Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
WFL Publisher Science and Technology Meri-Rastilantie 3 B, FI-00980 Helsinki, Finland e-mail: [email protected] Journal of Food, Agriculture & Environment Vol.12 (3&4): 12-18. 2014 www.world-food.net Food security of Northwest China under current water resources and food consumption patterns Jianping Li 1, Jing Chen 1 and Zhouping Shangguan 2* 1 School of Agriculture, Ningxia University, Yinchuan Ningxia, 750021, P. R. China. 2 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation,Chinese Academy of Sciences, Yangling Shaanxi, 712100, P. R. China. *e-mail: [email protected] Received 22 June 2014, accepted 24 September 2014. Abstract This study investigated the effects of water resources and food consumption patterns on the food security of Northwest China. A regional water requirement model (RWRM) and a food security model (FSM) were set up to evaluate the water shortage and food security of Northwest China, respectively. The results showed that the water resource shortage of Northwest China is severe and thus the status of food security is unsafe without food import; the urban food security of the region is better than the rural food security, and more water and energy are needed for the urban population; and the water shortage of Northwest China has increased dramatically since 1983 and will continue to increase in the future, having already reached 170 billion m3 in 2010 and will reach 400 billion m3 in 2050. Finally, some countermeasures that should be taken to safeguard the food and water securities of Northwest China are as follows: control the population growth according to the local conditions and the population and structure of the ethnic (minority) peoples; promote calorie-appropriate and energy-efficient diets instead of unhealthy diets; eliminate food wastes; and develop water-saving agriculture and breed water-saving crop varieties. The models and proposed countermeasures are expected to provide theoretical foundation and practical guidance for sustainable development and food security of Northwest China. Key words: Food security, agricultural water resource, food consumption pattern, Northwest China, model. Introduction In addition to population growth, industrial development and uncontrolled economic growth, water shortage is more and more recognized as a major threat to food security due to its restriction of agricultural production 1, 2. The changes in consumption patterns, i.e., the increasing proportion of water-intensive food (e.g. meat), may become the main cause of water shortage 3. Currently, approximately one third of the world’s population lives in countries suffering water shortage, including north China, west Asia, and Libya and Saudi Arabia, who have used water for irrigation that greatly exceeds their annual total water resources 4. Many authors estimate that a large part of the world’s population - up to two-thirds - will be affected by water shortage over the next decades 5, 6. In China, water resources uses can be divided into four forms: agricultural water (62% of the total amount), industrial water (24%), domestic water (12%), and eco-environmental water (2%) 7. Nearly all agricultural water is freshwater 8 and a shortage of freshwater exists all over the world 9. So water shortage fundamentally results from insufficient freshwater for food production 3, 10. Generally speaking, different amounts of water are required to produce different foods. For example, about 1 - 3 m3 of water is required to produce 1 kg of cereal, and about 13.5 m3 of water is required to produce 1 kg of beef in California 11. Consequently, different food consumption patterns require different amounts of water resources. With economic development and improved living standards, the proportion of water-intensive foods has been growing in food consumption patterns, so that more water resources are required to meet human food demands. For example, 12 a typical American diet which includes red meat requires twice as much water as a vegetarian diet to provide the same nutritional intake 12. Also, climate change can be a significant factor that affects agriculture and food production, exerting either a positive or a negative influence on food security. For instance, higher CO2 concentrations can have a positive effect on many crops by enhancing their biomass accumulation and final yields. However, extreme weather conditions due to climate change can have negative effect on food security by blocking food distribution, and causing food supplies to be unstable and stored foods to decompose 13. In arid regions, the difference between water resource supply and water demand is increasingly becoming acute due to increasing water requirements and unchanging or decreasing water supply. China is a drought-prone country suffering severe water shortage. Although the total water resources amount of China is 2.8 trillion m3, ranking sixth in the world, its per-capita water amount is only 2300 m3, 1/4th of the average level in the world. However, China is one of the 13 countries suffering water shortage 14. In terms of their spatial distribution, the water resources of China tend to decrease from its northeast coastal area to northwest inland area. Meanwhile, the agricultural water use efficiency of China is low and farmland soil salinization and environmental pollution are severe, particularly in the rural area of China 15. With its population growth and rapid industrialization, the industrial water and domestic water needs of China are increasing and their combined demand restricts the agricultural water use for food production. In the meantime, the food consumption pattern of China has shifted Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 20°0'0" N 20°0'0" N 30°0'0" N 30°0'0" N 40°0'0" N 40°0'0" N 50°0'0" N 50°0'0" N towards animal product-dominated patterns, particularly meatMaterials and Methods dominated ones, which mean that the agricultural water needs of Profile of study area: With the longitude ranging within 73°41'E China have further increased. The result will be that the water 111°15'E and latitude from 31°42'N - 49°33'N, Northwest China has supply for food production will be insufficient to meet all demands a total area of 3,045,600 km2, accounting for 30.8% of the total area which may result in food insecurity. Relevant data collected in the of China. It covers five provinces and autonomous regions from 2010 China Agriculture Yearbook 16 showed that China uses 48% southeast to northwest: Shaanxi, Ningxia Hui Autonomous of irrigation farmland to produce 75% of grain yield and more than Region, Gansu, Qinhai and Xinjiang Uygur Autonomous Region 90% of cotton and vegetables. Therefore, the agricultural water (Fig. 1). In late 2010, Northwest China had its peak population of use of China is a key factor that affects its food security. 96.6 million, which accounted for 7.2% of the total population of Northwest China is the region suffering the most severe water China and of which the minority population accounted for 19%. shortage, where the water and agricultural land resources are The landscape of Northwest China includes plateaus, basins and generally spatially unevenly distributed and the ecosystem is mountains. Characterized by low rainfall and high evaporation, fragile. The data collected from the Main Data Communique of the Northwest China is an arid and semi-arid region. The annual mean Sixth National Population Census 17 showed that Northwest China precipitation of Northwest China decreases from 400 mm in the has a population growth rate of more than 10‰, higher than the east to 200 mm in the middle part to less than 50 mm in the average national level of 5.7‰. Also, the food consumption pattern northwest. Northwest China has an annual total water resources of Northwest China differs greatly from the other regions of China. (surface and aquifer water) amount of 230 billion m3, which For instance, the animal products consumption of the former is accounts for 9% of that of China. Since a majority of agricultural higher compared with that in other regions. Northwest China is a irrigation facilities are poorly developed and most of farming district, where there are many minority ethnic peoples including practice is dry land farming, northwest China depends on Uygur, Hui, Tibetan, Mongolian and so on. Since these ethnic precipitation for the majority of crop production. peoples consume more fresh milk and meat-dominated foods, and only use grains as dietary supplements, Northwest China needs Methods: more agricultural water than other regions to produce foods in RWRM and its parameters: A RWRM was established, in terms of order to maintain its food security for its diverse population. water amount necessary to produce a unit of product and per Meanwhile, with the acceleration of implementing the Great capita food consumption, to calculate the amount of water resource Western Development Strategy in China where Northwest China that was used in agriculture to produce food, and to calculate the was zoned as one industrial development region, more and more total amount of water resource requirement using a proportional freshwater will be used by industry, which will probably rate of agricultural water use. The model is expressed as follows: n additionally limit water resources used by agriculture. In a word, 1 people will need more and more water resources to safeguard WRWR = βαδ (∑ M iWi )( Pr + Pu ) i =1 their food security, but there are limited water resources, which are insufficient to produce food for food security, in Northwest where WRWR represents the regional water requirement under China, as well as the limited water resources will 80°0'0" E 100°0'0" E 120°0'0" E 140°0'0" E be used by industry and other aspects instead of agriculture. Therefore, the sharp conflict between the water resources and food security are becoming acute, and how to tackle these conflicts N is a highly important topic that attracts attention from all the fields. Focusing on the water resource and food consumption patterns of Northwest China, the objectives of this study were to establish a regional water requirement model (RWRM) and a food security model (FSM) to evaluate the status of its water shortage and food security, respectively; develop models for predicting its future water and food security depending on the current status of water and food security, which were calculated by RWRM and FSM; and provide sustainable development-oriented countermeasures to tackle the conflicts between the water shortage and food security of the region depending on the models and analyses. The results will lay a theoretical Provincial capital foundation and provide practical guidance for the Study area sustainable development and food security of Provincial boundary Northwest China. 90°0'0" E 100°0'0" E 110°0'0" E 120°0'0" E Figure 1. Location of the study area. Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 13 the current food consumption pattern, 1/(βαδ) is ratio of water consumption for food production to the total water resources, β is the proportion of water supply to total water resource, α is the proportion of agricultural water to total water supply, δ is agricultural water use efficiency, M i is annual per-capita consumption of the i th food (kg), Wi is water amount necessary for to produce the i th food (m3 kg-1), n is food number, Pr is rural population, and Pu is urban population. The parameters of Wi are listed in Table 1 and those of Mi in Table 2. Wtotal is assumed to represent the total water resources . If WRWR > Wtotal, then there will be insufficient water resources and insufficient water supply to produce enough food for consumption under the current food consumption patterns. Otherwise, food and water security will be guaranteed. Different regions have different β over time; the average β is about 83% from 1980 to 2010. The average α is within 80 - 86%, which comes from the China Statistics Yearbook 13. The value of δ is from the published papers 18-20, ranging from 0.4 to 0.6. Since rural and urban food consumption patterns differed greatly, the rural and urban populations were Table 1. Actual water consumptions and energy water productivities for mostly consumed food items. Food items Cereals and roots Rice Wheat Maize Other Potatoes and other starchy roots Sugar and sweetener Oil corps and vegetable oils Soybeans and other oil crops Vegetable oils Vegetables and fruits Vegetables Fruits Animal products Beef Pork Poultry Mutton and goat meat Fish and sea food Eggs Milk Alcoholic 3 -1 Ei (kcal kg ) 1.31 0.98 0.84 1.24 0.23 1.02 3625 2633 2872 2709 699 3481 3.2 5.08 3314 8720 0.19 0.5 188 413 12.56 4.46 2.39 4.5 5 3.55 1 0.18 2021 3500 1708 2005 497 1455 670 490 FSM and its parameters: A FSM was established to convert food intake into energy intake to estimate food security. It was defined as: n E EI = ∑ M υ i Ei -1 Wi (m kg ) separately introduced into the RWRM so that the estimation and evaluation would not be biased. Food consumption patterns greatly influence water security. For example, beef production needs 13 times more water than wheat (Triticum aestivum L.) production to produce same amount of weight, and 17 times more water than wheat to supply same amount of energy 21. The study divided food consumption patterns into two types: rural and urban patterns, because rural people and urban people have different purchasing powers, dietary habits, and food consumption habits. Thus, the comparison errors resulting from ignoring these differences were reduced. Table 2 presents the annual per capita food consumption in the past 30 years (1980 - 2010), which indicates that the per capita annual consumption of all food items has increased, while the consumption of cereals has decreased. It also indicates that the per capita food consumption of the rural population was less than that of the urban population, again except for cereal consumption. i =1 where EEI is per capita energy intake per day (kcal), Mυi is daily per-capita consumption of the food (kg), Mυi = Mi /365, and Ei is the energy of the i th food (kcal kg-1), n is foods number (Table 1). Energy intake, recommended as the main indicator for measuring food security by FAO 24, consists of four requirements: i. Basal Metabolic Rate (BMR) for adults: 1300 - 1700 kcal per person per day. ii. Allowance for light activities: 1720 - 1960 kcal per person per day. iii. Allowance for appropriate activities: 2000 - 2310 kcal per person per day. iv. Allowance for labours or activities above the average intensity or surpassing appropriate activities: 2600 - 2950 kcal. This study adopted the average-weighted caloric requirement of 2300 kcal/person/day to measure food security, which was the calorie number required for appropriate activities. If EEI>2300 kcal, then the food security was adequate; and if 1700 kcal<EEI< 2300 kcal, the food security was low; and if EEI<BMR, the energy supply was insufficient and people were in the state of malnourished and starvation. However, with development of economic and improvement of the people’s living standard, the Sources: Actual water consumptions of cereals, soybean, vegetables and fruits from Liu et al. 21, fish and seafood from Zimmer and Renault 22, other food items from Chapagain et al. 23. Note: Wi is water amount necessary for to produce the i th food (m3 kg-1), Ei is the energy of the i th food (kcal kg-1). Table 2. Rural and urban food consumption patterns of northwest China over time. Food items Cereals and roots Vegetables Vegetable oils Pork Beef & goat meat Poultry Eggs Fish and sea food Milk Fruits Alcoholic 1980 Urban Rural 130 257 60 40 5 2 15 8 2 0 2 1 4 1 2 0 3 0 18 3 0 2 1985 Urban Rural 135 257 74 47 6 4 17 11 2 2 3 1 7 2 7 1 5 2 25 5 5 4 1990 Urban Rural 131 262 89 68 6 5 18 11 3 2 3 1 7 2 8 2 9 2 34 6 5 6 1995 Urban Rural 97 259 116 85 7 6 17 11 2 3 4 2 10 3 9 3 14 2 40 14 6 7 2000 Urban Rural 82 248 115 86 8 8 17 12 3 3 5 1 11 2 10 0 17 4 46 16 5 2 2005 Urban Rural 76 214 123 95 9 5 23 21 4 5 10 3 8 3 7 1 19 4 52 14 6 9 2010 Urban Rural 70 195 125 99 10 5 28 25 5 5 15 4 8 2 10 1 16 8 51 17 12 10 Source: National Bureau of Statistics (1981-2011) Notes: China Statistical Yearbooks generally tell consumption data by classifying food items into food groups. One example is the consumption of cereals and roots. So, the study divided the cereal and roots into there parts: 65% of wheat, 35% of rice, and 10% of roots, according to the food consumption habits of northwest China. 14 Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 per capita energy intake should increase as well as the measurement of food security in underdeveloped countries and developing countries. Data sources: The data for this study, including water resources, population and food consumption patterns, were from China Statistics Yearbook 16 and China Agriculture Yearbook 25. The parameters of the RWRM and FSM were extracted out of the published papers and China Statistics Yearbook 16 and China Agriculture Yearbook 25. The parameters of the predicted models (shown in Table 3) come from the regression models, which were developed by the data (from 1980 to 2010) that were calculated by RWRM and FSM. 3500 Population (104) 6000 5250 Rural population Per capita water resource Urban population 4500 3750 3250 3000 2750 3000 2500 2250 1500 2250 1980 1985 1990 1995 Year 2000 2005 Per capita water resource (m3) Analysis and Results Current water resources and population: The annual total water resources for Northwest China were almost stable around 230 billion m3 in the past 30 years, without much change from year to year (Fig. 2). Because of the exploding population, the annual per capita total water resource sharply decreased (Fig. 3) from 3400 m3 at the end of 1980 to 2300 m3 in 2010. In the meantime, the per capita water supply also decreased dramatically from 1019 m3 in 1980 to only 699 m3 at the end of 2010, which was far below the water shortage-warning line (1000 m3 per capita).With the increased water pollution and reduced usable fresh water resource, fresh 2010 Total water requirement and total water resources in northwest China (cu.m billion ) Figure 2. Population and per capita water resource reserves in the different years. 400 water resource for the people was significantly reduced 26. Figure 3 shows that the urban population has been growing linearly since 1980. Although it has a large base, the rural population has increased slowly since 1980. Because the urbanization and industrialization have caused many rural residents to migrate to the urban areas, and the natural increase in the rural population was offset by the amount of rural population who migrated to urban areas, the rural population has remained at approximately 53 million in the past 30 years. So, the urban population growth can be viewed as the population growth of Northwest China. Meanwhile, Northwest China will be a main area that has a population growth faster than the other regions of China, because the population growth rate is 14.05‰ (average value in the past 30 years), compared with the national average of 5.7‰. Therefore, more population, especially the urban population who consume more energy than rural residents, will threaten water security and food security. Status of water security: The regional water requirement is defined as the amount of water resources required for the present food consumption patterns and all other water use. The water requirement of Northwest China has been larger than its supply since 1982, and the gap between the former and the latter has increased dramatically year by year (Fig. 2). In 1980, the total water resources of 240 billion m3 were larger than the water requirement of 225 billion m3. This indicated that there was sufficient water for producing food and other uses and water resources were not a key constraining factor in agriculture and industry. However, the difference between the water requirement and the water supply has increased sharply from 5 billion m3 in 1982 to 170 billion m3 in 2010. By 2010, more than 80% of the total water resource was used for agriculture. Due to water shortage, the agriculture production will be reduced and food supply will be insufficient to meet food consumption, and food insecurity will occur without the importation of food. In the meantime, how to properly distribute the limited total water resource among agriculture, industry, life and ecology will be a big problem, and an irrational distribution will have a negative effect on the regional economy and society. Total water requirement Total water resources Status of food security: The average per capita energy intakes per day were obtained by the FSM model. The rural per capita energy 320 intake per day was less than the urban one during the past 30 years (Fig. 4). After 1983, the urban per capita energy intake per 280 day was over 2300 kcal, indicating that the urban food security of 240 Northwest China was safeguarded. The urban per capita energy intake per day reached a high record of 3100 kcal in 2000 and 1980 1985 1990 1995 2000 2005 2010 generally decreased from 2000 to 2010 but remained above 2700 Year kcal, surpassing the food security threshold of 2300 kcal. This Figure 3. Total water resources and total water requirement decrease resulted from the changes in food consumption patterns, of northwest China in the different years. which was the consumption of less cereal and more meat and vegetables. However, the rural food security Table 3. Forecast models and water securities in the following 40 years. was poor. The rural per capita energy intake per day was 1400 kcal in 1980, which was lower than that needed for the Basal Metabolic Rate for adults. The rural population suffered malnutrition and starvation in 1980s. The per capita energy intake per day has generally increased from 1400 kcal in 1980 to 2290 kcal Note: P is population, E is per capita energy intake per day (Kcal), W is amount of total water need for food, e is the base in 1998 but has remained below the food security 360 of the natural logarithm (approximately 2.7183), x is year, and R2 is determination coefficient. Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 15 Per capita energy intake per day (Kcal/person /day ) 3000 2700 2400 2100 1800 Urban area Rural area Food security line 1500 1980 1985 1990 1995 Year 2000 2005 2010 Figure 4. Per capita energy intakes per day of northwest China in the different years. threshold; the per capita energy intake per day has generally fluctuated around 2300 kcal after 1998, being 2400 kcal in 2000, 2250 kcal in 2005, and 2330 kcal in 2010. Thus, the food security for the rural population was nearly average. Therefore, the food security of Northwest China was safeguarded from 1998 to 2010, but this sufficient food security may not last long because of the population growth, water shortage, and living standard improvement. Food security and water security in the future: This study developed the Population Forecast Model (P), the Energy Intake per Capita per Day Model (E), and the Water Resource Requirement Forecast model (W) depending on the populations, per capita energy intakes per day, and total water resources and water requirement from 1980 to 2010. W – Wtotal, the differences between the water requirements and the existing total water resources, was used to evaluate the future water situation (Table 3). The forecast models depended on the economies, population and food patterns in the past 30 years to forecast the future. Table 3 shows that the population of northwest China is projected to grow exponentially from 110.5 million at the end of 2020 to 135.9 million in 2050, a 25.4 million increase, and more than 80% of the population will become urban residents in 2050. Meanwhile, the per capita energy intake per day and the regional water requirement will reach 3762 kcal and 625.5 m3 in 2050, respectively. The water gap (W – Wtotal) will increase sharply in the next 40 years. The total water resources will meet only 50% of the water requirement of 463.5 billion m3 in 2020 and the gap will reach 400.1 billion m3 in 2050. Consequentially, the population growth, sharp water gap increase and energy intakes of northwest China will threaten the food security because of the insufficient water for producing food in the future. Discussion Water shortage and food security have become primary factors that restrict the national economic progress of China. If water shortage evolves into a crisis, the effects may be far more severe than the crisis of oil shortage that we have experienced so far 27. Water security is the basis for food security, which is the basis for modern agriculture. Agriculture can save water resources to safeguard food security by consuming less water to produce more food 28, 29. At present, water resources for food security of China is facing challenges resulting from the water shortage, due to increasing industrial and urban water uses, lack of extensive water resources management, and water loss and soil erosion. Agricultural water use is crucial to China, because China has a big 16 population and suffers poverty. Two-thirds of the undernourished population (not enough food to eat) of the world live in seven countries (Bangladesh, China, the Democratic Republic of Congo, Ethiopia, India, Indonesia and Pakistan) and over 40% of the undernourished population live in China and India 30. Thus, water for food production cannot be diverted for other uses, especially in the rural area of Northwest China where much of the undernourished population lives. The typical water distribution pattern of China is that it is dry in its northwest and humid in its southeast, and its water supply differs across regions and time. Because the water supply of Northwest China represents a much smaller portion of China’s total water resource, it faces very serious problems with agricultural water shortage. Since agriculture is now the largest branch of water user, it is important to develop modern water-saving agriculture to safeguard the food security, water security, and ecology security of China. The measures for this purpose have been recognized by the scientists and governments 31, 32. In addition, most reserve cultivated-land resources of China are located in Northwest; it is difficult to exploit them because of water shortage. So, the option to safeguard food security by expanding the amount of cultivated land will be difficult to achieve. Insufficient food resulting from water shortage in Northwest China can be made up through trade 23 or food distribution. Our study showed that in 2010, the total water requirement of Northwest China was 390 billion m3, but the total water resources were only 230 billion m3. Also, the agricultural water requirement of 72.5 billion m3 is more than agricultural water supply of 42.5 billion m3, so that obviously the region does not have enough water to produce food under the current food consumption patterns. Nevertheless, both the rural and urban food securities of northwest China were good in 2010 mainly because reasonable food trade and grain circulation offset its food shortage. Where trade is possible at a reasonably low water cost, the crucial food security issue is whether the monetary and non-monetary resources at the disposal of the population are sufficient to allow everyone to get access to adequate food supplies rather than not whether the foods are sufficient, that is to say, food availability is not a key factor affecting food security. An important corollary to this is that regional self-sufficiency is neither necessary nor sufficient to guarantee food security at the regional level. It is noted that Hong Kong and Singapore are not self-sufficient (they don’t have agriculture) but their populations are food-secure, meanwhile, India is self-sufficient but a large part of its population is not food-secure 13. However, more and more people will suffer from food insecurity, if there are insufficient food supplies for trading or circulation. In other words, both food production and trading are important for safeguarding food security. The results of this study showed that the water requirement for food production has almost doubled from 1980 to 2010 (Fig. 3), largely due to an increase in animal products consumption in the recent decades. The models indicate that the future total water requirement for food production will be likely to increase in the next four decades. Even under the low modernization scenario, food consumption pattern shifts along with population growth will probably cause the total water requirement to reach 400 billion m3 per year in 2050, even taking into consideration relevant technological advances. This will undoubtedly put enormous pressure on limited water resources in Northwest China. The Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 RWRM model showed that there were five key factors affecting the regional water requirement of Northwest China: population, food consumption pattern, agricultural water, water supply capacity, and crop water use efficiency. The following countermeasures in terms of the five factors probably could guarantee the future water security and food security of Northwest China. First, the population growth of Northwest China should be regulated according to the local conditions. At present, the population of northwest China is mainly rural with many ethnic peoples living together, and thus the possibilities of the economic security, societal security and cultural security should be considered in a balanced way. Proper population countermeasures should be taken and timely adjusted according to the population and structure of the ethnic peoples to ensure common development and prosperity of all the nationalities concerned. While the population size will be controlled, the population’s quality of life should be improved. Second, caloric-appropriate diets and energy-efficient food consumption patterns instead of unhealthy diets should be promoted, and food wastes should be prohibited. In general, food consumption patterns are closely related to increasing affluence. However, eating habits probably plays a role in affecting the food preference of China’s population. For example, the meat consumption of China now exceeds what is recommended by China Nutrition Society 33, and Northwest China has higher meat consumption than other regions. In addition, the current diet shifts of Northwest China may be detrimental to the population’s health, and could cause higher incidences of diet-related diseases 34. Raising public consciousness and promoting the diet recommended by the CNS may help mitigate the future water shortage of China. Meanwhile, food losses of China resulting from seeding, feeding, harvesting, food processing, storage, transportation, and cooking are large, making up 30% of the total food production of the country. Consequentially, to eliminate all such food losses by educating the population in healthy diet, food producing and nutrition are wise measures to save food and water resources. Third, Northwest China should develop water-saving agriculture to guarantee the food and water securities. It is necessary for Northwest China to increase water use efficiency and then water supply as the total water resources are limited in the arid area. The key approaches for increasing the water supply of Northwest China can be summarized as follows: constructing reservoirs and implementing water diversion projects; reasonably exploiting and scientifically managing urban groundwater resources under the precondition of sustainable development economy and society; and trying to recycle waste water. Water-saving agriculture should be promoted to safeguard water security. Water-saving agriculture as an integrated system should include four aspects: rational uses of agricultural water resources, water-saving irrigation, agronomic water-saving techniques, and agricultural management 24. Governmental supports and encouragements will be necessary to achieve this system. Fourth, biotechnological as well as traditional breeding methods should be adopted as the efficient method to develop water-saving crops for the arid areas of northwest China to feed its growing population. Water-saving crops developed by modern biotechnology breeding cannot only improve water use efficiency but also can increase food production. In other words, more foods will be produced without additional or with lowered consumption of the currently existing water resources. Water-saving crop varieties, such as drought resistant wheat in Australia, drought tolerant cotton (Gossypium hirsutum L.) in America and drought tolerant fruit trees in Israeli 35, have good drought tolerance ability, stable yields and good qualities. Conclusions In brief, improving water use efficiency through biological approaches in combination with other water-saving methods and projects and establishing sustainable agriculture with limited water resources have become, and will continue to be, the challenges for agricultural scientists in the future. Acknowledgements This study was funded by the Startup Project of Doctor Scientific Research of Ningxia University (BQD2012008) and Key Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-JC408). References Rosegrant, M. W., Ringler, C. and Zhu, T. J. 2009. Water for agriculture: Maintaining food security under growing scarcity. Annu. Rev. Env. Resour. 34:205-222. 2 Fereres, E., Orgaz, F. and Gonzalez-Dugo, V. 2011. Reflections on food security under water scarcity. J. Exp. Bot. 62:4079-4086. 3 Liu, J. and Savenije, H. H. G. 2008. Food consumption patterns and their effect on water requirement in China. Hydrol. Earth Syst. Sc. 12:887-898. 4 FAO 2011. Review of global agricultural water use per country irrigation water withdrawal. Available from: http://www.fao.org/nr/water/ aquastat/water_use/index5.stm (accessed on 09.12.11). 5 Oki, T. and Kanae, S. 2006. Global hydrological cycles and world water resources. Science 313:1068-1072. 6 Heinz, I., Salgot, M. and Koo-Oshima, S. 2011. Water reclamation and intersectoral water transfer between agriculture and cities - a FAO economic wastewater study. Water Sci. and Techno. l63:1067-1073. 7 Wang, H. 2009. Establish positive and effective water-saving mechanism. Environmental Engineering 27:77-78. 8 Wallace, J. S. 2000. Increasing agricultural water use efficiency to meet future food production. Agr. Ecosyst. Environ. 82:105-119. 9 Pushpangadan, P. 2005. Combating freshwater scarcity - Response. Curr. Sci. India 88:1716-1717. 10 Karunaratne, A. S., Azam-Ali, S. N. and Steduto, P. 2011. Calibration and validation of FAO-Aquacrop Model for irrigated and water deficient bambara groundnut. Exp. Agr. 47:509-527. 11 Rijsberman, F. R. 2006. Water scarcity: Fact or fiction? Agr. Water Manage. 80:5-22. 12 Renault, D. and Wallender, W. W. 2000. Nutritional water productivity and diets. Agr. Water Manage. 45:275-296. 13 Schmidhuber, J. and Tubiello, F. N. 2007. Global food security under climate change. Proc. Natl Acad. Sci. USA 104:19703-19708. 14 Xie, G. D., Ge, L. Q., Zhang, C. X., Li, S. M., Qi, Y., Cao, S. Y. and He, T. T. 2011. An evaluation of China’s water footprint. Water Resource Manage. 25:2633-2647. 15 Wang, T., Huang, C. H., Xue, X., De Mascellis, R., Mele, G., You, Q. G., Peng, F. and Tedeschi, A. 2011. Effects of saline water irrigation on soil properties in northwest China. Environ. Earth Sci. 63:701-708. 16 National Bureau of Statistics (NBS) 1980-2011. China Statistics Yearbook. China Statistical Press, Beijing (China), 13:1-69. 17 National Bureau of Statistics (NBS) 2011. The main data communique of sixth national population census 2010. Available from: http:// www.stats.gov.cn (accessed on 29.10.11). 1 Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014 17 Wang, Y. J., Xie, Z. K., Malhi, S. S., Vera, C. L., Zhang, Y. B. and Wang, J. N. 2009. Effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi-arid Loess Plateau, China. Agr. Water Manage. 96:374-382. 19 Fang, Q. X., Ma, L., Green, T. R., Yu, Q., Wang, T. D. and Ahuja, L. R. 2010. Water resources and water use efficiency in the North China Plain: Current status and agronomic management options. Agr. Water Manage. 97:1102-1116. 20 Zhang, X. Y., Chen, S. Y., Sun, H. Y., Wang, Y. M. and Shao, L. W. 2010. Water use efficiency and associated traits in winter wheat cultivars in the North China Plain. Agr. Water Manage. 97:1117-1125. 21 Liu, J. G., Zehnder, A. J. B. and Yang, H. 2007. Historical trends in China’s virtual water trade. Water Int. 32:78-90. 22 Zimmer, D. and Renault, D. 2003. Virtual water in food production and global trade: Review of methodological issues and preliminary results. In Hoekstra, A. Y. (ed.). Virtual Water Trade. Proceedings of the International Expert Meeting on Virtual Water Trade. UNESCO-IHE, Delft, the Netherlands, pp. 25-47. 23 Chapagain, A. K., Hoekstra, A.Y. and Savenije, H. H. G. 2006. Water saving through international trade of agricultural products. Hydrol. Earth Syst. Sc. 10:455-468. 24 FAO 1975. State of Food and Agriculture, Rome, Italy. Available from: www.fao.org/publications (accessed on 7.12.12). 25 The Editorial Committee of China Agricultural Statistical Yearbook (ECCASY) 1980-2011. China Agriculture Yearbook. China Agriculture Press, Beijing (China) 1:1-39 (in Chinese). 26 Li, P. Y. and Qian, H. 2011. Human health risk assessment for chemical pollutants in drinking water source in Shizuishan City - Northwest China. Iran J. Environ. Healt. 8:41-48. 27 Zhang, Z. B. and Zhang, J. H. 2007. Water-saving agriculture: An urgent issue. J. Integr. Plant Biol. 49:1409-1409. 28 Mu, J. X. and Khan, S. 2009. The effect of climate change on the water and food nexus in China. Food Secur. 1:413-430. 29 Yang, H., Zhou, Y. and Liu, J. G. 2009. Land and water requirements of biofuel and implications for food supply and the environment in China. Energ. Policy 37:1876-1885. 30 FAO 2010. The state of food insecurity in the world: Addressing food insecurity in protracted crises. Available from: http://www.fao.org/ publications/sofi/2010/en/(accessed on 29.10.11). 31 Wang, Y. B., Wu, P. T., Zhao, X. N., Li, J. L., Lv, L. and Shao, H. B. 2010. The optimization for crop planning and some advances for water-saving crop planning in the semiarid Loess Plateau of China. J. Agron. Crop Sci. 196:55-65. 32 Wu, P. T., Zhu, D. L. and Wang, J. 2010. Gravity-fed drip irrigation design procedure for a single-manifold subunit. Irrigation Sci. 28:359369. 33 CNS 2007. Guide of food. Available from: http://www.cnsoc.org/cn/ nutrition.asp (accessed on 9.12.11). 34 Du, S. F., Mroz, T. A., Zhai, F. Y. and Popkin, B. M. 2004. Rapid income growth adversely affects diet quality in China particularly for the poor. Soc. Sci. Med. 59:1505-1515. 35 Theiveyanathan, S., Benyon, R. G., Marcar, N. E., Myers, B. J., Polglase, P. J. and Falkiner, R. A. 2004. An irrigation-scheduling model for application of saline water to tree plantations. Forest Ecol. and Manage. 193:97-112. 18 18 Journal of Food, Agriculture & Environment, Vol.12 (3&4), July-October 2014