灌溉耕地空间分布制图研究进展

[目的]灌溉耕地空间分布是管理水资源、指导农业生产和监控环境变化的基础数据,遥感是获取灌溉耕地空间分布的重要手段。科学总结有关区域灌溉耕地空间分布制图的研究进展,可为遥感在该领域的应用研究提供参考。[方法]文章全面收集近年来国内外利用遥感提取灌溉耕地的文献资料,系统分析了灌溉耕地制图的特征选择和主要技术方法,并展望了未来的发展方向。[结果]从分类特征的角度看,气候、生产方式和设施等农业相关地域条件是灌溉耕地制图的必要参考;灌溉引起的水分或植被生长状况差异是主要依据;引入参量的时序变化特征或新的特征参量是对单一影像信息不完善的有效补充。从分类方法的角度看,不同分类方法多局限于局地或区域尺度,规则普适性不高,真值数据收集困难,难以适应大尺度下多样的地域条件,导致无法高效及时地生产更新相应规模且合适分辨率的产品,大区域灌溉制图的主要方式仍依赖空间分配模型。[结论]未来发展而言,自动分类技术和遥感影像资源的丰富已为高效生产灌溉分布地图提供了基础条件,整合数据资源、挖掘特征参量和优化分类方法等3个方面应是未来的主要发展方向。     

中国农民专业合作社空间格局及其影响因素

目的 探索农民专业合作社的地域分异特征及其影响因素,对农业转型升级与乡村振兴战略实施有重要参考价值。方法 文章基于农民专业合作社工商注册数据,运用探索性空间分析方法和地理探测器分别从自然本底、资源禀赋、地理区位、经济基础等方面分析区域环境因素对农民专业合作社空间分布的影响。结果 （1）中国农民专业合作社主要分布在胡焕庸线东南部,其分布密度呈现以黄淮海平原为中心,圈层式向外递减特征。（2）中国农民专业合作社以种植业合作社和畜牧业合作社为主,两者占所有合作社的83.39%。（3）不同类型专业合作社呈现差异化空间分布特征。其中,种植业合作社集中分布在黄淮海平原和江汉平原,林业合作社集中分布在吕梁山、武夷山等主要山脉附近,畜牧业合作社集中分布在豫中、湘黔、甘陕等地区,渔业合作社集中分布在江汉平原、鄱阳湖和太湖周边区域;辅助业合作社集中分布在黄淮海平原、长江中下游平原和东北平原。（4）地理探测器结果表明,农民专业合作社分布是多种因素综合作用的结果,其中资源禀赋和自然本底对农民专业合作社分布解释力相对较强,社会经济基础次之,地理区位最小。然而,各主要因素对不同地区和不同类型专业合作社分布的影响大小有所差异。结论 上述研究结论可为不同地区因地制宜优化各种类型农民专业合作社分布、调整乡村产业结构和实现乡村产业振兴提供科学参考。     

福建省休闲乡村空间分布特征及其影响因素研究

目的 休闲乡村的发展是推进休闲农业持续健康发展并促进农业强、农村美、农民富的有效途径。目前学界在省域层面检验休闲乡村示范点分布及成因的研究较少。分析福建省最美休闲乡村示范点空间格局并探索其影响因素,验证示范点选址合理性的同时揭示空间分布的内在机理,在此基础上提出福建省休闲乡村发展的优化路径与建议,为休闲乡村的深入推进与良性可持续发展提供借鉴参考。方法 文章在利用ArcGIS10.7的基础上,采用最邻近指数、基尼系数、核密度估计值等参数,从空间分布形态、区域分布差异、空间分布密度三方面对2014—2020年福建省142个最美休闲乡村示范点的空间分布特征进行探究,并运用Moran''s I 指数、地理联系率与缓冲区分析等指标和方法剖析其影响因素。结果 （1）福建省最美休闲乡村示范点空间分布呈集聚性和不均衡性特征。（2）示范点在不同设区市和不同地理区域的分布存在差异。在福建9个设区市中,逾55%的示范点集中分布在福州、泉州、三明、宁德4市。在闽东南西北中五大地理区域内,闽南地区分布最为密集,闽东地区次之,闽中地区最少。（3）示范点空间分布密度存在明显差异,形成厦门北部1个高密度中心,厦门西南部——漳州东北部1个次高密度中心。（4）示范点分布受自然因素和人文因素双重影响。地形地貌是自然因素核心要素,人文因素关键包括社会经济发展水平、农业基础、交通区位、旅游资源禀赋和客源市场规模。结论 福建省最美休闲乡村示范点能够立足地区自然资源禀赋和经济社会条件因地制宜发展;休闲乡村建设应立足自身条件,遵循阶段性发展规律,着重考量自然因素和人文因素,往建设最适宜区去选址与布局;进一步说,福建省及同类地区在未来发展中应立足自身自然条件和资源禀赋,依托当地农业发展基础,抓住社会经济发展机遇,发挥各地区位优势和示范区溢出效应,从而推动休闲乡村空间布局优化与高质量发展。     

三江平原典型流域耕地利用水土资源匹配时空演变——以挠力河流域为例

目的 微观尺度分析耕地利用水土资源匹配时空动态及其变化趋势,旨在为高标准基本农田建设和耕地利用水土资源优化配置提供科学指导。方法 文章以三江平原挠力河流域为研究区,运用耕地水资源有效供给量与耕地需水量的比值法,探析2000—2020年研究区耕地利用水土资源匹配的时空动态;借助Theil-Sen趋势分析法和Hurst指数分析法,对研究区耕地利用水土资源匹配的空间变化趋势及其未来变化趋势持续性进行定量化分析。结果 （1）时序变化上,作物全生育期耕地利用水土资源匹配综合指数的频数分布呈双峰分布特征且其中轴线逐渐向高值移动。（2）空间动态上,作物全生育期耕地利用水土资源匹配呈现出空间异质性增强的变化特征,其相对高值区由流域中游东部向中游西部和下游西部转移,并且其Sen趋势度大于0的耕地面积比例达到94%以上。（3）未来变化趋势上,作物全生育期耕地利用水土资源匹配相对强持续性升高的耕地面积比例为93.73%,主要分布在流域中游西部和下游西部的大部分区域。结论 受气候变化和人工调控的影响,虽研究区作物全生育期耕地利用水土资源匹配程度较低,但在时空动态上均呈现出明显升高的变化特征,且呈现持续性升高的未来变化趋势,结果可为优化调配水土资源时空耦合关系提供决策依据。     

下辽河平原区耕地质量演变及障碍因素诊断

目的 为探究2008—2018年下辽河平原区耕地质量演变情况,明确该区域影响耕地质量变化的障碍因素及其分布。方法 文章将2016年耕地质量等级国家标准统一应用于2008年和2018年该区域耕地质量等级评价,采用障碍度模型对2008—2018年该区域耕地质量等级评价指标影响耕地质量的障碍程度进行诊断,依据每个指标障碍度大小排序确定影响耕地质量变化的障碍因素,根据不同区域评价指标障碍程度差异确定的障碍因素进行类型组合形成分区。结果 （1）11年间下辽河平原区耕地质量等级总体呈现上升趋势,以中高等级耕地为主。其中一、二等级耕地面积上升,三至九等级耕地面积出现下降且三等地下降幅度较大,下降的区域主要包括昌图县、台安县、辽中区、辽阳县和灯塔市等地。（2）研究区主要障碍因素类型区以单一指标灌溉能力、有机质、地形部位型障碍因素类型区为主。11年间障碍因素分区整体处于稳定状态,呈现为灌溉能力型障碍因素类型区为主,主要集中在北部和东南部地区、康平县、辽中区、凌海市和黑山县部分地区,障碍因素分区结构呈现由单一重度障碍转变为多种重度障碍并存的趋势。（3）2008—2018年下辽河平原区耕地质量等级上升了0.16等,耕地质量等级保持中高水平,等级上升的区域面积高于下降的区域,灌溉能力指标是影响下辽河流域耕地质量等级变化的主要指标之一,土壤有机质在11年间有所改善但变化较少。（4）单一指标型障碍因素类型区呈现下降趋势,而含有两个重度障碍度指标的面积呈现上升趋势,且障碍因素类型区增多,呈现重度障碍度指标复杂化的趋势。结论 2008—2018年下辽河平原区耕地质量等级总体上升反映了11年间耕地质量保护与提升等政策和措施取得了一定的成效,未来耕地质量保护与提升应该在明确耕地质量等级和主控障碍因素基础上确定更加精准的目标和方向,从而实现耕地质量等级的靶向提升。     

滇黔桂传统村落空间分布特征及其与旅游发展关系

目的 分析滇黔桂传统村落空间分布格局及其影响因素,并进一步探究传统村落保护与旅游经济运行关系。方法 文章选取云南、贵州和广西3省区的1 712个传统村落为研究样本,借助ArcGIS10.2、GeoDA、SPSS等工具及数理统计模型,探究滇黔桂3省区不同空间尺度传统村落空间分布特征、影响要素及其与旅游发展关系。结果 滇黔桂传统村落分布为显著的集聚类型,整体上分布在黔东南（黔东南）—桂东北（桂林）、滇西北（保山—大理—丽江）、滇东南（红河）3个集聚区。滇黔桂地区传统村落分布在不同空间尺度均表现出显著非均衡特征,传统村落分布的沿边性（省界或国界）和旅游开发指向性特征明显。89.83%传统村落都分布在2 000m以下的中低山区;在经济较为落后和旅游发展较早的两个区域形成传统村落集聚区;与现代交通干线分布呈现空间异位性且与交通密度呈现负相关特征;现有传统村落大多远离城市中心特征。滇黔桂地区国内旅游规模、国际旅游收入、旅游资源禀赋与传统村落分布呈正相关性,国内旅游收入、国际旅游规模与传统村落分布呈负向相关性,总体上旅游发展对传统村落入选有一定带动作用,但旅游响应作用依然有待进一步提升。结论 该研究发现传统村落呈现聚集分布特征,但其文化资源属性的经济价值暂未得到充分挖掘,其旅游经济效果不容乐观。     

省域视角下耕地自然质量空间格局与影响因素

目的 了解省域尺度耕地自然质量分布特征及影响因素,以期实现耕地质量省级可比,为因地制宜管理和引导耕地可持续利用提供参考。方法 文章采用多因素综合评价模型和1+X模型从4个维度15个测度指标对山西省耕地自然质量进行量化分析并揭示其空间分布机制;运用地理探测器模型探寻其核心影响因素及交互作用。结果 山西省耕地自然质量较差,优等地少而中低等地分布广泛,形成了南高北低,盆地高山地低的空间格局,整体分布与地形及积温分布趋同;因子探测结果表明有效土层厚度、≥10℃积温、年均降雨量、灌溉保证率和高程是影响耕地自然质量空间分异的主要因素,交互探测结果显示各因子交互作用的解释力都强于单因子解释力,进一步解释了耕地自然质量空间分布是多因素综合作用的结果。结论 将反映省级尺度耕地生态环境的指标纳入评价体系,能够纠正传统评价存在的偏差,此外,采用1+X模型进行生态环境系数修正使得评价结果更科学。     

耕地质量禀赋、社会分工对农户化肥减量技术采纳行为的影响——基于鄂豫两省样本农户的实证

目的 促进农户采纳化肥减量技术是保障农产品安全、治理农业污染和推动农业绿色发展的重要举措,文章旨在探究耕地质量禀赋与社会分工对农户采纳化肥减量技术的影响及其内在逻辑。方法 基于湖北和河南两省700户农户的微观调研数据,利用Ordered Probit模型分析了耕地质量禀赋与社会分工对农户化肥减量技术采纳行为的影响。结果 （1）耕地质量禀赋对农户化肥减量技术采纳行为具有显著正向影响,耕地质量禀赋每增加一个单位,化肥减量技术采纳率将提高25%,土壤越肥沃,灌溉条件越便利,通机耕路的耕地,农户越会采纳化肥减量技术。（2）耕地质量禀赋越好,则农户更愿意参与横向分工,促进其采纳化肥减量技术,中介效应为0.062,且纵向分工能明显缓解质量禀赋较差耕地对农户化肥减量技术采纳的负向影响。（3）耕地质量禀赋对小农户采纳化肥减量技术具有显著正向影响,且社会分工增强了耕地质量禀赋对小农户化肥减量技术采纳行为的促进作用,而耕地质量禀赋对大农户化肥减量技术采纳行为没有显著影响。结论 因此,多渠道提升农户耕地条件,全方位推进农业社会分工,对不同规模农户采取差异化的激励和引导策略,均是推广化肥减量技术的有效途径。     

基于SOM的乡村振兴基础条件分区研究以甘肃省天水市为例

目的 构建乡村振兴基础条件综合评价体系,明确不同分区乡村振兴的优势条件和不足条件,分类提出乡村振兴的建议。方法 文章基于数据可获取性及科学性等原则选择乡村主体、资源禀赋、产业基础、区位条件和自然环境等5个评价指标,运用熵权法确定指标权重,利用综合评价法计算2018年天水市乡村振兴基础条件综合得分,采用自组织映射法（SOM）以乡（镇）为单元进行分区,并根据不同评价因子得分明确各区发展基础的优势与短板。结果 （1）天水市乡村振兴基础条件有较大的差异性,综合条件较高和较差乡（镇）占比较少,基础条件一般的乡（镇）数量占比最大,各乡（镇）各评价指标具有较大的空间分异性;（2）天水市乡村振兴基础条件可以分为4个区,综合得分分别为0.009 4、0.007 7、0.006 2和0.004 6,4个分区结果的优势条件分别是产业基础、资源禀赋、资源禀赋、乡村主体,而其不足条件分别是资源禀赋、乡村主体、自然条件和产业基础。结论 天水市各乡（镇）乡村振兴的基础条件具有明显的空间差异性,乡村振兴战略实施应依托优并发挥优势条件,补齐短板,因地制宜推进。     

近20年湖南省耕地开发强度时空分异研究

目的 以县域为研究单元,对湖南省耕地开发强度进行测度,研究近20年来湖南省耕地开发强度时空变化特征。方法 文章运用变异系数、泰尔指数、重心分析、冷热点分析等多种方法揭示1999—2017年湖南省耕地开发强度时空格局演变特征。结果 （1）耕地开发强度总体上呈增长趋势,其区域差异性主要是由组间差异造成,其中湘南片区对组间差异的贡献率最大。（2）湖南省县域强度阶段性特征以上升为主要趋势,耕地开发强度空间分布不平衡,一级区和二级区主要分布于武陵、南岭和罗霄山脉等地势较高山区县域;三级区和四级区集中分布于中部往南北向延伸的地势较为平坦的地带。（3）耕地开发强度重心存在着从东北向西南转移的趋势,空间波动较小。（4）冷热点区域整体呈现出“热点区—次热点区—次冷点区—冷点区”的圈层结构分布形态,空间集聚格局相对稳定。结论 该研究结果为研究区制定区域差别化的耕地开发强度管控政策和农业空间管控决策提供更直观的参考。     

The impact of water scarcity on food,bioenergy and deforestation

We evaluate the impact of explicitly representing irrigated land and water scarcity in an economy‐wide model with and without a global carbon policy. The analysis develops supply functions of irrigable land from a water resource model for 282 river basins and applies them within a global economy‐wide model. The analysis reveals two key findings. First, explicitly representing irrigated land has a small impact on global food, bioenergy and deforestation outcomes. This is because this modification allows irrigated and rainfed land to expand in different proportions, which counters the effect of rising marginal costs for the expansion of irrigated land. Second, changes in water availability have small impacts on global food prices, bioenergy production, land use change and the overall economy, even with large‐scale (c. 150 exajoules) bioenergy production, due in part to endogenous irrigation and storage responses. However, representing water scarcity and changes in water availability can be important regionally, with relatively arid areas and/or areas with rapidly growing populations fully exhausting our estimated maximum irrigation capacity that allows for improved irrigation efficiency, lining of canals to limit water loss, and expanding storage to fully capture average annual water flows.     

Irrigation in Africa

Irrigation in Africa has not developed to the same extent as in Asia. The special features of Africa for developing and managing irrigation projects, the present status and future potential of both rainfed and irrigated agriculture in 50 African countries, and the main problems facing Africa in the area of irrigation are analysed.     

Impacts of climate change on lower Murray irrigation*

This article evaluates irrigated agriculture sector response and resultant economic impacts of climate change for a part of the Murray Darling Basin in Australia. A water balance model is used to predict reduced basin inflows for mild, moderate and severe climate change scenarios involving 1, 2 and 4°C warming, and predict 13, 38 and 63% reduced inflows. Impact on irrigated agricultural production and profitability are estimated with a mathematical programming model using a two‐stage approach that simultaneously estimates short and long‐run adjustments. The model accounts for a range of adaptive responses including: deficit irrigation, temporarily following of some areas, permanently reducing the irrigated area and changing the mix of crops. The results suggest that relatively low cost adaptation strategies are available for a moderate reduction in water availability and thus costs of such a reduction are likely to be relatively small. In more severe climate change scenarios greater costs are estimated. Adaptations predicted include a reduction in total area irrigated and investments in efficient irrigation. A shift away from perennial to annual crops is also predicted as the latter can be managed more profitably when water allocations in some years are very low.     

The impact of climate change on China's agriculture

This article examines how expected changes in climate are likely to affect agriculture in China. The effects of temperature and precipitation on net crop revenues are analyzed using cross-sectional data consisting of both rainfed and irrigated farms. Based on survey data from 8,405 households across 28 provinces, the results suggest that global warming is likely to be harmful to rainfed farms but beneficial to irrigated farms. The net impacts will be only mildly harmful at first, but the damages will grow over time. The impacts also vary by region. Farms in the Southeast will only be mildly affected but farms in the Northeast and Northwest will bear the largest damages. However, the study does not capture the indirect effects on farms of possible changes in water flow, which may be important in China.     

Macro–micro feedback links of water management in South Africa: CGE analyses of selected policy regimes

The pressure on an already stressed water situation in South Africa is predicted to increase significantly under climate change, plans for large industrial expansion, ongoing rapid urbanization, and government programs to provide access to water to millions of previously excluded populations. This article employs a general equilibrium approach to examine the economy‐wide impacts of selected macro and water‐related policy reforms on water use and allocation, rural livelihoods, and economy at large. The analyses reveal that implicit crop‐level water quotas reduce the amount of irrigated land allocated to higher‐value horticultural crops and create higher shadow rents for production of lower‐value water‐intensive field crops, such as sugarcane and fodder. Accordingly, liberalizing local water allocation within irrigation agriculture is found to work in favor of higher‐value crops, and expand agricultural production and exports and farm employment. Allowing for water trade between irrigation and nonagricultural uses fuelled by higher competition for water from urbanization leads to greater water shadow prices for irrigation water with reduced income and employment benefits to rural households and higher gains for nonagricultural households. The analyses show difficult trade‐offs between general economic gains and higher water prices, which place serious questions on subsidizing water supply to irrigated agriculture, i.e., making irrigation subsidies much harder to justify.     

Sustainable crop intensification through surface water irrigation in Bangladesh? A geospatial assessment of landscape-scale production potential

Changing dietary preferences and population growth in South Asia have resulted in increasing demand for wheat and maize, along side high and sustained demand for rice. In the highly productive northwestern Indo-Gangetic Plains of South Asia, farmers utilize groundwater irrigation to assure that at least two of these crops are sequenced on the same field within the same year. Such double cropping has had a significant and positive influence on regional agricultural productivity. But in the risk-prone and food insecure lower Eastern Indo-Gangetic Plains (EIGP), cropping is less intensive. During the dryer winter months, arable land is frequently fallowed or devoted to lower yielding rainfed legumes. Seeing opportunity to boost cereals production, particularly for rice, donors and land use policy makers have consequently reprioritized agricultural development investments in this impoverished region. Tapping groundwater for irrigation and intensified double cropping, however, is unlikely to be economically viable or environmentally sound in the EIGP. Constraints include saline shallow water tables and the prohibitively high installation and energetic extraction costs from deeper freshwater aquifers. The network of largely underutilized rivers and natural canals in the EIGP could conversely be tapped to provide less energetically and economically costly surface water irrigation (SWI). This approach is now championed by the Government of Bangladesh, which has requested USD 500 million from donors to implement land and water use policies to facilitate SWI and double cropping. Precise geospatial assessment of where freshwater flows are most prominent, or where viable fallow or low production intensity cropland is most common, however remains lacking. In response, we used remotely sensed data to identify agricultural land, detect the temporal availability of freshwater in rivers and canals, and assess crop production intensity over a three-year study period in a 33,750 km² case study area in southwestern Bangladesh. We combined these data with georeferenced and temporally explicitly soil and water salinity information, in addition to relative elevation classifications, in order to examine the extent of winter fallows and low productivity rainfed cropland that could be irrigated by small-scale surface water pumps. Applying observations of irrigated crop sowing dates and yields from 510 wheat, 550 maize, and 553 rice farmers, we also modeled crop intensification production scenarios within the case study area. We conservatively estimate that at least 20,800 and 103,000 ha of fallow and rainfed cropland, respectively, could be brought into intensified double cropping using SWI. Scenario analysis indicates that if 25%–75% of the fallow or low-intensity land were converted to irrigated maize, national aggregate production could increase by 10–14% or 29–42%, respectively. Conversion to wheat would conversely boost national production by 9–10% or 26–31%. Irrigated rice is however unlikely to contribute >3%. In aggregate, these actions could generate between USD 36–108 million of revenue annually among farmers. Intensification therefore has important land use policy and food and income security implications, helping to rationalizei SWI investments. Crop choice, water resource allocation, and water governance will however remain crucial considerations for irrigation planners.     

Irrigation production functions with water-capital substitution

The dynamics of biomass growth implies that the yield of irrigated crops depends, in addition to the total amount of water applied, on irrigation scheduling during the growing period. Advanced irrigation technologies relax constraints on irrigation rates and timing, allowing us to better adjust irrigation scheduling to the varying needs of the plants along the growing period. Irrigation production functions, then, should include capital (or expenditures on irrigation equipment) in addition to aggregate water. We derive such functions and study their water-capital substitution properties. Implications for water demand and adoption of irrigation technologies are investigated. A numerical example illustrates these properties.     

吉林省西部半干旱区玉米节水高产高效研究

吉林省西部半干旱区在乾安和前郭县选用15hm2耕地采用滴灌灌溉、地膜覆盖、大垄双行、高产品种、合理施肥等一系列综合配套技术,变雨养农业为雨养农业和设施农业相结合的现代农业,达到了节水、高产、高效的目的。     

明清广东山区灰粪和平原泥肥应用的历史演变

传统农业时代广东地区山区和平原分别以获取灰粪和泥肥作为主要肥源.山区制作灰粪的方法有烧畲作灰、樵采制灰、采集草皮泥制作厩肥等,却是山区植被减少、水土流失加剧的一个原因.珠三角平原则以潮灌和上泥获得珠江河道上沉积的泥肥,是维护当地水环境的生态技术措施.而过度依赖天然肥源都限制了多熟种植的发展和造成了地力的下降,造成粮食产量的减少.