气候变化对黄土丘陵沟壑区植被净第一性生产力的影响模拟

以黄土丘陵沟壑区典型小流域纸坊沟流域为例,利用当前气候状况和不同气候情景下的气象数据驱动植被净第一性生产力模型VSIM,模拟气候变化对黄土丘陵沟壑区植被净第一性生产力（NPP）的影响.结果表明：（1）流域NPP对温度升高比对降雨变化的反应更为敏感,土壤水分状况受降雨变化影响显著,温度升高后流域土壤水分也明显下降.（2）草本和半灌木群落的NPP由于温度升高降低最多,沙棘灌丛的NPP受降雨变化影响最为明显,而刺槐林、苹果林和柠条灌丛对降雨变化反应不敏感;（3）综合降雨和气温都增加的情况,流域NPP仍呈下降趋势,只有沙棘灌丛因降雨的增加NPP减小的程度明显降低;（4）大部分植被类型在降雨和温度升高后水分利用效率降低,只有沙棘灌丛和铁杆蒿群落在降雨增加后有所提高,除铁杆蒿群落外,降雨减少使得大部分植被类型的水分利用效率提高.     

黄土高原生态分区及概况

黄土高原地域广阔,水土流失区域差异显著。为了有效治理水土流失,评估水土流失治理技术和模式及生态恢复建设工程的成效性,需要对黄土高原进行区域划分。依据自然条件、水土流失治理技术和模式的区域性特征及差异,基于国家基础地理信息系统数据的县级行政界,对其进行合并,进行生态分区的划分,并分别统计其气候、地形地貌、植被特征及水土流失现状,以期为黄土高原水土流失治理技术和模式的改良优化提供依据。主要结论如下:(1)黄土高原分为黄土高塬沟壑区,黄土丘陵沟壑区,沙地和农灌区,土石山区及河谷平原区。其中黄土高塬沟壑区和黄土丘陵沟壑区分别划分为两个副区。(2)黄土高原的气候、植被、水土流失具有明显的分区差异。降水和植被覆盖度自东南向西北递减,二者在空间分布上具有很好的一致性,降水量大的分区,植被覆盖度也高。在年际变化方面,丘陵沟壑区B2副区降水量呈增加趋势,其他分区呈减小趋势,变化均不显著。80年代以来,黄土高原和各生态分区的植被覆盖度均逐渐增加,黄土丘陵沟壑区的增加量最大。各分区的面平均气温均呈非显著增加趋势,90年代以来增温明显。(3)1970年以来,黄土高原侵蚀产沙强度减弱趋势显著,至2002—2015年,多年平均输沙模数在0.13—3924 t km~(-2) a~(-1)之间,侵蚀强度最大为中度侵蚀(2500—5000 t km~(-2) a~(-1)),但面积较小,主要分布于第二高塬沟壑区的泾河流域。     

APSIM模型在黄土丘陵沟壑区不同耕作措施中的适用性

为了揭示黄土丘陵区不同耕作措施对作物生长发育和土壤水分的影响及相互作用规律,根据2002～2005年两个轮作序列(小麦→豌豆(W→P)和豌豆→小麦(P→W))的3种耕作措施(传统耕作(T)、免耕(NT)和免耕覆盖(NTS))的定位试验,对APSIM模型的适用性进行了研究.通过定位试验得到了一套APSIM模型的参数值,并对其进行了率定.运用均方根误差法对APSIM模型进行检验,结果表明:小麦和豌豆产量与生物量的模拟值与实测值具有显著的正相关(R＞0.9),误差范围在±15%之内;土壤贮水量的模拟值与实测值也具有显著的正相关(R＞0.7),误差范围在±20%以内.表明APSIM模型可以用来模拟不同耕作方式和不同轮作序列的小麦和豌豆产量、生物量及土壤水分的动态变化,模型可以用于指导作物生产及耕作措施的优化管理.     

青海大通退耕还林工程区主要造林树种生产潜力

通过对青海大通退耕还林工程区主要树种的气候生产潜力、现实生产潜力和实际生产力进行研究 ,揭示了该地区主要造林树种在实际存在的气候条件下可能达到的理论产量 ,当前技术经济管理水平条件下所能达到的最高产量 ,现行经营管理条件下所获得的实际产量 ;分析了目前林业的现实生产潜力、实际生产潜力分别与气候生产潜力之间的差距 ,预示了该地区林业的发展前景 ;从合理利用气候资源和充分发挥土地生产潜力角度 ,提出了退耕还林工程建设中优选的树种及其原则 ;指出了不同树种在经营管理水平上的差异及其解决建议。其结果对该地区退耕还林工程的具体实施具有重要的实践指导意义     

DEM栅格分辨率和子流域划分对杏子河流域水文模拟的影响

以黄土丘陵沟壑区杏子河流域为研究区,采用数字滤波法分割了杏子河招安水文站1958—1974年的基流量,评价了SWAT模型在该流域水文模拟的适用性,并分析了DEM栅格分辨率和子流域划分对SWAT水文模拟的影响。结果表明,SWAT模型适用于该流域年河川径流、地表径流、基流及产沙量的模拟。当DEM栅格分辨率在20—150 m之间时,SWAT能有效地模拟年河川径流、地表径流、基流及产沙量,各水文要素模拟结果的R2和NSE分别在0.93和0.51以上,RSR在0.43以下;而当栅格分辨率大于150 m时,各水文要素的模拟效果存在差异。子流域划分对流域产流模拟影响较小,而对产沙模拟影响较大。当子流域提取阈值在12—100 km2之间时,不同的子流域划分对产沙量几乎没有影响,若超出该阈值范围,模型会低估产沙量。因此,可针对不同的水文要素选择合适的DEM和子流域提取阈值,以提高模拟精度和运行效率。     

黄土丘陵沟壑区水分的植被生产力模型——以陕西清涧县为例

针对半干旱区水分的植被生产力问题,以黄土丘陵沟壑区典型地陕西清涧的人工刺槐林为研究对象,对植被生长量的成因进行理论假定和分析,结合该地刺槐的解析木分析资料和相对应的同期降水数据,研究了清涧地区刺槐生长与水分的关系,建立了该区水分一刺槐生长的半理论／半经验模型。结果表明：黄土丘陵沟壑区刺槐的材积生长率与水分的变化率具有较好的线性关系。     

封面说明

图片由中国科学院生态环境研究中心城市与区域生态国家重点实验室于洋2014年7月拍摄于甘肃省定西市龙滩流域,该流域属半干旱黄土丘陵沟壑区,海拔1840~2260 m,流域面积16.1 km2,多年平均降水量386.3 mm,降水量季节分配不均,春季降水较为稀少,主要集中在7—9月,且多暴雨事件发生,水土流失较为严重.流域年均气温为6.8℃,平均无霜期152 d,潜在蒸发量为1649.0 mm,年均相对湿度72%.流域土壤类型为黄绵土,流域内主要土地利用类型包括撂荒地、     

施肥进步在粮食增产中的贡献及其地理分异

采用中长期田间试验对８种模拟施肥模型在温带的海伦试验站、暖温带的沈阳试验站和亚热带的桃源试验站进行了６～１０年试验,以比较、评价施肥在粮食生产中的贡献．结果发现,施肥在作物产量形成中的贡献随施肥制度和气候的热量因素所影响;在最佳施肥条件下,施肥在产量中的贡献率分别为海伦（温带）３０％、沈阳（暖温带）３８％、桃源（亚热带）４４％．按这一实验结果可以一般地估计：当其他技术条件不变时,施肥在产量形成中的贡献率最高可达３０～４５％,随所在地区气候的热量条件而不同．     

基于航片的黄土高原丘陵沟壑区沟谷侵蚀定量监测

基于黄土丘陵沟壑区1979和1993年两期航片和地形图数据,采用数字影像测量方法生成数字正射影像图和数字高程模型,以地理信息系统为手段,研究了黄土丘陵沟壑区的一条沟谷在中尺度时间上的面积及深度变化,并对该变化的空间差异以及     

广东省植被潜在生产力的估算及其分布

本文应用Miami模型和Thornthwaite纪念模型,结合降水量、气温、蒸发量等气候资料,分别计算了广东省植被的可能净第一性生产力、谷物产量和木材生产量。并根据计算结果,绘制出植物气候生产力图。结果表明：广东省植被潜在生产力较大,因此,提高作物产量的潜力还很大;除局部小范围外,植被潜在生产力由沿海向内陆递减,并且等值线走向大致与海岸线平行;沿海的阳江、海丰和内陆的清远、佛冈等地的气候生产力最高,相反,粤北、粤东北山区和雷州半岛的生产力最低。     

黄土丘陵沟壑区水平梯田改土培肥增产技术措施体系

黄土丘陵沟壑区水平梯田改土培肥增产技术措施体系刘东海赵廷宁（宁夏西吉县农业局７５６２００）（北京林业大学水土保持学院１０００８３）赵国杰（宁夏西吉县农业技术推广站７５６２００）ＴｅｃｈｎｉｑｕｅｓｏｆＳｏｉｌＩｍｐｒｏｖｅｍｅｎｔａｎｄＹｉｅｌｄＩｎ...     

Yield responses of crops to changes in environment and management practices: Model sensitivity analysis. I. Maize

YIELD, a parametric crop production model, employs climatic data to calculate actual and potential yield for various crops and includes formulations for specific crop and growth stage effects. The objective was to demonstrate the sensitivity of YIELD for grain corn (maize) to changes in various environmental and decision-making inputs. Five temperature, five solar radiation, six relative humidity regimes, five water application schemes, and four irrigation frequencies were included in this study. The effects of different soil types and wind regimes on crop water requirements were investigated. The model output includes crop yield, water use efficiency, and management efficiency. Among the results, yield decreased on the average by 3.9% per one degree (C) increase in air temperature. A 1% change in solar radiation resulted in an average of 1% change in yield. Similar changes in relative humidity caused a yield change of about 0.8%.     

Mind the gap: how do climate and agricultural management explain the ‘yield gap’ of croplands around the world?

Aim As the demands for food, feed and fuel increase in coming decades, society will be pressed to increase agricultural production – whether by increasing yields on already cultivated lands or by cultivating currently natural areas – or to change current crop consumption patterns. In this analysis, we consider where yields might be increased on existing croplands, and how crop yields are constrained by biophysical (e.g. climate) versus management factors. Location This study was conducted at the global scale. Methods Using spatial datasets, we compare yield patterns for the 18 most dominant crops within regions of similar climate. We use this comparison to evaluate the potential yield obtainable for each crop in different climates around the world. We then compare the actual yields currently being achieved for each crop with their ‘climatic potential yield’ to estimate the ‘yield gap’. Results We present spatial datasets of both the climatic potential yields and yield gap patterns for 18 crops around the year 2000. These datasets depict the regions of the world that meet their climatic potential, and highlight places where yields might potentially be raised. Most often, low yield gaps are concentrated in developed countries or in regions with relatively high‐input agriculture. Main conclusions While biophysical factors like climate are key drivers of global crop yield patterns, controlling for them demonstrates that there are still considerable ranges in yields attributable to other factors, like land management practices. With conventional practices, bringing crop yields up to their climatic potential would probably require more chemical, nutrient and water inputs. These intensive land management practices can adversely affect ecosystem goods and services, and in turn human welfare. Until society develops more sustainable high‐yielding cropping practices, the trade‐offs between increased crop productivity and social and ecological factors need to be made explicit when future food scenarios are formulated.     

北方农牧交错区农业生态系统生产力对气候波动的响应——以准格尔旗为例

气候变化对区域生态系统结构和功能有重大影响。以中国北方农牧交错区的准格尔旗为例,利用气象和《统计年鉴》数据,采用数理统计方法分析准格尔旗1961—2009年降水量、平均气温的波动特征,计算出该地区1961—2009年农业生态系统NPP值和主要农作物的气候产量,论述了准格尔旗农业生态系统生产力对气候波动的响应。结果表明:(1)降水量和平均气温的年际、年内波动均显著。(2)准格尔旗农业生态系统生产力呈现阶段性地波动上升趋势。排除社会、科技等影响,气候生产力对气候波动表现出较强的敏感性,是作物气候生态适应的结果。(3)中国北方雨养旱作区,粮食气候产量受降水量年际波动(特别是7、8月)显著影响;谷子、糜黍、玉米、薯类、大豆和油料等农作物的气候产量与降水量年际波动呈显著正相关;谷子、糜黍的气候产量与生长季降水量年内波动呈显著负相关。集水型生态农业是北方农牧交错区生态环境友好的农业发展模式。(4)谷子、糜黍、薯类、大豆和油料等农作物的气候产量与6、7、8月平均气温年际波动呈显著负相关;生长季平均气温年内波动对谷子、糜黍、大豆和油料等农作物的气候产量有显著负面影响。因此,需要综合采取工程、生物和农业措施,将气候变化对主要农作物气候产量的不利影响降到最低。     

黄土丘陵区小流域土壤碳氮磷生态化学计量特征的空间变异性

土壤碳、氮、磷是植物重要的营养来源和保障生态系统健康的重要生态因子,其含量及化学计量比的动态平衡对生态系统的生产力具有重要影响,分析土壤碳、氮、磷养分含量及化学计量比的空间变异性和影响机制,对区域土壤养分管理以及土地可持续利用具有重要意义。本研究选取位于黄土高原东缘的三眼井小流域,利用经典统计与地统计相结合的方法,分析了研究区表层土壤(0~20 cm)有机碳(SOC)、全氮(TN)和全磷(TP)以及土壤碳氮磷的化学计量比的空间变异性和影响机制。结果表明:(1)研究区表层土壤SOC、TN和TP的平均值分别为3.97、0.83和0.6 g·kg-1,C∶N、C∶P、N∶P的平均值分别为4.73、6.02、1.26,均属于中等变异水平。(2)土地利用类型和地貌类型对研究区土壤SOC、TN具有显著影响,林地和荒草地高于梯田和退耕地,梁上高于沟谷;TP主要受土地利用类型的显著影响,梯田显著高于其他三种土地利用类型;土地利用类型对土壤C∶N、C∶P和N∶P的影响较为一致,表现为梯田显著低于其他土地利用类型;C∶N还受到坡度和地貌类型的显著影响,C∶P和N∶P还分别受到坡度和海拔的显著影响。(3)采用回归克里格法得到的预测图更能体现环境要素的作用,空间预测精度较高,土壤碳、氮、磷生态计量特征的空间分布格局具有明显差异。因此,针对土壤碳、氮、磷生态计量特征的空间分布格局,采取不同的有机旱作、平衡施肥及水土保持措施等,并进行合理的空间配置,有助于改善研究区土壤碳、氮、磷的平衡状况。     

Actual and potential yield for rainfed and irrigated maize in China

A crop yield model (YIELD), that uses climatic and environmental data to calculate yield and water consumption for a variety of major crops was applied specifically to maize (grain corn) in the region of China and Korea, by examining the parameters of potential and actual yield. A network of 241 stations provided the seasonal climatic input, which consisted of data averaged over approximately a 20 year period. Among the simulated results, highest yields under full irrigation (first growing season) occurred in the Yangtze River area, northward to Korea, Kweichou and Szechwan Provinces, and northcentral China, whereas least yield was found for the western interior. High yields exceeded 12,000 kg/ha per harvest. Under rainfed conditions, only the Yangtze River region retained its predominance. In order to achieve optimum crop yields, about 800 mm of irrigation water was needed in northcentral China, contrasted with none required in the south and east of China. Making certain dietary assumptions, the calculated grain corn production could potentially support between 700 and 400 million people, depending on the irrigation strategies adopted. If corn were used as feed stock for beef, only between 100 and 60 million persons could be supported. A sensitivity analysis was applied to determine the degree of error introduced by faulty, uncertain, or missing environmental input data for the stations utilized in this study.     

梯田景观的历史分布及典型国际案例分析

梯田是在大面积多山地形和较高人口密度条件下产生的山区土地高效利用方式,广泛分布于世界各地,并且在不同的地理气候条件下产生了不同的类型,具有重要的生态价值和文化价值.梯田作为陡坡耕作区古老的土壤保持措施,有利于农业集约化,一般而言,梯田建设的目的是为了保持水土,减少产流产沙,改善立地环境,便于农业生产.在当前社会经济发展的背景下,大面积的梯田遭到荒废,不仅浪费了土地资源,还易导致严重的土壤侵蚀、坡面坍塌和土地退化.本文综述全球不同地理区域和自然环境条件下梯田的起源、发展以及分布特征,主要选择亚洲、欧洲、美洲和非洲四大重点区域进行系统介绍,并针对每一大洲内的典型国家做了案例剖析.在此基础上,深入探讨梯田建设、利用和荒废过程与气候变化、国家政策、人口变迁等因素的关系,最后针对目前梯田区存在的水资源紧张和梯田荒废退化两个严重问题,提出了尚需开展的研究工作,以期为梯田的可持续利用与管理提供参考依据.     

内蒙古伊金霍洛旗农业生产力的评估与预测

运用伊金霍洛旗40年的气象与农业统计资料,分析了气候与化肥使用量对于粮食产量的综合影响．选取综合模型为基础,将化肥对粮食气候生产潜力的影响考虑为调节因子,建立了基于气候和化肥使用量的粮食产量评估模型．同时,基于伊金霍洛旗地区人口、气候以及化肥的未来变化情景,预测了未来30年的粮食需求增长量,指出在满足当地人民对粮食作物基本需求的基础上,从目前到2010年期间退耕面积达622～5948hm^2,相当于原有耕地的3％～31％;从2010年到2020年期间退耕面积最大,达3263～8164hm^2,相当于原有耕地的17％42％;随后10年由于土地单位面积的增产是有限度的,而人口继续增长,将导致耕地面积有所回升,但变动幅度不会太大,基本维持在2020年的水平。     

Degradation of cultivated bench terraces in the Three Gorges Area: Field mapping and data mining

Due to resettlements, construction of new infrastructure, and new land reclamation the rapid agricultural changes in the Three Georges Area (TGA) in Central China are expected to force the degradation of the cultivated terraced landscape. Consequently, increased soil erosion can hamper a sustainable land management in the mountainous TGA. This paper presents the model framework TerraCE (Terrace Condition Erosion) for determining the causes for different terrace conditions and terrace degradation based on field surveys and spatial data mining. For a total of 987 bench terrace plots in the Xiangxi catchment we collected data on their state of maintenance and terrace design to account for terrace stability and thus capability of soil conservation. Assessing the driving factors of terrace degradation was done by embedding terrain-based predictors and distance-transforms of remote-sensing data as indicators of environmental and anthropogenic influences. Random forests classification and regression models were applied for data mining. Terrace degradation in the Xiangxi catchment is obvious. The sequence of degradation ranges from ‘well maintained’ (21%), ‘fairly maintained’ (44%), and ‘partially collapsed’ (23%) to ‘completely collapsed’ (11%) terraces. The cross-validation error of the supervised TerraCE model is below 8%, allowing for reasonable and valid interpretations of the causes of terrace degradation. Data mining reveals indicators for anthropogenic effects such as the distance to settlements or to roads as major drivers for the spatial distribution of terrace conditions. The effect of relief, which can be regarded as the major natural driver for terrace degradation by erosive action is tributary but altered and overlaid by land use dynamics associated with the Three Gorges Dam. An important indicator representing a combined effect of terrain and human activity is the distance to stream channels of different orders. Applying TerraCE we reveal mechanisms of terrace degradation in disturbed environments and present a framework for standardized mapping and analysis of terrace degradation under cultivation. The approach might also be used to develop guidelines for terrace planning in mountainous terraced landscapes of limited carrying capacity, with respect to socio-economic as well as environmental conditions.     

基于APSIM模型的旱地春小麦产量对施氮量和施氮深度的响应模拟

氮是限制黄土高原旱农区作物水分生产潜力提升的重要因素,而氮肥适度深施是旱地作物提效增产的有效措施.本研究利用甘肃省陇中地区1990-2020年气象观测数据,基于APSIM模型模拟了不同施氮量和施氮深度的春小麦产量,以期为优化陇中旱农区小麦施肥策略提供理论依据.结果表明:模型模拟的春小麦产量、生物量和生育期0～200 c...