Field Experiment In Sweden Research Articles

Gendered ethnic discrimination and the role of recruiter gender. A field experiment

Relying on data from a large-scale field experiment in Sweden, this article studies discrimination in recruitment on the basis of gender and ethnicity combined with recruiter gender. The study includes 5641 job applications sent in response to advertised vacancies, and the employer callbacks to these. Gender and either a Swedish or a foreign-sounding name were randomly assigned to the applications, and recruiter gender was documented whenever available. Based on the callback rates, there is evidence of ethnic discrimination against foreign-named job applicants by both male and female recruiters. Also, male applicants with foreign-sounding names are discriminated more than female applicants with foreign-sounding names. Thus, the results show gendered ethnic discrimination in the Swedish labor market, and this does not appear to depend on recruiter gender in general. However, the patterns for gendered ethnic discrimination by recruiter gender vary across occupational categories.

Epiphytic microbiota in Swedish grass-clover herbage and the effect of silage additives on fermentation profiles and bacterial community compositions of the resulting silages.

To investigate the epiphytic microbiota in grass-clover herbage harvested at different sites and occasions; and to explore the effect of different silage additives on the resulting silage microbiota. Herbage was harvested from grass-clover leys at geographically distributed sites in a long-term field experiment in Sweden, in early and late season of two consecutive years. Different silages were made from the herbage using; 1) no additive, 2) acid-treatment, and 3) inoculation by starter culture. Herbages were analyzed for botanical and chemical composition, and the resulting silages for products of fermentation. Bacterial DNA was extracted from herbage and silage samples, followed by sequencing using Illumina 16S rRNA amplicon sequencing. Herbage microbiota showed no clear correlation to site or harvesting time. Silage additives had a major effect on the ensiling process; inoculation resulted in well fermented silages comprising a homogenous microbiota dominated by the genera Lactobacillus and Pediococcus. A minor effect of harvest time was also observed, with generally a more diverse microbiota in second harvest silages. Untreated silages showed a higher relative abundance from non-lactic acid bacteria compared to acid treated silages. In most silages, only a few bacterial amplicon sequence variants contributed to most of the relative abundance. The epiphytic microbiota in grass-clover herbage were found to be random and not dependent on site. From a microbial point of view, the most predictable and preferable silage outcome was obtained by inoculation with a starter culture. Acid-treatment with formic- and propionic acid surprisingly resulted in a less preferable silage. Silage making without additives cannot be recommended based on our results.

Relative entropy as an index of soil structure

AbstractSoil structure controls key soil functions in both natural and agro‐ecosystems. Thus, numerous attempts have been made to develop methods aiming at its characterization. Here we propose an index of soil structure that uses relative entropy to quantify differences in the porosity and pore(void)‐size distribution (VSD) between a structured soil derived from soil water retention data and the same soil without structure (a so‐called reference soil) estimated from its particle‐size distribution (PSD). The difference between these VSDs, which is the result of soil structure, is quantified using the Kullback–Leibler Divergence (KL divergence). We applied the method to soil data from two Swedish field experiments that investigate the long‐term effects of soil management (fallow vs. inorganic fertilizer vs. manure) and land use (afforested land vs. agricultural land dominated by grass/clover ley) on soil properties. The KL divergence was larger for the soil receiving regular addition of manure compared with the soils receiving no organic amendments. Furthermore, soils under afforested land showed significantly larger KL divergences compared to agricultural soils near the soil surface, but smaller KL divergences in deeper soil layers, which closely mirrored the distribution of organic matter in the soil profile. Indeed, a significant positive correlation (r = 0.374, p < 0.001) was found between soil organic carbon concentrations and KL divergences across all sites and treatments. Despite challenges related to modelling the VSD of the reference soil without structure, the proposed index proved useful for evaluating differences in soil structure in response to soil management and land‐use change and reflected the expected effects of soil organic matter on soil structure. We conclude that relative entropy shows great potential to serve as an easy‐to‐use index of soil structure, as it only requires widely available data on soil physical and hydraulic properties.Highlights A new index of soil structure is proposed based on relative entropy A method is developed that separates the effects of soil texture and structure on the pore space The index identified soil structural differences in response to land use and soil organic carbon concentrations (SOC) The index shows the potential to serve as an easy‐to‐use metric of soil structure

Ethnic Background and the Value of Self‐Employment Experience: Evidence from a Randomized Field Experiment*

AbstractWe use a randomized field experiment in Sweden to investigate how self‐employment experience is valued in the labour market. Our results show that self‐employment experience negatively impacts the likelihood of receiving a positive response from employers. For male applicants, this holds regardless of ethnic background, and independently of whether we consider applicants with experience solely from self‐employment, or applicants with combined experience from wage employment and self‐employment. For female applicants, the results are less clear‐cut. Our findings provide input into the discussion about the impact of self‐employment on the chances for individuals with different ethnic background to obtain wage employment.

Do schools discriminate against children with disabilities? A field experiment in Sweden

ABSTRACT This article presents the results of a field experiment in which fictitious parents of children with attention deficit hyperactivity disorder (ADHD) and type 1 diabetes mellitus (T1DM) sent inquiries to schools in Sweden about admission of their children to the mandatory preschool class. Results show that inquiries concerning a child with no medical condition were more likely to receive an invitation for a visit and more likely to receive a promising placement response than inquiries concerning a child with ADHD and T1DM. Discrimination was more prominent in the private sector and when the child was a boy or had ADHD.

Phosphorus desorption and isotope exchange kinetics in agricultural soils

AbstractTo improve phosphorus (P) fertilization and environmental assessments, a better understanding of release kinetics of solid‐phase P to soil solution is needed. In this study, Fe (hydr)oxide‐coated filter papers (Fh papers), isotopic exchange kinetics (IEK) and chemical extractions were used to assess the sizes of fast and slowly desorbing P pools in the soils of six long‐term Swedish field experiments. The P desorption data from the Fh‐paper extraction of soil (20 days of continual P removal) were fitted with the Lookman two‐compartment desorption model, which estimates the pools of fast (Q1) and slowly (Q2) desorbing P, and their desorption rates k1 and k2. The amounts of isotope‐exchangeable P (E) were calculated (E1min to E>3 months) and compared with Q1 and Q2. The strongest relationship was found between E1 min and Q1 (r2 = .87, p < .01). There was also an inverse relationship between the IEK parameter n (the rate of exchange) and k1 (r2 = .52, p < .01) and k2 (r2 = .52, p < .01), suggesting that a soil with a high value of n desorbs less P per time unit. The relationships between these results show that they deliver similar information, but both methods are hard to implement in routine analysis. However, Olsen‐extractable P was similar in magnitude to Q1 (P‐Olsen = 1.1 × Q1 + 2.3, r2 = .96), n and k1 were related to P‐Olsen/P‐CaCl2, while k2 was related to P‐oxalate/P‐Olsen. Therefore, these extractions can be used to estimate the sizes and desorption rates of the different P pools, which could be important for assessments of plant availability and leaching.

LONG-TERM stability of arsenic in iron amended contaminated soil.

This study aimed at elucidating the long-term efficiency of soil remediation where chemical stabilization of arsenic (As) contaminated soil using zerovalent iron (Fe) amendments was applied. A combination of chemical extraction and extended X-Ray absorption fine structure (EXAFS) spectroscopy technique was applied on soils collected from five laboratory and field experiments in Sweden and France. All soils were treated with 1wt% of zerovalent Fe grit 2-15 years prior to the sampling. The results indicate that all studied soils, despite the elapsed time since their amendment with Fe grit, had substantial amounts of ferrihydrite and/or lepidocrocite. These metastable and the most reactive Fe (oxyhydr)oxides (mainly ferrihydrite) were still present in substantial amounts even in the soil that was treated 15 years prior to the sampling and contributed most to the As immobilisation in the amended soils. This increases confidence in the long-term efficiency of As immobilisation using zerovalent Fe amendments. Both applied methods, sequential extraction and EXAFS, were in line for most of the samples in terms of their ability to highlight As immobilisation by poorly crystalline Fe phases.

DRIFTS band areas as measured pool size proxy to reduce parameter uncertainty in soil organic matter models

Abstract. Soil organic matter (SOM) turnover models predict changes in SOM due to management and environmental factors. Their initialization remains challenging as partitioning of SOM into different hypothetical pools is intrinsically linked to model assumptions. Diffuse reflectance mid-infrared Fourier transform spectroscopy (DRIFTS) provides information on SOM quality and could yield a measurable pool-partitioning proxy for SOM. This study tested DRIFTS-derived SOM pool partitioning using the Daisy model. The DRIFTS stability index (DSI) of bulk soil samples was defined as the ratio of the area below the aliphatic absorption band (2930 cm−1) to the area below the aromatic–carboxylate absorption band (1620 cm−1). For pool partitioning, the DSI (2930 cm−1 ∕ 1620 cm−1) was set equal to the ratio of fast-cycling ∕ slow-cycling SOM. Performance was tested by simulating long-term bare fallow plots from the Bad Lauchstädt extreme farmyard manure experiment in Germany (Chernozem, 25 years), the Ultuna continuous soil organic matter field experiment in Sweden (Cambisol, 50 years), and 7 year duration bare fallow plots from the Kraichgau and Swabian Jura regions in southwest Germany (Luvisols). All experiments were at sites that were agricultural fields for centuries before fallow establishment, so classical theory would suggest that a steady state can be assumed for initializing SOM pools. Hence, steady-state and DSI initializations were compared, using two published parameter sets that differed in turnover rates and humification efficiency. Initialization using the DSI significantly reduced Daisy model error for total soil organic carbon and microbial carbon in cases where assuming a steady state had poor model performance. This was irrespective of the parameter set, but faster turnover performed better for all sites except for Bad Lauchstädt. These results suggest that soils, although under long-term agricultural use, were not necessarily at a steady state. In a next step, Bayesian-calibration-inferred best-fitting turnover rates for Daisy using the DSI were evaluated for each individual site or for all sites combined. Two approaches significantly reduced parameter uncertainty and equifinality in Bayesian calibrations: (1) adding physicochemical meaning with the DSI (for humification efficiency and slow SOM turnover) and (2) combining all sites (for all parameters). Individual-site-derived turnover rates were strongly site specific. The Bayesian calibration combining all sites suggested a potential for rapid SOM loss with 95 % credibility intervals for the slow SOM pools' half-life being 278 to 1095 years (highest probability density at 426 years). The credibility intervals of this study were consistent with several recently published Bayesian calibrations of similar two-pool SOM models, i.e., with turnover rates being faster than earlier model calibrations suggested; hence they likely underestimated potential SOM losses.

Environmental performance of crop cultivation at different sites and nitrogen rates in Sweden

Nitrogen (N) fertilisation has positive and negative effects on the environmental impact of crop cultivation. The mechanisms governing these effects are highly site-dependent, a factor often ignored in assessments of the environmental impact of crop cultivation. By assessing outputs of crop rotations using a life cycle approach, this study explored how greenhouse gas emissions and marine eutrophication caused by crop cultivation (including upstream processes such as production of farm inputs) depend on fertiliser rate and the site at which the cultivation occurs. Cereal unit (CU) was used as the functional unit. The calculations were based on data from multi-site long-term field experiments in Sweden and site-dependent data and models for non-measured processes. Cultivation at three N levels was evaluated, where the highest N rate was close to current average practices and the lowest level corresponded to one-third of that. Site characteristics had a stronger influence on both greenhouse gas emissions and marine eutrophication (variations of up to 330% and 490%, respectively, within N levels) than N level (variations of up to 74% and 59%, respectively, within sites). Main sources of variation in greenhouse gas emissions were soil nitrous oxide emissions (58–810 g CO2eq CU−1) and soil organic carbon changes (14–720 g CO2eq CU−1), while variations in marine eutrophication were mainly explained by field-level waterborne N losses (0.9–8.2 g Neq CU−1). The large variation between sites highlights the importance of considering site characteristics when assessing the environmental impact of crop cultivation and evaluating the environmental consequences of crop management practices.

Impact of long-term N fertilisation on CO2 evolution from old and young SOM pools measured during the maize cropping season

The relationship between carbon (C) inputs and nitrogen (N) fertilisation is a key element of soil organic matter (SOM) dynamics, which remains poorly resolved. In temperate climates, it is critical to investigate the interactive effect of C and N inputs on SOM stabilisation under low or high substrate availability. We measured SOM content and in situ soil respiration in a long-term field experiment in Sweden, which started in 1956. In 2000, the previous C3 crops were replaced with C4 maize, making it possible to trace old- (C3-derived) and young-C (C4-derived) sources in CO2 and SOM under bare fallow, maize cropped with or without N-fertilisation (root C-inputs). Soil respiration and its isotopic composition were measured in the field prior to sowing, every second week during crop growth and once after harvest. During 1956–1999, the bare fallow lost 38% of its SOM, following an exponential decay trend. Despite root C inputs, total SOM content under C3 crops declined from 1.5% in 1956 to 1.4% and 1.2% C in fertilised and unfertilised treatments, respectively, in 1999. After the crop change in 2000, estimated C input increased by 5% (under fertilisation), but SOM content continued to decline (as before 2000), to 1.25% (fertilised) and 1.03% (unfertilised) in 2017. Analysis of δ13C revealed that 9 and 11% of young-C was retained in unfertilised and fertilised SOM, respectively. However, up to 70% of soil respiration derived from young-C. Comparing the contributions of old- and young-C to CO2 and SOM showed that, irrespective to the time of measurement, young-C was always more available for microbial decomposition than old-C, particularly under fertilisation. We conclude that the amount of C entering the soil through root inputs was insufficient to counterbalance SOM losses over time. Moreover, soil nutrient status and recent root-C availability appear to be important for CO2 release, and must be considered in further recommendations on maintaining/improving SOM stocks.

Short-term effects of loosening and incorporation of straw slurry into the upper subsoil on soil physical properties and crop yield

Subsoils that are compacted, nutrient-poor or low in soil organic matter (SOM) often limit crop growth and yield. Improvement of subsoil conditions by deep loosening is laborious and expensive and its positive effect may not last. This study investigated the effect of deep loosening and injection of slurry made from cereal straw (30 Mg dry mass ha−1) at 25–34 cm depth on soil properties and crop performance in a Swedish field experiment that started in autumn 2015 and monitored soil and crop properties during 2016. Loosening + straw incorporation into subsoil resulted in significantly higher soil organic carbon (SOC) content, potential plant-available water and porosity and lower bulk density (BD) in spring 2016 compared with the control. In autumn 2016, penetrometer resistance (PR) and BD were both significantly lower and SOC and porosity were significantly higher in the loosening + straw treatment compared with the control and loosening only (29–34 cm). Furthermore, BD was significantly lower in the loosening + straw treated subsoil than in the top soil layer of the control (0–10 cm). Observations indicated that more continuous pores were found in the loosening + straw treatment than in other treatments. Roots and soil faunas were found more frequently where straw was incorporated. Grain yield increased by 5.6% due to loosening + straw addition (P = 0.03) and by 4% due to loosening only (P = 0.06). These results indicate that loosening + straw input into upper subsoil had a positive short-term influence on soil physical properties, potential plant-available water and grain yield. Straw addition prolonged the positive effect of loosening.

Door-to-door canvassing in the European elections: Evidence from a Swedish field experiment

In this paper I report the results from a door-to-door canvassing experiment conducted in Sweden during the 2014 European elections. The canvassing was performed by members of the Social Democratic Party and the experiment closely resembles the partisan nature of most mobilizing campaigns in Europe. The paper is one of the first to provide causal evidence for the mobilizing effectiveness of canvassing outside the United States. Living in a household that was visited by canvassers increases the probability of voting by 3.6 percentage points. This effect is entirely driven by estimates twice as large for occasional and first-time voters. Compared to previous research, the high compliance rate gives precisely estimated effects that are closer to average treatment effects.

Seasonal dynamics of the soil microbial community: assimilation of old and young carbon sources in a long‐term field experiment as revealed by natural 13C abundance

SummaryMicrobial biomass is a small part of the total soil organic carbon (SOC) pool, but plays a major role in its turnover. A field experiment in Sweden, amended with different mineral and organic materials since 1956, was changed from continuous C3 plants to C4 vegetation (silage maize) in 2000. In 2012, soil samples from three fertilizer treatments (calcium nitrate, calcium nitrate plus straw and sewage sludge) and two controls (bare fallow and cropped unfertilized) were taken on three occasions (before, during and after cropping). Phospholipid fatty acids (PLFAs) were extracted from all soil samples and analysed for 12C and 13C contents in individual PLFAs. Seasonal variation in total PLFAs was small except for the most SOC‐rich treatment (sewage sludge). Weighted means of δ13C in PLFAs showed that the plots fertilized with calcium nitrate only had the largest δ13C values in PLFAs before (−20.24‰) and after the vegetation period (−20.37‰). However, during the vegetation period the values were much smaller (−21.85‰). This coincided with a strong increase in the PLFA 18:2ω6,9, indicating the use of old organic matter by fungi. Monounsaturated PLFAs indicative of Gram‐negative bacteria were more frequent before and after the growing season. This observed ‘rebound’ effect of the δ13C PLFA values during the vegetation period indicates that seasonal turnover of the microbial biomass can be substantial.

Influence of organic manures on carrot (Daucus carota L.) crops grown in a long-term field experiment in Sweden

AbstractThis study evaluated the effects of organic agriculture manuring systems on carrot (Daucus carota) root morphology and sugar and polyacetylene content. Carrots were harvested three times per season 2006–2007 in a long-term field experiment at Skilleby research farm, Sweden. The effects of pelleted chicken manure, fresh farmyard manure and composted farmyard manure (COM) were compared against control plots left unmanured since the field experiment started in 1991. The carrots were analyzed for root size, root shape, amount of soluble sugars and amount of falcarinol-type polyacetylenes. Differences between manuring systems were found to be smaller than the variation between harvest years and harvest occasions, probably due to the grass-clover ley included in the crop rotation system. On an average for the six harvests, manuring with COM increased root length by 6% compared with fertilizing with pelleted chicken manure. Carrots fertilized with pelleted chicken manure also had 6–7% lower total soluble sugar content than carrots manured with 50 t ha−1 of composted or fresh manure. The falcarinol to total falcarinol-type polyacetylenes ratio was 15.4% in carrots manured with 50 t ha−1 of composted or fresh manure and 14.7% in carrots fertilized with pelleted chicken manure. Seasonal fluctuations in falcarinol-type polyacetylenes were more pronounced in carrots manured with fresh or composted manure than in carrots fertilized with pelleted chicken manure. The results suggest that manuring organic carrots with compost may be the most beneficial strategy, at least in systems where fertilizer is applied only once per crop rotation, whether directly to the carrot crop or in the preceding crop.

Effects of intensity of forest regeneration measures on stand development in a nationwide Swedish field experiment

The general belief that intense regeneration measures are financially viable and essential for high sustained yields of commercial forest products has been inadequately tested. This field experiment evaluates effects of three different regeneration intensities 24–27 years after clear-cutting of 14 sites across Sweden. The treatments, designated high (HI), normal (NI) and low (LI), respectively, consisted of: mechanical site preparation and planting of large seedlings at 2×2 m spacing, with supplemental planting and pre-commercial thinning (PCT) when deemed necessary; standard local practices; and natural regeneration with no site preparation, artificial regeneration or PCT. Average crop seedling densities were highest and lowest (3359 and 1662 ha) under the HI and LI treatments, respectively, 4–8 growing seasons after planting. After 24–27 years, HI also resulted in higher mean stem volume (90 m ha) than LI (36 m ha) but was not significantly different from NI (65 m ha) and increasing the regeneration intensity was not consistently positive. In some cases, high planted seedling mortality and generally abundant natural regeneration resulted in minor (or no) differences between the treatments. The results illustrate that current Swedish regeneration standards may need revision in order to reflect contemporary societal and commercial demands.

Effects of autumn tillage and residue management on soil respiration in a long‐term field experiment in Sweden

AbstractSeveral previous field studies in temperate regions have shown decreased soil respiration after conventional tillage compared with reduced or no‐tillage treatments. Whether this decrease is due to differences in plant residue distribution or changes in soil structure following tillage remains an open question. This study investigated (1) the effects of residue management and incorporation depth on soil respiration and (2) biological activity in different post‐tillage aggregates representing the actual size and distribution of aggregates observed in the tilled layer. The study was conducted within a long‐term tillage experiment on a clay soil (Eutric Cambisol) in Uppsala, Sweden. After 38 y, four replicate plots in two long‐term treatments (moldboard plowing (MP) and shallow tillage (ST)) were split into three subplots. These were then used for a short‐term trial in which crop residues were either removed, left on the surface or incorporated to about 6 cm depth (ST) or at 20 cm depth (MP). Soil respiration, soil temperature, and water content were monitored during a 10‐d period after tillage treatment. Respiration from aggregates of different sizes produced by ST and MP was also measured at constant water potential and temperature in the laboratory. The results showed that MP decreased short‐term soil respiration compared with ST or no tillage. Small aggregates (< 16 mm) were biologically most active, irrespective of tillage method, but due to their low proportion of total soil mass they contributed < 1.5% to total respiration from the tilled layer. Differences in respiration between tillage treatments were found to be attributable to indirect effects on soil moisture and temperature profiles and the depth distribution of crop residues, rather than to physical disturbance of the soil.

Contribution of roots and amendments to soil carbon accumulation within the soil profile in a long-term field experiment in Sweden

The contribution of different C inputs to organic carbon accumulation within the soil profile in the Ultuna long-term continuous soil organic matter experiment, established in 1956, was determined. Until 1999, C3-crops were grown at the site, but since then maize (C4) has been the only crop. The effect of a total of 10 different inorganic nitrogen and organic amendment treatments (4Mg Cha−1yr−1) on SOC in topsoil and subsoil after 53 years was evaluated and the contribution from maize roots to SOC after 10 years of cultivation was estimated.Soil organic carbon (SOC) and δ13C signature were measured down to 50cm depth. The C content in the topsoil (0–20cm depth) was 1.5% at the start of the experiment. After 53 years of treatments, the average topsoil C content varied between 0.9 and 3.8% of soil dry weight, with the open fallow having the lowest and the peat amended the highest value. Nitrogen seemed to promote C accumulation in the topsoil treatment effects were smaller below 20cm depth and only two of the amendments (peat and sewage sludge) significantly affected SOC content down to 35cm depth. Despite this, penetrometer measurements showed significant treatment differences of compaction below 41cm depth, and although we could not explain these differences this presented some evidence of an initial treatment-induced subsoil differentiation. Ten years of maize growth affected the δ13C of SOC down to 22.5cm depth, where it varied between −25.16 and −26.33(‰), and an isotopic mass balance calculation suggested that maize C accounted for 4–8% of total SOC in the topsoil. Until less than 2500 years ago the site was a post-glacial sea floor and the 14C data suggest that marine sediment C still dominates the SOC in deeper soil layers. Overall, the results suggest that 53 years of treatments has caused dramatic changes on the stored C in the topsoil in several of the treatments, while the changes in the subsoil is much less dramatic and a small C accumulation in the upper subsoil was found in two of the treatments.The contribution from roots to SOC accumulation was generally equal to or greater than the contribution from amendments. The retention coefficient of root-derived C in the topsoil was on average 0.30±0.09, which is higher than usually reported in the literature for plant residues but confirms previous findings for the same experiment using another approach. This strengthens the conclusion that root-derived SOC contributed more to SOC than above-ground crop residues.

Experimental evidence from active placement efforts among unemployed in Sweden.

This article uses data from a field experiment in Sweden to analyze the effects of active placement efforts. In particular, the relative efficiency between combining job-search monitoring and job-search assistance, and monitoring alone, is analyzed. Although the impact estimates are generally imprecisely estimated, a general conclusion is that placement programs are effective policies in increasing the job exit rate for various groups of unemployed. I find that monitoring of job search is an efficient method to increase off-unemployment exit rate both alone and combined with job-search assistance services. The results, however, indicate that the combined services generate more permanent job exits.

Ethnic Preferences in Internet Dating: A Field Experiment

In an Internet field experiment in Sweden, we assessed the importance of ethnicity for successful online dating proposals for men. Randomizing names and occupation and holding physical appearance constant, our findings show that Swedishness is valued in the dating market and Arabs suffer an ethnic penalty, compared with both Swedes and Greeks. This implies that Arabs have a harder time finding dates, also in a frictionless setting as an Internet dating site.

Changes in organic carbon in topsoil and subsoil and microbial community composition caused by repeated additions of organic amendments and N fertilisation in a long-term field experiment in Sweden

The effects of 13 years of biennial application of four organic amendments (compost, green manure, farmyard manure and sewage sludge) on soil organic carbon (SOC) stocks, microbial biomass and community structure were compared with those of bare fallow, an unfertilised control and N-fertilised treatments. The experiment was conducted on a clay soil in western Sweden, in a randomised block design with four replicates. The crops grown were spring barley and oats. Changes in SOC mass were estimated by the ‘equivalent soil mass’ concept. Carbon inputs from crops were calculated from grain yields using linear allometric functions. The decomposition rate of soil organic matter was derived from a bare fallow treatment. Humification coefficients, defined here as the fraction of C input entering the SOC pool, for the organic amendments and crop residues were estimated by fitting a single-pool first order model to the final SOC stocks. The humification coefficient was highest for domestic waste compost (0.9) and lowest for above-ground crop residues (0.19). Crop yields were highest in sewage sludge-amended soil, probably due to favourable physical soil conditions, as indicated by lower bulk density (1.27–1.30gcm−3) than in the other treatments (1.32–1.38gcm−3). Despite addition of relatively high amounts of organic N, yields in other treatments receiving organic amendments were significantly lower than in those receiving mineral N fertiliser. In particular, the compost material was found to be highly recalcitrant, as indicated by its low C/N ratio (10) and low crop yield. Comparison of the correlation between phospholipid fatty acid (PLFA) concentration and SOC showed that compost supported relatively less microbial biomass than the other substrates tested. An important finding was that differences in SOC between treatments were significant to 40cm depth and that up to 27% of the SOC changes observed to 40cm depth occurred in the upper subsoil (25–40cm). Thus, SOC changes below ploughing depth should be considered in SOC balance studies.