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1.
About eight billion bushels of potatoes are produced annually throughout the world, 400 million of them in the United States. In the United States and England they are used principally for human consumption; in other European countries as livestock food and as raw material for the manufacture of starch, alcohol and other by-products.  相似文献   

2.
《Fungal Biology Reviews》2020,34(4):170-177
Dictyostelid cellular slime molds are a ubiquitous component of most soils, where they feed upon bacteria and other microbes and thus play an essential role in the soil ecosystem. Herein we review the available literature on dictyostelid cellular slime molds in China, especially their diversity and ecology. The patterns of distribution for these organisms in relation to the different habitats with which they are associated are analyzed and discussed. In addition, the assemblages of dictyostelids reported from China and the United States were compared. The CC value obtained (0.48) indicates that China and the United States are perhaps less similar than might be expected. Our data point out the need for further studies to characterize more completely the assemblages of dictyostelids associated with particular vegetation types or particular regions throughout the world.  相似文献   

3.
棉花是巴基斯坦唯一批准种植和使用的转基因作物。监管的不明确阻碍了生命科学公司为其他转基因作物寻求获批,但国家生物安全委员会仍在制定转基因食品、饲料和加工品的进口准则。2020年,巴基斯坦进口了大约220万t大豆,其中美国占据了近50%的市场份额。  相似文献   

4.
Oliveira  A.L.M.  Urquiaga  S.  Döbereiner  J.  Baldani  J.I. 《Plant and Soil》2002,238(2):205-215
We investigated the effects of an autumn sowing of contrasting cover crops (oats, rye and a combination of oats and rye) on soil aggregate stability, mycorrhizal colonization, phosphorus uptake and yield of sweet corn planted the following summer. Rye is a common cover crop in the middle Atlantic region of the United States of America. It grows slowly in the autumn, survives the winter, grows rapidly in the spring and flowers in the summer. Thus, herbicide is commonly used to kill rye prior to planting spring crops. Oats, in contrast, grows rapidly in the autumn but is killed by frost during the winter. Thus, with oats, potentially less herbicide is needed to prepare the field for spring planting. When compared to fallow, oats was as effective as rye in increasing mycorrhizal colonization of sweet corn, density of mycorrhizal hyphae, and soil aggregate stability. An oats cover crop may thus be a viable alternative to rye. The combination of cover crops (rye and oats), however, was significantly better than single species of cover crops in terms of sweet corn mycorrhizal colonization, P uptake and yield of sweet corn.  相似文献   

5.
The marama bean, Tylosema esculentum, is a drought- tolerant legume native to southern Africa. Its seeds are comparable to soybeans in protein content and quality, its oil content approaches that of peanuts, and the plants might be desirable as a forage legume. Although the marama bean has great potential as an arid land crop in the United States, studies of the species are extremely limited. The current investigations have demonstrated that the plants can be grown successfully in an arid region of the United States, at least under experimental conditions, and that a healthy seed crop can be expected in about 4.5 years.  相似文献   

6.
The United States is a major producer of many different types of oilseeds, but the predominant one is soybean, that remarkable legume whose meal and oil serve many animal feed, human food, and domestic industrial product needs. More than half of the soybeans and the products produced from them are exported. The 16 mill MT of soy meal processed and fed in the United States in 1981 constituted 88% of the total oilseed meal, 71% of the high-protein feeds, and 48% of total processed feeds. Of the total soy protein available, less than 5% goes into human food products such as meat extenders, simulated meats, baked goods, dairy product analogs, dietary foods, infant foods, and fermented food products. Less than 1% of soy protein in the United States is used in industrial products, mainly as a binder for pigmented paper coatings. Of the total soy oil available, about 95% is consumed in food products such as margarines, salad oils, and cooking oils. About 5% of soy oil is applied to nonfood uses such as alkyd paints, plasticizer/stabilizers for vinyl plastics, soaps, eraser factices, and many other lesser uses. Other major oilseeds produced in the United States include cottonseed, flaxseed, peanut, safflower, and sunflower. Corn oil is produced in significant quantities as a by-product of the corn starch industry. The oilseed crops having the greatest oil productivity are peanut and sunflower. However, sunflower meal has certain deficiencies for feed and food uses. If the United States is to draw upon oilseed crops as significant contributors to feed, food, industrial products, and agricultural fuel needs, greatly improved productivity will be needed either from new oilseed crops or from improved varieties of present commercial crops.  相似文献   

7.
Grapefruit is of American origin, possibly a natural hybrid between pummelo and orange of the Old World. The United States produces more than 90 percent of the world production in excess of 50 million boxes, and more than half of the American crop is now marketed in processed form.  相似文献   

8.
The major oilseed crops were domesticated primarily as sources of edible oil. However, in all cases, yields of by-products are greater than the oil fraction, and, in reality, all oilseed crops serve dual purposes as sources of oil and of protein for human food, animal feed, and industrial products. Each crop has special requirements for extraction and for processing of oil and meal, and each has limitations as to location and timing of production and as to processibility in oil mills originally designed for other crops. Further, each oilseed has unique cultural, economic and utilization characteristics; for example, rapeseed (Brassica) can be grown in cool climates with short growing seasons. Cottonseed (Gossypium) is a by-product of the more valuable fiber crop, and its availability is dictated by the profitability of growing cotton for the world market. Although peanuts (Arachis hypogaea) are used primarily as peanut butter and nuts in the United States, they are almost exclusively pressed for oil in other countries. In this paper, cultural practices and processing requirements of soybean (Glycine max), cottonseed, sunflower (Helianthus annuus), rapeseed, peanut, and sesame (Sesamum indicum) oils and byproducts are compared, as well as compositions of major oilmilling fractions, oils and proteins.  相似文献   

9.
Freshwater ecosystems provide vital resources for humans and support high levels of biodiversity, yet are severely threatened throughout the world. The expansion of human land uses, such as urban and crop cover, typically degrades water quality and reduces freshwater biodiversity, thereby jeopardizing both biodiversity and ecosystem services. Identifying and mitigating future threats to freshwater ecosystems requires forecasting where land use changes are most likely. Our goal was to evaluate the potential consequences of future land use on freshwater ecosystems in the coterminous United States by comparing alternative scenarios of land use change (2001–2051) with current patterns of freshwater biodiversity and water quality risk. Using an econometric model, each of our land use scenarios projected greater changes in watersheds of the eastern half of the country, where freshwater ecosystems already experience higher stress from human activities. Future urban expansion emerged as a major threat in regions with high freshwater biodiversity (e.g., the Southeast) or severe water quality problems (e.g., the Midwest). Our scenarios reflecting environmentally oriented policies had some positive effects. Subsidizing afforestation for carbon sequestration reduced crop cover and increased natural vegetation in areas that are currently stressed by low water quality, while discouraging urban sprawl diminished urban expansion in areas of high biodiversity. On the other hand, we found that increases in crop commodity prices could lead to increased agricultural threats in areas of high freshwater biodiversity. Our analyses illustrate the potential for policy changes and market factors to influence future land use trends in certain regions of the country, with important consequences for freshwater ecosystems. Successful conservation of aquatic biodiversity and ecosystem services in the United States into the future will require attending to the potential threats and opportunities arising from policies and market changes affecting land use.  相似文献   

10.
苏云金芽孢杆菌(Bt)微生物制剂是农业、林业和饮用水等领域用来控制靶标害虫幼虫的有效工具,至今已经有50余年的使用历史。同时其在美国、欧洲和其他一些国家被广泛用于经过认证的有机农业生产之中。目前已获审批的转基因Bt作物中最常使用的是Cry蛋白。Cry蛋白的作用机制、食品安全性以及致敏性已经经过啮齿类动物、农场动物和人体内试验和生物信息学研究的严格检验。Cry蛋白的杀虫作用只在靶标害虫的碱性消化道内,与中肠上皮细胞的特异蛋白受体结合才能起到杀虫作用,而其他非靶标生物体内(人类、猕猴、小鼠、大鼠和牛等)都被证明没有这种特异蛋白质受体。美国、欧洲和其他国家的管理机构都已经证实了转基因Bt作物和Cry蛋白在农作物和饮用水中残留的安全性。食物加工过程能够最大化地减少转基因作物中功能性Cry蛋白的摄入。转基因抗虫作物有利于降低农药杀虫剂的使用的同时,也能够有效防止玉米中伏马菌毒素的污染。  相似文献   

11.
Increasingly more studies are raising concerns about the increasing consumption of meat and the increasing amount of crops (cereals and oilseeds in particular) used to feed animals and that could be used to feed people. The evolution of this amount is very sensitive to human diets and to the productivity of feed. This article provides a 2050 foresight on the necessary increase in crop production for food and feed in three contrasting scenarios: diets with no animal products; current diets in each main region of the world; and the average diet of developed countries extended to the whole world. We develop empirical aggregate production models for seven world regions, using 43 years and 150 countries. These models realistically account for the contribution of feed from food plants (i.e. plants that would be edible for humans) and of grassland to animal products. We find that the amount of edible crops necessary to feed livestock in 2050 is between 8% and 117% of today's need. The latter figure is lower than that in comparable foresight studies because our models take into account empirical features occurring at an aggregate level, such as the increasing share of animal production from regions using less crop product per unit of animal product. In particular, the expected increase in animal production is estimated to occur mostly in Sub-Saharan Africa and Asia, where the amount of feed from food crops required per unit of animal product proves to be lower than that in other areas. This 117% increase indicates that crop production would have to double if the whole world adopted the present diet of developed countries.  相似文献   

12.
Phosphorus (P) is a widely studied element which is integral to many vital body functions. In ruminant nutrition, however, the degree of naturally occurring P deficiency in grazing cattle, the lack of uniformity in response to P supplementation, and even suggested P requirements have generated a great deal of confusion in the United States and around the world. Much of the confusion arises because animals have the ability to draw on skeletal P reserves when dietary P levels are inadequate. The mechanisms that control skeletal P withdrawal, the conditions that trigger withdrawal, and the rate and extent of withdrawal without affecting animal performance seem to be poorly understood. Another area of confusion involves the detrimental effect of P deficiency on feed intake which makes it unclear in many situations whether animal responses to P supplementation are due to P per se or simply to increased feed intake. This review attempts to discuss these and other important problems concerning the P nutrition of grazing cattle.  相似文献   

13.
United States production of oilseeds has increased 71% over the last 10 yr(1971–1981), from 42 to 72 mill tons. Soybeans have provided the big boost in output, accounting for 86% of the 30 mill ton gain, followed by sunflowers with 7%, cottonseed 7%, and peanuts 2%. Flaxseed and safflower output declined during the decade. Many factors contributed to the sharp boost in soybean output during this period. Because soybeans were competitively priced, market demand showed a steady growth and stocks remained relatively low. Soybeans provided favorable returns to growers and were widely used in rotations with other crops. Sunflower production skyrocketed since 1974 due to development of higher-yielding hybrid sunflower varieties and strong European demand for the seed. Costs of crop production in the United States have been continuing their relentless climb, spurred largely by rising fuel costs and more recently by high interest rates. Fertilizer and agricultural chemicals have also contributed to the increased costs. In the next decade, world demand for high protein meal and vegetable oils will continue to increase as population increases and use will expand in less developed countries. Much of these expanded oilseed requirements, particularly for soybeans and sunflower, will be provided by the United States.  相似文献   

14.
Ronald P 《Genetics》2011,188(1):11-20
The United States and the world face serious societal challenges in the areas of food, environment, energy, and health. Historically, advances in plant genetics have provided new knowledge and technologies needed to address these challenges. Plant genetics remains a key component of global food security, peace, and prosperity for the foreseeable future. Millions of lives depend upon the extent to which crop genetic improvement can keep pace with the growing global population, changing climate, and shrinking environmental resources. While there is still much to be learned about the biology of plant-environment interactions, the fundamental technologies of plant genetic improvement, including crop genetic engineering, are in place, and are expected to play crucial roles in meeting the chronic demands of global food security. However, genetically improved seed is only part of the solution. Such seed must be integrated into ecologically based farming systems and evaluated in light of their environmental, economic, and social impacts-the three pillars of sustainable agriculture. In this review, I describe some lessons learned, over the last decade, of how genetically engineered crops have been integrated into agricultural practices around the world and discuss their current and future contribution to sustainable agricultural systems.  相似文献   

15.
The northern walkingstick, Diapheromera femorata (Say), is the only stick insect of economic importance native to the United States. Young nymphs feed on various understory shrubs and trees whereas older nymphs and adults prefer oaks and cherries. Occasionally, field populations reach outbreak levels and cause complete tree defoliation. Widespread damage rarely occurs except those reported from Michigan (1930–1960), Wisconsin (1950–1960) and Arkansas and Oklahoma (1960–1975) where thousands to tens of thousands of hectares of trees were affected. The most recent infestations were detected in Arkansas, Maryland, and Pennsylvania with severe damage observed in localized areas. The morphology, life stages, host species, damage, biology, life history, natural enemies and management of this insect were reviewed. Host preference and insect predation were confirmed in Pennsylvania. Other notable stick insects in the United States and economically important species around the world are discussed to raise awareness about the ecological impacts of this understudied group of mostly nocturnal herbivores.  相似文献   

16.
This article presents an assessment of energy inputs of the European Union (the 15 countries before the 2004 enlargement, abbreviated EU‐15) for the period 1970–2001 and the United States for 1980–2000. The data are based on an energy flow analysis (EFA) that evaluates socioeconomic energy flows in a way that is conceptually consistent with current materials flow analysis (MFA) methods. EFA allows assessment of the total amount of energy required by a national economy; it yields measures of the size of economic systems in biophysical units. In contrast to conventional energy balances, which only include technically used energy, EFA also accounts for socioeconomic inputs of biomass; that is, it also considers food, feed, wood and other materials of biological origin. The energy flow accounts presented in this article do not include embodied energy. Energy flow analyses are relevant for comparisons across modes of subsistence (e.g., agrarian and industrial society) and also to detect interrelations between energy utilization and land use. In the EU‐15, domestic energy consumption (DEC = apparent consumption = domestic extraction plus import minus export) grew from 60 exajoules per year (1 EJ = 1018 J) in 1970 to 79 EJ/yr in 2001, thus exceeding its territory's net primary production (NPP, a measure of the energy throughput of ecosystems). In the United States, DEC increased from 102 EJ/yr in 1980 to 125 EJ/yr in 2000 and was thus slightly smaller than its NPP. Taken together, the EU‐15 and the United States accounted for about 38% of global technical energy use, 31% of humanity's energetic metabolism, but only 10% of global terrestrial NPP and 11% of world population in the early 1990s. Per capita DEC of the United States is more than twice that of the EU‐15. Calculated according to EFA methods, energy input in the EU and the United States was between one‐fifth and one‐third above the corresponding value reported in conventional energy balances. The article discusses implications of these results for sustainability, as well as future research needs.  相似文献   

17.
This paper provides an overview of the development of Americanist archeology in the United States.
Since the 1920s, there have been two, and sometimes more, interpretive communities among Americanist archeologists in the United States.
These reflect and are related to the development of U.S. society. One articulates the concerns of national capital and its allies; the other, the interests of
international capital and its allies. They are grounded in different theoretical traditions. The discourses produced by their proponents resonate with
particular world views that reflect different relations to power.  相似文献   

18.
About 50,000,000 brooms are manufactured annually in the United States from the long fibrous branches in the inflorescences oi this corn-like crop.  相似文献   

19.
Importers claim that each year they could process and sell approximately 15,000 tons ot pistachio nuts it they were available. Presently, only a small quantity are produced commercially in Caliiornia. Experimental work with selected imported varieties, breeding, cultivating, pruning and other horticultural practises at the United States Department of Agriculture's Plant Introduction Station at Chico, California has demonstrated the economic feasibility of this crop for American growers.  相似文献   

20.
From the secretly prepared chocolate-flavoring condiment oi the Aztec emperor, Montezuma, to the ice cream-flavoring ingredient oi today, vanilla has tor tour centuries been an important item in the spice trade of the world. Originally Mexican, about 90% oi the world’s 1,000 annual metric tons oi vanilla “beans” come from Mada’gascar, nearly 50% oi which are consumed in the United States.  相似文献   

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