Sub-regional dimensions of agricultural and environmental nitrogen: The case of Asia

Asia embraces a wide range of cropping environments, largely related to the diversity of climate. To meet the high food requirements of a very large population (some 59% of the earth's total) large inputs of mineral N fertilizer are required (44.2 Tg N.yr-1 in the mid 1990s).However, because of the low (20%-50%) overall efficiency of use of fertilizer N, sometimes coupled with heavy use in intensively-farmed areas (for example in parts of China), losses of fertilizer N from agricultural land are expected to be high. Part of the N lost is thought to cause pollution of the atmosphere and water resources.A sub-regional approach, based on the FAO Agroecological Zone (AEZ) concept, has the potential to provide meaningful assessments of the agricultural and environmental dimensions of N.The AEZ concept can also provide the rationale for locating Sub-regional Centers of the International Nitrogen Initiative (INI) by basing the considerations, as far as practicable, on agroecological conditions.     

Sub-regional dimensions of agricultural and environmental nitrogen: The case of Asia

Asia embraces a wide range of cropping environments, largely related to the diversity of climate. To meet the high food requirements of a very large population (some 59% of the earth's total) large inputs of mineral N fertilizer are required (44.2 Tg N·yr-1 in the mid 1990s). However, because of the low (20%-50%) overall efficiency of use of fertilizer N, sometimes coupled with heavy use in intensively-farmed areas (for example in parts of China), losses of fertilizer N from agricultural land are expected to be high. Part of the N lost is thought to cause pollution of the atmosphere and water resources. A sub-regional approach, based on the FAO Agroecological Zone (AEZ) concept, has the potential to provide meaningful assessments of the agricultural and environmental dimensions of N. The AEZ concept can also provide the rationale for locating Sub-regional Centers of the International Nitrogen Initiative (INI) by basing the considerations, as far as practicable, on agroecological conditions.     

Assessment of nitrogen ceilings for Dutch agricultural soils to avoid adverse environmental impacts

In the Netherlands, high traffic density and intensive animal husbandry have led to high emissions of reactive nitrogen (N) into the environment. This leads to a series of environmental impacts, including: (1) nitrate (NO3) contamination of drinking water, (2) eutrophication of freshwater lakes, (3) acidification and biodiversity impacts on terrestrial ecosystems, (4) ozone and particle formation affecting human health, and (5) global climate change induced by emissions of N2O. Measures to control reactive N emissions were, up to now, directed towards those different environmental themes. Here we summarize the results of a study to analyse the agricultural N problem in the Netherlands in an integrated way, which means that all relevant aspects are taken into account simultaneously. A simple N balance model was developed, representing all crucial processes in the N chain, to calculate acceptable N inputs to the farm (so-called N ceiling) and to the soil surface (application in the field) by feed concentrates, organic manure, fertiliser, deposition, and N fixation. The N ceilings were calculated on the basis of critical limits for NO 3 concentrations in groundwater, N concentrations in surface water, and ammonia (NH3) emission targets related to the protection of biodiversity of natural areas. Results show that in most parts of the Netherlands, except the western and the northern part, the N ceilings are limited by NH 3 emissions, which are derived from critical N loads for nature areas, rather than limits for both ground- and surface water. On the national scale, the N ceiling ranges between 372 and 858 kton year(-1) depending on the choice of critical limits. The current N import is 848 kton year(-1). A decrease of nearly 60% is needed to reach the ceilings that are necessary to protect the environment against all adverse impacts of N pollution from agriculture.     

The environmental consequences of altered nitrogen cycling resulting from industrial activity,agricultural production,and population growth in China

Human activities exerted very little effect on nitrogen (N) cycling in China before 1949. Between 1949 and 1999, however, rapid economic development and population growth led to dramatic changes in anthropogenic reactive N, inputted recycling N, N flux on land, N2O emission, and NH3 volatilization. Consequently, these changes have had a tremendous impact on the environment in China. In the current study, we estimated the amount of atmospheric wet N deposition and N transportation into water bodies from the watersheds and major valleys in China. Additionally, we addressed issues on leaching and accumulation of NO3- in the farmland under different climate zones, land use, and cropping systems as well as the potential influence of NO3- on underground water in China.     

Marine environmental issues of Southeast Asia: state and development

The seas of Southeast Asia play an important role in the economy of the surrounding countries. The region's constantly expanding coastal population and development has made great demands on marine resources, with growing evidence seen in the further degradation of the marine environment and continued exploitation of living as well as non-living resources. Integrated coastal area management has never been considered in the past while environmental protection measures and policies have largely been at local or national levels. Implementation of regional study programmes less than 10 years ago and ratification of international as well as regional agreements aimed at protecting the marine environment in recent times indicate a more enlightened approach to the problem.     

Data strategy for environmental assessment of agricultural regions via LCA: case study of a French catchment

Purpose

Various approaches have been carried out to extrapolate environmental assessments of farms to the regional level, some of them oversimplified and thus leading to high uncertainty. Key challenges include selection of a representative sample, construction of a farm/land use typology, the extrapolation strategy and dealing with data limitations. This work proposes a method for addressing these issues by means of statistically supported approaches.

Methods

We applied a novel approach combining a sampling strategy, estimation of farm-level environmental impacts via life cycle assessment (LCA), a farm typology based on principal component analysis, a statistical method for extending the farm sample given data constraints and finally linear extrapolation based on regional production and land use, taking into account the regional import–export balance. The approach was applied to a French case study, the Lieue de Grève catchment in the dairy-intensive Brittany region. A decision flowchart was developed to generalise the approach for similar applications dealing with farm and LCA data constraints. Additionally, innovative farm practices were modelled and their impacts propagated to the regional level.

Results and discussion

The typology developed identified “dairy”, “beef”, “dairy + beef” and “swine” farms as the dominant farm types in the region. While swine farms had the highest mean impacts per hectare, dairy and dairy + beef farms had impacts two to five times as high as those of beef and swine farms, when extrapolated to the entire catchment. Multiple linear regressions based on an extended farm and LCA dataset were used to predict environmental impacts of dairy farms lacking LCA results, thus increasing their sample size before extrapolation. The inclusion of farm and LCA data from a neighbouring region did not contribute to the accuracy of predicted impacts, as determined by comparing them to those of the farm closest to the dairy cluster’s centre, but rather produced significantly larger coefficients of variation. Results of tests of including two extra-regional farm and LCA datasets helped determine decision rules for the decision flowchart. Modelling of innovative agricultural practices yielded regional impacts consistent with previous estimates.

Conclusions

This approach provides a generalisable approach for farm typologies, data handling and regional extrapolation of farm-level LCAs, applicable to estimate environmental impacts of any agricultural area if requirements of a representative farm sample are met. We demonstrate the utility of the method for estimating effects of innovative agricultural practices on a region’s impacts by modelling practices on virtual farms and extrapolating their results.

     

Effects of nitrogen: phosphorus supply ratios on nitrogen fixation in agricultural and pastoral ecosystems

An analysis of data compiled from the literature confirms a strong inverse relationship between annual rates of nitrogen fixation and the soil nitrogen content in agricultural and pastoral ecosystems. However, this inverse relationship is strongly modified by the rate of application of phosphorus fertilizer, which strongly influences the activities of both symbiotic and non-symbiotic nitrogen fixing organisms. In the case of symbiotic legumes, the response of N-fixation to N and P is in part a result of changes in legume dominance within the plant community. These results, as well as supporting data presented from a review of experiments on nitrogen fixation in a variety of other terrestrial and aquatic ecosystems, provide important support for the hypothesis that phosphorus availability is a key regulator of nitrogen biogeochemistry. Published as Paper No. 9950, Journal Series, Nebraska Agricultural Research Division, University of Nebraska, Lincoln, NE, USA.     

The nitrogen cascade from agricultural soils to the sea: modelling nitrogen transfers at regional watershed and global scales

The nitrogen cycle of pre-industrial ecosystems has long been remarkably closed, in spite of the high mobility of this element in the atmosphere and hydrosphere. Inter-regional and international commercial exchanges of agricultural goods, which considerably increased after the generalization of the use of synthetic nitrogen fertilizers, introduced an additional type of nitrogen mobility, which nowadays rivals the atmospheric and hydrological fluxes in intensity, and causes their enhancement at the local, regional and global scales. Eighty-five per cent of the net anthropogenic input of reactive nitrogen occurs on only 43 per cent of the land area. Modern agriculture based on the use of synthetic fertilizers and the decoupling of crop and animal production is responsible for the largest part of anthropogenic losses of reactive nitrogen to the environment. In terms of levers for better managing the nitrogen cascade, beyond technical improvement of agricultural practices tending to increase nitrogen use efficiency, or environmental engineering management measures to increase nitrogen sinks in the landscape, the need to better localize crop production and livestock breeding, on the one hand, and agriculture and food demand on the other hand, is put forward as a condition to being able to supply food to human populations while preserving environmental resources.     

农业生态效率评价——以盆栽水稻实验为例

农业面源污染已成为我国主要环境污染源,但目前缺乏一套针对农业生产的综合评价体系,作为对农业面源污染评估和监督的依据.根据生态效率理论,结合农业生产的特点,建立了综合考虑经济效益、资源物质消耗和环境影响的农业生态效率评价指标体系.以不同氮处理下(0.05、0.15、0.25 g N kg-1)不同水稻品种(锡稻11和武粳4)的盆栽实验为例,以氨挥发、肥料使用量和经济产量等数据为基础,运用基于层次分析法的TOPSIS法对6个评价对象的农业生态效率进行了评价和排序,分析各对象在经济效益、资源物质消耗和环境影响方面的差异与特点,指出施氮量和作物品种都对生态效率具有明显的影响.该评价体系的建立,将为我国农业生产模式从片面追求产量向经济、资源、环境协调可持续发展起到一定的推动作用.     

The agro-production chain environmental management in the agricultural production-consumption chain

After promoting environmental certification of companies in a chain perspective (Udo de Haes & De Snoo, 1996) now the agro-production chain is worked out as a case study. The role of the different links in the chain, such as agricultural producers, processing industry, wholesale companies and retailers is discussed. Also the role of consumers and authorities is described. For every company in the chain the advantages of a company based approach will be a better image and a guaranteed-sale and/or supply. In comparison with a product based approach (ecolabelling) the steering forces in the agro-production chain will be the retailers and not the consumers. Because consumers only get information at company level the approach is less dependent on consumers behaviour in the shop.     

Cycling of nitrogen in modern agricultural systems

Summary Agro-ecosystems have developed from mixed- and multiple-cropping systems with relatively closed N cycles to intensively managed monocultures with large N inputs in the form of commercial fertilizers. Cultivation of increasingly larger areas of land has resulted in substantial losses of soil organic matter and N. Also, the move from slash and burn agriculture to intensively ploughed systems has resulted in losses through increased erosion.The use of N fertilizers has increased rapidly toca. 60 Tg N yr^–1 (1980/81), which is equivalent to at least 40% of the N fixed biologically in all terrestrial systems and 36% more than is fixed in all croplands. On a global scale, the major losses of N from agro-ecosystems are estimated to be: harvest, 30 Tg; leaching, 2 Tg; erosion, 2–20 Tg; denitrification 1–44 Tg; and ammonia volatilization, 13–23 Tg. However, the data base is very crude and several estimates may be wrong by as much as one order of magnitude.Additions of N fertilizers have both direct and indirect effects on soil microorganisms. The possible importance of such effects is briefly discussed and a specific example is given on long-term effects on soil microbial biomass and nitrification rates in 27-year-old cropping systems with different N additions: (i) 0 kg N ha^–1 yr^–1, (ii) 80 kg N ha^–1 yr^–1, (iii) farmyard manureca. 80 kg N ha^–1 yr^–1.Few detailed N budgets exist for agro-ecosystems, despite its major importance as a limiting plant nutrient and the large losses of N from such systems. In conclusion, preliminary nitrogen budgets for four cropping systems (barley receiving 0 or 120 kg N ha^–1 yr^–1; meadow fescue ley with 200 kg N ha^–1 yr^–1 and a lucerne ley) are presented, with special attention to N flow through the soil organisms.Keynote address     

Synanthropic primates in Asia: Potential sentinels for environmental toxins

Macaques are similar to humans both physiologically and behaviorally. In South and Southeast Asia they are also synanthropic, ecologically associated with humans. Synanthropy with humans raises the possibility that macaques come into contact with anthropogenic toxicants, such as lead and mercury, and might be appropriate sentinels for human exposures to certain toxic materials. We measured lead (Pb) and mercury (Hg) levels and characterized the stable isotopic compositions of δ¹⁵N and δ¹³C in hair from three groups of free‐ranging macaques at the Swoyambhu temple in Kathmandhu, Nepal, an urban population that has abundant contact with humans. Hair lead levels were significantly higher among young macaques and differed among the three groups of macaques that were sampled. Hair Hg levels were low. No statistical association was found between stable isotopic compositions (δ¹⁵N and δ¹³C) and Pb and Hg levels. Our data did not find evidence that lead levels were associated with diet. We conclude that, in this population of macaques, behavioral and/or physiologic factors may play a significant role in determining exposure to lead. Chemical analysis of hair is a promising, noninvasive technique for determining exposure to toxic elements in free‐ranging nonhuman primates. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Assessing potential desertification environmental impact in life cycle assessment. Part 2: agricultural case study in Spain and Argentina

Purpose

Land use in dry lands can result in a final stage where land is completely depleted or entirely degraded causing the desertification phenomenon. The first part (part 1) of this series of two articles proposed a methodology to include desertification in life cycle assessment (LCA). A set of variables to be measured in the life cycle inventory, characterization factors, and an impact assessment method for the life cycle impact assessment phase were proposed. This second part (part 2) aims at showing the application of the model proposed in part 1 on two case studies of agricultural activities.

Methods

The impact model proposed is applied to plots of land devoted to agricultural activities in two countries: Argentina and Spain. In the agricultural plots of Spain (1SP to 9SP), two crops were analyzed: winter wheat (Triticum aestivum) and rapeseed (RS, Brassica napus). Two crops were considered in the Argentinean case study: rapeseed (RS, B. napus) and digit grass (Digitaria eriantha) (10AR to 17AR). A bare soil state is considered in both countries as a reference state. Both case studies consider only the agricultural stage in the inventory of a complete life cycle assessment study. Both also consider only one impact category in life cycle environmental assessment: desertification impact due to land occupation.

Results and discussion

On the basis of the obtained results, it can be inferred that cultivating 1 ha of rapeseed and 1 ha of wheat has the same impact on the analyzed plots in Spain and improves the reference state conditions in 50 % of the cases. Moreover, rapeseed grown in Mendoza produces almost the same impact as in some of the Spanish plots. Normalized areas of plots could be useful to compare results in different regions of the world to avoid the influence of the area of occupation in results.

Conclusions

The proposed model implies a contribution of significant importance because so far there has not been an impact assessment tool for land use in dry lands within the LCA framework. The main strength of the proposed model is that it allows a simple way to quantify the desertification impact. Also, it is emphasized that the model can be adapted virtually without difficulty to the evaluation of all types of crops with different management practices in different regions in the life cycle impact assessment stage.     

Ecological dimensions of Appalachian agricultural diversity, 1880–1910

This research uses aggregate statistical sources to describe agricultural diversity in a 31 county area of Appalachian Kentucky over the period 1880–1910. In particular, it considers the distribution and duration of forest farming in this region. It examines the causes of agricultural diversity by testing a series of hypotheses conceptually based in ecological theory. For 1880, counties differed in the degree to which they had the characteristics expected for forest farming. This variation was geographically patterned. While there was still geographical variation in county agricultural characteristics in 1910, sufficient change had occurred so that none of the counties continued to closely conform to the pattern expected for forest farming. Variation and change in county agricultural characteristics were found to be related to population density and growth, soil quality, the presence of railroads, and the development of commercial coal mining.This material is based upon work supported by the National Science Foundation under Grant no. BNS 8519633. Maps for this paper were prepared by the University of Kentucky Cartography Laboratory. Ronald Eller, Ronald Lewis, and Karl Raitz each provided useful information for this study. The assistance of Andrea Allen and Belinda Jo Williams was essential to the completion of this project. Sara A. Quandt's and Endre Nyerges' constructive comments substantially improved this paper. The comments of two anonymous reviewers were also instructive in improving this work. To each of these individuals the author expresses his thanks.     

Mountain forest islands and Holocene environmental changes in Central Asia: A case study from the southern Gobi Altay, Mongolia

A multi-proxy case study conducted on Central Asia's most isolated mountain forest sheds light on the apparent decline of forest in the Subboreal time period and the incisive environmental changes from dark taiga to steppe in the Gobi Altay of Southern Mongolia over the last 5000 yr.

New vegetation records from the ‘Gobi Gurvan Saykhan’ (43°30′ N/103°10′ E) reveal long distance disjunctions of birch–willow forests as well as a number of herbaceous forest plants. Thus the question arises as to whether long-distance dispersal or fragmentation, following climatic changes and human interference, are more plausible explanations for such a pattern. Analysis of current plant distribution patterns lead to conclusions which are corroborated by zoological surveys of the Gobi Altay: During the Holocene, dark taiga forests apparently existed approximately 600 km to the southeast of their present range, and pollen analysis and charcoal remains provide evidence of a forest decline during the Subboreal time period. The presence of humans during these environmental changes is highly probable as pollen indicating human presence was found. Thus, it is assumed that humans at least contributed to the subboreal forest decline and the spreading of sagebrush and pastures. Moreover we cannot rule out with certainty that disjunctions of forest flora between the Gobi Altay and the forests of north-eastern Tibet are indicative of migration through the present North China desert, as forests may have partly replaced deserts during the moister periods of the Holocene. This multidisciplinary approach implies a mid-Holocene and subboreal scenario, which is new for Central Asia and more in accordance with the environmental history of the Holocene in the western desert belt of the Old World.     

Phosphorus loss from land to water: integrating agricultural and environmental management

Phosphorus (P), an essential nutrient for crop and animal production, can accelerate freshwater eutrophication, now one of the most ubiquitous forms of water quality impairment in the developed world. Repeated outbreaks of harmful algal blooms (e.g., Cyanobacteria and Pfiesteria) have increased society's awareness of eutrophication, and the need for solutions. Agriculture is regarded as an important source of P in the environment. Specifically, the concentration of specialized farming systems has led to a transfer of P from areas of grain production to animal production. This has created regional surpluses in P inputs (mineral fertilizer and feed) over outputs (crop and animal produce), built up soil P in excess of crop needs, and increased the loss of P from land to water. Recent research has shown that this loss of P in both surface runoff and subsurface flow originates primarily from small areas within watersheds during a few storms. These areas occur where high soil P, or P application in mineral fertilizer or manure, coincide with high runoff or erosion potential. We argue that the overall goal of efforts to reduce P loss to water should involve balancing P inputs and outputs at farm and watershed levels by optimizing animal feed rations and land application of P as mineral fertilizer and manure. Also, conservation practices should be targeted to relatively small but critical watershed areas for P export.     

Combining life cycle assessment and economic modelling to assess environmental impacts of agricultural policies: the case of the French ruminant sector

The International Journal of Life Cycle Assessment - Numerous policy instruments are applied to agricultural production in the European Union (EU27). Implementing them may significantly influence...     

The response of catarrhine primates to pleistocene environmental fluctuations in East Asia

Examination of the patterns of distribution for five catarrhine genera (Gigantopithecus, Pongo, Hylobates, Macaca, andRhinopithecus) during the Pleistocene and Holocene in China indicates that the geographical ranges of individual genera shifted independently of one another in response to conditions of increasing seasonality. All genera examined saw their distributions shift southward, with the shifting subtropical and tropical zones, during the Pleistocene. This occurred earlier in the Pleistocene for the larger apes, and later for smaller forms. This apparent paradox is readily explained by the inability of large-bodied apes to satisfy the high metabolic demands of a relatively large brain as well as those of an absolutely larger body. Monkeys were somewhat less affected and their greater relative success is attributed to their abilities to survive in more highly seasonal environments by exploiting a wider variety of plant foods and to produce offspring more quickly, thanks to shorter gestation times and shorter interbirth intervals.     

Hidden responses to environmental variation: maternal effects reveal species niche dimensions

Species responses to fluctuating environments structure population and community dynamics in variable ecosystems. Although offspring number is commonly used to measure these responses, maternal effects on offspring quality may be an important but largely unrecognised determinant of long‐term population growth. We selected 29 species across a Mediterranean annual plant phylogeny, and grew populations of each species in wet and dry conditions to determine responses in seed number and maternal effects (seed size, seed dormancy, and seedling growth). Maternal effects were evident in over 40% of species, but only 24% responded through seed number. Despite a strong trade‐off between seed size and seed number among species, there was no consistent trade‐off within species; we observed correlations that ranged from positive to negative. Overall, species in this plant guild show a complex range of responses to environmental variation that may be underestimated when only seed number responses are considered.     

Taking things public: a contribution to address human dimensions of environmental change

This paper addresses the question of environmental change in Amazônia, by looking at the experiences of the large-scale biosphere–atmosphere (LBA) experiment in the Amazon, and three other enterprises—the extractive reserves, the Pilot Programme to Conserve the Brazilian Rain Forest (PPG7) and ecological-economic zoning—that address questions of sustainable development in the region. The LBA experience shows how the integration with the social sciences can be critical for science to explore its own outcomes for society, while the other programmes expose environmental change as a problem with too many intersections within society, so the outcomes of any initiative depends on placing it before a complex, tense and wide arena.