The impacts of climate change on wheat yield in the Huang-Huai-Hai Plain of China using DSSAT-CERES-Wheat model under different climate scenarios

Climate change has been documented as a major threat to current agricultural strategies.Progress in understanding the impact of climate change on crop yield is essential for agricultural climate adaptation,especially for the Huang-Huai-Hai Plain(3H Plain)of China which is an area known to be vulnerable to global warming.In this study,the impacts of climate change on winter wheat(Triticum aestivum L.)yield between the baseline period(1981–2010)and two Representative Concentration Pathways(RCP8.5 and RCP4.5)were simulated for the short-term(2010–2039),the medium-term(2040–2069)and the long-term(2070–2099)in the 3H Plain,by considering the relative contributions of changes in temperature,solar radiation and precipitation using the DSSAT-CERES-Wheat model.Results indicated that the maximum and minimum temperatures(TMAX and TMIN),solar radiation(SRAD),and precipitation(PREP)during the winter wheat season increased under these two RCPs.Yield analysis found that wheat yield increased with the increase in SRAD,PREP and CO2 concentration,but decreased with an increase in temperature.Increasing precipitation contributes the most to the total impact,increasing wheat yield by 9.53,6.62 and 23.73%for the three terms of future climate under RCP4.5 scenario,and 11.74,16.38 and 27.78%for the three terms of future climate under RCP8.5 scenario.However,as increases in temperature bring higher evapotranspiration,which further aggravated water deficits,the supposed negative effect of increasing thermal resources decreased wheat yield by 1.92,4.08 and 5.24%for the three terms of future climate under RCP4.5 scenario,and 3.64,5.87 and 5.81%for the three terms of future climate under RCP8.5 scenario with clearly larger decreases in RCP8.5.Counterintuitively,the impacts in southern sub-regions were positive,but they were all negative in the remaining sub-regions.Our analysis demonstrated that in the 3H Plain,which is a part of the mid-high latitude region,the effects of increasing thermal resources were counteracted by the aggravated water deficits caused by the increase in temperature.

Proton accumulation accelerated by heavy chemical nitrogen fertilization and its long-term impact on acidifying rate in a typical arable soil in the Huang-Huai-Hai Plain

Cropland productivity has been significantly impacted by soil acidification resulted from nitrogen （N） fertilization, especially as a result of excess ammoniacal N input. With decades＇ intensive agricultural cultivation and heavy chemical N input in the Huang-Huai-Hai Plain, the impact extent of induced proton input on soil pH in the long term was not yet clear. In this study, acidification rates of different soil layers in the soil profile （0-120 cm） were calculated by pH buffer capacity （pHBC） and net input of protons due to chemical N incorporation. Topsoil （0-20 cm） pH changes of a long-term fertilization field （from 1989） were determined to validate the predicted values. The results showed that the acid and alkali buffer capacities varied significantly in the soil profile, averaged 692 and 39.8 mmolc kg-1 pH-1, respectively. A significant （P〈0.05） correlation was found between pHRC and the content of calcium carbonate. Based on the commonly used application rate of urea （500 kg N ha-1 yr-1）, the induced proton input in this region was predicted to be 16.1 kmol ha-1 yr-1, and nitrification and plant uptake of nitrate were the most important mechanisms for proton producing and consuming, respectively. The acidification rate of topsoil （0-20 cm） was estimated to be 0.01 unit pH yr-1 at the assumed N fertilization level. From 1989 to 2009, topsoil pH （0-20 cm） of the long-term fertilization field decreased from 8.65 to 8.50 for the PK （phosphorus, 150 kg P205 ha-1 yr-1; potassium, 300 kg K20 ha-1 yr-1; without N fertilization）, and 8.30 for NPK （nitrogen, 300 kg N ha-1 yr-1; phosphorus, 150 kg P2Os ha-1 yr-1; potassium, 300 kg K20 ha -1 yr-1）, respectively. Therefore, the apparent soil acidification rate induced by N fertilization equaled to 0.01 unit pH yr-1, which can be a reference to the estimated result, considering the effect of atmospheric N deposition, crop biomass, field management and plant uptake of other nutrients and cations. As protons could be consumed by some field practices, such as stubble return and coupled water and nutrient management, soil pH would maintain relatively stable if proper management practices can be adopted in this region.

Water consumption in summer maize and winter wheat cropping system based on SEBAL model in Huang-Huai-Hai Plain, China

Crop consumptive water use is recognized as a key element to understand regional water management performance. This study documents an attempt to apply a regional evapotranspiration model（SEBAL） and crop information for assessment of regional crop（summer maize and winter wheat） actual evapotranspiration（ET a） in Huang-Huai-Hai（3H） Plain, China. The average seasonal ET a of summer maize and winter wheat were 354.8 and 521.5 mm respectively in 3H Plain. A high-ET a belt of summer maize occurs in piedmont plain, while a low ET a area was found in the hill-irrigable land and dry land area. For winter wheat, a high-ET a area was located in the middle part of 3H Plain, including low plain-hydropenia irrigable land and dry land, hill-irrigable land and dry land, and basin-irrigable land and dry land. Spatial analysis demonstrated a linear relationship between crop ET a, normalized difference vegetation index（NDVI）, and the land surface temperature（LST）. A stronger relationship between ET a and NDVI was found in the metaphase and last phase than other crop growing phase, as indicated by higher correlation coefficient values. Additionally, higher correlation coefficients were detected between ET a and LST than that between ET a and NDVI, and this significant relationship ran through the entire crop growing season. ET a in the summer maize growing season showed a significant relationship with longitude, while ET a in the winter wheat growing season showed a significant relationship with latitude. The results of this study will serve as baseline information for water resources management of 3H Plain.

Temperature and Precipitation Suitability Evaluation for the Winter Wheat and Summer Maize Cropping System in the Huang-Huai-Hai Plain of China

The Huang-Huai-Hai Plain is the most important winter wheat and maize production region in China.In response to the increasing population pressure,the Chinese authorities strongly invested in improving the irrigation systems and increasing ground and surface water exploitation within the plain to increase the crop productivity.This resulted in a reduction of water resource availability and in turn indirectly affected the suitability of various agricultural ecosystems in the plain.The main purpose of this study was to review the suitability of temperature and precipitation for the winter wheat and summer maize cropping system in the Huang-Huai-Hai Plain,in order to provide a preliminary irrigation scheme.This analysis provides a first attempt to enhance the water resource management as well as to increase the water use efficiency.For this aim,a GIS-based multicriteria analysis procedure has been developed consisting of（1） definition of objectives（evaluated entities） and database building;（2） definition of evaluation criteria;（3） standardization of the criteria;（4） combination of the criteria;（5） classification of the objectives;and（6） integration of the objectives.The land suitability classification maps were transformed into maps of required irrigation amounts for each growing stage of the winter wheat and summer maize cropping system.The study also exemplified the limitations and proposed future research activities that will improve the detail and accuracy of the evaluation results.

Spatiotemporal variation of drought characteristics in the Huang- Huai-Hai Plain, China under the climate change scenario

Understanding the potential drought characteristics under climate change is essential to reduce vulnerability and establish adaptation strategies, especially in the Huang-Huai-Hai Plain （3H Plain）, which is a major grain production area in China. In this paper, we investigated the variations in drought characteristics （drought event frequency, duration, severity, and intensity） for the past 50 years （1961-2010） and under future scenarios （2010-2099）, based on the observed meteorological data and the Representative Concentration Pathway （RCP） 8.5 scenario, respectively. First, we compared the applicability of three climatic drought indices： the standardized precipitation index （SPI）, the standardized precipitation evapotranspiration index based on the Penman-Monteith equation （SPEI-PM） and the same index based on the Thornthwaite equation （SPEI-TH） to correlate the recorded agricultural drought areas. Then, we analyzed the drought characteristics using ＇run theory＇ for both historical and the future RCP 8.5 scenario based on the best performing index. Correlation analyses between drought indices and agricultural drought areas showed that SPEI-PM performed better than SPI and SPEI-TH in the 3H Plain. Based on the results of SPEI-PM, drought risks including duration, severity and intensity during 1961-2010 showed an decreasing trend. However, under the RCP 8.5 scenario, drought is expected to rise in frequency, duration, severity, and intensity from 2010-2099, although drought components during the 2010-2039 are predicted to be milder compared with historical conditions. This study highlights that the estimations for atmospheric evaporative demand would create differences in the prediction of long-term drought trends by different drought indices. The results of this study can help inform researchers and local policy makers to establish drought management strategies.

Acid and Alkali Buffer Capacity of Typical Fluvor-Aquic Soil in Huang-Huai-Hai Plain

Soil acid and alkali buffer capacity, as a major indicator for evaluating its vulnerability and resistibility to acidification and alkalization, is an important factor affecting the sustainable agriculture, through knowledge on which soil acidification process can be predicted and modified. In this study, titration curve method was adopted to investigate the pH buffer capacity （pHBC） of fluvor-aquic soil, and separate titration curves were established by adding incremental amounts of either standardized hydrochloric acid （HC1） （0.12 mol L^-1） or sodium hydroxide （NaOH） （0.10 mol L^-1） to soil suspended in deionized water （soil：solution = 1：5）. Soil pH was measured after 7 d resuspension and isothermal equilibrium （T = 25℃）. Linear regressions were fitted to the linear portion of each titration curve and the slopes of these lines were derived as the soil pHBC. The results showed that significant correlations between the amounts of adding acid or alkali and each pH change were presented, and titration curve method was feasible for measurement of pHBC on typical fluvor-aquic soil in Huang-Huai-Hai Plain, and the coefficients of determination were higher than the similar researches on acid soil （R^2 = 0.96）. The slope-derived pHBC of acid and alkali were 158.71 and 25.02 mmol kg^-1, respectively. According to the classification of soil buffer systems, the soil tested belongs to the calcium carbonate buffer system, carbonates contribute the most to pHBC, and the contribution of soil organic matter relatively less than it.

A Study on the Driving Factors of Food Production in Huang-Huai-Hai Plain Based on Path Analysis

The effects of 14 factors on food production in Huang-Huai-Hai Plain are analyzed by path analysis in this paper,and then the linear regression models of them are established by SPSS software. The results show that electricity consumption for agriculture,growing area of crops,the affected area,annual average temperature and arable land area at the end of the year have great effects on food production. Finally some recommendations are put forward to improve the food production in Huang-Huai-Hai Plain such as improving the level of agricultural mechanization,stabilizing food production,preventing natural disasters and increasing the effective irrigation area.

Effect of water fluctuation on agricultural production in the Huang-Huai-Hai Plain, China

The biggest load of water resources for agricultural economy in the Huang-Huai Plainwill only arcount for 67.1 % of the forecasted irrigated area in 2010. The irrigated area and thequantity of water diverting from the Huanghe River was 2.2 million hm2 and 10.8 billion m3respectively in the lowe reaches of the river in the 1990s. The annual amount of yield increase forgrain is 6.3 billion kg calculated by converting and the annual benefit of yield-increase is 4.4 billionRMB yuan in the irrigated area of the region. The daily economic losses of industry and agricultureby absence of flow in the area in the 1990s is 44. 1 million RMB yuan. The annual water quantity willbe increased by 9.9 billion m3 after diverting water from the Huanghe River and 12.6 billion m3 afterdiverting water from the Changjiang River respectively in the plain in 2010.

未来气候变化对黄淮海冬小麦-夏玉米轮作系统生产力影响

揭示未来气候变化对黄淮海平原冬小麦-夏玉米轮作系统作物物候和产量的影响,对保障我国粮食安全具有重要意义。本研究基于文献收集的多站点多年份大田试验数据来校准和验证APSIM-Wheat和APSIM-Maize模型,并结合CMIP6数据集10个全球气候模型(Global climate models,GCMs)预测的未来气象数据,驱动校准验证后的APSIM模型,模拟分析了SSP2-4.5和SSP5-8.5两种温室气体排放情景下黄淮海地区冬小麦-夏玉米轮作系统在2021—2060年(2040s)和2061—2100年(2080s)作物物候期和产量的变化情况。基于多元线性回归方法分析其变化趋势,并结合随机森林(Random forest,RF)模型分析了气候要素与作物生殖生长期变化对作物产量的正负效应及其重要性。结果表明:与基准期(1981—2020年)相比,冬小麦营养生长期总体缩短,生殖生长期总体延长,产量增加,且在SSP5-8.5情景下变化更明显;与基准期相比,夏玉米营养生长期、生殖生长期都将缩短,产量增加,但相较于SSP2-4.5,夏玉米在SSP5-8.5情景下出现减产趋势;与SSP2-4.5相比,在SSP5-8.5情景下冬小麦-夏玉米轮作系统的周年全生育期缩短,周年总产量增加,且冬小麦产量占比有所增加。在未来时段,冬小麦产量主要与生育期内太阳辐射、日均温及累计降雨量之间呈正相关关系,但日均温及累计降雨量的增加不利于在SSP5-8.5情景下2080s时间段内实现冬小麦增产;夏玉米产量与气象因子的相关性与冬小麦类似,但夏玉米产量始终与日均温直接呈显著负相关。通过随机森林模型分析可知,冬小麦生殖生长期、生育期内累计降雨量对冬小麦产量影响最大;夏玉米生育期内CO_(2)浓度、日均温及累计降雨量对夏玉米产量影响最大。总体上,未来气候变化将导致黄淮海地区冬小麦生殖生长期延长,夏玉米生殖生长期缩短,产量增加;但随着时间推移,温度及降雨量对作物产量的正效应会逐渐转变为负效应,导致夏玉米在SSP5-8.5情景下2080 s时间段内出现减产趋势,可见未来作物产量变化主要取决于气候因子对作物产量的正效应与作物生长期缩短的负效应的共同作用结果,而非单一因素所决定。本研究可为黄淮海地区冬小麦-夏玉米轮作系统作物生产及应对未来气候变化影响提供科学依据和理论指导。

基于SPEI-PM指数的黄淮海平原干旱特征分析

利用黄淮海平原45个气象站点1961—2014年月值气象数据,基于Penman-Monteith蒸散模型计算了标准化降水蒸散指数(SPEI),对黄淮海平原近54年干旱变化趋势、发生频率和持续性特征进行了分析,并探讨了SPEI指数与河南、河北和山东省农业干旱面积的关系,结果表明:(1)改用Penman-Monteith蒸散公式后,SPEI干旱指数在黄淮海平原呈整体上升趋势,即趋于湿润;(2)近54年干旱演变具有明显的年代际差异,20世纪60年代干旱频率最高,而21世纪初(2000—2014)干旱频率整体偏低;(3)黄淮海平原干旱发生具有持续性的特点,20世纪60年代遭受的持续性干旱最为严重,平均干旱持续时长约2.6个月,21世纪初下降到1.5个月;(4)河南、河北和山东省的农业干旱面积年际变化表明,干旱面积呈减少趋势,2000年以后年均受灾面积、成灾面积和绝收面积比2000年之前分别下降了58.0%、44.4%和49.1%;(5)农业干旱面积与SPEI具有中等以上的相关强度,其中对山东省受灾、成灾和绝收面积相关系数r达到-0.7以上,表明基于Penman-Monteith蒸散模型的SPEI指数在黄淮海平原具有良好的适用性。

2004-2005年黄淮海地区冬小麦冻害成因分析

以北京、天津、菏泽、驻马店、商丘、阜阳6个站点为代表,分析了黄淮海平原2004-2005年冬季冬小麦的冻害成因。研究表明,冬小麦冻害的发生主要是由于从小麦播种至当年12月20日积温过高,造成部分麦田在入冬前就完成了6-8片叶的生长,甚至进入了拔节期,再加上从当年12月20日至次年2月底黄淮海大部分地区气温比常年偏低1.3℃左右,且冷暖交替突变,麦苗抗寒锻炼不足,春性品种过多和播种量过大等原因。

黄淮海平原浅层地下水中NO_3-N含量的空间变异与分布特征

通过GPS定位取样分析和GIS处理 ,研究了黄淮海平原浅层地下水中NO3-N含量的空间变异和分布特征。结果表明 ,黄淮海平原浅层地下水中NO3-N含量在 35～ 5 0km的取样密度下 ,没有半方差结构 ,各取样点之间变异性较大 ;黄淮海平原有 10 %的面积浅层地下水中NO3-N含量超过 2 0mg·L-1,主要分布在天津至济南一线和淮河流域的新蔡、阜阳和蚌埠一带。徐州至连云港一带的苏北地区及山东的潍坊地区 ,浅层地下水中的NO3-N含量一般在 10～ 2 0mg·L-1之间 ,约占黄淮海平原总面积的 11 5 %。浅层地下水中NO3-N的含量与地下水埋深密切相关 ,NO3-N含量超过 2 0mg·L-1的地下水埋深一般在 3m以上 ,地下水埋深在 10m以下时 ,其中的NO3-N含量均不超过 10mg·L-1。这表明 ,目前通过土壤NO3-N的淋失对该区地下水中NO3-N含量影响深度一般不超过 10m。此项研究结果对于黄淮海平原持续发展 ,制定优化的高效水肥管理措施和方案有一定指导意义。

1961-2013年黄淮海平原降蒸差的时空变化特征

基于黄淮海平原41个气象站点1961-2013年逐日气象数据,利用Penman-Monteith公式计算潜在蒸散量,采用降水量与潜在蒸散量差值即降蒸差表征区域水分盈亏状况,结合Arc GIS地统计分析、趋势分析及Morlet小波分析,探讨黄淮海平原各季降蒸差的时空变化特征。结果表明：黄淮海平原降蒸差呈南北差异分布,在-650~100mm区间变化,南部高于北部。夏季降蒸差最高,秋、冬季次之,春季水分亏缺最严重,多年平均亏缺量为210.61mm,远高于其它季节。站点季节降蒸差的年际变化总体呈上升趋势。各农业亚区蒸散量差异不大,降蒸差差异主要由降水导致,鲁西平原鲁中丘陵水浇地旱地二熟区（Ⅵ区）降蒸差最高,为-21.63mm,海河低平原缺水水浇地二熟兼旱地一熟区（Ⅲ区）最低,为-560.42mm。6个亚区春季水分亏缺量分别占区域年总亏缺量的56.4%、51.7%、40.6%、59.7%、59.3%和66.1%。周期分析表明,黄淮海平原Ⅰ-Ⅳ各农业亚区春季降蒸差变化主周期皆为28a,黄淮平原南阳盆地水浇地旱地二熟区和江淮平原丘陵麦稻两熟区（Ⅴ和Ⅵ区）为10a,未来一段时间春季降蒸差将处于偏低期。黄淮海平原水分亏缺量季节性差异较大,干旱发生风险较高,尤以春旱发生频率较高。

耕地土壤重金属污染时空变异对比--以黄淮海平原和长江中游及江淮地区为例

搜集已发表文献中位于黄淮海平原、长江中游及江淮地区耕地土壤重金属数据,利用单因子指数法和内梅罗综合指数法评价耕地表层土壤重金属污染程度,分析农区耕地、城郊耕地、工矿附近耕地和污灌区耕地重金属污染现状;并结合1980s土壤普查数据,分析1980s～2000s期间研究区的时空变异特征.结果表明:(1)研究区耕地污染重金属处于安全水平,黄淮海平原80%以上和长江中游及江淮地区60%以上的点位处于清洁范围.(2)长江中游及江淮地区的重金属污染比黄淮海平原严重.单因子评价结果表明长江中游及江淮地区耕地土壤重金属污染点位超标率为35.02%,是黄淮海平原(15.97%)的2倍;内梅罗评价结果显示两区污染比例分别为20.29%和13.17%,前者的轻度和重度污染比例均大于后者,其重度污染比重约是后者的3倍.(3)研究区不同区位污染比重从大到小依次为工矿附近耕地、污灌区耕地、农区耕地和城郊耕地.(4)1980s～2000s期间,重金属污染呈增加趋势,黄淮海平原Cd、Zn、Hg、As和长江中游及江淮地区Cd、Ni、Zn、Cu、Hg、As超标点位比例分别增加:12.78%、6.34%、1.98%、0.91%和14.02%、11.36%、7.28%、5.49%、1.93%、0.72%;污染加剧主要分布在天津、河北沧州、山东济南和湖南岳阳等地.城镇化、工业化以及农业发展进程中,黄淮海平原和长江中游及江淮地区耕地土壤正面临着重金属污染的威胁,需对严重污染区域采取有效措施,防治重金属污染.

基于NDVI的黄淮海平原2001-2010年植被覆盖变化分析

基于黄淮海平原2001-2010年MODIS-NDVI数据集,结合同时期的降水数据、土地利用数据和植被盖度数据,利用相关系数法、差值法和趋势影响法,得出NDVI的变化趋势及其驱动力,分析了黄淮海平原2001-2010年的植被覆盖变化。结果表明:年总降水量与年均NDVI呈较高相关性的区域只在黄淮海平原的林地和草地得以体现,相关系数R达到0.72~0.86,而其他区域表现为不相关;黄淮海平原植被盖度总体呈上升趋势;不同植被覆盖类型中,农业用地的年均NDVI差值变化最小;土地利用转移和植被盖度变化是影响黄淮海平原植被覆盖变化的主要因素。

Land use transitions and their dynamic mechanism: The case of the Huang-Huai-Hai Plain

Land use transition refers to changes in land use morphology, including dominant morphology and recessive morphology, of a particular region over a period of time driven by various factors. Recently, issues related to land use transition in China have attracted interest among a wide variety of researchers as well as government officials. This paper examines the patterns of land use transition and their dynamic mechanism in the Huang-Huai-Hai Plain during 2000-2010. First, the spatio-temporal patterns of land use transition, their character- istics and the laws governing them were analyzed. Second, based on the established con- ceptual framework for analyzing the dynamic mechanism of land use transition, a spatial econometric regression analysis method was used to analyze the dynamic mechanism of the five types of major land use transition in the Huang-Huai-Hai Plain at the county level. Land use pattern changes in the study area were characterized by an increase in construction land, water body and forested land, along with a decrease in farmland, unused land and grassland. The changes during 2000-2005 were much more significant than those during 2005-2010. In terms of factors affecting land use transitions, natural factors form the basis, and they have long-term effects. Socio-economic factors such as population and GDP, however, tend to determine the direction, structure, size and layout of land use transition over shorter time periods. Land law and policy factors play a mandatory guiding and restraining role in land use transitions, so as to improve the overall efficiency of land use. Land engineering is also an important tool to control land use transitions. In general, the five types of major land use transition were the result of the combined action of various physical, social and economic factors, of which traffic condition and location condition had the most significant effects, i.e. they were the common factors in all land use transitions. Understanding the spatio-temporal process of land use transitions and their dynamic mechanisms is an important foundation for utilizing land resources, protecting regional ecological environment and promoting sustain- able regional socio-economic development.

基于径流-蒸散发-蓄水量协同率定的平原区水文模拟研究

平原区无统一流域出口断面,相关模型参数率定与水文模拟是水文学研究的薄弱环节和难点问题。以黄淮海平原为研究对象,基于实测数据、遥感反演结果及同化的区域水循环通量和储量等多源要素数据集,利用可变下渗容量(VIC)模型,构建了基于径流、蒸散发和蓄水量协同率定的模型参数率定方法,评估了其在黄淮海平原水文模拟中的适用性,并利用机器学习、广义似然不确定性估计等方法分析了该模型对水文模拟精度、模型参数异参同效性和径流模拟不确定性等方面的改进效果。得到的主要结论为:①VIC模型在黄淮海平原具有较好的适用性,与实测值相比,模拟径流和蒸散发量在率定期的相关系数大于0.9,蓄水量的相关系数大于0.6;②对于VIC模型的6个参数,第2层土壤厚度d 2最敏感,其次是可变下渗曲线指数B,其余参数敏感性较弱;③与传统的单一径流率定方法相比,参数协同率定方法提高了蒸散发量和蓄水量的模拟精度,减小了模型参数的优选空间与不确定性置信区间,模拟径流的90%置信区间约缩小26%,降低了水文模拟的不确定性。研究成果对水文模拟技术进步具有重要的支撑作用。

Exploring the urban-rural development differences and influencing factors in the Huang-Huai-Hai Plain of China

Uneven urban and rural development is one of the main reasons for the decline of the countryside.This imbalance could be measured by the urban-rural difference index(URDI).Existing studies on urban-rural differences have focused on single dimension between urban and rural areas,and lack a systematic multi-dimensional measurement.Based on the construction of an index system and model for measuring urban-rural differences,this study took the Huang-Huai-Hai Plain(HHHP)as the study area,explores the spatial pattern of urban-rural differences in the area,and used geographical weighted regression models to identify the factors affecting urban-rural development differences.Results show that the mean value of URDI in the HHHP was 0.295,and the URDI in its western region was higher than that in the east.The average URDI was relatively high in the western counties along the Beijing–Guangzhou Railway.The low level of urban-rural'population-land-industry'development in the HHHP is an important reason for the small differences between urban and rural areas.Improvements in road transportation infrastructure have led to an increase in the urban-rural development gap.However,the driving force of the road network on urban development is greater than that on rural areas.The role of county economic agglomeration is gaining strength.In the process of rapid economic development,more attention should be paid to the development of the rural economy and the overall revitalization of the countryside.The equivalent allocation of social service facilities is an effective way to solve the problem of urban-rural imbalance.Further analysis demonstrated that terrain factors have relatively little influence on the URDI.This study provides a new perspective and measurement method for understanding the integration of urban and rural development,and provides a useful reference for guiding the urban-rural integration development and the rural revitalization.

TWO-WAY SIMULATIONS FROM REGCM2 COUPLING WITH SUCROS IN THE HUANG-HUAI-HAI-PLAIN IN EAST CHINA

A two-way coupling simulation from the NCAR's regional climate model REGCM2 (called R-2 hereafter) and the SUCROS model for crop growth developed by the Wageningen Agricultural University,the Netherlands (both models,when in combination,denoted as R/S) are carried out on the interactions between crops and atmosphere in the Huang-Huai-Hai Plain in East China. Evidence suggests that the R/S simulations can depict pretty well the dynamic biology-based interactions between the factors,revealing reasonably both the day-to-day variations in leaf area index (LAI) and land surface physics therein,and particularly the improvement of the simulation, independently by use of the R-2,of summer precipitation and surface temperature in the research region.As a result,the present research is of significance to the further understanding of the interaction between the climate system and the terrestrial ecological systems.

封丘县典型农田土壤质量与时空变化特征

黄淮海平原作为我国重要的粮食产区,系统全面地评价该区域典型潮土的质量变化,对指导农业生产具有重要意义。以典型潮土分布的封丘县作为研究区,选取1984、2003和2011年的17项土壤指标,基于土壤参与生态过程中作物生产、碳固存、持水净化和养分运移等功能,构建土壤综合质量评价系统,采用主成分分析结合逼近理想点排序法(TOPSIS)计算各功能得分及土壤质量综合指数,通过GIS空间插值描述封丘县27年内潮土耕作区土壤质量和功能的时空变化特征。结果表明:(1)封丘县土壤全氮、全磷、碱解氮、有效磷、速效钾和有机质含量及阳离子交换量、饱和导水率和孔隙度均呈现不同程度的提升趋势;全钾含量、pH、容重、田间持水量和有效含水量则呈逐年降低趋势;(2)封丘县土壤作物生产、碳固存和养分运移功能得分均有所提升,增长率分别为9.29%、9.68%和7.36%,持水净化功能得分则降低4.17%;(3)封丘县土壤质量综合指数提升较为明显,1984年全县耕地土壤质量综合指数均≤2.0,2003年综合指数>2.0的耕地面积占全县总面积的8.44%,2011年提升至24.05%。整体而言,封丘县该时期的耕地保护和利用模式基本是有效的,封丘县耕地整体质量不断向好的方向发展,相关结果可以为黄淮海地区耕地资源可持续利用提供参考。