Potential and attainable food production and food security in different regions

Growing prosperity in the South is accompanied by human diets that will claim more natural resources per capita. This reality, combined with growing populations, may raise the global demand for food crops two- to four-fold within two generations. Considering the large volume of natural resources and potential crop yields, it seems that this demand can be met smoothly. However, this is a fallacy for the following reasons. (i) Geographic regions differ widely in their potential food security: policy choices for agricultural use of natural resources are limited in Asia. For example, to ensure national self-sufficiency and food security, most of the suitable land (China) and nearly all of the surface water (India) are needed. Degradation restricts options further. (ii) The attainable level of agricultural production depends also on socio-economic conditions. Extensive poverty keeps the attainable food production too low to achieve food security, even when the yield gap is wide, as in Africa. (iii) Bio-energy, non-food crops and nature compete with food crops for natural resources. Global and regional food security are attainable, but only with major efforts. Strategies to achieve alternative aims will be discussed. <br>     

The environmental implications of intensified land use in developing countries

The major agricultural intensifications in the developed world over the last half century have produced a range of important environmental problems. These include pollution, damage to wildlife and landscape and other issues, both on- and off-site. These are largely being controlled by scientific investigation and Government regulation. As developing countries increase agricultural production over the next 30 years, this may also cause even more serious environmental damage.<br>The paper distinguishes between production-related on-site damage, and off-site and more extensive effects. Both may involve soil and water effects, such as soil erosion, salinization, siltation, eutrophication and loss of water quality. The use of more agrochemicals can damage water quality, health, wildlife and biodiversity. Loss of habitat from the extension of farming is particularly damaging to biodiversity. A developing off-site problem is the production of greenhouse gases by farming systems, including the conversion of forests to farmland. In the future the introduction of genetically engineered species of plants, animals or microbes will need secure control.<br>Work, probably on a catchment basis, is necessary to understand and control these problems. The three main requirements are much better environmental information from the developing world; the selection of environmental indicators to be monitored; and the support of local farmers in protecting the environment. There are encouraging indications of farmer concern and action over obvious on-site damage, but this may not extend to extensive off-site issues. The main danger is that developing food scarcity would cause the environmental issues to be ignored in a race for production. <br>     

Introduction and conclusions for a Discussion entitled Land resources: on the edge of the Malthusian precipice?

Introduction and conclusions for a Discussion hosted by the Ciba Foundation and entitled Land resources: on the edge of the Malthusian precipice? Discussion held on the 4th and 5th December 1996, and organized and edited by D. J. Greenland, P. J. Gregory and P. H. Nye. <br>     

New native crops for the arid Southwest

Agricultural production in the arid Southwest is heavily dependent upon water for irrigation. If current trends of water use continue, the amount of water available to agriculture in the year 2000 will only meet approximately 50% of the needs of currently available irrigated crop land. Development of new crops with low irrigation needs is of highest priority. None of the major crop plants of the world is well adapted to arid lands. However, in the Sonoran Desert, more than 375 species of noncultivated food plants have been identified, and approximately 40 of these served as major local food resources for native people in the region. Research and development of new crops must address the issues of water use, productivity, chemical composition, and quality. Domestication of native species that have evolved and became adapted to arid conditions in the Southwest is considered to be a good strategy. Research and development programs on such native, new crops as guayule, jojoba, and buffalo gourd are well underway. New domestication programs involvingCuphea species for medium-chain fatty acids,Lesquerella species for hydroxy fatty acids,Grindelia camporum for resin production, and interspecific hybrids ofBaccharis for landscape plant materials are described. The role of the USDA Agricultural Research Service, state agricultural experiment stations, and industry in the development of new crops is discussed.     

西北干旱区利用间套作促进能源植物的高产高效

在全球性能源紧缺和我国能源植物大规模种植困难等大背景下,优质、充足的原料供应已成为制约生物质能源产业发展的主要限制因素。在确保能源植物高效生产和克服"与粮争地、与人争粮"现实的同时,挖掘我国边际土壤高产高效生产能源植物的土地优势和增产潜力。通过筛选评价适宜西北干旱地区高抗逆的新型能源植物种类,开发应用能源植物与粮经作物间套作栽培技术,实现新型能源植物对逆境资源的高效利用和可持续规模化种植,提高能源植物的生产力和优化能源物种的区域配置,增加土地产值和农民收入,缓解能源紧缺,达到经济、生态和社会效益多赢,为我国能源和粮食安全提供技术支撑。     

The Influence of Agricultural Trade and Livestock Production on the Global Phosphorus Cycle

Trends of increasing agricultural trade, increased concentration of livestock production systems, and increased human consumption of livestock products influence the distribution of nutrients across the global landscape. Phosphorus (P) represents a unique management challenge as we are rapidly depleting mineable reserves of this essential and non-renewable resource. At the same time, its overuse can lead to pollution of aquatic ecosystems. We analyzed the relative contributions of food crop, feed crop, and livestock product trade to P flows through agricultural soils for 12 countries from 1961 to 2007. Due to the intensification of agricultural production, average soil surface P balances more than tripled from 6 to 21 kg P ha⁻¹ between 1961 and 2007 for the 12 study countries. Consequently, countries that are primarily agricultural exporters carried increased risks for water pollution or, for Argentina, reduced soil fertility due to soil P mining to support exports. In 2007, nations imported food and feed from regions with higher apparent P fertilizer use efficiencies than if those crops were produced domestically. However, this was largely because imports were sourced from regions depleting soil P resources to support export crop production. In addition, the pattern of regional specialization and intensification of production systems also reduced the potential to recycle P resources, with greater implications for livestock production than crop production. In a globalizing world, it will be increasingly important to integrate biophysical constraints of our natural resources and environmental impacts of agricultural systems into trade policy and agreements and to develop mechanisms that move us closer to more equitable management of non-renewable resources such as phosphorus.     

Interactions between plant nutrients,water and carbon dioxide as factors limiting crop yields

Biomass production of annual crops is often directly proportional to the amounts of radiation intercepted, water transpired and nutrients taken up. In many places the amount of rainfall during the period of rapid crop growth is less than the potential rate of evaporation, so that depletion of stored soil water is commonplace. The rate of mineralization of nitrogen (N) from organic matter and the processes of nutrient loss are closely related to the availability of soil water. Results from Kenya indicate the rapid changes in nitrate availability following rain.<br>Nutrient supply has a large effect on the quantity of radiation intercepted and hence, biomass production. There is considerable scope for encouraging canopy expansion to conserve water by reducing evaporation from the soil surface in environments where it is frequently rewetted, and where the unsaturated hydraulic conductivity of the soil is sufficient to supply water at the energy limited rate (e.g. northern Syria). In regions with high evaporative demand and coarse-textured soils (e.g. Niger), transpiration may be increased by management techniques that reduce drainage.<br>Increases in atmospheric [CO₂] are likely to have only a small impact on crop yields when allowance is made for the interacting effects of temperature, and water and nutrient supply. <br>     

Agroecological zones and the assessment of crop production potential

The rapidly growing world population puts considerable pressure on the scarce natural resources, and there is an urgent need to develop more efficient and sustainable agricultural production systems to feed the growing population. This should be based on an initial assessment of the physical and biological potential of natural resources, which can vary greatly. The agroecological zonation (AEZ) approach presents a useful preliminary evaluation of this potential, and ensures that representation is maintained at an appropriate biogeographic scale for regional sustainable development planning. The principal AEZs of the world, as described by the Technical Advisory Committee of the Consultative Group on International Agricultural Research, are presented along with their extent and characteristics. Net primary productivity of terrestrial vegetation can be assessed from weather data, and it varies from 1 t dry matter ha^-1 yr^-1 in high latitude zones and dry regions to 29 t ha^-1 yr^-1 in tropical wet regions, depending on the climatic conditions. To assess the crop production potential, length of the growing period zones, a concept introduced by the UN Food and Agriculture Organization, is very useful as it describes an area within which rainfall and temperature conditions are suitable for crop growth for a given number of days in the year. These data, combined with the information on soils and known requirements of different food crops, can be used to assess the potential crop productivity. Some perspectives on AEZs and crop production potential are presented by describing the manner in which production potential can be integrated with present constraints. Efforts to intensify production should place emphasis on methods appropriate to the socio-economic conditions in a given AEZ, and on promotion of conservation-effective and sustainable production systems to meet the food, fodder and fuel needs for the future. <br>     

Root architecture

<正>Numerous research publications over the past 20 years have made it quite clear that a better understanding of the molecular and genetic basis for variation in root system architecture(RSA)will greatly aid the development of crop varieties with improved and more ef ficient nutrient and water acquisition under limiting conditions.In many parts of the world,especially in developing     

Closing Yield Gaps: How Sustainable Can We Be?

Global food production needs to be increased by 60–110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P₂O₅, and K₂O) to attain the potential yields. Globally, N-fertilizer application needs to increase by 45–73%, P₂O₅-fertilizer by 22–46%, and K₂O-fertilizer by 2–3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends on the way management strategies for closing yield gaps are chosen and implemented.     

Reflections on food security under water scarcity

Forecasts on population growth and economic development indicate that there will be substantial increases in food demand for the forthcoming decades. We focus here on the water requirements of food production, on the issue of whether there would be enough water to produce sufficient food in the future, and we offer options to face this challenge based on recent trends observed in some agricultural systems. Given the competition for water faced by the agricultural sector, and the uncertainties associated with climate change, improving the efficiency of water use in both rain-fed and irrigated systems is the main avenue to face the challenge. In rain-fed agriculture, managing the risk associated with rainfall variability is a promising option to increase productivity. In irrigated systems, a case study on the improvements in water productivity in Andalusia, Spain, is used to illustrate some of the opportunities to make progress. Progress in reducing irrigation water use in recent decades has been substantial, but decreasing the consumptive use of crops is a much more difficult challenge. The need for more research and technology transfer on improving water-limited crop production is highlighted, and emphasis is placed on interdisciplinary approaches to gain the insight needed to achieve new breakthroughs that would help in tackling this complex problem.     

Halophyte crop cultivation: The case for Salicornia and Sarcocornia

Increasing soil salinization and the growing scarcity of fresh water dictate the need for a creative solution to attain sustainable crop production. To accomplish this aim, the domestication of inherently salt tolerant plant species with economic value is proposed as a straightforward methodology. Most studies investigating salt tolerance mechanisms are linked to small, experimental systems that cannot be generalized to the real agricultural context. The crops Salicornia and Sarcocornia, however, with their extreme salt tolerance and long history of consumption by humans, make the ideal model plants on which to base a halophyte growth strategy. New applied technologies were developed for leafy vegetable production using small-scale greenhouse and in-field studies. Several cultivation systems adapted to the irrigation water salinity and the available soil conditions are described. Daylength manipulation and a repetitive harvest regime partially elucidated the flowering patterns of Salicornia and Sarcocornia and showed that flowering should be prevented for maximal vegetable production. Additionally, the beneficial effect of saline irrigation on quality parameters via the enhancement of stress-induced secondary metabolites with antioxidant capacity should be considered during cultivation. This review summarizes the recent developments in growing halophytes for food production with saline irrigation, using Salicornia and Sarcocornia as a case study.     

Matching roots to their environment

Background

Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers.

Scope

This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future.     

The Role of Latin America’s Land and Water Resources for Global Food Security: Environmental Trade-Offs of Future Food Production Pathways

One of humanity’s major challenges of the 21st century will be meeting future food demands on an increasingly resource constrained-planet. Global food production will have to rise by 70 percent between 2000 and 2050 to meet effective demand which poses major challenges to food production systems. Doing so without compromising environmental integrity is an even greater challenge. This study looks at the interdependencies between land and water resources, agricultural production and environmental outcomes in Latin America and the Caribbean (LAC), an area of growing importance in international agricultural markets. Special emphasis is given to the role of LAC’s agriculture for (a) global food security and (b) environmental sustainability. We use the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT)—a global dynamic partial equilibrium model of the agricultural sector—to run different future production scenarios, and agricultural trade regimes out to 2050, and assess changes in related environmental indicators. Results indicate that further trade liberalization is crucial for improving food security globally, but that it would also lead to more environmental pressures in some regions across Latin America. Contrasting land expansion versus more intensified agriculture shows that productivity improvements are generally superior to agricultural land expansion, from an economic and environmental point of view. Finally, our analysis shows that there are trade-offs between environmental and food security goals for all agricultural development paths.     

Review: Insect meal: a future source of protein feed for pigs?

Are insects the farm animal of the future? A key agenda for agricultural production systems is the development of sustainable practices whereby food and feed can be produced in an environmentally efficient manner. These goals require novel approaches to complex problems and demand collaboration between scientists, producers, consumers, government and the general population. The provision of feed for animals is a major contributor to land and water use and greenhouse gas (GHG) emissions. Further, overfishing and a reduction in available land and water resources on which crops can be grown has led to an increase in price of protein ingredients such as fish meals and oils and soybean meals. Determination of novel solutions to meet the feed protein requirements of production animals is key to the development of sustainable farming practices. The Australian pork industry aims to develop production systems that efficiently use available resources (such as feed and energy) and limit the production of emissions (such as manure waste and GHGs). Invertebrates (insects e.g. black soldier flies) are naturally consumed by monogastric and aquatic species, yet the large-scale production of insects for feed (or food) is yet to be exploited. Most insects are low producers of GHGs and have low land and water requirements. The large-scale production of insects can contribute to a circular economy whereby food and feed waste (and potentially manure) are reduced or ideally eliminated via bioconversion. While the concept of farm-scale production of insects as domestic animal feed has been explored for decades, significant production and replacement of traditional protein sources has yet to be achieved. This review will focus on the potential role of insect-derived protein as a feed source for the Australian pig production industry.     

基于水足迹的作物生产生态效率评价——以陕西省为例

传统生产函数很少考虑农业生产中自然资源的要素功能，也无法表达化肥、农药的使用对环境产生的损害。研究将绿水、蓝水和灰水足迹，分别代表降水资源、灌溉水资源和作物生产的环境影响，引入农业生产函数，采用随机前沿方法测算陕西省作物生产生态效率，并分析其影响因素。结果表明：1）1985-2018年间陕西省作物生产总水足迹呈上升趋势，作物生产单位面积用水强度不断增强。单位面积水足迹及蓝、绿、灰水占比与气候、种植结构，灌溉条件和农业污染相关。2）研究期内，陕西省作物生产生态效率以2003年为分界点呈现先降后升趋势，陕西省作物生产生态效率的U型波动对应政府对耕地资源保护和农业污染管控政策变化。3）作物生产生态效率低下的区域集中在生产落后的农业区和农业条件差的工业区，农业耕地质量差，灌溉条件匮乏，低效率（产值角度）的灌溉和化肥农药施用以及落后农业生产方式是导致作物生产生态效率低下的主要原因。4）研究期内，陕西省作物生产经历了从规模报酬递增，到规模报酬递减2个阶段，与耕地面积的变化基本对应。短期内，考虑各投入要素的产出弹性调整种植结构和化肥农药施用量是提高作物生产生态效率的有效措施，而促进农业产业升级和技术革新是推动作物生产生态效率提升的根本路径。     

全球气候变化对农业生态系统的影响研究进展

全球大气中CO2浓度升高、气温升高及降水量的变化等是全球气候变化对农业生产和农业生态系统影响最为重要的几个生态因子,其影响主要表现在对农作物产量、生长发育、病虫害、农业水资源及农业生态系统结构和功能等方面.在过去的几十年,全球气候变化已对我国农业和农业生态系统,特别是我国北方旱区农业造成重大影响,其中不少影响是负面的或不利的.本文综述了全球气候变化对农业水资源、农田土壤养分变化、农作物生长发育、农作物病虫害与杂草、粮食安全及农业生态系统的结构和功能等方面的影响.针对21世纪全球气候变化对我国农业生产和农业生态系统带来的挑战,探讨了今后研究的重点和难点问题.     

Population momentum and the demand on land and water resources

Future world population growth is fuelled by two components: the demographic momentum, which is built into the age composition of current populations, and changes in reproductive behaviour and mortality of generations yet to come. This paper investigates, by major world regions and countries, what we know about population growth, what can be projected with reasonable certainty, and what is pure speculation. The exposition sets a frame for analysing demographic driving forces that are expected to increase human demand and pressures on land and water resources. These have been contrasted with current resource assessments of regional availability and use of land, in particular with estimates of remaining land with cultivation potential. In establishing a balance between availabilty of land resources and projected needs, the paper distinguishes regions with limited land and water resources and high population pressure from areas with abundant resources and low or moderate demographic demand. Overall, it is estimated that two-thirds of the remaining balance of land with rainfed cultivation potential is currently covered by various forest ecosystems and wetlands. The respective percentages by region vary between 23% in Southern Africa to 89% in South-Eastern Asia. For Latin America and Asia the estimated share of the balance of land with cultivation potential under forest and wetland ecosystems is about 70%, in Africa this is about 60%. If these were to be preserved, the remaining balance of land with some potential for rainfed crop cultivation would amount to some 550 million hectares. The regions which will experience the largest difficulties in meeting future demand for land resources and water, or alternatively have to cope with much increased dependency on external supplies, include foremost Western Asia, South-Central Asia, and Northern Africa. A large stress on resources is to be expected also in many countries of Eastern, Western and Southern Africa <br>     

Der Beitrag der Grünen Gentechnik

Yield increase: the contribution of plant biotechnology Modern plant breeding is facing increasing challenges to meet future needs caused by global climate changes, decreasing reserves of fossil fuels, an increasing world population as well as an aging society. Therefore, besides input traits, breeding aims focus on renewable resources and to ensure production of sufficient high quality food and feed. In particular, the world‐wide rising in energy demand harbors the risk that more and more agricultural land will be used for industrial purposes instead for food production. Therefore, breeding of highly productive crop plants for the production of valuable biological materials is of great importance. To optimize the production of valuable compounds a profound molecular and biochemical knowledge of the underlying metabolic pathways and the availability of technologies for the transfer of these findings into crop plants are needed. Plant biotechnology can be a key technology being important for deciphering molecular relationships as well as being required for the implementation of these findings into breeding programs.     

Adaptation of global land use and management intensity to changes in climate and atmospheric carbon dioxide

Land use contributes to environmental change, but is also influenced by such changes. Climate and atmospheric carbon dioxide (CO₂) levels’ changes alter agricultural crop productivity, plant water requirements and irrigation water availability. The global food system needs to respond and adapt to these changes, for example, by altering agricultural practices, including the crop types or intensity of management, or shifting cultivated areas within and between countries. As impacts and associated adaptation responses are spatially specific, understanding the land use adaptation to environmental changes requires crop productivity representations that capture spatial variations. The impact of variation in management practices, including fertiliser and irrigation rates, also needs to be considered. To date, models of global land use have selected agricultural expansion or intensification levels using relatively aggregate spatial representations, typically at a regional level, that are not able to characterise the details of these spatially differentiated responses. Here, we show results from a novel global modelling approach using more detailed biophysically derived yield responses to inputs with greater spatial specificity than previously possible. The approach couples a dynamic global vegetative model (LPJ‐GUESS) with a new land use and food system model (PLUMv2), with results benchmarked against historical land use change from 1970. Land use outcomes to 2100 were explored, suggesting that increased intensity of climate forcing reduces the inputs required for food production, due to the fertilisation and enhanced water use efficiency effects of elevated atmospheric CO₂ concentrations, but requiring substantial shifts in the global and local patterns of production. The results suggest that adaptation in the global agriculture and food system has substantial capacity to diminish the negative impacts and gain greater benefits from positive outcomes of climate change. Consequently, agricultural expansion and intensification may be lower than found in previous studies where spatial details and processes consideration were more constrained.