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Large quantities of organic manures and soiled water are generated by cattle housing every year. These organic wastes are stored until soil conditions are suitable for landspreading or there is a crop requirement for nutrients. After land application, some nitrogen (N) is lost through the direct emission of nitrous oxide (N2O), a powerful greenhouse gas (GHG) produced by nitrification and partial denitrification of mineral N. The objective of this research was to investigate whether N2O losses could be mitigated after applying cattle slurry pre-mixed with the nitrification inhibitor dicyandiamide (DCD) during anaerobic storage. Contrary to our initial hypothesis, DCD mixed with slurry did not degrade for up to six months post amendment during an incubation study. These results highlight the feasibility of amending cattle slurry with DCD directly into slurry tanks any time before land application. This incubation experiment also showed that a slow release of DCD in slurry could be achieved if the amendment used was beads of a chitosan xerogel impregnated with DCD. A field study revealed that slurry application to grassland plots can cause large N2O emissions under wet and mild conditions when ammonia emissions are expected to be low. Slurry incubated with DCD for six month was effective at significantly (P < 0.01) decreasing N2O net cumulative emissions, which were 88% lower than in the slurry treatment with no DCD. The addition of DCD to slurry also reduced the fraction of N2O in the total GHG net cumulative emissions from 52% down to just 10%. Mixing slurry with DCD during storage could therefore offer farmers a cost-effective, practical, mitigation alternative to DCD broadcast application for the reduction of agricultural N losses.

Emissions of ammonia and greenhouse gases from animal manure are an environmental concern and new techniques should be carefully examined to establish their effect on emissions across the whole management continuum, including storage operations. Biogas plants are becoming more common at farm facilities and the management of digestate raises some concerns regarding potential emissions to the air when mechanical separation is adopted. The aim of this study was to evaluate how mechanical separation affects ammonia and greenhouse gas emissions from the storage of different fractions obtained from separation of codigested pig and cattle slurries. A laboratory scale experiment was carried out in a temperature controlled room where 25 L of unseparated digestate and the relative solid and liquid fractions were stored in duplicates for 32 days at 17 °C. Each manure was sampled weekly for chemical analysis (total nitrogen, ammoniacal nitrogen, total solids, volatile solids and pH). Potential emissions from agitated samples were estimated twice a week using a dynamic chamber technique and acid traps for ammonia and a trace gas analyser for carbon dioxide, methane and nitrous oxide. Results from chemical analyses indicated that mechanical separation of digested manure increased nitrogen losses during storage when both separated fractions are taken into account, by 35 and 86% for the pig and cattle slurries, respectively. However, the flux measurements from the agitated samples showed that there was a lower potential for ammonia emissions during storage for the separated fractions than the digested unseparated slurry (9 and 23% reductions for the pig and cattle slurries, respectively), probably due to the lower TAN concentration of the liquid fraction. The treatment resulted in a significant reduction (40%) of GHG emissions for cattle slurries but had no consistent effect for pig effluents. The results of this study suggest that adoption of mitigation techniques should be considered for the management of the liquid and solid fractions of digestates in order to reduce the increased environmental impact during storage.

Manure management at dairy production facilities, including anaerobic digestion (AD) and solid-liquid separation (SLS), has shown strong potential for the abatement of greenhouse gas (GHG) and ammonia (NH3) emissions. However, previous study results are inconsistent and the combined effect of AD + SLS remains to be quantified. This study evaluated the effects of AD, SLS, and AD + SLS on GHG and NH3 emissions during manure storage through land application over nine months. AD and SLS alone significantly (P

The effect of combined chemical–mechanical pig slurry separation on ammonia (NH 3 ) emissions was investigated in a field scale study. We determined the amount of volatized ammonia emitted from the solid and liquid fractions of raw pig slurry during its storage and after its broadcast to an alfalfa ( Medicago sativa L.) meadow under summer and winter conditions. The solid fraction accounted for the largest NH 3 losses during both storage and land application. Chemical–mechanical separation of raw pig slurry under winter conditions caused a slight (−2%) reduction in NH 3 emissions during manure management (storage + broadcast application), as opposed to an emission increase of as much as 17% for separation under summer conditions. Evidence from this study suggests that environmental benefits are possible if solid and liquid fractions are managed using state-of-the-art NH 3 mitigation options, such as covered manure storage and band spread slurry application.

This introductory paper provides an overview of the contributions to this special issue, addressing four key questions related to conservation agriculture (CA) in Sub-Saharan Africa and South Asia: What is the impact of CA on yields? What is the impact of adopting CA on farmers’ profits? What are the environmental impacts of adopting CA? How well does CA fit with wider agricultural, social, economic and political contexts for small-scale farmers? Papers in this special issue find that yield increases under CA are possible but uncertain given the low average yields that pertain in these regions, and yield gains are more likely to be observed after several years. CA is not widely adopted in Sub-Saharan Africa and South Asia owing to a lack of economic incentive for smallholder farmers—that the process of conversion to CA is not profitable over planning horizons of most farmers. There is no clear trend for greater carbon sequestration under CA, so the potential for subsidizing farmers to adopt CA using payments for ecosystem services/carbon credit schemes seems limited in scope. There is early evidence that farmers perceive a benefit from CA adoption in regions that are prone to erratic rainfall, suggesting a potential risk mitigation role. In addition, throughout this overview paper we offer a commentary on some of the scientific issues that constrain our ability to understand the performance of CA in these systems more comprehensively.

This paper analyzes the determinants of farmer adoption of conservation farming practices using panel data from two rounds of the Rural Incomes and Livelihoods Surveys that were implemented in 2004 and 2008. Conservation farming (CF) has been actively promoted in seven of Zambia's nine provinces since the 1980s. CF has the technical potential to contribute to food security and adaptation to climate change; however, rigorous analyses of the determinants of adoption/dis-adoption of these practices, are still scarce. This paper fills this gap by combining rich panel data with historical rainfall data to understand the determinants of adoption and intensity of two CF practices: minimum soil disturbance and crop rotations. Controlling for the confounding effects of household level unobservables, we find that extension services and rainfall variability are the strongest determinants of adoption, suggesting that farmers use these practices as an adaptation strategy to mitigate the negative effects of variable and delayed rainfall. Furthermore, our findings highlight the role of agro-ecological and socio-economic constraints in explaining adoption, as well as the potential role and effectiveness of interventions to support it. Eastern province shows a significantly different trend in terms of both adoption and the intensity of adoption, indicating that the long-established CF activities in the province have had some impact – though high dis-adoption rates are observed even in this province.

This paper reviews the agroecosystems and agricultural biodiversity in Southern Africa and highlights the importance of the agricultural landscape in biodiversity conservation and the important role that the traditional farming systems play in conserving biodiversity. The review established that agrobiodiversity is of great importance to both small scale and large commercial farmers in Southern Africa through its provision of ecosystem services. The paper also highlights the significant loss of agrobiodiversity as a result of human population pressure and the transition from traditional mixed farming systems which is characterized with high agrobiodiversity, to modern monoculture farming resulting in decline of species diversity. Although concerted efforts are being made to promote the sustainable use and management of this agrobiodiversity, there need to have a multi-stakeholder approach so that conservation efforts are successful, a role that is currently played by the SADC Plant Genetic Resources Centre in Southern African conservation of agrobiodiversity.

Results from the UK were reviewed to quantify the impact on climate change mitigation of soil organic carbon (SOC) stocks as a result of (1) a change from conventional to less intensive tillage and (2) addition of organic materials including farm manures, digested biosolids, cereal straw, green manure and paper crumble. The average annual increase in SOC deriving from reduced tillage was 310 kg C ± 180 kg C ha−1 yr−1. Even this accumulation of C is unlikely to be achieved in the UK and northwest Europe because farmers practice rotational tillage. N2O emissions may increase under reduced tillage, counteracting increases in SOC. Addition of biosolids increased SOC (in kg C ha−1 yr−1 t−1 dry solids added) by on average 60 ± 20 (farm manures), 180 ± 24 (digested biosolids), 50 ± 15 (cereal straw), 60 ± 10 (green compost) and an estimated 60 (paper crumble). SOC accumulation declines in long-term experiments (>50 yr) with farm manure applications as a new equilibrium is approached. Biosolids are typically already applied to soil, so increases in SOC cannot be regarded as mitigation. Large increases in SOC were deduced for paper crumble (>6 t C ha−1 yr−1) but outweighed by N2O emissions deriving from additional fertiliser. Compost offers genuine potential for mitigation because application replaces disposal to landfill; it also decreases N2O emission.&nbsp

Few empirical studies have rigorously analyzed the downstream economic benefits of watershed protection to generate economic values of watershed services. By developing a conceptual framework and using household level economic and environmental data to illustrate its empirical tractability, this paper addresses the neglected, but critical, question of the importance of watershed services to farming communities in southeast Asia. A case study from Flores, Indonesia provides evidence of a substantive, quantified economic benefit of watershed service based on a fixed-effects regression model of water collection costs. The paper also offers lessons for researchers at all stages of data collection and analysis and a research agenda for enhancing our toolkit for policy analysis. This discussion of conceptual, empirical and methodological issues collectively suggests that ecosystem valuation can provide critical input into the design and evaluation of conservation and development policies in the tropics. © 2004 Elsevier B.V. All rights reserved.

Questions of land use/land cover change have attracted interest among a wide variety of researchers concerned with modeling the spatial and temporal patterns of land conversion and understanding the causes and consequences of these changes. Among these, geographers and natural scientists have taken the lead in developing spatially explicit models of land use change at highly disaggregate scales (i.e. individual land parcels or cells of the landscape). However, less attention has been given in the development of these models to understanding the economic process — namely, the human behavioral component — that underlies land use change. To the extent that researchers are interested in explaining the causal relationships between individual choices and land use change outcomes, more fully articulated economic models of land use change are necessary. This paper reviews some of the advances that have been made by geographers and natural scientists in developing these models of spatial land use change, focusing on their modeling of the economic process associated with land use change. From this vantage point, it is argued that these models are primarily “ad hoc,” developed without an economic theoretical framework, and therefore are susceptible to certain conceptual and estimation problems. Next, a brief review of traditional economic models of land use determination is given. Although these models are developed within a rigorous economic framework, they are of limited use in developing spatially disaggregate and explicit models of land use change. Recent contributions from economists to the development of spatially explicit models are then discussed, in which an economic structural model of the land use decision is developed within a spatially explicit framework and from which an estimable model of land use change is derived. The advantages of this approach in terms of simulating policy scenarios and addressing econometric issues of spatial dependency and endogeneity are discussed. We use some specific examples from ongoing research in the Patuxent Watershed, Maryland, USA to illustrate our points. The paper concludes with some summary remarks and suggestions for further research. © 2001 Elsevier Science B.V. All rights reserved.

The objective of this paper is to simulate the location of land-use change, specifically forest disturbance, in Costa Rica over several decades. This paper presents a GIS-based model, GEOMOD2, which quantifies factors associated with land-use, and simulates the spatial pattern of land-use forward and backward in time. GEOMOD2 reads rasterized maps of land-use and other biogeophysical attributes to determine empirically the attributes of land that humans tend to use. Then GEOMOD2 uses the patterns of those biogeophysical attributes to simulate the spatial pattern of land-use change. GEOMOD2 can select locations for land-use change according to any of three decision rules based on (1) nearest neighbors, (2) stratification by political sub-region, and/or (3) the pattern of biogeophysical attributes. GEOMOD2 simulates the progressive loss of closed-canopy forest in Costa Rica for 1940, 1961 and 1983, which are the years for which maps of land-use are available. Also, GEOMOD2 extrapolates the pattern of land-use to the year 2010. When GEOMOD2 extrapolates land-use change over several decades, it is able to classify correctly between 74 and 88% of the grid cells, for two categories: forest versus non-forest. Over various simulation runs, Kappa ranges from 0.31 to 0.53. The model’s ability to predict the location of disturbance is best when the model is driven by the location of biogeophysical characteristics, most importantly lifezones.

This paper concentrates on what are perceived as critical issues which should be addressed if a productive and sustainable agriculture is to be achieved in Latin America. The attainment of such an agriculture is dependent on new technological innovations, policy changes and more socio-equitable economic schemes. By using several examples of biological control and integrated pest management programs as case studies, ways of promoting the transition of chemical intensive commercial agriculture to low-input management are explored. Similarly, the paper describes non-governmental efforts utilizing the agroecological approach to help the great mass of resource-poor farmers, mostly confined to marginal soils, hillsides and rainfed areas, to achieve year-round food self-sufficiency, reduce their reliance on scarce and expensive agricultural chemical inputs, and develop production systems that rebuild the productive capacities of their smallholdings.

The savannas of eastern Colombia located in the Orinoco river basin represent 18% of the Latin American neotropical savannas, and those areas that are tillable and closer to markets are subject to considerable anthropic pressure in the quest for intensification. Historically, and even today, beef cattle production constitutes the main land use, and much of it is subjected to extensive management. This paper describes for the first time, the use of cattle grazing experiments to assess methane (CH4) emissions from neotropical savanna-based beef breeding systems, and with the support of published research conducted next to them, estimates of the carbon (C) footprint in carbon dioxide equivalents (CO2-eq) for the whole system. Over 5 years and covering complete reproductive cycles, a conventional weaning (CW) herd system was compared to an early weaning (EW) herd system, that represented a modest degree of more intensive savanna management. Differences were found between the two management practices in total CH4 emissions, emission intensities [kg CH4 kg –1 calf born and kg CH4 kg –1 liveweight gain (LWG)] and emission efficiencies (kg CO2-eq kg –1 calf born and kg CH4 kg –1 LWG), that mostly associated with the different lactation lengths. When both herd systems were carried over until calves, later yearlings, reached to 25 months of age, the differences in favor of EW breeding herd system were diminished. The calculated C footprint in (CO2-eq) of both management practices was near neutral subjected to a number of assumptions and the use of limited published information on savanna C stocks and CH4 and nitrous oxide (N2O) emissions from soil, and it is posited that both herd systems were nearly in equilibrium. The available data and results show the need for further information on the neotropical savanna C stocks and C sequestration potential of soils of the Orinoco river basin. More reliable datasets regarding below-ground C inputs and CH4 and N2O emissions from soil are needed to provide a useful basal benchmark for, and approach to, future analyses of environmental impact of more intensive beef herd systems in the region.

In this paper we present effects of four paired agricultural management practices (organic matter (OM) addition versus no organic matter input, no-tillage (NT) versus conventional tillage, crop rotation versus monoculture, and organic agriculture versus conventional agriculture) on five key soil quality indicators, i.e., soil organic matter (SOM) content, pH, aggregate stability, earthworms (numbers) and crop yield. We have considered organic matter addition, no-tillage, crop rotation and organic agriculture as “promising practices”; no organic matter input, conventional tillage, monoculture and conventional farming were taken as the respective references or “standard practice” (baseline). Relative effects were analysed through indicator response ratio (RR) under each paired practice. For this we considered data of 30 long-term experiments collected from 13 case study sites in Europe and China as collated in the framework of the EU-China funded iSQAPER project. These were complemented with data from 42 long-term experiments across China and 402 observations of long-term trials published in the literature. Out of these, we only considered experiments covering at least five years. The results show that OM addition favourably affected all the indicators under consideration. The most favourable effect was reported on earthworm numbers, followed by yield, SOM content and soil aggregate stability. For pH, effects depended on soil type; OM input favourably affected the pH of acidic soils, whereas no clear trend was observed under NT. NT generally led to increased aggregate stability and greater SOM content in upper soil horizons. However, the magnitude of the relative effects varied, e.g. with soil texture. No-tillage practices enhanced earthworm populations, but not where herbicides or pesticides were applied to combat weeds and pests. Overall, in this review, yield slightly decreased under NT. Crop rotation had a positive effect on SOM content and yield; rotation with ley very positively influenced earthworms’ numbers. Overall, crop rotation had little impact on soil pH and aggregate stability − depending on the type of intercrop; alternatively, rotation of arable crops only resulted in adverse effects. A clear positive trend was observed for earthworm abundance under organic agriculture. Further, organic agriculture generally resulted in increased aggregate stability and greater SOM content. Overall, no clear trend was found for pH; a decrease in yield was observed under organic agriculture in this review.

There are increasing calls in Africa for ‘sustainable intensification’ of agriculture with the aim of increasing productivity whilst minimizing the negative environmental and social impacts. This paper questions whether adopting a landscape approach—and in particular the retention of forests within agricultural landscapes—could fulfill these goals for smallholder farmers in some regions of Africa. Using a landscape in Southern Ethiopia comprised of three zones of increasing distance from a legally protected forestas a case study, the performance of a stratified sample of 27 farms was assessed through detailed surveys and empirical measurements. While livestock productivity was found to be higher closer to the forest, no difference was found for crop or total farm productivities across the three zones. Partial nutrient balances (a productivity dimension of farm sustainability), redundancy (a proxy of resilience), and equality in the distribution of livestock increased with increasing proximity to the forest. Dependency on external inputs also decreased with increasing proximity to the forest. We conclude that, under certain conditions, the retention of forests in agricultural landscapes, and the use of these forests for livestock grazing and fuelwood collection, may promote sustainability, greater resilience and equality of smallholder farming systems, without compromising on-farm productivity. Thus, landscape approaches may provide a pathway to sustainable intensification, and may represent a research and development arena that deserves increasing attention in the sustainable intensification debate.

In this paper we propose to extend methods for agricultural impact assessment to study the adaptations that agricultural producers are likely to consider in response to climate change – i.e., the use of different combinations of crop or livestock species and associated changes in management. Analysis of these kinds of adaptations, referred to here as “between-system adaptations” – requires estimates of the counterfactual productivity and cost of production for prospective systems that are not observable in the locations where they could be used. We propose two methods that we call simulation matching and propensity score matching. We apply and compare the results of these methods in a study of wheat-based systems in the U.S. Pacific Northwest. We find substantial differences between the two methods, but these differences do not appear to be systematic or associated with characteristics of the systems. We conclude that the method used for estimating the productivity of the new system introduces an element of uncertainty into adaptation analysis, in addition to the other data, model and scenario uncertainties. Further research is warranted to evaluate alternative methods for analysis of between-system adaptations and their associated uncertainties.

Particulate matter emitted from tunnel-ventilated animal feeding operations (AFOs) is known to transport malodorous compounds. As a mitigation strategy, vegetative environmental buffers (VEBs) are often installed surrounding AFOs to capture particulates and induce lofting and dispersion. Currently, point measurements are the primary means by which VEB performance has been investigated. The existing techniques lack spatial and temporal resolution and fail to assign the observed particulate reduction to capture, lofting, or dispersion. This study presents a technique for estimating the capture efficiency of a VEB using lidar and attributes all observed reduction to particulate capture, thereby delineating the effects of capture and lofting. The experiments revealed a capture efficiency ranging from 21 to 74%. Instantaneous lidar scans showed periodic lofting well above the VEB, but when scans were averaged over several hours, the plumes appeared Gaussian. This paper documents experimental evidence quantifying the capture efficiency of a VEB. It also establishes an experimental framework for future studies on the efficacy of various emissions mitigation strategies.

On the western coast of Madagascar, the dry tropical forest of Kirindy may disappear in the next 50 years because of its rapid conversion into agricultural land by slash-and-burn cultivation. The slash-and-burn fields are cultivated during 3 years in average and are further abandoned because of soil depletion, weed invasion and finally lower crop yields. As a consequence, new forest areas are regularly cleared from the primary forest, causing deforestation. In addition, Madagascar is situated in a region with high cyclonic activity. Violent storms hit the western coast every 3-4 years, leading to intense rainfalls and floods. These events may enhance soil physical degradation and nutrient leaching, thereby accentuating the soil depletion by slash-and-burn agriculture and with it, the forest conversion rate. Focusing on the combined effects of historic land management and prevailing climatic conditions, this paper investigates: (1) the temporal evolution of soil fertility along with crop performance from cultivation up to field abandonment, and (2) the relative effects of land use (crop cultivation) and extreme climatic events (heavy rain, cyclonic storms) on soil and crop properties. We used a space-for-time substitution approach in slash-and-burn corn (Zea mays L) fields to describe dynamics of soil fertility and crop performance. We sampled soils and plants during two seasons: (a) a normal rainy season, in 2014, and (b) a cyclonic rainy season, in 2015. We found that under the cyclonic storm, soil becomes not only N and P deficient, but the K concentration also steeply drops. Overall, this leads to a dramatic reduction of corn performance. While a decrease in grain yield due to slash-and-burn agriculture reaches about 37.5% after three years of cultivation on the same field (from 4 to 2.5 t ha(-1)), it decreases up to 75% after a single cyclonic rainy season (from 4 to 1 t ha(-1)). On the sidelines of the study, a locust pest also damaged half of the corn fields in 2014, driving the corn yield down to zero on those particular fields. Given what precedes, the study points out the fragility of traditional agricultural techniques against natural hazards. Along with global Warming, the frequency and intensification of natural disasters are expected to increase, impacting negatively and strongly the livelihoods of rural farmers. This raises the urgent need to increase farmer's awareness to alternative and more sustainable agricultural practices. (C) 2017 Elsevier B.V. All rights reserved.

Food production comes at an ecological cost, and the lack of sustainability of South Africa’s crop production systems is becoming increasingly worrisome. While small scale emerging and homestead subsistence farming are significant in the agricultural sector, food production is dominated by large scale commercial agriculture. In this paper we analyse the ecological impact of South African commercial crop production and what can be done about it. Impact categories considered are divided into what we consider ‘better-researched’ problems: fresh water depletion, salinisation, soil degradation, eutrophication and land use change; and into what we consider ‘emerging’ problems for agriculture: greenhouse gas emissions, soil profile acidification, ecotoxicity and non-renewable resource consumption. While there is a paucity of quantitative information, it is clear that after decades of cultivation many of our agroecosystems are degraded or degrading. Sustainable crop production and food security are ‘wicked’ problems – containing dynamic social, economic and biophysical complexities. Increased stakeholder engagement to better understand these problems, the tradeoffs linked to finding solutions and to involve those with the resources to turn knowledge into action is required. Collecting key data, turning it into information within local contexts (involving the ecology, agronomy, sociology, psychology, economics and other disciplines simultaneously) and communicating it effectively to allow learning and adaptive management at various spatial and temporal scales is essential. An example is the display of river flows on a website in real-time to help farmers manage and adapt irrigation practices better, and to connect them with other stakeholders to improve understanding of the responsibilities of managing water at local and catchment scales.

The paper investigates the relative influence of landscape characteristics, production intensity and the EU’s Common agricultural policy interventions on the diversity of farmland birds. For this purpose, data from the Farmland Bird Monitoring Scheme in Slovenia and high spatial resolution data from the national agricultural databases in the period 2008–2019 were analysed with the Boosted Regression Trees (BRT). The diversity of farmland birds was found to be highest in open, diversely cropped and extensively to moderately intensively managed landscapes in Natura 2000 sites where farm holdings were allocated a low average amount of both direct payments and payments for agri-environmental measures (AEM) and organic farming (OF). Furthermore, the highest diversity of the subgroup of grassland specialists was associated with very open and extensively managed grassland landscapes with low stocking density ( The intensification of production, particularly in the beef and dairy sectors, which has been supported by the Common agricultural policy direct payments, and forest succession in marginal areas were identified as the potential key drivers of the recent farmland biodiversity loss in Slovenia. The future CAP income support schemes should be redesigned to ensure at least neutral if not positive overall effects on farmland biodiversity by gradual phasing-out of references to (historic) production levels, increased conditionality and more effective voluntary agri-environmental measures.

10 p.-2 fig.-6 tab., The impact of Cry1Ab-expressing Bt maize (event MON810) on non-target fauna has been a major concern since its deployment in Europe. In this paper, we have assessed the levels of Cry1Ab in rhizosphere soil samples from a Bt maize crop and evaluated the potential effects of Bt maize on soil microarthropods by a three-year trial in an experimental farm-scale field in Central Spain. The Cry1Ab toxin was detected in decaying soil organic matter (OM) from Bt maize plots up to three months after harvest, with values ranging between 0.10 and 0.18 ng Cry1Ab/mg OM, but it showed low insecticidal activity. The study focused on Acari and Collembola, the two major components of the soil microarthropod community. They accounted for 88% of the total specimens collected, and they were identified at the suborder and species level, respectively. Interestingly, Cry1Ab was detected for the first time in field collected collembolans, Entomobrya spp., demonstrating their exposure to the toxin. The abundance of mites and collembolans and the frequency of occurrence of the main collembolan species did not rely on the type of maize except for Parisotoma notabilis, more abundant and frequent in Bt maize plots. However, significant differences among years were common in both groups. Noticeably, we found higher values of species richness and diversity of collembolans in Cry1Ab-expressing Bt maize than in non-Bt plots, which could be explained under different scenarios. Our results suggest that continuous cultivation of Bt maize does not negatively affect soil microarthropods, indicating that Bt maize could be compatible with this community., This work received financial support from the Spanish MINECO (formerly named MICINN) through the project AGL2009-08813 and a grant received by María Arias-Martín (BES-2010-037303), and from the Spanish MARM (formerly named MMA).

Forest expansion into formerly agricultural land plays a relevant role for generating carbon sinks eligible under afforestation activities in the Kyoto Protocol (KP) carbon accounting framework. This paper provides a methodological framework for the multi-temporal assessment of carbon accumulated in these new forest stands, at the reference years of the KP commitment periods: remote sensing analyses, integrating optical imagery and airborne laser scanning data with field survey, are combined with the carbon simulation model CO2FIX to project carbon changes. The approach is applied to a case study in the central Apennines (Italy) to assess the carbon sink associated to these new forests at the years 2008,2012 and 2020. The approach is based on forest cover change detection and growing stock mapping,while the multi-temporal carbon sink analysis is performed by means of the CO2FIX model. In the considered test area, the results highlight a compound annual rate of forest expansion equal to 0.26% for the period 1990–2012. The overall carbon stored by the new stands is 21.1 Mg ha 1 (relative standard error less than 10%) at the year 2012, projected to reach 33.5 Mg ha 1 at the year 2020. L'articolo è disponibile sul sito dell'editore http://www.journals.elsevier.com/

The mineralization (or decomposition) processes of soil organic matter (SOM), from organic to inorganic, play important roles in supplying most of nutrient for plant growth. Thus, understanding the spatial pattern and regulating mechanisms of soil nitrogen mineralization rate (N-min) and its temperature sensitivity (Q(10)) is of great significance for evaluating ecosystem productivity and the supply of soil available nitrogen (N). Here, data derived from 212 published papers in Chinese terrestrial ecosystems were used to explore the spatial pattern and regulating mechanisms of N-min and Q(10). The results showed that the average N-min was 2.78 +/- 0.18 mg N kg(-1) d(-1) at an incubation conditions of 25 degrees C across Chinese terrestrial ecosystems, and it decreased gradually with increasing latitude (P < 0.01). The N-min values were the highest in farmlands (3.08 +/- 0.20 mg N kg(-1) d(-1)), followed by forests (2.35 +/- 0.42 mg N kg(-1), d(-1)) and grasslands (0.57 +/- 0.13 mg N kg(-1) d(-1)). The Q(10) values differed significantly among different ecosystems (P < 0.01), with an average of 1.58. The Q(10) values increased significantly with increasing latitude, supporting the hypothesis that the Q(10) values are higher in colder regions. Path analysis showed that N-min is mainly affected by mean annual temperature and SOM content, whereas Q(10) is primarily affected by soil total nitrogen. The activation energy (E-a) of N-min and substrate quality index (A) was strongly negatively correlated, indicating that the carbon-quality temperature hypothesis is applicable to N-min at a large spatial scale. These findings provide new evidence that soil N availability in colder regions is likely to increase due to higher Q(10) under global warming scenarios, which may promote ecosystem productivity at higher latitudes. (C) 2015 Elsevier B.V. All rights reserved.

Over-application and inefficient use of nitrogen (N) fertilizer is a serious issue throughout China, with adverse environmental and economic impacts. In this paper we present evidence of this in the wheat/maize double cropping system in the Guanzhong Plain in Shaanxi Province, northwest China. Results show the economic benefits of overcoming this problem are greatest for the lowest income farmers. We also outline new advisory approaches that could aid delivery of information to farmers. Evidence of excessive N fertilizer applications, and opportunities to maintain or even increase crop yields with lower rates of N, are presented from several sources. A survey of N applications to maize by 80–100 farmers showed that 77% were applying N at rates in excess of those recommended by the local advisory agencies. Experiments with maize and wheat at 120 sites, testing a range of N application rates, show remarkably small yield responses to applied N and high yields even when no N is applied. This is mainly because of large nitrate residues accumulated in the soil from past N fertilizer applications. Trials were conducted in 30 farmers’ fields comparing the farmer’s usual N rate with a lower rate based on a combination of local recommendations and measurements of nitrate in soil. On average, N rates to maize and wheat could be decreased by 70% and 20%, respectively, with no loss of yield and sometimes small increases. Economic assessments and household surveys showed the economic benefits for farmers of moving to more rational use of N fertilizer. Even a 30% reduction in N use would increase household income by 2–9%, and a 50% reduction by 4–15%. In all cases the poorest farmers benefit the most because fertilizer represents a larger percentage of their expenditure, so policies and practices leading to more rational N use are clearly pro-poor. Advisory approaches based on an N budget approach are outlined as an alternative to traditional approaches where farmers are simply given a recommended application rate. Simple in-field measurements of nitrate concentration in soil, using commercially available nitrate-sensitive strips giving a color reaction, may be a useful supplement for field-specific advisory work if the logistics at village level can be organised.

Nitrogen (N) fertilizer stabilizers (including urease inhibitors (UI), nitrification inhibitors (NI) and double inhibitors (DI)) are promising tools to mitigate N pollution from agricultural production. For a better understanding of how N stabilizers impact on the fate of fertilizer-N, we conducted a comprehensive meta-analysis of data from experiments that used the 15N as a tracer to investigate the effects of N stabilizers on fertilizer-N recovery in the soil-crop system. We combined this with boosted regression tree (BRT) model analysis to further interpret the contribution of soil properties and experimental conditions. The dataset consisted of 72 papers (227 observations). Our results suggest that UI, NI and DI significantly enhanced the fertilizer-N uptake by the crop by 24.1, 10.5 and 47.6 %, respectively, the fertilizer-N retention in the soil by 5.8 % (UI) and 15.0 % (NI), and the fertilizer-N recovery in soil-crop system by 16.4, 10.2 and 27.5 %, respectively. On the contrary, the fertilizer-N loss is reduced by 32.9, 14.5 and 37.6 % for UI, NI and DI, respectively. Soil pH, organic matter content, inhibitor compound and nitrogen application rate were the most important explanatory variables for the impact of UI and NI amendments on fertilizer-N recovery. These findings have major implications for N stabilizer application strategies in agricultural systems, where an important consideration is the mitigation of potentially detrimental environmental consequences.

Native bees are in decline as many species are sensitive to habitat loss, climate change, and non-target exposure to synthetic pesticides. Recent laboratory and semi-field assessments of pesticide impacts on bees have focused on neonicotinoid insecticides. However, field studies evaluating influences of neonicotinoid seed treatments on native bee communities of North America are absent from the literature. On four Conservation Areas of Missouri, we sampled row-cropped (treated, n = 15) and reference (untreated, n = 9) agricultural fields, and their surrounding field margins for neonicotinoids in soil and non-target vegetation (i.e., native wildflowers). Wildflowers were further collected and screened for the presence of fungicides. Concurrently, we sampled native bees over three discrete time points throughout the agricultural growing season to assess potential impacts of seed treatment use on local bee populations over time. Neonicotinoids were detected in 87% to 100% of treated field soils and 22% to 56% of reference field soils. In adjacent field margin soils, quantifiable concentrations were measured near treated (53% to 93% detection) and untreated fields (33% to 56% detection). Fungicides were detected in < 40% of wildflowers, whereas neonicotinoids were rarely detected in field margin vegetation (< 7%). Neonicotinoid concentrations in margin soils were negatively associated with native bee richness (beta = -0.21, P < 0.05). Field margins with a combination of greater neonicotinoid concentrations in soil and fungicides in wildflowers also contained fewer wild bee species (beta = -0.21, P < 0.001). By comparison, bee abundance was positively influenced by the number of wildflower species in bloom with no apparent impact of pesticides. Results of this study indicate that neonicotinoids in soil are a potential route of exposure for pollinator communities, specifically ground-nesting species. Importantly, native bee richness in non-target field margins may be negatively affected by the use of neonicotinoid seed treatments in agroecosystems. Missouri Department of Conservation; Missouri Cooperative Fish and Wildlife Research Unit; USDA-NIFAUnited States Department of Agriculture (USDA) [MO-HANR0007]; MDC; University of Missouri; U.S. Fish and Wildlife ServiceUS Fish & Wildlife Service; U.S. Geological SurveyUnited States Geological Survey; Wildlife Management Institute; USDA-NIFA through Multi-State Working Group W3045 [MO-MSNR0002] We are grateful for the analytical support provided by the Water Sciences Laboratory at the University of Nebraska-Lincoln and the USDA AMS National Science Lab in Gastonia, NC. We thank W. Boys, D. Corcoran, G. Graells, K. Kuechle, J. Piercefield, and A. Wilcox for their involvement with field data collection. Special thanks to the MDC Area Managers for their willing participation in this research: D. Bryant, C. Freeman, C. Smith, and N. Walker. We appreciate M. Arduser (MDC retired) and J. LaRose for assisting in more challenging bee identification. Our appreciation to N. Michel (National Audubon Society) for statistical troubleshooting. We thank C. Otto (USGS) and three other anonymous reviewers for their valuable insights into development of this paper. This work was funded through a cooperative agreement with the Missouri Department of Conservation in collaboration with L. Webb and K. Goyne. Partial support was also provided by Missouri Cooperative Fish and Wildlife Research Unit and USDA-NIFA through Hatch funding (MO-HANR0007) and Multi-State Working Group W3045 (MO-MSNR0002). The Missouri Cooperative Fish and Wildlife Research Unit is jointly sponsored by the MDC, the University of Missouri, the U.S. Fish and Wildlife Service, the U.S. Geological Survey, and the Wildlife Management Institute. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Public domain – authored by a U.S. government employee

Surface irrigated agriculture in arid and semi-arid regions contributes to downstream environmental degradation. Changes in irrigation system operational scenarios (ISOS) can represent an economic alternative to reduce surface runoff impacts. At the same time the use of vegetative filter strips (VFS) can have a positive impact on the ecological health of rural landscapes by reducing erosion, improving water quality, increasing biodiversity, and expanding wildlife habitat. The goal of this paper is, using a combination of field data and mechanistic modeling results, to evaluate and compare the spatial effectiveness of improvements in ISOS and introduction of VFS to reduce surface runoff pollution in the semi-arid/arid furrow irrigation agroecosystem that exceeds current regulatory turbidity limits (25 NTU). Five main factor interactions were studied: four soil textures, two field slopes, three ISOS, six filter vegetation types, and ten filter lengths. Slope and runoff volume were identified as the two main drivers of sediment export from furrows. Shifting from current ISOS to less water consumptive irrigation practices reduce runoff in addition to sediment delivery to comply with environmental regulations. The implementation of 3 to 9 m vegetative buffers on experimental parcels were found to mitigate sediment delivery (greater than 90% sediment reduction) on tail drainage ditches but had limited effect in the reduction of runoff flow that can transport other dissolved pollutants. These findings were insensitive to filter vegetation type. Thus, introduction of improved ISOS is desirable while VFS may be targeted to specific hot spots within the irrigation district. This study shows that the adoption of dense vegetation buffers in vulnerable semi-arid irrigated regions can be effective to mitigate agricultural impacts and provide environmental protection. However, it should not be adopted as an alternative to proper on-site irrigation practices, rather as a complementary off-site pollution control practice. This study was funded through the USDA National Integrated Water Quality Program (NIWQP) under the grant entitled “Protecting Water Resources by Engaging Stakeholders in Targeted Implementation of Filter Strips” (Grant No. 2009-51130-06098). The authors wish to thank Elaine Brouillard (Roza-Sunnyside Board of Joint Control, Sunnyside, Washington) and R. Troy Peters (Washington State University)for their assistance in providing data and information on irrigation practices

Forest seed bank assessments are scarce in Madagascar and thus little is known about the relationships between the seed banks and vegetation dynamics on which secondary succession processes rely. The objective of this paper is to analyse the effects of slash-and-burn agriculture on soil seed banks and their dynamics along secondary forest successions. The aim of this work is to determine the effects of agricultural practices (cropping duration, tillage regime and fallow age) on seed bank density (SBD) and diversity (SBSR) during secondary succession periods (

The environmental impacts of livestock production are attracting increasing attention, especially the emission of greenhouse gases (GHGs). Currently, pork is the most widely consumed meat product in the world, and its production is expected to grow in the next few decades. This paper deals with the production of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) by animals and by manure from pig buildings, with a focus on the influence of rearing techniques and nutrition. GHG emissions in piggeries originate from animals through CO2 exhalation and CH4 enteric fermentation, and from manure through the release of CO2, CH4 and N2O. The level of the CO2 exhalation (E-CO2, pig) depends on the physiological stage, the body weight (BW), the production level and the feed intake of the animals concerned. Enteric CH4 (E-CH4, pig) is principally related to dietary fibre intake and the fermentative capacity of the pig’s hindgut. Based on a review of the literature, the following equations are proposed in order to estimate E-CO2, pig (in kg day−1) and E-CH4,pig (in g day−1) for fattening pigs: E-CO2, pig = 0.136 × BW0.573; E-CH4,pig = 0.012 × dRes; with BW (in kg) and dRes for digestible residues (in g day−1). Numerous pathways are responsible for GHG production in manure. In addition, the microbial, physical and chemical properties of manure interact and modulate the level of emissions. Influencing factors for removal systems for both liquid and solid fractions of manure have been investigated. A large range of parameters showing an impact on the level of GHG production from pig houses has been reported. However, few of these can be considered unquestionably as GHG mitigation techniques because some strategies have shown contradictory effects depending on the gas, the circumstances and the study. Nevertheless, frequent manure removal seems to be an efficient means to reduce concurrently CO2-, CH4- and N2O-emissions from pig buildings for both slatted and bedded floor systems. Manure removal operations may be associated with specific storage conditions and efficient treatment in order to further reduce emissions. Several feeding strategies have been tested to decrease GHG emissions but they seem to be ineffective in reducing emissions both significantly and durably. In general, good management practices that enhance zootechnical performance will have beneficial consequences on GHG emission intensity. Taking into account the results described in the literature regarding CO2-, CH4- and N2O-production from animals and manure in pig houses, we estimate total GHG emissions to 448.3 kg CO2equiv. per slaughter pig produced or 4.87 kg CO2equiv. per kg carcass. The fattening period accounts for more than 70% of total emissions, while the gestation, lactation and weaning periods each contribute to about 10% of total emissions. Emissions of CO2, CH4 and N2O contribute to 81, 17 and 2% of total emissions from pig buildings, representing 3.87, 0.83 and 0.11 kg CO2equiv. per kg carcass, respectively.

This paper examines drivers of land-cover change in the U.S. Great Plains in the last half of the twentieth century. Its central aim is to evaluate the dynamics of grassland preservation and conversion, across the region, and to identify areas of grassland that were never plowed during the period. The research compares land-cover data from 400 sample areas, selected from and nested within 50 counties, to aggregate data from the agricultural and population censuses. The spatially explicit land-cover data were interpreted from aerial photographs taken at three time points (1950s, 1970s and 2000s). Sample areas were chosen using a stratified random design based on the Public Land Survey grid with in the target counties, in several clusters across the region. We modeled the sequences and magnitudes of changes in the interpreted air photo data in a multi-level panel model that included soil quality and slope of sample areas and agricultural activities and employment reported in the U.S. Censuses of Agriculture and Population. We conclude that land retirement programs and production subsidies have worked at cross purposes, destabilizing micro-level patterns of land use in recent decades, increasing levels of switching between cropland and grassland and reducing the size of remaining areas of native grassland in the U.S. Great Plains.

This paper presents the assessment of a NDVI-based parametric model (C-Fix) and a bio-geochemical model (BIOME-BGC) for the simulation of semi-natural grassland primary productivity in Italy. The two models are first calibrated using the gross primary productivity (GPP) data of an eddy covariance flux tower placed over a Mediterranean-temperate hilly area in Central Italy. Next, they are applied to estimate the net primary productivity (NPP) of three independent areas representative of different eco-climatic zones. The first area shows a typical Alpine climate, while the other two are characterized by more or less pronounced Mediterranean features. The accuracy of the NPP estimates is assessed through comparison with destructive dry matter measurements taken in the three areas. The results obtained support the capability of the two models to predict spatial NPP differences across the various grassland sites. The greatest estimation errors are found in the mountain area, mostly due to inaccuracies in the meteorological input data. These errors affect particularly the outputs of the bio-geochemical model and are mitigated by the use of C-Fix, which exploits the remotely sensed information related to the seasonal evolution of green biomass.

Increased crop yield is a commonly reported benefit of adding biochar to soils. However, experimental results are variable and dependent on the experimental set-up, soil properties and conditions, while causative mechanisms are yet to be fully elucidated. A statistical meta-analysis was undertaken with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass). Results showed an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%. However, the mean results for each analysis performed within the meta-analysis covered a wide range (from −28% to 39%). The greatest (positive) effects with regard to soil analyses were seen in acidic (14%) and neutral pH soils (13%), and in soils with a coarse (10%) or medium texture (13%). This suggests that two of the main mechanisms for yield increase may be a liming effect and an improved water holding capacity of the soil, along with improved crop nutrient availability. The greatest positive result was seen in biochar applications at a rate of 100 t ha−1 (39%). Of the biochar feedstocks considered and in relation to crop productivity, poultry litter showed the strongest (significant) positive effect (28%), in contrast to biosolids, which were the only feedstock showing a statistically significant negative effect (−28%). However, many auxiliary data sets (i.e. information concerning co-variables) are incomplete and the full range of relevant soil types, as well as environmental and management conditions are yet to be investigated. Furthermore, only short-term studies limited to periods of 1 to 2 years are currently available. This paper highlights the need for a strategic research effort, to allow elucidation of mechanisms, differentiated by environmental and management factors and to include studies over longer time frames.

A variety of options exist for mitigation of greenhouse gas (GHG) emissions from agriculture. This paper discusses the use of the SIMSDAIRY modelling framework to analyse the whole-systems response to different methods, acting singly or in combination, to mitigate GHG emissions from a typical dairy farm in the UK. These methods comprise farm management changes, new technologies and/or plant and/or animal new functional traits focused on mitigating GHG. Different functional units were used in order to ensure that the different aspects of the farm performance were analyzed in the most relevant way (e.g. concentration of NO3− in leachate or kg GHG emitted per unit of milk). Examples of the methods that were tested and discussed are some relating fertilization, diet, systematic and genetic changes in the system. We conclude that the effectiveness of the combined GHG mitigation methods cannot be assessed simply by adding the effectiveness of each method applied singly. Effective GHG mitigation methods may in some cases increase emissions of other forms of pollution and have very different impact on farm profitability. This study also evidences the importance of selecting the right unit of reference to measure efficacy to reduce GHG emissions and highlights the importance to integrate this type of study with socio-economic studies in order to assess the full potential of these mitigation methods.

This paper describes an integrated application of classical hydrogeological methods and multi-isotopic methods (δ15N, δ 18ON O3, δ34S, δ 18OS O4, δ13C) to assess the fate of groundwater nitrate in the Osona area, declared vulnerable to nitrate pollution by the Catalan Government in 1998, where nitrate is derived from intensive pig farming activities. Previous studies, involving a small area, indicated the occurrence of denitrification processes and their relationship with pyrite oxidation [Vitòria, L., Soler, A., Canals, A., Otero, N., 2008. Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: example of Osona (NE Spain). Appl. Geochem. 23, 3597-3611]. For the present study, groundwater samples were collected at 60 production wells at three different periods between April 2005 and May 2006 to confirm that denitrification takes place in a larger area than that studied by Vitòria et al. [Vitòria, L., Soler, A., Canals, A., Otero, N., 2008. Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: example of Osona (NE Spain). Appl. Geochem. 23, 3597-3611]. The aim of the study was to characterize the denitrification processes that control natural attenuation and to study their spatial and temporal variations. Nitrate concentration ranged from 10 to 529 mg/l, with 82% of the wells above the drinking water threshold of 50 mg NO3/l. Nitrate isotopic composition ranged from +5.3‰ to +35.3‰ for δ15N and from +0.4‰ to +17.6‰ for δ 18ON O3, and the samples showed a positive correlation between δ15N and δ 18ON O3, with a εN/εO ratio of 1.8, consistent with denitrification processes. The link between denitrification and pyrite oxidation is demonstrated by coupling chemical data with nitrate and sulfate isotopes. Furthermore, a spatial distribution of samples with significant denitrification was observed, allowing us to determine two main hydrogeological zones where natural attenuation was most effective. In several of the studied points, denitrification processes related to pyrite oxidation predominated and an estimation of the isotopic enrichment factors was performed using the temporal variations of nitrate concentration and the isotopic composition of dissolved nitrate (δ 15NN O3 and δ 18ON O3). Finally, using estimated isotopic enrichment factors, an approximation of the degree of natural attenuation of nitrate was performed on those samples showing clear denitrification, and a median value of 30% of contaminant diminution was obtained This work has been financed by CICYT projects CGL2005-08019-C04-01 and 02, CGL-2008-06373-CO3-01 and 02/BTE from the Spanish Government, the local authorities (Consell Comarcal d’Osona), the Catalan Water Agency (Age` ncia Catalana de l’Aigua), the local private association of livestock raising (ASSAPORC), the project SGR2005-00933 from the Catalan Government, the I3P Programme funded by the EU, and the ‘‘Jose´ de Castillejo’’ program of the Spanish Government

Remnants of medieval field patterns, called “pluzina” in the Czech Republic, are valuable historical landscapes, similar in character to the bocage landscapes typical for some countries in Western Europe. The original historical pattern of fields and meadows has persisted due to the stabilizing network of hedgerows. As in other countries, the development of these medieval fields in recent decades for intensive agriculture or residential purposes has led to their dramatic decline. This study evaluates the dynamics of the development of medieval pluzina hedgerows during the second half of the 20th century in the Plzen Region of the Czech Republic, using three datasets from 1840, 1950 and 2005. Between 1950 and 2005, 341 out of 483 hedgerows disappeared in the study areas, and the total length of the hedgerows decreased by 71%. At the same time, the average hedgerow width increased from 7.2 m in 1950 to 13.1 m in 2005. The study further tests the influence of three natural factors (natural soil fertility, slope gradient and aspect) and of historical (1950) and current (2005) land uses on the disappearance of hedgerows. The most significant factor that has contributed to the disappearance of hedgerows is the current land use in adjacent areas, grassland being by far the most conducive to the persistence of pluzinas. In addition, current land use has significantly influenced the hedgerow dynamics when assessed in interactions with slope gradient and with historical land use. The results of the study further show a significant influence of natural soil fertility. Our findings confirm two main trends which lead to the disappearance of medieval land use systems. Extensification of agricultural land leads to its abandonment and to afforestation of fields adjacent to the hedgerows as a result of spontaneous succession. On the other hand, intensification means that land adjacent to the hedgerow is used as arable land and gradual expansion leads to field enlargement, hedgerow removal and consequently to the disappearance of the entire medieval field patterns. The paper also discusses the principles of conservation and restoration of these valuable historical landscapes.

Reducing the vulnerability of agriculture to climate change while increasing primary productivity requires mitigation and adaptation activities to generate profitable co-benefits to farms. The conversion of woody-wastes by pyrolysis to produce bio-char (biologically derived charcoal) is one potential option that can enhance natural rates of carbon sequestration in soils, reduce farm waste, and substitute renewable energy sources for fossil-derived fuel inputs. Bio-char has the potential to increase conventional agricultural productivity and enhance the ability of farmers to participate in carbon markets beyond traditional approach by directly applying carbon into soil. This paper provides an overview of the pyrolysis process and products and quantifies the amount of renewable energy generation and net carbon sequestration possible when using farm bio-waste to produce bio-char as a primary product. While this research provides approximate bio-char and energy production yields, costs, uses and risks, there is a need for additional research on the value of bio-char in conventional crop yields and adaptation and mitigation options.

Intensive farming generally needs large additions of organic matter (OM) to avoid losses of fertility or low yields. Application of compost is a common source of OM for agricultural soils. Metal accumulation and DTPA-extractability in a sandy soil after three successive applications of municipal solid waste compost (MSWC) under intensive farming conditions are described in this paper. MSWC was applied for three consecutive crops in a plot of the soil in a greenhouse at a rate of 2.1, 2.1, and 1.8 kg m-2 on a dry matter basis, respectively. One more crop was planted, but no compost was applied to monitor residual effects of the treatment. A control plot did not receive any compost during the experiment. As is done in actual agricultural practice, a rotation of crops was used during the experiment. Tomato (Lycopersicon esculentum) was the first crop, followed by zucchini (Cucurbita pepo var. melopepo), green pepper (Capsicum annuum), and finally tomato again. The experiment lasted 2 years and 7 months. Although moderate rates of MSWC were used and metal content of the compost was below the legal limits in Spain, increases in metal contents were observed in the soil, compared with the control treatment without the MSWC. After the second application of compost, increases in aqua regia-extractable (pseudo-total content) Zn and Pb were found in the 0-25 cm layer, and after the third application, Cu and Ni contents were also increased. Furthermore, increases in DTPA-extractable (available content) concentrations of metal contents were observed at higher rates than in aqua-regia extractable contents, suggesting that metals added with compost were more available than native metals in soils. In the 25-50 cm depth in the soil, increases due to MSWC also were found for aqua regia- and DTPA-extractable Zn and Pb after three applications of MSWC. The increases in the available fraction of the metal after MSWC application, the sandy characteristics of the soil, and the high irrigation rate could have favoured metal leaching through the soil profile. The results suggest that Spanish legislation for allowable limits of metals in MSWC is not protective enough, and lower limits in compost are necessary.

The clearing land of trees and introduction of exotic pastures to enhance pasture production and associated monetary gains has been a common practise in Queensland. Previous studies on tree clearing emphasised the gains in pasture production, but over periods of less than 10–15 years after clearing, thus potentially misleading land managers who plan to continue grazing beyond that time. The present research follows an integrated approach to quantify the pasture yield and the effects of tree clearing on pasture species composition, soil properties (organic carbon, available N (NO3−), pHw and microbial biomass (C and N)), and litter production over time-since-clearing on a grazing property in central Queensland, and to evaluate the implications of our findings for the region. The cleared pasture systems were taken at 33 year age of clearing in comparison to their paired uncleared pastures for three major tree communities representative of the region: Eucalyptus populnea, Eucalyptus melanophloia and Acacia harpophylla. The paper evaluates the effects of clearing on individual attributes as well as an integrated effect of these attributes, i.e. overall ecological services. Pasture production generally increased with clearing but plant diversity, litter production and potential return of N and P through litter decreased. Among soil attributes, clearing of trees adversely impacted upon soil pH and microbial biomass, which play an important role in nutrient availability and mineralisation. This, the initial gains in pasture production are not sustainable over time. The multivariate analysis for such ecological attributes suggests that at the >33 year age of clearing, the ecological state of pasture systems changed compared to that at 5 year or 11–13 year or to the uncleared system. A disturbed pasture system will most likely take longer to revert to the original state compared to the time that would have taken to harvest the benefits. The results are important for landholders and policy makers to comprehend the real gains and losses following tree clearing for pasture development over the long term.

Green accounts or input–output accounting systems (IOA) have been developed in countries with intensive agricultural production to facilitate voluntary improvements in farm environmental performance. There is a need for an overview of indicators used and a review of results and experiences reported. Ten IOA systems covering the topics of the farm’s use of nutrients, pesticides and energy were selected from a survey of 55 systems and compared in this paper. The approaches and indicators used vary from systems based on good agricultural practices (GAP) to accounts based systems that use physical input–output units. Many IOA systems use farm gate nutrient balances, pesticide use per hectare and energy use per kilogram product. These indicators are easy to calculate but the resulting value needs separate interpretation for the farmer. Other systems include modeled emissions and rate the yearly farm results using closed scales, which allows for easy interpretation but builds on implicit normative assumptions of best practices. Participating farmers were most often reported to be motivated for the use of IOA but empirical evidence of improved environmental farm performance was scarce. IOA systems should be linked with production planning tools used by the advisory services. Farmers and advisors needs better reference values to evaluate the indicator levels (environmental performance) on the individual farm possibly based on analysis of a larger number of farms. The statistical properties of IOA indicators need to be researched regarding: (1) the relation between changed management practice and changes in indicator values on a given farm over a period of time; (2) the relative importance of systematic versus coincidental differences in environmental performance of a set of farms. It is concluded that IOA systems could become effective tools for agri-environmental improvement of European farms given further development and standardization.

Many external effects of land use change are based on modifications of lateral flows of soil, water, air, fire or organisms. Lateral flows can be intercepted by filters and thus the severity and spatial range of external effects of land use change is under the influence of filter effects. Wherever lateral flows are involved, research results cannot be simply scaled on an area basis, and overall impact does not follow simple linear causal relationships. This complexity has consequences for relationships amongst the primary agents who initiate or exacerbate external effects, other stakeholders who are affected by them and policymakers who attempt to mitigate problems that reach sufficient visibility in society. In this paper we review how the relative importance of lateral flows and filter effects differs among a number of externalities, and the implications this has for research methods. If flows and filters are incompletely understood, policies may be based on fallacies. Whereas ‘fire-breaks’ act as filters in the lateral flow of the high temperature pulse of a fire, smoke from land-based fires can be intercepted only by rainfall acting as a filter and the external impact of smoke is determined by the atmospheric conditions governing lateral flow and chemical transformations along the pathway. Causal relations in smoke and haze problems are relatively simple and may form a basis for designing policy interventions to reduce downwind damage. For biodiversity issues, landscape connectivity, the absence of filters restricting dispersal and movement of organisms, is increasingly recognised as an influence on the dynamics of species richness and its scaling relations. Biodiversity research methods can extend beyond the current descriptive stage into clarifying causal relations with a lateral flow perspective. The question whether connectivity is in fact desired, however, depends on stakeholder interests and situation. Forest functions in watershed protection, presumably leading to a continuous flow of clean water in the dry season through the subsoil instead of a rapid surface transfer, have been generally attributed to the trees rather than the forest, with its rough surface structure, swamps and infiltration sites. A new synthesis of site-specific hydrological knowledge and tree water balance studies may be needed to separate myth from reality, and avoid wasting public funds on tree planting under the heading of reforestation, without restoring the hydrological regime of a real forest. Soil movement can be intercepted at a range of scales and in as far as soil transport entails movement of soil fertility, filter zones can be very productive elements of a landscape. To achieve ‘integrated natural resource management’ all external effects of land use will somehow have to be taken into account in farmer decision making about the use of natural resources on and off farm. Farmers’ ecological knowledge may include concepts of lateral flows and should be further explored as an integral part of a new landscape ecological approach. © 2004 Elsevier B.V. All rights reserved.

Interactions between the diversity of primary producers (plants) and of decomposers (microbes and mesofaunal communities), the two key functional groups that form the basis of all ecosystems have major consequences on the functioning of agricultural ecosystems. Soil microorganisms control the transformation and mineralization of natural compounds and xenobiotics. The soil microbiota, existing in extremely high density and diversity, rapidly modify the energetic performance and activity rates to changing environmental conditions. Thus, the microbial consortium possesses the ability to accommodate environmental constraints by adjusting (i) activity rates, (ii) biomass, and (iii) community structure. These parameters are particularly important to take into consideration when evaluating soil quality. The present paper gives an overview about the possibilities to use bacterial and fungal populations as an indicator for soil quality. Furthermore also the applicability of nematodes for the determination of soil health will be discussed.

This paper demonstrates a methodology to estimate nitrogen flow due to human activities in three rural hamlets located at different elevations in the Cianjur–Cisokan watershed area, West Java, Indonesia. The rural ecosystem in each hamlet was divided into several components and material transfers between components due to human activities were estimated, mainly by interview, and converted to nitrogen. Then a component model of nitrogen flow in each hamlet was constructed. Nitrogen balances of the three hamlets were positive: 87–267 kg N ha −1 per year. Two indices, NSENO (nitrogen surplus per unit edible nitrogen output) and NSEEO (nitrogen surplus per unit edible energy output), were newly proposed. These indices showed that nitrogen surplus of the hamlet with the lowest elevation where paddy fields are dominant was the least when producing crops with the same nutritional value as those grown in other hamlets. Application of unused local resources, mud and human excrement, can reduce nitrogen surplus by 49–96 kg N ha −1 per year and can provide subsidy of US$ 310–370 per year.

Most agricultural landscapes are a mosaic of farmers’ fields, semi-natural habitats, human infrastructures (e.g. roads) and occasional natural habitats. Within such landscapes, linear semi-natural habitats often define the edges of agricultural fields. This paper reviews the role and interactions within and between the flora of these elements. In temperate, intensive agriculture, such field margin habitats, which historically had true agricultural functions, now are important refugia for biodiversity. As manmade habitats, field margins may also have important cultural roles as part of our landscape heritage, e.g. hedges in Britain. Whilst field margins are not usually specific habitat types, they contain a variety of plant communities in a variety of structures. These may range from aquatic elements to ruderal and woodland communities. Studies demonstrate a variety of interactions between fields and their margins. Agricultural operations, such as fertiliser and pesticide application, have effects on the flora. Some margin flora may spread into crops, becoming field weeds. Margins also have a range of associated fauna, some of which may be pest species, while many are beneficial, either as crop pollinators or as pest predators. The biodiversity of the margin may be of particular importance for the maintenance of species at higher trophic levels, notably farmland birds, at the landscape scale. Margins contribute to the sustainability of production, by enhancing beneficial species within crops and reducing pesticide use. In northwestern Europe, a variety of methods to enhance diversity at field edges have been introduced, including sown grass and flower strips. The impact of these on weed flora and arthropods indicate mostly beneficial effects though conflicts exist, notably for the conservation of rare arable weed species.

It is now recognised that nutrient losses from the steeply sloping hillsides of the tropics and subtropics occur not only through soil erosion, but through the net transfer of annual crop residues to more profitable parts of the farming system. Studies of soil nutrient balances across Africa are showing evidence of widespread mining of the soil resource within the smallholder farming sector, as the organic matter and nutrient source is not replenished in annually cropped hillside fields. This paper presents information that is central to the understanding of the farming systems employed by smallholder farmers within the highlands of South West Uganda. A time static model of organic resource flows was developed with a smallholder farming community, using visible flow data from farm surveys and semi-structured interviews, to describe this situation. The model explores the sources, whereabouts and current management strategies of organic resources and defines their flow around the farming system. Results confirm a net transfer of 24 Mg ha−1 yr−1 (P

The value of environmental indicators largely depends upon the spatial and temporal scale that they represent. Environmental indicators are dependent upon data availability and also upon the scale for which statements are required. As these may not match, changes in scales may be necessary. In this paper a geostatistical approach to analyse quantitative environmental indicators has been used. Scales, defined in terms of resolution and procedures, are presented to translate data from one scale to another: upscaling to change from high resolution data towards a low resolution, and downscaling for the inverse process. The study is illustrated with three environmental indicators. The first concerns heavy metals in the environment, where the zinc content is used as the indicator. Initially, data were present at a 1 km 2 resolution, and were downscaled to 1 m 2 resolution. High resolution data collected later showed a reasonable correspondence with the downscaled data. Available covariates were also used. The second example is from the Rothamsted’s long-term experiments. Changes in scale are illustrated by simulating reduced data sets from the full dataset on grass cuts. A simple regression model related the yield from the second cut to that of the first cut in the cropping season. Reducing data availability (upscaling) resulted in poor estimates of the regression coefficients. The final example is on nitrate surpluses on Danish farms. Data at the field level are upscaled to the farm level, and the dispersion variance indicates differences between different farms. Geostatistical methods were useful to define, change and determine the most appropriate scales for environmental variables in space and in time.

This paper documents the events leading to the imminent collapse of an attempt to rehabilitate a degraded ecosystem in central Tanzania, focusing on the consequences of the failure to systematically monitor socio-economic and environmental indicators. A decision was taken in 1979 to evict all grazing livestock from a 1200 km2 semi-arid area, the so-called Kondoa Closed Area, in central Tanzania due to their destructive effect on contour ridges and bunds that had been constructed in an attempt to arrest land degradation. Although the closure was successful in that the vegetation quickly regenerated and soil erosion was arrested, the evictions resulted in severe hardship for the agro-pastoralists in the area. As a result, it was decided a decade later to allow the reintroduction of cattle on condition that they were totally confined and were of improved dairy breeds. Although performance and economic data have generally been positive, the top–down approach to the introduction of the cows, the lack of baseline data, followed by the withdrawal of external funding, have resulted in increased illegal free-grazing and the near collapse of the attempt to convert a degraded ecosystem to sustainable use. It is concluded that the probable collapse of the ecosystem in the Kondoa Closed Area is a result of the initial top–down approach to the introduction and implementation of the project, inadequate monitoring of socio-economic and environmental indicators, and ultimately to the withdrawal of donor funding.

The majority of the large number of existing land use models lack a proper validation, often because of data problems. Moreover, despite recognition of the necessity to incorporate a multi-scale analysis, scale dependencies are normally not considered during validation. In this paper, a multi-scale land use change modelling framework, conversion of land use and its effects (CLUE), is calibrated for Costa Rica and validated at five spatial resolutions for Honduras and Costa Rica. Both countries experienced locally very strong actual land use changes. Calibration runs show that the model is very sensitive to changes in the autonomous development parameter, which defines the influence of the finest resolution. Validation results are very satisfactory for both countries. Especially, changes in major land use types are reproduced with the model. Changes in localised land use types are more difficult to project. The magnitude of gains and magnitude of losses are slightly underestimated in all cases. The multi-scale validation demonstrates that results improve strongly, and exponentially, with decreasing spatial resolution. Strong reduction of the number of observations results in a correlation between actual and modelled changes that approximates the perfect value of 1. The study demonstrates that the CLUE modelling framework can reproduce changes as they took place in Central America in the 1970s and 1980s, and shows how conclusions can differ depending on the scale at which validation is performed.

Ever increasing attention is being paid to the environmental impact of intensive agricultural practices, and in this context organic farming is gaining recognition as a relatively friendly production system. In general, the risk of harmful environmental effects is lower with organic than with conventional farming methods, though not necessarily so. This review examines organic farming in the light of European conditions with special regard to recent research findings from Denmark. It specifies the environmental problems caused by modern farming practices and discusses appropriate indicators for assessing their impact. A driving force-state-response (DSR) framework is employed to organise and understand the processes and mechanisms that lie behind the impact of agriculture on nature and the environment. Important groups of environmental indicators are selected that characterise (a) the aquatic environment (nitrate and phosphorus leaching), (b) the soil (organic matter, biology and structure), (c) the ecosystem (arable land, semi-cultivated areas, small biotopes and landscape), and (d) resource usage and balances (nitrogen, phosphorus, potassium and energy use). The paper also reviews several empirical studies. With regard to soil biology, organic farming is usually associated with a significantly higher level of biological activity (bacteria ( Monera), fungi (Mycota), springtails (Collembola), mites (Arachnida), earthworms (Lumbricus terrestris)), due to its versatile crop rotations, reduced applications of nutrients, and the ban on pesticides. In most cases there is also a lower surplus of nutrients and less leaching with organic than with conventional farming. However, poor management (e.g., the ploughing of grass and legumes (Fabates) at the wrong time of year with no subsequent crops to capture the mineralised nitrogen), low self-sufficiency in feed, and problems with certain production systems (such as those involved in organic pig farming, i.e., grazing sows, low crop yields), can lead to a high level of leaching in some organic systems. Organic farming is faced with a need to expand and develop in line with increasing demands for organic food and growing environmental concerns. This requires closer attention to the goals, values and principles on which organic practices are based, and more research into the influence of organic farming on different aspects of the environment. © 2001 Elsevier Science B.V. All rights reserved.

Linyphiid spiders are important generalist predators of insects in agricultural habitats. Their ability to rapidly disperse and colonise disturbed habitats makes them important as a natural form of pest control, often present before other predatory groups arrive. This paper examines the distribution of Erigone atra and E. dentipalpis, which are amongst the commonest linyphiid species to be found on agricultural land in Scotland. The habitat preferences of these species were assessed using abundance and proportion data from 71 independent sites sampled using pitfall traps over 2 years and a selection of repeat first-year sites sampled during the second year, incorporating a range of land-uses from extensive moorland, through grasslands to intensive arable fields. E. atra dominated in autumn sown crops, and E. dentipalpis dominated at the other end of the agricultural management spectrum in low-intensity grasslands. Both species were considered absent from upland and moorland habitats. Linear regression modelling was used to create a model which best estimated the variance in proportions of E. atra in the catch across the sites using a selection of vegetation, soil, management and landscape variables. This model was based on data from 58 sites where Erigone species were abundant and explained 66% of the variation in E. atra. The variables included were increasing vegetation biomass above 50 mm and increasing levels of mixed grazing (both positive), and a combination of increasing plant species richness and vegetation stem density (negative). The efficiency of the model was examined using data from 13 sites which were sampled in the subsequent year to assess the effects of no changes and changes in land-use on the proportions of the two species. Only two sites were considered inaccurate (more than 20% different from the model), suggesting a relatively high level of accuracy. Interaction between the two species was tested for and not found to explain the differences in proportion observed. Comparisons with other studies were carried out, showing similar trends in proportions and in some of the variables identified as important. The influence of specific variables on each species is described in light of possible allometric-type effects, and the importance of these species for conservation and pest control in agriculture is discussed.

If, as many climate change analysts speculate, industrial and other emissions of CO2 can be offset by substitution of biofuels, large areas of land, including agricultural land, may be converted to the production of biomass feedstocks. This paper explores the feasibility for the Missouri‐Iowa‐Nebraska‐Kansas (MINK) region of the US of converting some agricultural land to the production of switchgrass (Panicum virgatum L.), a perennial warm season grass, as a biomass energy crop. The erosion productivity impact calculator (EPIC) crop growth model simulated production of corn (Zea mays L.), sorghum (Sorghum bicolor(L.) Moench), soybean (Glycine maxL.), winter wheat (Triticum aestivumL.) and switchgrass at 302 sites within the MINK region. The analysis is done for both current climatic conditions and a regional climate model-based scenario of possible climate change. Daily climate records from 1983 to 1993 served as baseline and the NCAR-RegCM2 model (RegCM hereafter) nested within the CSIRO general circulation model (GCM) provided the climate change scenario. Crop production was simulated at two atmospheric CO2 concentrations ([CO2]) at 365 and 560 ppm to consider the CO2-fertilization effect. Simulated yields of the perennial switchgrass increased at all sites with a mean yield increase of 5.0 Mg ha 1 under the RegCM climate change scenario. Switchgrass yields benefited from temperature increases of 3.0‐8.0 C, which extended the growing season and reduced the incidence of cold stress. Conversely, the higher temperatures under the RegCM scenario decreased yields of corn, soybean, sorghum and winter wheat due to increased heat stress and a speeding of crop maturity. With no CO2-fertilization effect, EPIC simulated maximum decreases from baseline of 1.5 Mg ha 1 for corn, 1.0 Mg ha 1 for sorghum, 0.8 Mg ha 1 for soybean and 0.5 Mg ha 1 for winter wheat. Simulated yields increased for all crops under the RegCM scenario with CO2 set to 560 ppm. Yields increased above baseline for 34% of the soybean and 37% of the winter wheat farms under RegCM/[CO2] D 560 ppm scenario. Water use increased for all crops under the higher temperatures of the CSIRO scenario. Precipitation increases resulted in greater runoff from the traditional crops but not from switchgrass due to the crop’s increased growth and longer growing season. Simulated soil erosion rates under switchgrass and wheat cultivation