Role of root and tuber crops in food production strategy for semi-subsistence agriculture

Persistent population pressure on agricultural land in the tropics has led to the evolution of food production strategies heavily weighted towards increasing productivity per unit of land. In many of these same areas, tropical root crops represent a major item in the national food economies. Given this scenario, this paper examines the potential role of tropical root crops in meeting domestic food needs. First, the present contribution of root crops to food production is briefly summarised and used to provide simple guidelines for allocating research resources. These guidelines are somewhat deficient in that they overlook a number of energetic considerations of importance at both the individual producer and national level. To illustrate, a two-goods model of a semi-subsistence agricultural production unit is constructed and some conclusions drawn which lend weight to the opinion that tropical root crop research should receive high priority.     

丘陵山区农业机械化现状与发展

农业机械化发展对推进农业现代化建设至关重要,尽管中国农业机械化得到了全程、全面发展,但不同地区之间仍存在较大差异.丘陵山区特殊的地理环境,导致其农业机械化基础薄弱、发展缓慢,极大地限制了中国农业机械化整体水平的提高.系统总结了丘陵山区农业机械化转型升级过程中存在的突出问题,在此基础上建议优先进行农机、农艺高度融合的农田宜机化改造,重点研发特色经济作物生产全程机械化装备,探索集成作物生产智慧管控系统,强化主体培育和政策支持.这不仅有助于解决丘陵山区农业机械化发展难题,补齐丘陵山区农业机械化短板,提高丘陵山区农业生产力水平,还可以充分发挥农业机械化在实现共同富裕中的积极作用,推动乡村振兴战略全面实施,促进中国农业可持续和现代化发展.     

基于遥感DSI指数的干旱与冬小麦产量相关性分析

利用2000—2012年MODIS ET/PET和NDVI数据集构建干旱指数(DSI),监测山东省和河南省冬小麦主产区的农业干旱,并在地级市尺度上进一步评估冬小麦关键生育期干旱对冬小麦产量的影响。结果表明:2010年9月—2011年2月山东省特大干旱过程显示的DSI不仅能监测气象干旱,还能较好地反映农业干旱在空间上的差异性以及时间上的演变。不同冬小麦生育期干旱对冬小麦产量影响不同,灌浆期干旱对冬小麦产量的影响最大,干旱致使土壤水分亏缺,影响了作物正常的灌浆强度,进而导致作物减产;其次是拔节期;返青期干旱对产量基本没有影响。     

我国主要农作物生产机械化及发展策略

我国农业生产都开始广泛实行机械化的生产,能否面实行农作物的机械化生产,是今后我国农业走向现代化的重要标志.文章就针对我国农业实行机械化生产的现状和应用等方面进行阐述,并提出有效地改进措施和建议,为全面实行我国主要农作物走向现代化生产提供参考.     

阜新市机械化保护性耕作实施进展

阜新市地处辽宁西部的半干旱地区,旱灾、风灾频繁,土地贫瘠、水土流失严重,不良的气候条件严重地影响了农业生产,造成了农作物产量低而不稳,农民增收困难.自2001年在该地区实施了机械化保护性耕作以来,土壤理化性能逐步得到改善,作物生长条件及农业生态环境日趋好转,促进了粮食增产和农民增收,使农业生产逐渐步入了良性循环和可持续发展的轨道.为此,总结了阜新市5年来实施机械化保护性耕作的经验和做法,为北方干旱地区推广保护性耕作提供了借鉴经验和技术参考.     

Adapting to climate change: Agricultural system and household impacts in East Africa

The East African region exhibits considerable climatic and topographic variability. Much spatial and temporal variation in the response of different crops to climate change can thus be anticipated. In previous work we showed that a large part of this variation can be explained in terms of temperature and, to a lesser extent, water effects. Here, we summarise simulated yield response in two crops that are widely grown in the region, maize and beans, and investigate how the impacts of climate change might be addressed at two levels: the agricultural system and the household. Regionally, there are substantial between-country and within-system differences in maize and bean production responses projected to 2050. The arid-semiarid mixed crop-livestock systems are projected to see reductions in maize and bean production throughout most of the region to 2050. Yields of these crops in the tropical highland mixed systems are projected to increase, sometimes substantially. The humid-subhumid mixed systems show more varied yield responses through time and across space. Some within-country shifts in cropping away from the arid-semiarid systems to cooler, higher-elevation locations may be possible, but increased regional trade should be able to overcome the country-level production deficits in maize and beans caused by climate change to 2050, all other things being equal. For some places in the tropical highlands, maize and bean yield increases could have beneficial effects on household food security and income levels. In the other mixed systems, moderate yield losses can be expected to be offset by crop breeding and agronomic approaches in the coming decades, while more severe yield losses may necessitate changes in crop types, movement to more livestock-orientated production, or abandonment of cropping altogether. These production responses are indicative only, and their effects will be under-estimated because the methods used here have not accounted for increasing weather variability in the future or changes in the distribution and impacts of biotic and other abiotic stresses. These system-level shifts will take place in a context characterised by high population growth rates; the demand for food is projected to nearly triple by the middle of this century. Systems will have to intensify substantially in response, particularly in the better-endowed mixed systems in the region. For the more marginal areas, the variability in yield response, and the variability in households’ ability to adapt, suggest that, even given the limitations of this analysis, adaptation options need to be assessed at the level of the household and the local community, if research for development is to meet its poverty alleviation and food security targets in the face of global change.     

Co-evolutionary scenarios of intensification and privatization of resource use in rural communities of south-western Niger

Agricultural production in the semi-arid agro-ecosystems of the Sahel centres on cereal staple crops and pastoralism with increasing crop–livestock integration. Animals mobilize soil fertility through manure production, graze crop by-products, and transfer nutrients from distant pastures to cropped areas. Yet in these systems various interacting factors, i.e. climate variability, poor soil fertility, poverty, and institutional constraints limit the capacity of agriculture to keep pace with the growing needs of an increasing human population.The major trends associated with population growth are (1) increasing area cropped at the expense of rangelands; (2) reduced availability of and access to good quality grazing resources, and (3) seasonal migration of labourers and transhumance of herds. These trends lead to co-evolution of farming systems towards increased privatisation of resource use.This study examines the implications of the development processes where farming systems co-evolve with their surroundings. It explores the impact of integrated management of livestock and crops in rural communities on both the livelihoods of differently endowed farms, and on the agro-ecosystem. Different scenarios explored the co-evolution of three sites situated in Western Niger with their environment. The sites differ in relative area cropped. The scenarios simulate the different future outcomes for varying socio-economic and biophysical criteria with either current or more intensive management.Explorative bio-economic models are used to compare a range of farm, livelihood and ecological indicators, and to reveal social and ecological trade-offs.If current agro-ecosystems and their environments co-evolve towards increased privatisation of grazing resources, then soil fertility is likely to deteriorate on the lands managed by the agro-pastoral groups. Soil fertility may improve on lands managed by the livestock-scarce farmers settled in villages, at the cost of declining farm incomes. The agro-pastoral groups are likely to resort to more distant pastures for feed. The village-based, livestock-endowed farms will resort to feeding on on-farm crop residues. Intensification, though associated with relative decreases in real incomes, will enhance food security in these new systems, except for the poorer settled farmers.     

农业机械化水平对中国粮食生产技术效率的空间溢出效应研究——基于农机跨区作业视角

提升农业机械化水平是落实国家“藏粮于技”战略中的重要一环，利用1998—2020年中国31个省(市、区)的面板数据，采用空间杜宾模型，研究农业机械化水平对粮食生产技术效率的直接影响和空间溢出效应。研究发现：第一，农业机械化水平对粮食生产技术效率具有显著的空间溢出效应，在其他影响因素不变的情况下，其他地区粮食生产技术效率加权值每提升1%，本地粮食生产技术效率提升约0.579%；第二，从不同农机类型来看，农业机械化水平对粮食生产技术效率的空间溢出效应主要通过大中型农机实现，影响系数为0.252；第三，农业机械化水平对粮食生产机械效率的空间溢出效应存在于不同经纬度之间，在水稻跨区作业省份中，农业机械化水平对粮食生产技术效率的空间溢出效应为0.027。因此，提出通过进一步优化农机跨区作业机型、改进粮食品种、提升田间管理技术等方式扩大不同地区粮食作物的种植、生长和收获时间差，为农机跨区作业创造条件，实现资源效益最大化。     

商洛市农业投入产出效率研究

运用CCR模型评估了2015—2019年商洛市农业投入产出效率，结果表明，总体上商洛市农业投入产出效率较高，但个别年份仍存在一定程度的投入冗余和产出不足。为更好地提升商洛市农业发展，应加大农村教育投入，培养新型农民；加快基础建设，推进农业现代化；统筹整合涉农资金，提高资金使用效率；促进农村土地流转，形成规模效益。      

元江——红河流域农业灌溉及其发

元江—流域内水资源时空分布极不均匀，上游是资源性缺水地区，中下段又是水资源极度丰富地区，普遍存在严重的季节性缺水问题。流域内贫困面大，种植业在农村经济中占主导地位，面临脱贫致富与保护生态环境的矛盾，不合理的水资源开发及农业灌溉方式，极易造成严重的水土流失和水环境污染。通过分析流域内的农业生产和灌溉用水管理现状，提出切合各地实际、易于被群众所掌握、投资小见效快的农业高效节水灌溉模式     

农业干旱卫星遥感监测与预测研究进展

干旱是影响农业生产的主要气候因素.传统的农业干旱监测主要是基于气象和水文数据,虽然能提供监测点上较为精确的干旱监测结果,但是在监测面上的农业干旱时,仍存在一定的局限.遥感技术的快速发展,尤其是目前在轨的卫星传感器感测的电磁波段涵盖了可见光、近红外、热红外和微波等波段,为区域尺度农业干旱监测提供了新的手段.充分利用卫星遥...     

作物干旱胁迫补偿效应研究进展

干旱是作物生长环境中普遍存在的逆境胁迫之一,在一定范围的干旱胁迫后复水短期内,作物在生理生化代谢和生长发育等方面产生补偿或超补偿效应的正面效应,以弥补干旱胁迫期间对作物造成的伤害和损失.补偿效应是作物抵御逆境胁迫的重要调节机制,也是对作物进行有效水分调控,实现节水高效农业的主要生理依据.文中从生长、生理生化、代谢及产量补偿效应及其影响因素等进行了综述.在此基础上,提出今后可从胁迫-复水条件下作物农艺及生理指标的补偿机制,光合作用的补偿规律及反馈机制,水分胁迫后补偿效应的效益评价3个方面进行研究.对于完善和丰富生物性节水理论和指导农业高效用水管理,发展节水灌溉和提供作物水分生产力具有重要的理论意义和实用价值.     

我国农业应对干旱灾害的技术研究现状及展望

干旱灾害对农业生产的威胁最大,造成农业经济损失较严重。分析了我国农业干旱具有发生频率高、持续时间长、受灾范围广、经济损失大、突发性和季节性较强的特点,从农艺技术、化学调控措施、节水灌溉技术与应急抗旱装备等方面,探讨了目前我国农业应对旱灾的技术研究现状,分析了我国农业生产过程中应对干旱存在的问题,提出今后我国农业应对干旱灾害的研究重点,主要是加强对农作物干旱发生发展规律的研究,大力推广农业节水技术提高作物水分利用效率,加强研发适合区域农业生产特点的应急性抗旱装备,大力开展抗旱预警技术研究与防控预案制定等方面。     

地膜覆盖技术探讨

地膜覆盖技术是通过创造不同于露地栽培的农田土壤环境,达到增温保墒、蓄水防旱、抑制杂草、促进作物根系发育、改善作物品质等目的。简述地膜覆盖技术的产生与发展,分析其促进作物增产的机理,介绍该技术的应用效果和技术要点,供农业生产者参考。     

基于作物空间信息特征的灌区种植结构优化研究

针对目前北方许多大型灌区种植结构不合理、农业需水量偏大、水资源紧缺等问题,提出了一种基于作物空间信息特征的种植结构优化方法,通过调整种植结构和优化空间分布,减少农业需水量,提高农业效益。利用地统计学(GS)和地理信息系统(GIS)的空间处理能力,分区计算了灌区多年平均参考作物需水量(ET0)和作物需水量(ETc),并统计分区内作物单产和产值信息;构建了基于作物空间信息特征的多目标优化模型,设计了2种作物种植结构方案。结果表明,与传统多目标种植结构优化模型相比,基于作物空间信息特征的种植结构优化方法在节水效果和农业效益上都有一定的优势。     

山西省丘陵山区农作物全程机械化探索

在分析我国丘陵山区农机化发展研究概况的基础上,重点从地形地貌、农作物生产情况方面分析了山西省丘陵山区农作物机械化生产现状,指出了山西省丘陵山区农作物全程机械化发展的优势,并从地形条件、种植农艺、人员整体素质、基础设施、农机装备数量、研发能力、政府支持度等方面分析了制约山西省丘陵山区农作物全程机械化发展的制约因素,给出了发展意见和措施,以期对今后山西省丘陵山区农机化的发展提供参考。     

Promoting the adoption of natural resource management technology in arid and semi-arid areas: Modelling the impact of spineless cactus in alley cropping in Central Tunisia

The arid and semi-arid areas of North Africa are becoming deserts. Most of the research and development projects in these areas aim at developing alternative technologies to reduce land degradation and favour sustainable economic activities. The ‘spineless cactus-alley cropping system’ is an interesting alternative in the low rainfall areas of North Africa. This system limits land degradation by the use of perennial crops, produces cheap and drought resistant sources of feed, and favours biomass production in the inter spaces. The important question is how to promote the adoption of this technology. A bio-economic model has been developed to identify the conditions of development of the ‘spineless cactus-alley cropping system’ in an agro-pastoral community of Central Tunisia. Scenarios relating to different types of institutional support, either monetary or informational, were analysed. The results revealed larger cash flow, more livestock and less cereal cultivation on marginal land. Adoption of the technology is clearly favoured by public financial support and also largely by transmission of information on the expected yield of the system. The findings suggest that extension services play a crucial role in creating awareness among farmers of the impact of technology in terms of yields and income diversification.     

Integrated agricultural research and crop breeding: Allelopathic weed control in cereals and long-term productivity in perennial biomass crops

Future agricultural research will need to increasingly integrate ecological, physiological and molecular methods, in order to understand agricultural crops in situ and their interaction with the environment as well as organisms impacting on their long-term health and productivity (‘agricultural eco-genomics’). The need for integration will increasingly implicate on crop breeding strategies for most agricultural systems. In this paper, implications are highlighted for two contrasting areas of agricultural research related to sustainable crop production: first, the possibilities to utilize crop allelopathic activity to suppress weeds as an alternative to chemical weed control; and second the increasing interest to environmentally friendly and sustainable produce perennial energy crops on agricultural land. ‘Sustainability’ in agriculture is difficult to define unequivocally, but frequently implies the increased utilization of ecological processes. Breeding strategies towards increased utilization of allelopathic crops require initially the integration and verification of allelopathic processes in various agricultural contexts, because there is currently great uncertainty about the predictable operation of allelopathic activity in different ecological contexts. Breeding programs for future biomass crops, most promising are perennials such as Salix, would greatly benefit from the integration of ecological information affecting long-term productivity, e.g., eco-physiological growth determinants at stand level and the biological control of pests. Agricultural eco-genomics could facilitate a compromise between intensive agriculture and the frequently expressed demand for greater sustainability in agriculture.     

基于粒子群优化小波神经网络模型的春玉米生育阶段干旱预测

【目的】为更好地开展区域性作物生长季气候干旱预测,指导春玉米高效节水补灌生产。【方法】采用皮尔逊相关系数方法选取了与干旱指数最相关的因子,利用阜新市阜蒙县1965—2019年逐日气象数据,探索建立了粒子群算法优化的小波神经网络模型(PSO-WNN),将春玉米不同生育阶段的水分亏缺指数结果进行对比验证模型精度,并利用模型模拟预测未来5 a干旱发生情况。【结果】通过模型验证,春玉米5个生育阶段(播种—出苗阶段、出苗—拔节阶段、拔节—抽雄阶段、抽雄—乳熟阶段、乳熟—成熟阶段)的均方根误差(RMSE)分别为0.0419、0.0174、0.0481、0.0297、0.0421,决定系数R2分别为0.8402、0.9853、0.8990、0.9575、0.9177,且预测结果与实际干旱等级相符。【结论】文中构建的模型适用于阜新地区春玉米干旱预测,未来5 a该地区春玉米在播种—出苗阶段可能无旱或轻旱,出苗-拔节阶段可能发生中旱甚至特旱,生育后期干旱程度逐渐减弱,拔节—抽雄和抽雄—乳熟两个阶段出现轻旱概率较高,乳熟—成熟阶段出现干旱的概率较低,程度较小,表明未来几年该地区春玉米生产应该更多关注出苗—拔节阶段的旱情。