Nitrogen Fertilizer Production Research Articles

On fertilizer‐induced soil carbon sequestration in China's croplands

AbstractApplications of fertilizer, often thought to enhance carbon sequestration in agricultural soils, are of no value to the mitigation of climate change if the carbon dioxide released during the production and distribution of nitrogen fertilizer exceeds the incremental carbon storage in soils from its use. Nitrogen fertilizer is also a source of the greenhouse gas nitrous oxide. The recent analysis of carbon sequestration in cropland soils of China does not apply these ‘discounts’ to the global warming mitigation expected from greater use of fertilizer; doing so would likely eliminate all the climate benefits of the postulated enhanced carbon sequestration.

Honey and sugar as surrogate products: an emergy evaluation

Exploitation of natural resources has reached an unsustainable level, due to the enormous growth of world population. Industrialized intensive agriculture, in particular, demands a great quantity of natural resources. White sugar is a widespread agricultural product. Its production from sugar beet or sugarcane is very expensive from the point of view of resource exploitation and sustainability. The aim of this paper is to compare white sugar and honey as sweeteners. We compared both processes of production in terms of emergy in order to establish the environmental costs and benefits of both. Transformities of honey and sugar were calculated per unit product and per unit area of land. Honey was found to have a better environmental performance than sugar production, due to the low quantity of non-renewable resources required. The environmental loading ratio indi- cated that honey production is more environmentally friendly than sugar production. Agriculture has changed dramatically in the last fifty years. We have seen great development in food and fibre production, due to new technologies, mechanization, use of chemicals, and specialization. On the other hand, the costs have been significant. The major environmental costs are topsoil deple - tion, groundwater contamination, and the effects of massive use of fertilizers. The direct and indirect costs necessary to support this kind of agriculture make exploitation of natural resources unsustain- able. Production of food and fibres implies degradation of natural resources: water (quality and quantity), soil erosion (accelerated by ploughing), and air pollution (e.g. greenhouse gas emissions from burning fossil fuels, nitrogen fertilizer production and use, excessive ploughing). Intensive and industrial agriculture depends on non-renewable energy sources, namely fossil fuels, which implies all the negative aspects related to the use of petroleum derivatives. Sugar is a major industrialized agricultural product due to great annual demand. This widespread product is invariably derived from sugarcane or sugar beet. These crops demand many inputs (1). Table 1 shows world sugar production and consumption in 2004-2005. Since most environmental problems caused by sugar are related to mass production and consump- tion, analysis of other natural products as surrogates of sugar can be interesting. Among the alternatives, that would also help to diversify the supply of agricultural products, in some cases safeguarding local production, honey is a possible substitute for sugar as sweetener. In this paper, we evaluate the sustainability and environmental performance of honey and sugar production by an accounting methodology known as emergy evaluation. This method measures the work that nature does to support these processes, comparing them from the point of view of use of resources. It involves calculating and comparing different specific emergies. Data on these production processes is available in the literature (2, 3), and a complete emergy assessment of honey and sugar production can be found in a Chinese study (4).

Nitrogen flow and use efficiency in production and utilization of wheat, rice, and maize in China

China has long been the world’s most populous nation and faced the double challenge of ensuring its food security without causing catastrophic damage to the environment. Since the early 1960s, Chinese agricultural development has been premised on large domestic increases in nitrogen (N) fertilizer production and consumption. However, current utilization of fertilizer is far beyond optimum, with the fate of excess N largely unknown. Here, we report on N flows, losses, and use efficiency in the production and utilization of three major grain crops using data from 2004. We also use a scenario analysis to explore strategies for improving N use efficiency. Our calculations show that N use efficiency in food production and utilization is much lower than previously published estimates. Mean N surpluses of crop fields were 144 kg/ha for wheat, 184 kg/ha for rice, and 120 kg/ha for maize. We estimate that between 50% and 85% of N harvested as grain is lost for utilization by humans and animals. Fertilizer N use efficiency (FNUE) values in crop–animal system for wheat, rice, and maize were 13.4%, 11.3%, and 3.7%, respectively. This means 7.5, 8.9 and 27.1 kg of N fertilizer were required to produce 1 kg of N in food via fertilization for these three grains. Major room exists for improving the efficiency of N flow in Chinese crop systems. Our scenario analyses shows that increases in N use efficiency of fertilizer applied to cropland (RE), decreasing ratios of grain N headed to plant food processing (GUP), and increasing efficiency in animal production (ANU) would result in a marked decrease in N loss from these three crops amounting to one million ton of N, which accounted for 6% of total chemical fertilizer input. Improved N management in Chinese food production has major ramifications for global estimations of N use efficiency and environmental pollution by reactive N, particularly nitrous oxide emissions, a major anthropogenic contributor to global climate change.

Wax production from renewable feedstock using biocatalysts instead of fossil feedstock and conventional methods

Background, aim, and scope Using renewable feedstock and introducing biocatalysts in the chemical industry have been suggested as the key strategies to reduce the environmental impact of chemicals. The Swedish interdisciplinary research program "Speciality Chemicals from Renewable Resources-Greenchem" is aiming to develop these strategies. One target group of chemicals for Greenchem are wax esters which can be used in wood coatings to replace paraffin wax made from fossil crude oil. The aim of this study was to conduct a life cycle assessment of wax esters based on rapeseed oil produced by biocatalysts (enzymes). The scope was to compare the environmental performance of wax esters with paraffin wax produced by conventional methods. Materials and methods The study has a cradle-to-gate perspective and the functional unit is "1-kg wax product ready to use in a wood coating product." Extensive data collection and calculations have been performed for the wax esters, whereas existing life cycle inventory data have been used for the paraffin wax. Results The energy input into the wax ester production is about one third of the energy input in paraffin wax production. However, the wax ester has a higher contribution to the global warming potential (GWP) due to high emissions of nitrous oxide from rapeseed cultivation. Referring to a cradle-to-grave perspective, including waste incineration, the contribution to the GWP will, however, be 3.5 times higher from paraffin wax. Wax ester makes a higher contribution to the acidification and eutrophication potential, due to emissions from soil from rapeseed cultivation, but five times lower contribution to the photochemical ozone creation potential. From a land-use perspective and a global warming point of view, it is more efficient to produce paraffin wax and grow high-yielding, short-rotation coppice (Salix) to replace fuel oil than it is to grow rapeseed for wax ester production. Discussion Overall, this study shows the importance of studying the environmental performance of a product not only from a gate-to-gate perspective but, instead, considering the environmental performance from cradle-to-gate. The biocatalytic production of the wax ester consumes less energy than the conventional chemical method, but the raw material step, cultivation of rapeseed contributes much to both acidification and eutrophication. When the waste treatment step is included, the contribution to GWP, however, for paraffin wax will be 3.5 times higher than for the wax ester. Conclusions From a gate-to-gate perspective, replacing conventional chemical processes by biocatalysts using enzymes leads to energy savings and reduces emissions. However, from a cradle-to-gate perspective, the use of renewable feedstock, such as rapeseed oil, may counteract some of these benefits. Concerning the GWP benefit from using renewable feedstock instead of fossil feedstock, the final waste treatment step must be included, thereby applying a cradle-to-grave perspective. Recommendations and perspectives The introduction of biocatalysts as a key strategy in reducing the environmental impact from the chemical industry is supported by the results in this study. On the other hand, it is not obvious that the key strategy of using renewable feedstock in chemical production per se leads to benefits concerning all environmental impact categories. Thus, much more attention needs to be paid to the choice of potential renewable feedstock options, the minimization of energy inputs, and the biological emissions from the soil in the cultivation of feedstock crops, improved gas cleaning in nitrogen fertilizer production plants, and the alternative use of the arable land, in optimizing the overall environmental benefits of an increased use of renewable feedstock in the chemical industry.

Life cycle assessment of the winter wheat-summer maize production system on the North China Plain

A life cycle assessment (LCA) method was used to examine the environmental impact of the winter wheat-summer maize production system on the North China Plain. The LCA considered the entire system required to produce 1 ton each of winter wheat and summer maize. The analysis included raw material extraction and transportation, agrochemical production and transportation, and arable farming in the field. First, all emissions and resource consumption connected to the different processes were listed in a life cycle inventory (LCI) and related to a common unit (1 ton of grain). Subsequently, a life cycle impact assessment (LCIA) was conducted, in which the inventory data were aggregated into indicators for environmental effects, including energy depletion, climate change, acidification, aquatic eutrophication, human toxicity, aquatic and terrestrial ecotoxicity. For winter wheat systems, energy depletion and acidification were the most relevant environmental impacts, and energy depletion and aquatic eutrophication were the primary concerns for summer maize systems. The results revealed that the most important source of environmental impact in the winter wheat-summer maize production system in Huantai County was the production and application of nitrogen fertilisers. The environmental impacts of winter wheat were much stronger than those of summer maize due to higher inputs and lower use efficiency of agrochemicals.

Use of electrodialysis and reverse osmosis for the recovery and concentration of ammonia from swine manure

This project aimed at producing a concentrated nitrogen fertilizer from liquid swine manure using electrodialysis (ED) and reverse osmosis (RO), as a mean to help resolve the excess nutrient problem faced by many swine producers, and offer an alternative to chemical nitrogen fertilizer production. Different types of ED membranes were evaluated based on the NH4+ transfer rate, current efficiency and membrane stability. A combination of CMB/AMX membranes was retained due to its high NH4+ transfer rate and chemical stability. The maximum total ammonia concentration (NH3–N) achievable by ED was limited by water transport from the manure to the concentrate compartment, and ammonia volatilization (17%) from the open concentrate compartment. Results suggested that, under the conditions of this experiment, a maximum total NH3–N concentration of about 16g/L could be reached with the ED system. An ED concentrate (8.7g/L of total NH3–N) was also fed to TFC-HF reverse osmosis membranes. A mass balance analysis revealed that the RO permeate, which represented 49.6% of the initial volume, contained 8.6% of the ammonia. However, the RO concentrate contained only 66.6% of the initial total NH3–N, suggesting that 21.2% of the ammonia was volatilized during the concentration test with RO membranes. Ammonia concentration in the RO concentrate reached approximately 13g/L, which is similar to the maximum concentration that could be achieved by ED. These results suggest that the use of ED and RO membranes to recover and concentrate ammonia is potentially interesting but the process must include an approach to minimize ammonia volatilization or trap volatilized ammonia.

Symbiotic nitrogen fixation in legume nodules: process and signaling. A review

The Green Revolution was accompanied by a huge increase in the application of fertilizers, particularly nitrogen. Recent studies indicate that a sizeable proportion of the human population depends on synthetic nitrogen (N) fertilizers to provide the 53 million t N that is harvested globally in food crops each year. Nitrogen fertilizers affect the balance of the global nitrogen cycle, pollute groundwater and increase atmospheric nitrous oxide (N2O), a potent “greenhouse” gas. The production of nitrogen fertilizer by industrial nitrogen fixation not only depletes our finite reserves of fossil fuels, but also generates large quantities of carbon dioxide, contributing to global warming. The process of biological nitrogen fixation offers an economically attractive and ecologically sound means of reducing external nitrogen input and improving the quality and quantity of internal resources. Recent studies show that in irrigated cropping systems, legume N is generally less susceptible to loss processes than fertilizers. Biological nitrogen fixation (BNF) has provided a number of useful paradigms for both basic and applied research. Establishing a fully functional symbiosis requires a successful completion of numerous steps that lead from recognition signals exchanged between the plant and bacteria to the differentiation and operation of root nodules, the plant organ in which nitrogen fixation takes place. The initial sensing of the two organisms by each other starts with the release of root exudates by the plant that include flavonoids and nutrients such as organic acids and amino acids. Flavonoids secreted by the host plant into the rhizosphere function as inducers of the rhizobial nod genes. nod gene induction results in the secretion of lipochitin oligosaccharides that are thought to bind to specific plant receptor kinases that contain LysM motifs, such as NFR1 and NFR5 in Lotus japonicus and LYK3 and LTK4 in Medicago truncatula. This initiates a complex signaling pathway involving calcium spiking in root hairs. The result is that the root hairs curl and trap the rhizobia, which then enter the root hair through tubular structures known as infection threads that are formed by the plant. The infection threads then grow into the developed nodule tissue. Ultimately, the invading bacteria are taken into the plant cell by a type of endocytosis in which they are surrounded by a plant-derived peribacteroid membrane (PBM). The resulting symbiosomes fill the plant cell cytoplasm and as plant and bacterial metabolism develops, the bacteria become mature bacteroids able to convert atmospheric nitrogen to ammonium. To increase knowledge of this system of particular importance in sustainable agriculture, major emphasis should be laid on the basic research. More work is needed on the genes responsible in rhizobia and legumes, the structural chemical bases of rhizobia/legume communication, and signal transduction pathways responsible for the finely orchestrated induction of the symbiosis-specific genes involved in nodule development and nitrogen fixation. This review unfolds the various events involved in the progression of symbiosis.

Engineering Contractors in the Chemical Industry. The Development of Ammonia Processes, 1910–1940

Ammonia is the crucial intermediate for the production of nitrogen fertilisers. BASF, today still one of the largest chemical companies in the world, was the first company to develop a process for the synthesis of ammonia from its compounds hydrogen and nitrogen: the well‐known Haber–Bosch process. Other processes were developed as well in the 1910s and ’20s but these technologies have often been classified as ‘imitations’, neglecting the crucial role they played in the take‐off of the fertiliser industry in the late 1920s and neglecting engineering contractors, companies that specialised in the design and construction of plants for the process industries. Engineering contractors diffused ammonia synthesis across the world and enabled the take‐off of the fertiliser industry. This paper attempts to show the role engineering contractors can play in the chemical industry and attempts to give a more balanced account of the history of ammonia synthesis by focusing on the fertiliser industry instead of BASF.

Effect of hydroxyl and nitrate ions on the sorption of ammonium ions by sulphonic cation exchangers

The sorption of ammonium ions and ammonia by the H+ form of sulphonic acid cation exchangers Amberlite 252, Lewatit 2629 and Relite C 360 from a solution containing NH 4NO 3 in the range of 0 to 0.214 equ/L and NH 3 in the range of 0.353 to 0 equ/L was investigated to establish the possibility of their application for the recovery of ammonium from caustic condensate generated in nitrogen fertilizer production. Breakthrough and elution curves were obtained, determining the concentration of ammonium with Nessler's reagent. The sorption of ammonium and ammonia depends on the concentration ratio of ammonia to ammonium nitrate [NH 3]/[NH 4NO 3]. On decreasing [NH 3]/[NH 4NO 3], the concentration ratio of hydroxyl to nitrate ions [OH −]/[NO − 3] and the effluent pH prior to NH + 4 breakthrough also decrease. This results in a decrease in the NH + 4 sorption because of a deficiency in the neutralization of hydrogen ions released (ordinary cation-exchange process). Thus, adverse circumstances create an unfavorable medium for NH + 4 removal from the caustic condensate. Maximum sorption of NH + 4 is attained at [NH 3]/[NH 4NO 3] ∼1.2. A further decrease in [NH 3]/[NH 4NO 3] is followed by a significant decrease in the effluent pH, which leads to an increase in the concentration of protonated sulphonic acid groups (-SO 3H), resulting in a decrease in the ion-exchange ability of the cation exchangers under investigation with respect to NH + 4 removal. The concentration (g/L) of NH 4NO 3 in the eluate from the cation-exchanger regeneration, carried out using 0.7 bed volumes (BV) of 20% HNO 3, amounts to 136.7 for Relite C 360, 119.5 for Lewatit K 2629 and 96.7 for Amberlite 252. The content of undamaged beads after 100 cycles (each cycle comprises saturation with caustic condensate, containing ammonia and ammonium, successive regeneration with 20% nitric acid and washing) is from 97 to 99.8%. Resistance to boiling in 20% HNO 3 solution is from 97 to 99.8%. These are applicable for the recovery of NH 4NO 3 from the caustic condensate in the nitrogen fertilizers production, preventing economic damage and environmental contamination from nitrogen compounds.

Economics of Recovering Value from Recycling Treated Biosolids to Land

AbstractThis paper demonstrates the economic value of recycling treated biosolids to land in terms of (a) the effect on agricultural yield and (b) the avoidance of environmental and social costs of using conventional mineral fertilisers. Replicated field trials show that yield increases can be achieved when biosolids are used in conjunction with mineral fertilisers, compared with using conventional fertilisers. Relevant environmental and social costs of the production and use of both nitrogen and phosphate fertilisers and recycled biosolids are estimated. By recycling biosolids to agricultural land, the external costs associated with conventional mineral fertilisers can be fully recovered. The total replacement value of biosolids is the sum of the values of the increased yields and the replaced external costs. For digested cake this is equal to £2.64/tonne and for granules £10.85/tonne; in both cases the replacement value exceeds the external costs of biosolids. These costs and benefits should be taken into account in the development of environmental policy related to wastewater treatment.

Trials to create artificial nitrogen-fixing symbioses and associations using in vitro methods: An outlook

Biological nitrogen fixation is the most important process in which some prokaryotic organisms fix N2 into ammonium. From an agricultural standpoint, biological nitrogen fixation (BNF) is critical because industrial production of nitrogen fertilizers seldom meets agricultural demands. To increase the BNF is one of the main challenges for the future. There are different possibilities for extending biological nitrogen fixation to the economically important plants. One of the possibilities is to create new artificial systems between diazotrophic bacteria and different higher plants. This is the main topic of the present review article which discusses the establishment of new associative and/or symbiotic systems, via introduction of diazotrophic bacteria into the roots by different methods; and incorporation of nitrogen-fixing bacteria in the entire plant by in vitro methods, through the establishment of intracellular endosymbioses via induced uptake of bacteria by plant protoplasts (endocytobiosis), and establishment of intercellular associations by forced introduction of bacteria into the plant tissues (exocytobiosis). The common characteristic of the methods to create artificial plant-microbe systems for atmospheric nitrogen fixation is the use of in vitro plant systems: cells, tissues and organ cultures. The review pays particular attention to new bacterial inoculation procedures for introduction of the diazotrophic bacteria inside the plant tissues.

169 Progress in the Development of a Sustainable Production System for Fresh-market Tomatoes

In the production of fresh-market vegetables, off-farm inputs, such as, plastic, nitrogen fertilizer, fungicides, insecticides, and herbicides are routinely used. One aim of the sustainable agriculture program at the Beltsville Agricultural Research Center is to develop systems that reduce these inputs. We have completed the second year of a study designed to examine foliar disease progress, foliar disease management, and marketable fruit yield in staked fresh-market tomatoes grown in low- and high-input production systems. Specifically, four culture practices (black plastic mulch, hairy vetch mulch, dairy manure compost, and bare ground) were compared in conjunction with three foliar disease management treatments (no fungicide, weekly fungicide, and a foliar disease forecasting model, TOMCAST). Within all culture practices, use of the TOMCAST model reduced fungicide input nearly 50%, compared with the weekly fungicide treatment, without compromising productivity or disease management. With regard to disease level, a significant reduction of early blight disease severity within the hairy vetch mulch was observed in 1997 in relation to the other culture practices. Early blight disease severity within the black plastic and hairy vetch mulches was significantly less than that observed in the bare ground and compost treatments in 1998. In addition, despite a 50 % reduction in synthetic nitrogen input, the hairy vetch mulch generated yields of marketable fruit comparable to or greater than the other culture practices. It appears that low-input, sustainable, production systems can be developed that reduce the dependence on off-farm inputs of plastic, nitrogen fertilizer, and pesticides, yet generate competitive yields.

Water for Food Production: Will There Be Enough in 2025?

This year marks the 200th anniversary of the publication of Thomas Malthus’s famous essay postulating that human population growth would outstrip the earth’s food-producing capabilities. His writing sparked a debate that has waxed and waned over the last two centuries but has never disappeared completely. Stated simply, Malthus’s proposition was that because population grows exponentially while food supplies expand linearly, the former would eventually outpace the latter. He predicted that hunger, disease, and famine would result, leading to higher death rates. One of the missing pieces in Malthus’s analysis was the power of science and technology to boost land productivity and thereby push back the limits imposed by a finite amount of cropland. It was only in the twentieth century that scientific research led to marked increases in agricultural productivity. Major advances, such as the large-scale production of nitrogen fertilizers and the breeding of high-yielding wheat and rice varieties, have boosted crop yields and enabled food production to rise along with the world population (Dyson 1996). Between 1950 and 1995, human numbers increased by 122% (US Bureau of the Census 1996), while the area planted in grain expanded by only 17% (USDA 1996, 1997c). It was a 141% increase in grainland productivity, supplemented with greater fish harvests and larger livestock herds, that allowed food supplies to keep pace with population and diets for a significant portion of humanity to improve. Despite this remarkable success, concern about future food prospects has risen in recent years because of a marked slowdown in the growth of world grain yields, combined with an anticipated doubling of global food demand between 1995 and 2025 (McCalla 1994, FAO 1996). Whereas annual grain yields (expressed as threeyear averages) rose 2–2.5 % per year during every decade since 1950, they registered growth of only 0.7% per year during the first half of the 1990s (Brown 1997, USDA 1997a, 1997b). Excluding the former Soviet Union, where the political breakup and economic reforms led to large drops in productivity, global grain yields increased an average of 1.1% per year from 1990 to 1995, approximately one-half the rate of the previous four decades (Brown 1997). Today, the principal difference between those analysts projecting adequate food supplies in 2025 and those anticipating significant shortfalls is the assumed level of productivity growth—specifically, whether annual productivity over the next three decades is likely to grow at closer to the 1% rate of the 1990s or the 2–2.5% rate of the previous four decades. Water—along with climate, soil fertility, the choice of crops grown, and the genetic potential of those crops— is a key determinant of land productivity. Adequate moisture in the root zone of crops is essential to achieving both maximum yield and production stability from season to season. A growing body of evidence suggests that lack of water is already constraining agricultural output in many parts of the world (Postel 1996, UNCSD 1997). Yet to date, I am aware of no global food assessment that systematically addresses how much water will be required to produce the food supplies of 2025 and whether that water will be available where and when it is needed. As a result, the nature and severity of water constraints remain ill defined, which, in turn, is hampering the development of appropriate water and agricultural strategies. In this article, I estimate the volume of water currently consumed in producing the world’s food, how much additional water it will take to satisfy new food demands in 2025, and how much of this water will likely need to come from irrigation. I then place this expected irrigation demand in the context of global and regional water availability and trends. Finally, I discuss the policy and investment implications that emerge from the analysis.

Energy savings in the nitrogen fertilizer industry in the Netherlands

We study the specific energy consumption for the production of nitrogen fertilizers and the various options that are available to reduce this consumption. The average energy consumption for ammonia production (by means of steam reforming of natural gas) in 1988 was 33.5 GJ/ton (LHV). The technical energy savings potential for the year 2000 is 16% [the specific energy consumption thus falls to 28.0 GJ/ton (LHV)]. The profitable energy savings potential is a potential saving of 6% with a payback period of less than three years. The thermodynamic minimum energy consumption using the steam reforming route is 19.1 GJ/ton (LHV). We calculate the effect that savings in ammonia production will have on the energy required for the production of several types of N-fertilizers (urea, nitric acid, ammonium nitrate, and CAN).

Energy efficiency in nitrogen fertilizer production

This paper deals with estimating energy consumption and potential energy savings by improving energy efficiency for production of selected nitrogen fertilizers. The paper also discusses economic importance, economic consequences, and policy implications of improving energy efficiency for nitrogen fertilizer production. Improving energy efficiency is one of the most important and viable policy options to lower nitrogen fertilizer prices. Three strategies to improve energy efficiency for nitrogen fertilizer production are discussed: (1) energy-efficient retrofits; (2) energy-efficient new processes; and (3) operational efficiency and energy management. Efficient operations and energy management are not only desirable but also an economically feasible strategy in most developing countries. The developing countries should be careful in adopting exotic energy-efficient innovations.

Nitrogen fixation and hydrogen metabolism in photosynthetic bacteria

The photosynthetic bacteria are found in a wide range of specialized aquatic environments. These bacteria represent important members of the microbial community since they are capable of carrying out two of the most important processes on earth, namely, photosynthesis and nitrogen fixation, at the expense of solar energy. Since the discovery that these bacteria could fix atmospheric nitrogen, there has been an intensification of studies relating to both the biochemistry and physiology of this process. The practical importance of this field is emphasized by a consideration of the tremendous energy input required for the production of artificial nitrogenous fertilizer. The present communication aims to briefly review the current state of knowledge relating to certain aspects of nitrogen fixation by the photosynthetic bacteria. The topics that will be discussed include a general survey of the nitrogenase system in the various photosynthetic bacteria, the regulation of both nitrogenase biosynthesis and activity, recent advances in the genetics of the nitrogen fixing system, and the hydrogen cycle in these bacteria. In addition, a brief discussion of some of some of the possible practical applications provided by the photosynthetic bacteria will be presented.

Small Nitrogen Fertilizer Factories in our Country Increased Their Output by a Big Margin

(NCNA, May 14, 1976) Under the impetus of the great struggle to beat back the right deviationist attempt to reverse correct verdicts, the broad masses of workers, cadres, and technical personnel in the small nitrogen fertilizer factories across our country persist in taking class struggle as the key link in all work and earnestly study Chairman Mao's important directives. With the deepening of their criticism of Teng Hsiao-p'ing, the top unrepentant capitalist-roader inside the Party, and his revisionist line, as well as his reactionary and criminal acts, the factories are seething with enthusiasm for the revolution and are boosting their production every day. As a result of their new achievements in production, in the first quarter of this year, they overfulfilled the target for nitrogen fertilizer production set in the state plan for the entire country, achieving a 50 percent increase over the same period last year. Small nitrogen fertilizer factories located in over twothirds of the provinces, municipalities, and autonomous regions of our country augmented their output by more than 30 percent over the same period in the preceding year. Such increases as well as their distribution area and the output of small nitrogen factories were unprecedented in history. They eloquently testify to the fact that the struggle to criticize Teng Hsiao-p'ing and beat back the right deviationist attempt to reverse correct verdicts serves as a mighty impetus to stimulating the vigorous development of nitrogen fertilizer production by small factories.

Fruit and Vegetable Production and the Energy Shortage1

Abstract Coincident with the world food shortage, ever-increasing food prices and the shortage and high and rising costs of energy, attention is now being directed to the energy-efficiency of agricultural production (1, 5, 6, 12, 13, 18, 30, 31, 34, 40, 45, 47, 48, 52). Although the energy used annually for agriculture in the United States (48) and Canada is not a large percentage of the national totals some feel that to ensure energy supplies “agriculture must stake a claim” (27). The “claim” must stress the form of energy because current agricultural technology is so dependent on liquid fuels for machinery operation and natural gas for the production of nitrogen fertilizers (40). As an important segment of the agricultural industry, horticulturists must also “stake a claim” to energy if they believe fruits and vegetables make a legitimate contribution to food supplies. Fruit and vegetable production is considered energy-extravagant because of the high energy inputs needed compared to the usable energy output (13, 47), although few studies of the energy relationships of individual horticultural crops have been reported. Presented herein are energy calculations for the production of some fruits and vegetables for which production data in Ontario are available with a discussion of the place of fruits and vegetables in a food supply system and the flaws inherent in judging production efficiency solely on an energy basis.

CORROSION NEWS FROM ABROAD

Stress‐corrosion cracking of steel in nitrates. The production of nitrogen fertilisers has shown up some corrosion problems, particularly the intercrystalline stress‐corrosion cracking of carbon and low‐alloy steels in nitrates. This is allowed by the structure of carbon steels and related to their susceptibility to ageing. For cracking to occur, the corrosive environment must attack the material selectively, with the overall corrosion level remaining negligible, and tensile stresses of a certain magnitude must be acting within the material.

Current Situation of Fertilizer in Japan

Abstract Nitrogenous Fertilizer The production of nitrogenous fertilizer in 1953 Fertilizer Year (August 1953–July 1954) showed an increase of 293.000 metric tons or 11.4% over the preceding year through furtherance of rationalization of the industry as well as better conditions of electricity. This increase was attributable to that of ammonia form fertilizer, which was 331,000 tons over preceding year, while calcium cyanamide showed a slight decrease as per Table 1.