Modeling policy and agricultural decisions in Afghanistan

Afghanistan is responsible for the majority of the world’s supply of poppy crops, which are often used to produce illegal narcotics like heroin. This paper presents an agent-based model that simulates policy scenarios to characterize how the production of poppy can be dampened and replaced with licit crops over time. The model is initialized with spatial data, including transportation network and satellite-derived land use data. Parameters representing national subsidies, insurgent influence, and trafficking blockades are varied to represent different conditions that might encourage or discourage poppy agriculture. Our model shows that boundary-level interventions, such as targeted trafficking blockades at border locations, are critical in reducing the attractiveness of growing this illicit crop. The principle of least effort implies that interventions decrease to a minimal non-regressive point, leading to the prediction that increases in insurgency or other changes are likely to lead to worsening conditions, and improvements require substantial jumps in intervention resources.     

不同水资源情景下干旱区未来土地利用/覆盖变化模拟——以黑河中上游张掖市为例

应用回归分析方法确定对研究区土地利用/覆盖变化有重要贡献的10种驱动因子,用线性规划方法确定模型输入文件中模拟期间每年的各种土地利用类型面积.用ArcView空间分析的方法建立驱动力文件,利用SPSS13.0软件分析每种驱动力的权重(β值),建立Logistic方程,并将其作为模型输入文件.建立可利用水资源总量分别为18.0×10⁸m³,26.5×10⁸m³,35.0×10⁸m³的3种情景假设,应用CLUE-S模型模拟张掖市2001-2020年土地利用/覆盖变化变化.模拟结果显示:1)三种情景下,耕地的面积都在减少,耕地面积的减少量与可利用水资源总量呈负相关;2)林草地面积在3种情景下均增加,林草地面积的变化与可利用水资源总量呈正相关;3)在3种情景假设下,水域面积的变化都不明显;4)城镇用地面积变化与水量也呈正相关;5)未利用地面积持续减少.     

基于原状土蒸渗仪的潜水蒸发昼夜变化及差异性比较

为探究潜水蒸发昼夜变化及差异,利用五道沟水文实验站蒸渗仪群,进行了砂姜黑土和黄潮土两种代表土壤裸地及种植小麦和玉米三种情景下的实验。结果表明:有作物时,不同需水阶段昼夜潜水蒸发差异明显。需水大时,受蒸腾作用影响,潜水蒸发较大,两种土壤均为白天大于夜间。玉米生长初期需水小,但夏季白天气温较高,均为白天大于夜间。而小麦生长初期,冬季气温低,砂姜黑土昼夜差异不明显,各有大小,黄潮土则为夜间较大。裸土时,黄潮土受夜间水汽凝结及白天毛管断裂影响明显,夜间会大于白天。砂姜黑土则反之。     

农业种植规模与降水量变化对农用地下水开采量影响识别

以石家庄平原区作为研究区域,运用相关分析及回归分析阐明农用地下水开采量与降水量及小麦—玉米种植规模之间的关系。降水量与农用地下水开采量之间的相关系数较小,但作为农作物需水的重要水源,降水量通过影响农业地下水开采强度影响地下水开采总量。农业地下水开采强度在丰水年时明显减小,在枯水年时明显增大。小麦和玉米作为主要的耗水型作物,其种植面积与农用地下水开采量关系密切,随小麦—玉米种植面积的增加(减小),农用地下水开采量表现出明显的增加(减小)趋势。1981年之前,小麦—玉米种植面积每增加1×104 hm2,农用地下水开采量平均增加0.69×108 m3;1981年之后,小麦—玉米种植面积每增加1×104 hm2,农用地下水开采量增加0.23×108 m3。     

北京大清河流域生态涵养区富硒土壤资源分布特征和来源解析

北京是典型的硒缺乏地理分布区,但近些年研究成果表明局部地区土壤达到富硒水平,掌握该区富硒分布特征对于开展北京地区的富硒环境研究和开发利用富硒土地资源具有重要意义。本文以北京大清河流域生态涵养区1615km~2地球化学调查数据为基础,采用原子荧光光谱(AFS)等方法测定了研究区1297件表层土壤、25组玉米及对应根系土壤和15件岩石中Se等地球化学指标;利用相关分析、多元统计分析方法,结合GIS技术,研究土壤和农作物中硒含量特征、富硒成因来源以及土壤硒与碳铁磷等其他元素的关系,评价富硒土地的安全性。结果表明:研究区土壤硒含量区间为0.055～0.465mg/kg,背景值为0.257mg/kg,呈现富硒特征,厘定出360.4km~2富硒土地资源。当地种植的玉米硒含量变化范围为0.028～0.70mg/kg,几何均值为0.20mg/kg,80%的玉米样本为富硒农产品,且土壤富硒与作物富硒空间分布一致,指示土壤硒是作物体内硒的重要供给来源。研究认为,地质背景和成土母质是研究区富硒土地资源分布的主控因素,河流相沉积的暗色岩系是重要的土壤硒来源。富硒土地整体环境质量清洁安全,仅3.23km~2(面积占比0.2%)土壤重金属(镉汞铅)含量超风险管控值,在土地开发过程中需重点关注。     

水稻、小麦与土壤中重金属Cd含量的关系模拟研究

土壤污染防治工作已成为提升耕地质量、保护国土生态安全的重要任务之一.为了科学预测我国大宗农作物(如水稻、小麦)与土壤重金属含量的关系,减少安全利用类农用地的大量农产品与土壤的协同监测,实现重金属污染农用地的安全利用,本研究以重金属Cd为例,选取对水稻、小麦Cd含量影响较大的土壤Cd含量、土壤pH值、土壤阳离子交换量(C...     

Pollution effects of wastewater sludge application to sandy soils with particular reference to the behaviour of mercury

Hammarsdale, an industrial centre about 40 km inland from the coastal city of Durban, South Africa experiences effluent treatment problems typical of highly industrialised centres. The majority of the factories in the area manufacture textiles, with the remainder comprising chemical manufacturers and a large chicken processing plant. Effluent produced by these industries constitutes approximately 97% of the flow to the local wastewater treatment works. This is operated by Umgeni Water, a regional water supply authority which has an interest in pollution control as part of its integrated catchment management strategy. The activated sludge treatment process employed at the works produces a sludge which, following dewatering, is transported to a nearby land disposal site which has been engineered to ensure environmentally acceptable use is made of the site. The heavy metal concentrations of the sludges produced by the Hammarsdale Wastewater Works have long been a matter of concern, in particular the elevated concentrations of Hg. Investigations of the land disposal site showed that the Hg is bound in the upper topsoil (0–10 cm), and only very low concentrations are found in the subsoil. As the soils at the disposal site possess low cation exchange capacities, the difference between Hg concentrations in the top and subsoils may be attributed to binding of the Hg by organic matter introduced by sludge addition. Current research on the disposal area is focused on the movement of Hg, N and other elements through the soil profile into plants, surface and groundwater resources, with the ultimate aim of identifying suitable crops for cultivation at the site following its use as a sludge disposal facility.     

Agricultural transformation in Zimbabwe: Lessons for South Africa after apartheid

When Zimbabwe became independent in 1980, reversing historical inequalities became a primary rural development objective. Growth, it was argued, must also generate greater equity. As part of their overall plan, sophisticated agricultural institutions were made available to black farmers and a land resettlement program enacted. Due to constitutional constraints, international pressure, fears about restructuring the economy too rapidly, and a class alliance between white farmers and an emerging black bourgeoisie, limited highveld land was reallocated and large-scale commercial farmers maintained their historical privileges. The only significant change in the subsector was increased capital intensity of production. Small-scale black farmers with access to good land and productive resources have responded remarkably to new production opportunities. In only 7 years, black production of maize and cotton more than doubled and marketed contributions rose from less than 10% to approximately half of national sales. The pattern of agricultural development, however, is spatially and socially limited. New forms of uneven rural development are emerging. The majority of rural blacks still have inadequate land and off-farm income resources to insure subsistence levels of consumption on an annual basis. The rural crisis persists. In South Africa, a Zimbabwe-type small farm development strategy would help a minority of households who are already relatively privileged in terms of access of land, agricultural capital and off-farm income resources. To achieve rural growth and equity, new forms of social organization in farming must be developed concurrent with a major land redistribution program. Zimbabwe's strategy has successfully generated short-term growth but cannot fulfill longer-term rural development objectives.     

Mapping land limitations for agricultural land use planning using fuzzy logic approach: a case study for Marinduque Island,Philippines

This study demonstrated the use of fuzzy logic approach in mapping land limitations for agricultural land use planning using publicly available data for the province of Marinduque, Philippines. The paper focused only on the two major crops in the province, coconut, and banana. Based on the results, slope is the major factor limiting the production of these two crops. Slope is identified as a limitation in approximately 80% and 18% of the agricultural land of the province for coconut and banana production, respectively. Other land limitations for coconut production in the province include rainfall, soil, and combination of these factors with slope. In the case of banana, soil and combination of this factor with slope were identified as land limitations.

     

粮食产量对气候变化驱动水资源变化的响应

水资源是支撑粮食生产的重要因素之一,气候变化驱动下的水资源变化及对粮食产量的影响是当前研究的国际前沿和热点问题。以汾河流域冬小麦和夏玉米2种主要粮食作物为研究对象,利用线性回归、人工神经网络、支持向量机、随机森林、径向基网络、极限学习机等6种机器学习算法构建粮食产量模拟模型,基于气候弹性系数法分析水资源量对气候变化响应关系,在流域尺度上研究粮食产量对气候变化驱动水资源变化的综合响应。结果表明:①机器学习算法能够较好地模拟汾河流域的冬小麦和夏玉米产量;②降水增加10%导致汾河流域水资源量增加19.4%,气温升高1℃导致水资源量减少4.3%;③当降水减少10%~30%时,冬小麦产量减少6.4%~19.3%,夏玉米产量减少4.0%~15.0%;④当气温升高0.5~3.0℃时,冬小麦产量预计增加1.8%~17.1%,夏玉米产量预计增加1.2%~7.9%;⑤汾河流域冬小麦产量对降水和气温变化的敏感性大于夏玉米。相关成果对于区域水资源管理和农业生产策略制定具有重要的科学意义和实用价值。     

河南洛阳市土壤和农作物中钼分布规律与影响因素研究

钼是人体和农作物必需的有益元素,具有防癌抗癌作用。由于不同地区土壤中钼含量和土壤酸碱性的不同,农作物中钼含量有很大差异,同时不同农作物对钼的吸收也不相同。研究不同农作物中钼富集规律可以为健康地质发展、富钼农产品开发、功能农业发展、种植结构调整提供依据。本文以洛阳市硒资源详查区及其他农业种植区为研究区,通过采集22种大田种植的农作物及其根系土,采用电感耦合等离子体质谱法（ICP-MS）测定土壤和农作物钼含量,研究了不同农作物钼含量特征及其影响因素。结果表明：洛阳市土壤钼含量较高,是中国土壤富钼特色地区。绿豆、豇豆、黑豆、黄豆、红小豆和花生是富集钼的主要农作物,钼平均含量>9mg/kg,富集系数>500%,属于钼的超富集农作物。芝麻、豆角、谷子、小麦、玉米和油菜籽钼含量较高,钼含量均值介于0.446～2.437mg/kg,富集系数介于40%～300%,属于富钼农作物。辣椒、大蒜、红薯、秋葵的钼含量介于0.1～0.3mg/kg,富集系数介于10%～30%,属于高钼农作物。苹果、梨、葡萄、石榴、樱桃与中药材银条的钼含量<0.05mg/kg,富集系数<5%,是低钼农作物。大多数农作物钼含量与根系土钼含量呈正相关,而苹果、葡萄、石榴、樱桃等水果钼含量与根系土钼含量呈负相关。研究揭示了在碱性环境下土壤中的钼更容易被农作物吸收。区内农作物与中国其他地区相比均呈富钼特征,是开发富钼农业产业的有利地区。依据不同农作物钼含量,选择出绿豆、豇豆、黑豆、黄豆、红小豆和花生是研究区特色富钼农产品,芝麻、豆角、谷子、小麦、玉米和油菜籽是富钼农产品,辣椒、大蒜、红薯、秋葵属于高钼农作物。本成果为研究区富钼农产品开发、调整种植结构提供了科学依据。     

1998～2007年中国农业用水分析

中国农业用水在未来将面临巨大的挑战。根据国际农业用水研究和政策领域近10年出现的范式变迁的核心内容,建立了基于"绿水"、"蓝水"的中国农业用水的新综合分析框架。并利用广义农业水资源量和广义农业水土资源匹配的概念和评估方法,分析了全国1998～2007年10年间4种主要粮食作物(水稻、小麦、玉米和大豆)的农业用水、耗水以及水分生产力变化趋势和现状。结果表明:中国广义农业水资源量中57%来源于耕地有效降水的"绿水",43%来源于耕地灌溉"蓝水"。主要粮食作物水分生产力水平已经接近或达到世界较高水平。未来继续提升水分生产力的任务将会更加艰巨。因此,为保证中国粮食安全,建议国家设立"粮食安全水资源红线"。同时,根据广义农业水资源量的分析计算,主要粮食作物用水安全红线应该划定在大约7800亿m3左右。     

GIS支持下的农业土地资源评价研究—以贵阳市区为例

本文基于土地质量评价的“压力－状态－响应”（PSR）模型，选取土壤重金属污染作为评价的一个压力为指标，应用GIS对贵阳市区农业土地资源进行了综合质量评价。定量评价的结果表明，区域农业土地资源中大部分土地资源重较好，但旱地和水田共有17．11km^2的重金属重度污染区，这部分耕地已不适宜种植农作物，同时，适合人类耕作的高质量耕地由于土壤重金属污染减少了近1／3，说明贵阳市区进行土壤重金属污染防治具有重要的意义。     

贵州省安顺市耕地表层土壤养分元素分布特征

望谟县坝达金矿位于黔西南地区,大地构造位置为扬子板块西南缘。本文通过对望谟县坝达金矿矿床地质特征、1∶10 000土壤地球化学特征进行综合分析和研究,旨在对望谟县坝达金矿进行找矿远景分析。通过矿床地质特征研究表明,Ⅰ、Ⅱ、Ⅲ矿体均呈脉状,赋矿岩石为领好组一段的含碳酸盐碎屑岩类;矿体产出受两条走向北西的断层破碎带控制;产出于两断裂之间的次级断层内金以自然金、半裸露金和碳酸盐、黄铁矿等包裹金形式存在。1∶10 000土壤地球化学圈定了Ⅰ-Au-As,Ⅱ-Au-As,Ⅲ-As-Sb-Hg,Ⅳ-Au-Hg四个综合异常区,并发现Au和As相关性最强,且在Ⅰ-Au-As异常查证中发现了金矿化。因此,综合研究认为该矿区存在深部隐伏矿体的可能。     

黑龙江省克山县土壤-作物系统硒元素地球化学特征

黑龙江省克山县是我国克山病区.通过分析土壤表层（0～20 cm）样品809件,深层（150～200 cm）样品205件,对不同类型土壤中微量元素Se的含量、有效态含量、农作物籽实Se含量特征进行了研究.结果显示：土壤表层Se元素含量平均为0.249×10^-6,低于全国平均值,高于世界、和东北平原黑龙江省土壤平均值,土壤表层Se含量以足硒为主要特征,足硒土壤面积达93.95%;土壤深层Se含量平均为0.167×10^-6,明显低于土壤表层,Se含量不足或缺Se土壤面积占62.62%;不同类型土壤表层Se含量由高到低顺序为黑钙土=草甸土 > 黑土 > 暗棕壤,深层Se含量由高到低依次为暗棕壤 > 黑土 > 草甸土 > 黑钙土,与土壤表层高低顺序相反;不同土地利用类型Se含量显示建设用地和耕地Se含量较高,林地和水利用地含量较低,反映Se含量受人类活动影响明显;玉米、大豆、水稻主要农作物籽实Se含量平均为0.033×10^-6,呈低Se特征.     

Modeling of bore hydrographs to determine the impact of climate and land-use change in a temperate subhumid region of southeastern Australia

To determine the relative impact of climate and human intervention on groundwater elevations in western Victoria, southeast Australia, bore hydrograph fluctuations in three aquifers were modelled using a transfer function noise model (PIRFICT) and an auto-regressive model (HARTT), which give generally comparable results. Most of the groundwater-level fluctuations (>90%) are explained by climatic variation, particularly rainfall. The overall non-climate-related trend in groundwater level is downward and small but statistically significant (??.04 to ??.066 m/yr), and is probably due to the widespread replacement of grazing land by wheat and canola cultivation, as these crops use more water than pasture. A large non-climate-related trend (??.30 m/yr) for bores in an irrigation area is mainly related to groundwater extraction. The response time of the system is rapid (only 4.85 years on average), much faster than previously estimated. Rates of groundwater flow are much slower; groundwater ages are up to ~35,000 years. Response times effectively represent the time for the system to move to a new state of hydrologic equilibrium; this prediction of the time scale of the impacts of land-use change on groundwater resources will allow the development of better strategies for groundwater management.     

Aspects of agricultural land use in Ireland

Ireland's soil regions consist largely of Luvisols, Cambisols, and Gleysols. Approximately 60% of Ireland's land area is subject to varying degrees of soil limitations. Twenty-five percent of the land area comprises wet lowland mineral soils. Ninety percent of Ireland's agricultural area comprises pasture, hay, and silage. Approximately 30% of the agricultural area is devoted to dairying, and 55% to cattle production. is devoted to dairying, and 55% to cattle production. Trends in agricultural land use indicate that tillage declined substantially while livestock showed a substantial increase particularly in the decade 1965–1975. Research concludes that over 2.8 million ha has a capacity to carry at least 100 LU/40 ha (100 acres). Levels of fertilizer use in Ireland are below EEC levels. The highest fertilizer use levels are associated with the eastern and southern areas of Ireland. Tillage crops occupy only 10% of the agricultural area, while they account for 26% of tertilizer and lime use.     

苏鲁人类扰动区表土花粉组合与植被关系的研究

利用江苏和山东地区70个农田和非农田表土样品研究不同土地类型的花粉特征,为使用孢粉作为研究手段分析古代农业提供重要参考资料。结果表明所有植被类型的花粉谱均以草本花粉为主,但是含量明显不同,表现为农田>荒地>林地。其中禾本科谷物类型含量的变化最大,农田最高达41%,荒地高于11%,林地低于8%。谷物类禾本科花粉传播距离很短,其百分含量在10~20m内急剧衰减至27.6%,500m以外降低至20%以下;十字花科花粉也有相似的变化规律。藜科花粉对农田和荒地具有同等指示意义,可能与人类活动强度与方式有关。中华卷柏含量增加表明人类活动加强。油菜、水稻、小麦和玉米等谷物类花粉产量或者在土壤中保存存在差异:十字花科>玉米型禾本科>水稻型禾本科>小麦型禾本科。降趋势对应分析(DCA)结果表明,通过花粉相对百分含量,可以较好地区分水田、麦田和非农田,但油稻田与麦稻田、荒地与林地难以区分。     

Engineering geological data in support of municipal land use planning—a case study in Analandia, southeast Brazil

This paper presents a method for transforming the information of an engineering geological map into useful information for non-specialists involved in land-use planning. The method consists of classifying the engineering geological units in terms of land use capability and identifying the legal and the geologic restrictions that apply in the study area. Both informations are then superimposed over the land use and a conflict areas map is created. The analysis of these data leads to the identification of existing and forthcoming land use conflicts and enables the proposal of planning measures on a regional and local scale. The map for the regional planning was compiled at a 1:50,000 scale and encompasses the whole municipal land area where uses are mainly rural. The map for the local planning was compiled at a 1:10,000 scale and encompasses the urban area. Most of the classification and operations on maps used spatial analyst tools available in the Geographical Information System. The regional studies showed that the greater part of Analandia’s territory presents appropriate land uses. The local-scale studies indicate that the majority of the densely occupied urban areas are in suitable land. Although the situation is in general positive, municipal policies should address the identified and expected land use conflicts, so that it can be further improved.     

贵州喀斯特农业生产中多种矿物元素液态肥的应用效果分析

为改变贵州喀斯特地区农产品产出率低、品质差的现状,从喀斯特生态地质环境脆弱、土壤缺少微量元素等特征入手,利用富含矿物元素的硅酸盐岩,开发生产多元素液态矿物肥料,补偿喀斯特地区农作物生长需要的矿物营养元素。2002年以来经100多个农户及贵州省各地土肥站、农业科研生产部门在贵州喀斯特地区十几个县市进行了700多亩种植试验,获得了农作物产量增加和农产品质量提高的效果。施用多元素液态矿物肥种植的水稻、玉米、辣椒、油菜、烤烟、水果及蔬菜等20多个农作物,其90%以上的作物增产超过5%,70%增产超过10%,农产品的蛋白质提高1～2个百分点,稻谷支链淀粉提高2.7%,果实的外观色、香、味、形得到明显改观。实践证明施用多元素液态矿物肥料是提高喀斯特地区农产品产出率的新途径。