculture and food systems. Major environmental problems with regard to agriculture and food systems are identified as global warming, nutrient enrichment and pollution of water resources, reductions in biodiversity and soil degradation. The growing global trade and development within organic food and farming systems holds a potential to offer economic and environmental benefits for developing countries, but at the same time holds a risk of increasing the environmental load from long-distance transport and of pushing organic food and agricultural systems toward the conventional farming model and thereby diminishing the environmental benefits of organic farming. The case studies in China and Brazil show that the total greenhouse gas emissions associated with imported organic soybeans from China is 429 kg CO2 eq. per tonne soybean, whereas imported organic orange juice from small-scale farmers in São Paulo, Brazil is 424 g CO2 eq. per litre orange juice. Transport accounts for 50-60% of the total greenhouse gas emissions from the imported organic plant products. As a comparison, transport only account for 1-15% for imported meat products, since the greenhouse gas emissions per kg meat is a lot higher than for plant products. However, the actual contribution from transport is the same. The mode of transport is a determining factor in that truck transport has a much higher greenhouse gas emission per km than sea transport. Thus, sea transport from South America (reloaded to trucks in Rotterdam) is comparable to truck transport from Italy and France and lower than truck transport from Spain and sea transport from South Africa and China (also reloaded in Rotterdam) in terms of greenhouse gas emissions per kg imported product. It should be noted that greenhouse gas emissions from the agricultural production can vary (due to inputs, yields etc.) among countries and in some cases outweigh the emissions from transport. Comparing organic and conventional small-scale production until farm gate in the case studies, greenhouse gas emissions per kg organic product is found to be 60-75% of a comparable conventional production in the case study area. The nutrient enrichment (eutrophication) per kg organic product is 38-82% of a comparable conventional production whereas land use per kg organic product is 10-13% higher. Higher crop diversity is found on small organic compared to small conventional orange farms in Brazil, which may have a positive effect on biodiversity along with the absence of pesticides and the interrow vegetation. No differences are found in biodiversity potential in the Chinese case study except the absence of pesticides. Comparing large and small organic orange farms in Brazil, greenhouse gas emissions, eutrophication potential and copper use per hectare is found to be significantly lower on organic small-scale than on large-scale organic orange plantations. The shortcomings of LCA as a tool for evaluating environmental soundness of agricultural products, especially with regards to including biodiversity and soil carbon changes, are discussed. The studies in Brazil and China find that including estimated soil carbon changes widens the difference in greenhouse gas emissions per kg product between organic and conventional, but there is a need for methodological development on how to estimate and include this. A methodological approach to include soil carbon changes in LCA is suggested

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

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

The biophysical effects of potential changes in irrigated crops on diurnal land surface temperature in Northeast China

Irrigated crops have experienced a significant global expansion. The biophysical response of climate change to irrigated crop expansion in different regions, particularly in terms of monitoring the influence mechanism of nighttime land surface temperature (LST) change, however, remains insufficiently explored. Taking the three northeastern provinces of China as our study area, we apply window analysis, partial correlation analysis, and geographical detector to quantitatively characterize the spatial and temporal distribution pattern of daytime and nighttime LST (diurnal LST) and biophysical parameters, and the main driving mechanism of diurnal LST change. The results showed that irrigated crop expansion led to asymmetric changes in daytime (−2.11 ± 0.2°C, 97.4%) and nighttime (0.64 ± 0.2°C, 79.9%) LST. ΔLSTDT had a negative correlation with ΔLE (63%), but a positive correlation with ΔSSR and ΔH (91% and 77%). This revealed that the cooling effect caused by the superposition of the output latent heat flux and the absorbed solar shortwave radiation was greater than its heating effect. ΔLSTNT and ΔLE had a positive connection across 69% of the region. ΔLSTNT demonstrated a negative correlation with ΔSSR and ΔH in 82% and 75% of the regions, respectively. At this time, the superposition of latent heat flux and heating potential term produces a greater heating effect. The explanatory power of the single factor (the mean of q<0.50) of biophysical parameters for diurnal LST variation was significantly smaller than that of the interaction factor (the mean of q>0.50, p<0.01). This study shows more detailed dynamic information of diurnal LST and biophysical parameters from 8day scale. The findings highlighted the critical role of asymmetric changes in the diurnal surface thermal environment caused by irrigated crop expansion in the global climate from a land surface hydrothermal energy balance perspective

Implementing an Agro-Environmental Information System (AEIS) Based on GIS, Remote Sensing, and Modelling -- A case study for rice in the Sanjiang Plain, NE-China

Information on agro-ecosystems is crucial for understanding the agricultural production and its impacts on the environment, especially over large agricultural areas. The Sanjiang Plain (SJP), covering an area of 108 829 km², is a critical food base located in NE-China. Rice, soya bean and maize are the major crops in the SJP which are sold as commercial grain throughout China. The aim of this study is to set up an Agro-Environmental Information System (AEIS) for the SJP by employing the technologies of geographic information systems (GIS), remote sensing (RS), and agro-ecosystem modelling. As the starting step, data carrying interdisciplinary information from multiple sources are organized and processed. For an AEIS, geospatial data have to be acquired, organized, operated, and even regenerated with good positioning conditions. Georeferencing of the multi-source data is mandatory. In this thesis, high spatial accuracy TerraSAR-X imagery was used as a reference for georeferencing raster satellite data and vector GIS topographic data. For the second step, the georeferenced multi-source data with high spatial accuracy were integrated and categorized using a knowledge-based classifier. Rice was analysed as an example crop. A rice area map was delineated based on a time series of three high resolution FORMOSAT-2 (FS-2) images and field observed GIS topographic data. Information on rice characteristics (i.e., biomass, leaf area index, plant nitrogen concentration and plant nitrogen uptake) was derived from the multi-temporal FS-2 images. Spatial variability of rice growing status on a within-field level was well detected. As the core part of the AEIS, an agro-ecosystem modelling was then applied and subsequently crops and the environmental factors (e.g., climate, soil, field management) are linked together through a series of biochemical functions inherent in the modelling. Consequently, the interactions between agriculture and the environment are better interpreted. In the AEIS for the SJP, the site-specific mode of the DeNitrification-DeComposition (DNDC) model was adapted on regional scales by a technical improvement for the source code. By running for each pixel of the model input raster files, the regional model assimilates raster data as model inputs automatically. In this study, detailed soil data, as well as the accurate field management data in terms of crop cultivation area (i.e. rice) were used as model inputs to drive the regional model. Based on the scenario optimized from field observation, rice yields over the Qixing Farm were estimated and the spatial variability was well detected. For comparison, rice yields were derived from multi-temporal FS-2 images and the spatial patterns were analysed. As representative environmental effects, greenhouse gas of nitrous oxide (N2O) and carbon dioxide (CO2) emitted from the paddy rice fields were estimated by the regional model. This research demonstrated that the AEIS is effective in providing information about (i) agriculture on the region, (ii) the impacts of agricultural practices on the environment, and (iii) simulation scenarios for sustainable strategies, especially for the regional areas (e.g. the SJP) that is lacking of geospatial data