Process Of Agricultural Intensification Research Articles

Against wastelanding: distributed design at the pace of soil in the Conca de Barberà

This paper proposes a methodology for designers to work in the extensive yet marginal landscapes that are produced as part of the process of agricultural intensification. The distributed design approach, which focuses on enriching the existing bioinfrastructure of the soil, emerged out an ongoing research project in the Conca de Barberà, Spain. The project involves managing an interconnected series of currently unproductive on unmaintained fields through the rotational grazing of horses, with the hypothesis that the systematic grazing regime will catalyse soil biological activity. By attending to the soil infrastructure, the project necessarily developed a unique design approach. Management decisions became design problems and design work took on something of the call and response of management. Though it was shaped by the specific constraints and opportunities of the research project, the methodology is applicable to a wide variety of design projects in extensive landscapes with limited resources.

Rapid land cover change in agricultural valleys of the Atacama Desert, Chile

The profound landscape modification produced by agriculture is considered one of the main threats to biodiversity worldwide. Although the main ecological impacts are likely due to agricultural expansion into natural areas, changes in crop types and production intensification also induce significant ecological changes. We studied the land cover change process in four agricultural valleys (Lluta, Azapa, Vítor and Camarones) in the Atacama Desert of Chile between 2003 and 2019, divided into four equal periods. Using spatial data and logistic regression, we assessed the driving factors of land cover change. The Azapa valley showed the highest rate of land cover change, reaching 36.4% of netting and greenhouses landscape cover by the end of the study, and 50.4% annual rate of increase during the 2007–2011 period. Intensification was observed as the anti-aphid netting cover expanded mainly in Azapa and in the last four years in Vítor and Lluta valleys. Most land cover change was related to low slopes and elevation or sites closer to roads or surrounded by already cultivated land, like agriculture expansion on barren soil or native shrubland loss. High population density was significantly correlated with land cover change (p < 0.01). If land cover change into netting continues as observed, it is possible that landscape homogenization occurs in the short term in almost all valleys. Anyway, disentangling how landscape change works and the involved drivers, could be useful to understand landscape simplification in arid lands that are under an agricultural intensification process.

Impact of cropping systems on soil quality

The agricultural intensification process implemented during the last 20 years consisted of replacing a crop-pasture rotation system with a continuous no-till cropping system that affected the functional properties of the soil in the medium term. The hypothesis of this study was that the annual cropping intensification process could be characterized, at the commercial level, by soil property indicators that capture changes in the pathway of cropping systems (CSs) in the medium term. The objectives were: i) to identify CSs based on land use; and ii) to characterize soil properties associated with different CSs. Based on this, a database was built with the land use description from 2014 to 2020 of 45 farms belonging to farmers associated with FUCREA and AUSID. A Principal Component Analysis (PCA) was performed with 14 land use indicators to select those that best summarized all the information. The selected indicators were pasture-crop ratio (PCR), soybean frequency during the summer annual cropping phase (SSbCF), intensification of annual cropping phase index (IAI), and intensity of soil use index (ISI). By performing a Cluster Analysis with these indicators, the following CSs were identified: pasture-crop rotation (ROT-PC), continuous cropping with high frequency of C4 photosynthesis species (CC_Corn), and continuous cropping with high frequency of soybean (CC_Soybean). Based on the identified CS, 64 representative sites were selected within a 60 km radius from the coordinates −33.17 S and −57.80 W, Uruguay's most influential annual cropping area, assessing 46 soil properties sensitive to changes in their management in the medium term and capable of affecting productivity. A PCA was used to select the properties that best summarized the information. A Linear Discriminant Analysis (LDA) with the selected variables and the identified CS groups determined a loss in soil fertility (organic carbon and electrical conductivity) and nutrient availability (potassium), which is related to CS diversification (CC_Soybean> CC_Corn>ROT-PC).

Socioeconomic factors influencing the uptake of tissue culture banana technology in Kisii County, Kenya

Many nations have worked hard over the years to provide food security for there entire country, albeit with various degrees of success. The intensification of agriculture has been significant in order to feed the growing population. The banana tissue culture technology is one of the technologies used to aid the process of agricultural intensification. Due to its long history of food production, including the cultivation of bananas, the Kisii region is a significant contributor to Kenya's food security. However, because of issues brought on by social and economic considerations, the region's food output has been declining. Despite efforts to distribute this technology to small-scale farmers, majority of research studies in Kisii County show poor rates of technology adoption. The objective of this study was to examine the socioeconomic factors affecting implementing tissue culture bananas in Kisii County. The research used a descriptive study design. Two hundred respondents were chosen at random from the sample to participate in the study. Survey forms, interview schedules, and observation checklists were used for data collection. The means between adoption categories were declared at p < 0.05 in t-tests between tissue culture banana adoption and numerical factors. Chi-square tests were performed between adoption and categorical factors, and p < 0.05 was used to determine whether there were significant connections between the variables. The study adopted a logistic regression model with maximum likelihood estimation to calculate the likelihood that farmers will adopt tissue culture bananas as impacted by various socioeconomic factors. Results showed that the availability of extension services (p = 0.000), cost of seedlings (p = 0.000, x2=79.1), ability to purchase land (p = 0.006, x2=16.3), access to financing (p = 0.007, x2=7.468), education level (p = 0.015), ability to afford seedlings (p = 0.000, x2=17.6), labour availability (p = 0.005, x2=10.735), availability of farm inputs (p = 0.000, x2=35.9) and the size of household (p = 0.05, Std=1.8) were significant to tissue culture banana adoption. Socio-economic factors ought to be taken into account in order to assist a number of stakeholders in boosting banana output and enhancing food security.

Long-Term Camelid Husbandry and Agricultural Intensification in the Southern Nasca Region, Peru: Insight from Faunal Isotopes

Abstract We examined stable isotopes (δ13C, δ15N, and δ34S) of camelid, cavid, and cervid remains from Upanca, an archaeological site located in the Southern Nasca Region on the south coast of Peru. Occupation at the site began in the Middle Archaic (around 3200–3000 BC) and continued through the Nasca period (AD 100–650). Remains predating 2500 BC show low δ13C and δ15N values, whereas remains after this time show increasing and especially more variable isotopic values. We interpret this pattern as marking both a process of agricultural intensification and camelid husbandry diversification. Agricultural intensification began first with C3 plants in fertilized fields, beginning around 2200 cal BC, followed by an increasing use of C4 plants (maize, kiwicha, or both), particularly after 800 cal BC. By the beginning of the first millennium, people were using a diverse range of strategies to raise llamas and alpacas, including feeding them wild or cultivated C3 plants, feeding them cultivated C4 plant foods, mixing C3 and C4 plant foods, foddering some in natural coastal environments, and acquiring still other camelids by hunting wild stocks (guanaco, vicuña). Data also suggest that cavids were consuming at least some C4 products after 1000 cal BC and that the use of C4 plants increased over time.

Mapping crop producer perceptions: The role of global drivers on local agricultural land use in Brazil

Agricultural trade and climate change have altered land cover and land use worldwide. For example, the recent growth of international soybean demand has been associated with 1.3 Mha primary Amazon forest loss and up to 13-fold increase in double-cropping areas in Brazil. Many studies have tried to understand which and how global and local drivers affect deforestation and agricultural intensification processes at the landscape level, yet few have incorporated the direct perspectives of actual land users. Under the influence of a variety of social, economic, and cultural factors, producers are the ones who make decisions that will cause a significant impact on the environment. In this paper, we adopted Fuzzy Cognitive Maps (FCMs), a semi-quantitative modeling approach to represent complex decision-making systems, and we modeled land use and agricultural management perceptions of 27 crop producers from the three states - Mato Grosso, Goiás, and Tocantins - important soybean production and export areas in Brazil. We analyzed individual models and integrated them into aggregated regional models to compare individual and regional differences among the producers. In addition, we simulated how producers from the three states will make land-use decisions under more trade and extreme climatic events scenarios using the FCMs. Our results indicate that extreme climatic events are among the most important factors producers consider when it comes to the sustainability of their operations. Climate change scenarios have a stronger overall impact than trade scenarios on local land-use changes, causing a 12% reduction in total agricultural production. The improvement of technology packages can effectively mitigate climate change risks and has an overall positive impact on land-use intensification than expansion. On the other hand, sharing accurate climate information and socio-economic improvements such as credits have larger impacts on agricultural expansion than productivity itself. Moreover, the model complexity shows differences among the three states. Soybean trade has more weight in the perception of producers in Goiás and Tocantins than Mato Grosso. Based on the results, we discuss the importance of co-designing place-based, alternative policies and mitigation options for both agricultural intensification and environmental conservation, taken into consideration through the intertwined global and local forces.

Beyond the boom-bust cycle: An interdisciplinary framework for analysing crop booms

The expansion of commercial agriculture is one of the primary drivers of livelihood and land-use changes in the world. Globalisation and other factors have intensified this expansion to the point where booms in single cash crops overtake entire regions before going bust, a pattern that is particularly pervasive in resource frontiers. Using case studies across the Mekong Region, a place which serves as a harbinger for crop booms globally, we propose a new analytical framework for understanding and governing crop booms. We combine multiple theoretical approaches to study crop booms and draw on insights from case study work conducted across temporal and spatial scales. The framework consists of three components: 1) the nested nature of crop boom-bust trajectories, 2) the cyclical spatial and temporal patterns of crop booms, and 3) the variegated pathways and impacts of agrarian change. The framework presents new insights into the processes of agricultural intensification in frontier spaces. As such, it facilitates a better understanding of the drivers, characteristics and impacts of crop booms for researchers and decision-makers alike with the intention of supporting efforts to develop more sustainable pathways in the region and beyond.

Organizational and economic substantiation of the level of development and effective intensification of cattle breeding

A conceptual model has been developed for increasing the efficiency of intensification based on the balanced development of the livestock and fodder industries, a methodology for establishing reserves for the growth of production and sales proceeds. Scientific and practical recommendations for the level of economic entities on the development of programs for thdevelopment of agricultural production, an algorithm for their implementation, a strategy for the formation and strengthening of competitive advantages are presented. As part of improving the methodological tools for studying the processes of agricultural intensification, a set of scientific and methodological approaches has been developed to substantiate the level of development and efective intensification of livestock breeding.

Predictable patterns of unsustainable intensification

ABSTRACT To increase understanding of agricultural intensification processes over time and their sustainability, we studied dimensions of sustainability in the context of ongoing expansion of intensive, commercial mono-cropping of banana in Southwestern Uganda. In our approach we considered five dimensions of sustainability: economic, agricultural productivity, environment, social and human. We compared farming systems in 1998 and 2018 and integrated a gender lens. A total of four focus group discussions, two group interviews and fifteen individual interviews (8m / 7f) were conducted, complemented with a discourse analysis of newspaper articles. Results show that although intensification of banana production increased the average income level indicating improvement in the economic dimension, it did not yield sustainable outcomes in the other dimensions. The integrated analysis of five dimensions of sustainability illuminated aspects often neglected in assessment studies or policy-making around agricultural intensification, in particular socio-economic and gender dynamics. We further recognized that the observed local trends are part of a set of patterns that take place throughout the world. We conclude that to advance sustainable development, stakeholders should move away from the current over-emphasis on economic values prioritizing the individual, and that avoiding patterns of unsustainable development requires broadening to environmental and community values.

Management of Soil Fertility and Agricultural Intensification in NW Iberia, 1750–1900

Abstract This article describes agricultural practices of fertilization in the NW of the Iberian Peninsula between 1750 and 1900, where a leguminous plant called gorse (Ulex Europaeus) was used as bedding for livestock in order to produce manure. During the period examined, this whole region experienced a process of agricultural intensification which resulted in a net loss of nutrients in the soil. Peasants dealt with the increasing nutrient requirements by adapting land and livestock management in order to produce more manure during the second half of the 20th century. However, this was done at the expense of nutrient reserves in extensively managed areas, all of which resulted in an unsustainable agricultural pattern. Our data also suggest that the context of nutrient scarcity could be related to changes in the migration pattern, which started to be more intense after 1850 and preferred distant destinations (America), thus switching from seasonal to permanent stays.

Does the Breeding Biology of the Eurasian Stone-Curlew Burhinus oedicnemus in South-Western Morocco Differ between Grazed Steppe and Irrigated Farmland?

Birds associated with steppe and pseudosteppe habitats are one of the most threatened avian communities in Europe, given their recent decline due to agriculture intensification and land abandonment. Large-scale conversion of natural and rural areas into irrigated farmlands is ongoing in North Africa, but the effects of this habitat modification on steppe bird species are not investigated. In this study, we investigated the breeding biology of the Eurasian Stone-curlew nesting in grazed steppes and irrigated farmlands in south-western Morocco. Breeding data were collected during 2017 and 2018 breeding seasons on 59 nests. Egg volume was significantly higher in grazed steppes than in irrigated farmlands (37.3 ± 2.30 cm3 vs 35.1 ± 2.11 cm3, average ± SD), possibly due to greater food availability in the former habitat. On the other hand, daily nest survival over the incubation period did not differ between habitats and it was quite high (0.85 [95% CI: 0.71–0.93]) also when compared to the data available for other regions. These results suggest that birds nesting in protected areas characterized by traditional pastoralism might find better conditions for reproduction which allow them to lay larger eggs. In addition, the ongoing process of agricultural intensification in the area does not seem to affect the likelihood of nest failure. Our data add to the few available pieces of evidence regarding the effect of breeding habitat on the reproductive biology of the Stone-curlew in the southern range of its distribution. Further data are needed in order to understand the conservation implication of our findings and, in particular, how the observed variability of egg size might affect chick quality and survival.

Improved ecological insights commission new conservation targets for a crepuscular bird species

AbstractKnowledge on species’ ecological requirements is the key to an effective evidence‐based conservation. An adaptive approach can refine management recommendations following the outcomes of previous actions or as improved scientific knowledge about a species’ ecology becomes available. Following severe population declines the majority of the Swiss European Nightjar (Caprimulgus europaeus) population is now restricted to a small core area in the canton of Valais, despite the local application of evidence‐based restoration measures to the breeding habitats. The habitat use of this crepuscular bird species is presumed to be restricted to semi‐open oak‐pine scrublands and rocky steppe. By deploying miniature GPS loggers we assessed the spatial and habitat selection of 42 individuals (25 individuals in 2018 and 30 individuals in 2019; comprising 13 redeployments between years) in five study sites in the canton Valais. We highlight the importance of using fine‐scaled movement data to obtain insight into complex multi‐scale habitat requirements of a species. Nightjars used multiple habitats, indicating the importance of complementary resources to breed (e.g. open forest and shrub) and to forage (e.g. semi‐extensive grasslands and vineyards). The connectivity between these resources was influenced by habitat configuration and composition. Given these new insights for future conservation strategies, our results also suggest that national‐level land use changes, mainly due to agricultural intensification processes, have contributed to the long‐term population declines in Switzerland. We therefore consider our result in the context of knowledge gaps for species that exploit complementary habitats and the potential shortcomings for conservation planning on discrete species showing complex ecological requirements.

Capabilities Under Telecoupling: Human Well-Being Between Cash Crops and Protected Areas in North-Eastern Madagascar

Global change processes are increasing their pace and reach, leading to telecoupled situations, where distant factors come to outpace local determinants of land use change. Often, these dynamics drive agricultural intensification processes, with as yet unclear implications for the well-being of human populations living in the areas affected. This study explores how two key telecoupling dynamics affect local well-being in the biodiversity hotspot of Madagascar. It focuses on forest frontier landscapes, which are undergoing processes of agricultural intensification as a consequence of distant factors. Concretely, we look at how the recent establishment of two, largely externally funded, terrestrial protected areas, Masoala National Park and Makira Natural Park, and the ongoing price boom for two export cash crops, vanilla and clove, have influenced the well-being of local populations in the country’s north-east. We present data from eight focus group discussions conducted in four villages located on the periphery of the two protected areas. Drawing on the ‘capabilities approach’, we identify the key components of the local understanding of well-being, lay out the interconnections between these components, and explore how the two telecoupling processes explored affect well-being dynamics. Our findings reveal that well-being components present bundle characteristics, where increases or decreases in one component lead to parallel increases or decreases in a set of them. We further ascertain that telecoupling processes might lead to trade-offs between well-being components. These findings highlight the need for a holistic understanding of human well-being when planning protected areas, and when designing governance mechanisms to steer local landscapes under intense cash crop price fluctuations towards sustainable outcomes.

Large-scale versus small-scale agriculture: Disentangling the relative effects of the farming system and semi-natural habitats on birds’ habitat preferences in the Ethiopian highlands

While the Western World is facing an inexorable decline of its farmland biodiversity following continuous intensification of production modes, agricultural landscapes in Africa are still largely dominated by small-scale subsistence farming operated by smallholders, mostly harbouring high biodiversity. However, as most African countries are confronted to an unprecedented population growth and a rapid economic development, efforts to intensify food production are widespread, with concomitant potentially negative effects on biodiversity. We conducted a study in a highly contrasted agricultural landscape of the Ethiopian highlands comprising two distinct farming systems: large-scale farming relying on modern, combine machinery and technology (e.g. enhanced crop varieties, application of herbicides, pesticides and synthetic fertilizers) vs small-scale traditional farming. Our objective was to disentangle the effects upon avian biodiversity of the operating farming system and the extent of semi-natural habitat features in the wider landscape. We performed a model selection approach to assess habitat selection by the overall bird community as well as the wintering, endemic and open habitat species, respectively. Our results show that habitat preferences of birds in the Ethiopian highlands were mainly driven by the amount of semi-natural habitats within the landscape, with varying effects depending on the farming system itself. While large-scale farming had overall more negative effects on birds, some typical open habitat species were mostly restricted to these wide-open landscapes. Our findings thereby suggest that both farming systems could coexist as long as semi-natural habitats are preserved and agricultural management maintained in its current practices. We emphasize the urgent need to conduct further studies integrating the socio-economic aspects in order to better predict future impacts of agricultural intensification processes on African farmland biodiversity.

Indigenous peoples' land rights and agricultural expansion in Latin America: A dynamic panel data approach

Agricultural expansion remains an important cause of deforestation in Latin America. There is an on-going debate about whether increasing agricultural productivity leads to land-sparing or Jevons paradox. At the same time, recognizing the customary rights of indigenous peoples and local communities can be particularly effective at slowing down deforestation. We consider ten Latin American countries over the period 1990 to 2010 and use dynamic panel data models to assess whether: a) there is a difference between short-run and long-run effects of improvements in agricultural productivity and b) different land tenure systems are capable of directing the process of agricultural intensification towards land-sparing. Our results allow us to draw a number of stylised conclusions. In general, we observe that higher agricultural productivity per-se is land-sparing, albeit the long-run effects appear smaller than the short-run effects. Most importantly, the overall effect of increased productivity crucially depends on the institutional context. In this respect, increasing the forest area owned or managed by indigenous peoples promotes land-sparing, while increasing the forest area administered by governments and/or owned by private individuals and companies promotes Jevons paradox. In the long-run, the agricultural expansion effects of increasing the forest areas owned by private individuals and companies are stronger than those associated with the expansion of forest areas administered by the government. We also note that the formal recognition of land ownership to indigenous peoples and local communities manifests its beneficial effects in the long-run.

Frozen Histories or Narratives of Change? Contextualizing Land-Use Dynamics for Conservation of Historical Rural Landscapes.

Current research has identified extensive changes in land-use structure and land management of Central European rural landscapes due to shifting political and economic trajectories. These changes are exemplified by diverse processes of agricultural intensification, privatization and land fragmentation, land abandonment and overall changes in modes of production. The extensive record of these historically specific processes has posed a fundamental challenge for rural landscape conservation, which is addressed in this paper. First, we identify the key contradictions in rural landscape conservation, which include (i) conservation based on cultural versus environmental/ecological values, (ii) conservation based on spatial landscape patterns versus individual landscape features, and (iii) conservation based on the preservation of past landscapes versus conservation that also address the processes of change. Subsequently, we use a case study of an existing open-air museum in Zubrnice, northern Czechia, to analyze and discuss these dichotomies. In this regional case study, we first contextualize the land-use/land-cover change (LULC) reconstructed from old maps using a thorough archive (documentary proxies) and field research (survey of agrarian terraces, clearance cairns, and remnants of orchards) that enabled the construction of a narrative of specific landscape structures and features. Finally, we integrate the collected data with a novel methodological approach that allow for the spatial identification of the landscape segments that represent the narratives of historical change in modes of rural production and are therefore suitable for integration within the existing open-air museum to improve its conservation and education status.

Effects of protected area establishment and cash crop price dynamics on land use transitions 1990–2017 in north-eastern Madagascar

ABSTRACTWe applied a participatory mapping approach supported by very high-resolution satellite imagery to reconstruct spatially explicit, year-to-year land use transitions in two highly biodiverse, data-scarce forest frontier landscapes in north-eastern Madagascar. We explored these transitions in the light of major continuous trends and discrete events highlighted by local farmers as influencing their land use decisions. Our results suggest that the process of establishing protected areas first reinforced ongoing deforestation, but later led to a significant reduction of forest loss rates. Recent cash crop booms appear to have induced agricultural intensification processes in our study landscapes, while also putting additional pressure on forests, as people may be encouraged to clear forest for cash crop cultivation. These findings are crucial to understanding rapid land use change processes in forest frontier contexts in the humid tropics, and especially to informing natural resource governance and development initiatives in complex mosaic landscapes.

Spatial and temporal variation of human appropriation of net primary production in the Rio de la Plata grasslands

Latin America, and particularly, the Rio de la Plata Grasslands (RPG), are one of the regions with the highest rates of land use change worldwide. These changes drastically alter ecosystems energy flows, affecting biodiversity, atmospheric composition, and the ecosystem capacity to provide services. In this work we evaluated the impact of these changes on Net Primary Production (NPP), one of the most important and integrative ecosystem attributes, through the calculation of Human Appropriation of NPP (HANPP), a very complete indicator of human impact on ecosystems. Our results provide a comprehensive and fine grained description of HANPP patterns over an entire biogeographycal region for two periods that encompass a strong agricultural intensification process. We used medium resolution land use maps and NPP estimates from sub-national level agricultural statistics and remotely sensed data modeling. Results show that the human impact on the energy flow in RPG ecosystems reached very high levels compared to other regions of the world. The average appropriation of was 42% of the potential vegetation NPP in 2001/2002 and it increased 4.5% during the last years due to an intense land use changes. Most of the HANPP was explained by harvest rather than by land use changes, mainly in the last period due to crops yield increase and the expansion of double crop system as a common agronomic practice. High HANPP values found were associated to a set of environmental impacts that affect ecosystems sustainability and their ability to provide ecosystem services.

Cities and agricultural transformation in Africa: Evidence from Ethiopia

Due to the rapid growth of cities in Africa, more rural farmers are providing staple foods to urban residents. However, empirical evidence on how urbanization affects these farmers is scarce. To fill this gap, this paper explores the relationship between proximity to a city and the production behavior of rural staple crop producers. More in particular, we analyze data from teff producing farmers in major producing areas around Addis Ababa, the Ethiopian capital. We find that farmers more closely located to Addis Ababa face higher wages, land rental rates, and teff prices, leading to better incentives to intensify production as seen in the uptake of modern inputs. Moreover, we observe that land and labor productivity as well as profitability in teff production improve with urban proximity. Our results suggest that better connectivity of rural farmers to cities and growing urban demand for food are important associates of the process of agricultural intensification and transformation in Ethiopia.

Spatial and temporal dynamics of shifting cultivation in the middle-Amazonas river: Expansion and intensification

Shifting cultivation is the main land-use system transforming landscapes in riverine Amazonia. Increased concentration of the human population around villages and increasing market integration during the last decades may be causing agricultural intensification. Studies have shown that agricultural intensification, i.e. higher number of swidden-fallow cycles and shorter fallow periods, reduces crop productivity of swiddens and the regrowth capacity of fallows, undermining the resilience of the shifting cultivation system as a whole. We investigated the temporal and spatial dynamics of shifting cultivation in Brazilian Amazonia to test the hypotheses that (i) agriculture has become more intensive over time, and (ii) patterns of land-use intensity are related to land accessibility and human population density. We applied a breakpoint-detection algorithm to Landsat time-series spanning three decades (1984–2015) and retrieved the temporal dynamics of shifting cultivation fields, which go through alternating phases of crop production (swidden) and secondary forest regrowth (fallow). We found that fallow-period length has decreased from 6.4 to 5.1 years on average, and that expansion over old-growth forest has slowed down over time. Shorter fallow periods and higher frequency of slash and burn cycles are practiced closer to residences and around larger villages. Our results indicate that shifting cultivation in riverine Amazonia has gone through a process of agricultural intensification in the past three decades. The resulting landscape is predominantly covered by young secondary forests (≤ 12 yrs old), and 20% of it have gone through intensive use. Reversing this trend and avoiding the negative consequences of agricultural intensification requires land use planning that accounts for the constraints of land use in riverine areas.