Download PDF Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China

Free download. Book file PDF easily for everyone and every device. You can download and read online Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China file PDF Book only if you are registered here. And also you can download or read online all Book PDF file that related with Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China book. Happy reading Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China Bookeveryone. Download file Free Book PDF Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China at Complete PDF Library. This Book have some digital formats such us :paperbook, ebook, kindle, epub, fb2 and another formats. Here is The CompletePDF Book Library. It's free to register here to get Book file PDF Resource Use and Agricultural Sustainability: Risks and Consequences of Intensive Cropping in China Pocket Guide.

The reviewed countries have implemented specific provisions for seasonal immigration, which makes up a significant part of seasonal labour. These provisions include temporary immigration schemes that allow employers to hire foreign nationals when qualified citizens are not available Canada, Korea, and the United States , schemes that provide sponsorship of employers for foreign workers, including skills training components Australia , regional programmes to attract newcomers to regions with shortages, and the removal of impediments regarding labour costs for employing foreign workers Estonia.

In Sweden, in addition to incentives that promote employment in the green industries e. To reduce labour shortages, it is also important to ensure that taxation is not so high that it discourages participation in labour markets, in particular for low-cost jobs in food and agriculture, and to ensure legislation and tax provisions do not impede farm transmission. Several of the reviewed countries have recently introduced promising programmes or regulations to improve their management of water resources, with a particular emphasis on agriculture.

For example, Brazil has initiated steps to bolster the use of water charges for hydropower facilities and agriculture users. These water charges aim to help improve water allocation while helping to recover regulatory agency recover charges. A well-functioning financial market facilitates access to finance for farmers and agri-food firms. Many countries provide investment support to farms and food processing firms, but it would be more efficient to address the causes for the lack of access to credit at market conditions e.

Finally, an effective competition policy, including low barriers to entry and exit, facilitates access to a diversity of affordable inputs for farmers and to food for consumers. Competitive conditions also encourage innovation and productivity growth, including through their impact on structural change along the value chain.

Business regulations have generally become more supportive of innovation over time. In particular, starting a business has become easier in many countries, thus improving competition. Reduce barriers to trade Trade can facilitate the flow of goods, capital, technology, knowledge, and people needed to innovate. In OECD countries, trade policy does not generally restrict access to modern technologies and farm inputs. Tariffs on capital and intermediate goods are particularly low in Australia, Canada, Japan, and the United States.

This increases the cost of capital, inputs and machinery equipment that are needed to innovate, and thus affects the competitiveness of the agri-food sector. In the reviewed countries, some farm sectors are also protected from foreign competition. Trade facilitation procedures have improved in most of the reviewed countries since , but countries should explore the scope for further trade facilitation, e. There are few restrictions to foreign direct investment in the reviewed countries, with the exception of agricultural land in a few of them.

Making the agriculture research and innovation system more responsive to needs Continuous innovation in technologies, practices and organisation facilitate the development of a more productive and environmentally sustainable food and agriculture sector. Research and innovation play a dominant role in driving productivity growth in the short and long term in all the countries reviewed.

The theoretical pathways between innovation and productivity are backed by empirical evidence from both sector-level and farm-level estimates. Innovation can also improve sustainability if incentives to that effect are in place. Improving the responsiveness of agricultural innovation systems to needs, and the acceptance of innovation by consumers and society, is thus crucial.

Agricultural innovation systems are diverse The agricultural innovation system AIS is the main vehicle to develop agronomic and technological solutions to improve the productivity and sustainability of food and agricultural production. Encompassing the adoption of these solutions, the system involves a wide range of actors including policy makers, teachers, researchers, advisors and brokers of innovation, farmers, agri-food companies, co-operatives, non-profit organisations NGOs , and consumers.

Sustainable agriculture - Wikipedia

AISs in the reviewed countries are very diverse in terms of ambitions, institutional set-up, and funding mechanisms. For example, country reviews cover the two countries that contribute the most to world public investment in agricultural research — China and the United States — as well as small economies with greater reliance on imported knowledge. The contribution of public research organisations under agriculture-related ministries to agricultural research is particularly important in Argentina, Brazil, Colombia, Korea, Japan, and the United States, while that of specialised universities dominate in other countries.

Governments traditionally play an important role in agricultural innovation systems Governments provide strategic guidance, financial support to researchers and advisors in public and private organisations, and research infrastructure such as databases, laboratories and information and communication technologies ICT.

In many countries the public sector dominates agricultural research.

Search form

Governments also encourage private investment in research and innovation through investment support, tax policy, intellectual property rights IPR protection, and more generally policies that enable investment. Governments have traditionally played an important role in organising and financing training and advisory systems, thus facilitating innovation at the farm level, and public systems continue to dominate in some countries. Agricultural innovation systems are in transition Changes are in response to the recognition in many of the reviewed countries that new challenges require a different approach to innovation.

The main trend in innovation policy is to improve the impact of public expenditure and make the system more collaborative and demand-driven to increase adoption. Despite progress, however, top-down approaches continue to dominate in most countries, although mechanisms are in place to improve responsiveness to needs, as outlined below.

Various trends in public funding for agricultural research are found across countries, depending on the indicator. Public funding mechanisms for agricultural research has also changed, as the share of competitive projects in total funding increases. Efforts to foster public-private collaboration have been made in most of the reviewed countries, using funding and institutional mechanisms.

The importance of international co-operation is acknowledged in all the countries as it helps to reduce costs and to pool resources and exploit synergies on regional or global challenges. Table 4. It enables linking these budget lines to policy considerations through classification by socioeconomic objectives. However, it provides only a partial indicator of investment in public agricultural research, since it refers to research funding instruments dedicated specifically to agriculture.

Renewed policy attention is being given to improving the adoption of innovation in farms and firms through improvements in the enabling environment and specific investment support. Farm advisory systems are in transition to adapt to new needs and to provide a wider range of advice requiring re-training and flexibility. New intermediary actors have emerged to meet these needs.

Based on the experience in the countries reviewed, the common principles noted below would make the AIS more efficient and responsive to needs. Improve the governance of agricultural innovation systems Government priorities for agricultural research and innovation need to be co-ordinated and communicated clearly. They should be part of a longer-term strategy for agricultural innovation, which takes into account long-term challenges such as climate change, and consumer and societal demands. They should also be integrated into wider growth policy strategies. A common finding from the country reviews is the need to better involve stakeholders in the definition of objectives, starting at an early stage of the definition process.

For example in Canada, an objective of Value Chain Round Tables VCRTs , which bring together key industry leaders from across the value chain with federal and provincial government policy makers, is to share information about challenges and opportunities, identify research, policy, regulatory and technical requirements, and to create co-operative long-term strategies. Co-ordination between the various public and private research organisations at the national and sub-national levels needs to be improved.

A good practice is to give a co-ordinating role to a specific national institution and to clarify the mandates of organisations. In Sweden, efforts to strengthen the general innovation system have focused on improving governance and linkages, including the grouping of public research institutes into a single holding entity. This should enable continuous improvement, but also help identify where more profound changes are needed to meet objectives.

Comprehensive, coherent and regular evaluation procedures should be developed. Ideally, these should include independent evaluations and cover a wide range of indicators of efforts, outputs and impacts that go beyond research excellence and financial considerations. In Australia and the United States, research evaluation procedures are in place that include impact assessment. Simplify research programming to improve effectiveness and transparency In some of the countries reviewed, government funding of research and innovation goes through multiple channels, making access of funds and evaluation of programmes quite complex.

The efficiency of research funding mechanisms should also be reviewed on a regular basis to ensure higher impact. At the same time, a challenge is to explore innovative ways to generate new breaking through ideas to overcome current constraints, for example through demand-driven funding mechanisms.

However, 7. Fuglie and Toole contains a detailed analysis of this issue and estimations of the impact of public expenditure on agricultural research in the United States on private agricultural research. Estimating the impact of public expenditure on agricultural research on private research as part of evaluation procedures should help target public policy and improve complementarity.

The United States offers a good example of complementarity between public and private agricultural research, facilitated by the strong investment of some multinational companies in agricultural research, and regular assessment of public research investments. Knowledge infrastructure is a public good that facilitates public and private research activities and enables innovation. It is particularly important to support the development of ICT infrastructure and general purpose technologies, as well as specific knowledge infrastructure such as databases and institutions, which require long-term stable funding as done in Brazil.

Since they joined the European Union in , Estonia and Latvia have upgraded research infrastructure using EU structural funds. In some countries, however, the decline in public funding for agricultural research and the high reliance on project funding were identified as potential issues for the longterm performance of the AIS. Governments should dedicate public funds to long-term riskier large-scope research projects and projects that aim to improve long-term sustainability in food and agriculture. They should also dedicate specific funds for policy-relevant research, i. A first step is to remove institutional constraints to public research organisations to engage in co-operation activities with the private sector.

Many of the general innovation policies of the reviewed countries include funding mechanisms that support PPPs. For instance, Canada offers PPP support as part of its agricultural policy. In the reviewed countries where agricultural research is organised by commodity sector, research is often focused on improving profitability.

Public co-funding thus needs to ensure broader sustainability issues are covered. An option is to create cross-sector thematic areas and projects, including environmental issues, or to broaden the scope and membership of existing commodity research systems. Strengthening the capacity of smaller domestic companies to engage in research and innovation, possibly using incentives targeted to their needs, is important for the performance of the whole sector.

Investments are normally driven by market demand, but governments also provide different kinds of incentives. Few mechanisms supporting innovation in private companies are sector-specific, but some programmes target innovation in small- and medium-size enterprises SMEs e. The extent to which they benefit agri-food companies in the countries reviewed is not clear. The evaluation of programmes that support research and innovation in private companies should be strengthened to ensure they are efficient and reach their intended beneficiaries.

The increase in IPR protection in recent decades has prompted higher investment in food and agriculture research and innovation by enabling firms to recover their investment. In some of the reviewed countries, however, enforcement of IPR protection needs to be improved. To facilitate the innovation process, Australia grants innovation patents with a shorter protection of eight years. Governments should facilitate the development of alternative sources of funding for research and innovation, through appropriate legislation.

This funding remains within the value chain, except in Sweden. In the Netherlands, revenues from patents fund research Innovation Box. Strengthen linkages within the agricultural innovation system and across sectors Research and innovation in food and agriculture increasingly benefit from advances in other sectors and general-purpose research, such as genetics and digital technologies. It is thus crucial to promote and enable research co-operation across sectors.

The integration of the agricultural system in the general innovation system should ensure better use of public funds, increased efficiency of innovation systems through the pooling of complementary expertise and resources, and higher spill-over across sectors. As they focus on local needs, regional innovation systems are well-placed to identify synergies across sectors and actors that can benefit rural development. Stronger linkages between AIS actors researchers, educators, extension services, farmers, industry, NGOs, consumers and others also contribute to improving the efficiency and relevance of the system.

This does not necessarily require institutional reforms, but rather mechanisms to facilitate connections and co-ordination. To foster balanced partnerships, governments need to strengthen and harness the capacity of private companies and farmer organisations to participate in research partnerships via project funding and support to networking and training activities, as done by the EU innovation and agricultural policy or the Canadian Value Chain Round Tables. The link between research and technical assistance, in particular, requires strengthening in many of the countries reviewed.

This can be done by adding a technology transfer component to research projects, or by valuing and encouraging networking between researchers, advisors and producers. It is important to facilitate the sharing of knowledge in order to strengthen innovation by improving public understanding of the importance of innovation in food and agriculture, in the sector and in society, and building trust in science through increased transparency and education.

For example, Japan established a platform for open innovation in agriculture that includes all agricultural innovation actors, private companies, universities, and research institutions in non-agricultural sectors. To facilitate international co-operation, governments can, for example, remove institutional constraints to public research organisations that impede the hiring of foreign researchers or trainees, or to engage in activities that are not directly of national interest.

Governments can also support the integration of research data and sharing of experience at the international level, student and staff exchanges, and the sharing of equipment and laboratories. EU Member States illustrate the benefits from the EU-wide innovation policy, which supports collaborative, multi-country projects and provides complementary funding to national research and innovation organisations. Strengthen farm advisory systems to facilitate adoption The potential benefits of innovations are only realised if they are effectively implemented.

Farm advisory systems need to be flexible in order to respond to changing demands at the farm level. A role for the government is to encourage a varied supply of relevant advice from diverse public and private suppliers, while ensuring needs are met. In the Netherlands, for example, a diversity of private companies provide a wide range of advisory services since the privatisation of the public service. In Estonia, the government provides guidance but delivery is made by independent organisations. In such a pluralistic and competitive system, public resources should focus on services that the private sector typically under-provides, including advice to small, semi-subsistence farmers to broaden their opportunities, targeted advice on sustainable technologies and practices, and use experience to better understand issues and needs.

In the United States, for example, support to technical assistance and research projects is provided for within agri-environmental policies. A role for the government is also to facilitate the sharing of experiences through networking, and the development of open databases, and to ensure advisors have up-to date knowledge — possibly through certification — and to facilitate continuous life-long training. Address skills need in food and agriculture Matching labour and skills demand from food and agriculture is a growing issue in many countries.

Agriculture-related education in particular can contribute by becoming more attractive to students, anticipating new skills demand and adapting courses accordingly, offering long-life training to all workers in the sector. Governments should ensure training and re-training programmes respond to needs, including for digital, environmental and management skills, and cover all workers, including immigrants, women and seasonal workers. This requires discussion with education actors and the private sector to identify long-term needs.

In the Netherlands, the Green Table was created in to continue collaboration among educational institutions on common interest regarding discussion and negotiation with the government; relationships between education and the labour market; and maintenance of a good knowledge infrastructure. To meet future needs, it is important to change traditional public perception and to be more proactive in reaching non-traditional agricultural students.


  • How to feed the world - without killing everything | News | The Guardian!
  • Counselling in the Workplace (Counselling in Context).
  • Lose Weight & Gain Muscle - High Protein Vegetarian Breakfast Recipes.
  • So what are the other answers?.
  • Innovation, Productivity and Sustainability in Food and Agriculture by OECD - Issuu!
  • How To Work The Amateur Radio Satellites!

Ensuring a stable and enabling policy and regulatory environment to facilitate investment A broader role for the government is to ensure that the general policy and regulatory environment is conducive to investment that leads to productivity and sustainability improvements. Two areas for improvement are outlined in this section: regulations and sustainability incentives. Modernise regulations The regulatory environment for entrepreneurship affects food and agricultural companies.

Lecture 8: Key Indicators of Sustainable Agriculture

Following OECD Good Regulatory Practices OECD, a , the countries reviewed are encouraged to simplify their regulatory system where necessary, and to make regulations clearer, more transparent, more easily accessible, and more coherent across jurisdictions. Regulatory collaboration between and within countries should also be enhanced to reduce regulatory heterogeneity.

Urban agriculture

Regulatory co-operation between the United States and Canada provides an opportunity to revisit differences between federal and provincial regulations. While some regulations may be perceived as slowing innovation, others stimulate the development of innovative solutions that enable the industry to meet requirements. This is the case, in particular, with environmental regulation.

Align policies and regulations towards sustainability improvements Regulations on natural resources are central to ensuring the long term sustainable use of natural resources. In large part, they determine access to and use of land, water and biodiversity resources, and impose limits on the impact of industrial and agricultural activities on natural resource e. Several countries have set regulations to restrict agricultural land expansion to forested areas e. Brazil and Colombia , to discourage farmland fragmentation Turkey , or to prevent agricultural land conversion to urban uses Japan and Korea.

While qualitative comparison can be made based on country reviews, the evaluation of environmental regulatory stringency for agriculture and the role of regulations and their effectiveness require further investigation. Evidence from the country reviews suggests that policy incentives towards environment and resource sustainability need to be realigned by removing environmental harmful subsidies, such as fuel tax rebates, and using taxation or market mechanisms to meet environmental objectives.

Sweden was one of the first countries to introduce taxes on pesticides in The Netherlands introduced in a charge to fund the production of sustainable energy in addition to the standard tax on energy.

Can we ditch intensive farming - and still feed the world?

Another important water resource impact is the effect of irrigated agriculture on riparian ecosystems and wetlands. Agricultural diversions can intercept the water needed to replenish and preserve these ecosystems.

In addition, irrigated agriculture can concentrate salts in drainage water that flows downstream to other users as well as to aquatic ecosystems that are sensitive to salinity levels [ Williams , ]. The global area of wetlands has halved since , largely as a result of agricultural appropriation of both land and water [ Zedler and Kercher , ]. This process is ongoing. The impact of agricultural diversions has been recognized in national regulations that prescribe the minimum flow needed to preserve riparian and wetland systems.

Although the ecological benefits of ephemeral rivers are not adequately captured by such low flow requirements these limits do give a sense of the problem. If taken seriously, these requirements increase water scarcity considerably. The major increases in fertilizer use that have driven the rise in global crop production have also had major impacts on water and land resources as well as the atmosphere.

The impacts of agriculture on the global nitrogen cycle and on the accumulation of reactive nitrogen in water, soil, and the atmosphere are well documented [ Galloway and Cowling , ; Galloway et al. These changes have led to eutrophication of fresh and marine waters, contamination of groundwater, changes in greenhouse gas composition and atmospheric ozone levels, and soil acidification [ Vitousek et al. Fertilizer use has also gradually increased the stock of phosphorous in soil and aquatic reservoirs [ Smil , ].

By comparison, the adverse environmental impacts of potassium appear to be much less than those associated with nitrogen and phosphorous [ Arienzo et al. Since nutrient augmentation is a major component of the agricultural intensification process, it is likely that total fertilizer applications will increase rather than decrease.

In light of this, it is particularly important to insure that agricultural practices minimize biologically active nitrogen and phosphorous residuals not utilized by crops. A useful measure of sustainable use is the nitrogen use efficiency NUE , which measures the fraction of applied biologically active nitrogen that remains in the crop system harvested biomass, recycled crop residues, and soil. A similar concept can be applied to phosphorous. Cassman et al. Although much of this reactive nitrogen is eventually denitrified to molecular nitrogen, it has significant effects as it travels through the environment.

Also, an increasing amount of this nitrogen appears to be accumulating as production outstrips natural denitrification capabilities [ Robertson and Vitousek , ]. Mueller et al. Phosphorous is overapplied in Europe, China, and South America. Nutrient use efficiencies must be improved in order to obtain yield gains without further increasing the discharge of reactive nutrients to the natural environment. These sources vary significantly with time, space, and cropping practices.

Better process understanding and monitoring methods will likely be the keys to development of efficiency improvements that are both effective and economically feasible [ Smil , ; Erisman et al. Knudsen et al. Since yield gaps have not decreased anywhere near as much as pesticide use has increased, additional applications appear to be giving diminishing return.

The adverse environmental and human health impacts of pesticides are well documented and it is now reasonable to ask whether the crop production increases obtained from extensive pesticide use have been worth the costs [ Pimentel , ]. The primary challenge for the industry in recent years has been to maintain existing yields by dealing with new pests and diseases. Losses due to pests remain quite high, despite widespread pesticide use. These losses are presumably less than those experienced before the widespread introduction of pesticides, although there are few controlled experiments.

Tilman et al. They emphasize the value of combining chemical agents with other means of pest control, including crop rotation and more diversity within the field. Considering the diminishing returns cited above, it seems unlikely that increased use of chemical pesticides will provide yield improvements. It seems more likely that pesticides will be viewed as one component of a multifaceted pest management program that includes biotechnology, conservation tillage, and creative land use techniques [ Tilman et al.

Such a program could become an important part of a broader agricultural intensification strategy. One of the primary impacts of expanded food production on land resources is soil degradation, which can reverse the gains obtained from converting forest or grasslands to agricultural use and can threaten yield increases obtained from nutrient enrichment or other means. The estimates of suitable cropland cited earlier are based on simplified descriptions of soil properties and climate that do not explicitly account for the possibility of soil degradation or loss of currently cultivated land.

Degradation processes that can be aggravated by agricultural activity include water and wind erosion, physical and chemical weathering, and salt accumulation [ Lal et al. It is difficult to assess how serious a problem soil degradation could be on a global scale [ Govers et al.


  1. So we need to find more land to cultivate then?.
  2. Design, Synthesis, Multifunctionalization and Biomedical Applications of Multifunctional Mesoporous Silica-Based Drug Delivery Nanosystems!
  3. Sustainable Agriculture Program | National Institute of Food and Agriculture.
  4. The Three Musketeers.
  5. Urban agriculture - Wikipedia.
  6. How to feed the world - without killing everything | News | The Guardian;
  7. GLASOD, a widely cited study based on expert judgment, produced a global map of soil degradation that is summarized by Bridges and Oldeman [ ]. They estimate that the global area with moderate or worse soil degradation is about 13 million km 2 , a value that is comparable in magnitude to total global cropland. Unfortunately, the estimate and associated soil maps have not been verified or reproduced and they represent a single snapshot in time [ Sonneveld and Dent , ].

    More recent studies have attempted to quantify soil degradation through surrogates derived from the normalized difference vegetation index NDVI but NDVI changes may reflect land use conversion e. Rengasamy [ ] reviews soil salinity on a global scale, citing estimates that about 10 million km 2 of the total global land area of million km 2 has saline or sodic soils.

    It is unclear how much impact this has had on crop production. Since tropical forests represent a significant fraction of uncultivated land suitable for crops, the possibility of soil degradation in these areas is particularly important to consider. A number of investigators have discussed the vulnerability of tropical soils, where soil fertility is generally poor due to fast turnover of soil organic matter and nutrient leaching that can be accelerated by agriculture [ Ewel , ; Ramankutty et al.

    Although tropical forests are currently being converted to cropland at a rapid rate, it is likely that soil fertility in the newly cropped areas will decrease over time and that lime and nutrients will need to be added to maintain acceptable yields [ Ramankutty et al. Conversion of forest and savannah to agriculture has an indirect impact on land resources through its effect on habitats and biodiversity.

    In a survey of habitat conversion, Hoekstra et al. Since native species promote agricultural productivity by regulating pests and maintaining natural nutrient cycles, there is significant benefit to integrating agriculture, as much as possible, with natural habitats [ Tscharntke et al. However, the connections, positive or negative, between management practices in particular locations and ecosystem services from native species are often difficult to quantify.

    It is generally agreed that adverse impacts will be greater if the agriculture that replaces natural systems puts stress on water resources more likely if the land is irrigated , degrades soils, or increases the flux of excess nutrients and pesticides into the environment [ Tilman et al. Although food security problems can occur over a range of space and time scales and at various income levels, they tend to be more severe at the local level, during transient climatic or economic disturbances, and they tend to have a more serious impact on the poor.

    Such studies can identify bounds on sustainable production and indicate whether local needs can be satisfied with local resources. China is a large agricultural producer that has experienced rapid population growth, a changing diet, and stress on water and land resources, including groundwater overdraft, nutrient enrichment, soil degradation, loss of biodiversity, and desertification.

    In the past 60 years, water tables have dropped continuously at a rate of 0. The natural groundwater flow system is recharged at the piedmont of the Taihang mountains on its western boundary as well as in the plain. While in the past it had its discharge in the Bohai Sea, the flow direction has been reversed in both the lower and the shallow aquifer layers due to the formation of deep cones of depression in heavily exploited areas [ Cao et al. The North China Plain overexploitation is a consequence of the intensification of agriculture since the s.

    While the natural annual precipitation of — mm is sufficient to support one grain crop per year under average rainfall conditions, the double cropping of mainly winter wheat and summer maize with a combined evapotranspiration of — mm can only be sustained by the depletion of groundwater resources. This transfer is not sufficient to bring the aquifer back to a balance between recharge and pumping.

    The only other viable option is to change the cropping system. Since rainfall is concentrated in summer, winter wheat is responsible for most of the groundwater overpumping. Reduction of this crop seems to be the most efficient solution to the overdraft problem, especially considering the low profit made with wheat. Some of the issues become more concrete when looking at a smaller subunit, Guantao county in Handan prefecture.

    GTranslate

    The aquifer system is composed of a shallow phreatic aquifer and a deeper confined aquifer. The deeper aquifer is used by households and industry, but also by agriculture in parts of the county where the salinity of the phreatic aquifer is too high. Agricultural use of the lower aquifer will be forbidden, creating a gap in irrigation water supply of 6. The shallow aquifer is an important resource for agriculture since surface water supply from reservoirs and rivers is very limited. The gap between pumping and recharge in the shallow aquifer is Estimates of the supply and costs for these options are summarized in Table 1.

    Overall, water efficiency has improved considerably over the last 50 years in North China Plain [ Jia et al. Water saving irrigation requires a relatively small subsidy since higher yield and savings in fertilizer compensate for some of the cost. Presently, however, it is not treated to a sufficient level and its use in irrigation is not advisable as it may lead to soil pollution.

    In many cases, this was caused by irrigation with wastewater. It is clear from the table that Yellow River transfer is the cheapest way to reduce the gap between supply and demand. The only measure that can entirely eliminate the gap is abandonment of the winter wheat crop. Covering the gap could start with the cheapest method before going to the next more expensive method to provide the remaining water.

    McKinsey Resources Group [ ] suggested this net marginal cost curve method as a strategy for closing China's national water gap. Alternatively, the winter wheat option can be viewed as a backup to be used when less expensive measures are insufficient. The Yellow River is an example where upstream consumptive use has contributed considerably to flow depletion in the downstream, to an extent that the traditionally perennial river went dry in 7 of the 10 years from to In the most severe case, this occurred for up to days over the km reach upstream of the river's mouth [ Zhang et al.

    Strict management and slightly better rains improved the situation considerably [ Ringler et al. No more serious flow interruption has occurred in the past decade, although the low flows are still below minimum ecological demands. The conflict between irrigation agriculture and ecology is clearly revealed in the inland basins of China such as the Hei and Tarim River Basins. In both cases, upstream consumptive use led to drying up of the lower river stretches and terminal lakes.

    In , the State Council decreed that, of the total annual flow of 3. This new regulation made the farmers turn to groundwater for irrigation, which resulted in overdraft and the decline of groundwater tables in some areas. In the long run, groundwater is more useful for buffering drought years than for compliance with the downstream requirement. The Tarim River had no flow beyond Daxihaizi reservoir for 30 years from to This left km of river, between the reservoir and the terminal Taitema lake wetland, without water, destroying riparian ecosystems.

    In , the basin managers began a large experiment by reducing irrigation diversions and reserving a portion of the reservoir releases as ecological water for the downstream area [ Hou et al. This experiment has subsequently become standard practice. Groundwater tables along the river were monitored and showed the positive impact of the releases. Initially, infiltrating water had to lift the low groundwater table into the region of 10 m below ground, the suitable depth for the phreatophyte Populus euphratica trees growing along the river course.

    Only then could the tree transpiration start. The corridor that is watered in this way is much narrower than the original Populus belt [ Schilling et al. The amount of water released from Daxihaizi for ecological flows is worth This loss is about the same as the value of the agricultural production of the neighboring Yanqi Basin, which provides a large part of the ecological water flow from its Lake Bosten.

    However, it is still relatively small when compared to the agricultural production value of 9. These examples suggest that reduction of agricultural water consumption to achieve sustainable water use is feasible. However, it results in production losses that have to be covered by increased imports. This process works only so long as there are water surpluses and production potential elsewhere.

    As more areas become resource limited, sustainability becomes more difficult to achieve, especially with regard to conservation of natural ecosystems and biodiversity. Food security involves at least three different requirements. First, global production needs to meet global demand or there will be shortages. This is, of course, a necessary rather than a sufficient condition for security.

    In addition, local populations need enough water, land, and nutrient resources to feed themselves or they need an income sufficient to purchase the food they cannot grow. Finally, food production must be conducted in a way that sustains the environment it depends upon. This implies that the methods used to achieve food security should preserve the quality of water, land, and ecological resources. It is useful to consider the connection between the global perspective of the first requirement and the local perspective of the second.

    Many water security analyses focus on regional or local scales. Examples include studies of China's groundwater overdraft problems and of droughts in Australia and the western U. There is extensive evidence for water scarcity on these scales, although less for water scarcity at the global scale. Similar comments apply to land shortages, which are more important at regional scales than globally.

    A large fraction of the global population now lives in environments that simply do not have the local resources needed to reliably support a growing population. This includes most residents of large urban areas. Food security in such areas is maintained by trade and the associated movement of virtual water and land resources. It not only saves on space, but can also be managed to use water and energy more efficiently, as water can be pumped to the top and allowed to flow down by gravity. Some systems use hydroponics, by which the plants are immersed in water containing mineral solutions, in place of soil.

    Temperatures can be carefully controlled, water reused, and nutrients recycled. Software systems can control the delivery mechanisms and monitor how the plants are faring. Our new-found abilities to control light, temperature, air and other environmental factors open up new vistas for farming. Underground growing used to be reserved for mushrooms and niche crops such as forced rhubarb, grown in large warehouses.

    If LEDs can take the place of sunlight, a far greater variety of plants can thrive in these conditions, making not only rooftops but basements and disused underground spaces from worked-out mines to old railway lines potentially viable venues for growing short-cycle foodstuffs.

    Our reliance on artificial fertiliser and intensive farming techniques did not happen overnight, but took decades. Along the way, these methods revolutionised farming and enabled huge population growth and economic growth. We now have a wealth of scientific evidence that shows that continuing down the same path would risk runaway climate change, the extinction of species vital to human life, pollution of our water and air, and the death of our soils.

    Experts say a second revolution is now needed, that will encompass not just our growing methods but consumption habits and our entire food economy. This would have to involve farmers, retailers, governments and consumers. For this century, there will be a plurality of alternatives, and combinations of new and ancient technology, and all have their place. There are lots and lots of things we can and need to do.

    The briefing. From urban farming to drones, innovation can help fill the gap between production and consumption by Fiona Harvey. Why do we need to grow more food? So we need to find more land to cultivate then? Chart Fertilisers that have improved poor soils have also had unintended harmful consequences. Facebook Twitter Pinterest. Topics The briefing.