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Sampling and analysis or visual examination of soil to assess its status and use potential is widely practiced from plot to national scales. However, the choice of relevant soil attributes and interpretation of measurements are not straightforward, because of the complexity and site-specificity of soils, legacy effects of previous land use, and trade-offs between ecosystem services. Here we review soil quality and related concepts, in terms of definition, assessment approaches, and indicator selection and interpretation. We identify the most frequently used soil quality indicators under agricultural land use. We find that explicit evaluation of soil quality with respect to specific soil threats, soil functions and ecosystem services has rarely been implemented, and few approaches provide clear interpretation schemes of measured indicator values. This limits their adoption by land managers as well as policy. We also consider novel indicators that address currently neglected though important soil properties and processes, and we list the crucial steps in the development of a soil quality assessment procedure that is scientifically sound and supports management and policy decisions that account for the multi-functionality of soil. This requires the involvement of the pertinent actors, stakeholders and end-users to a much larger degree than practiced to date. [ABSTRACT FROM AUTHOR]

Agricultural management practices can modify soil properties in ways that may disrupt the abundance and activity of beneficial organisms in the soil. We assessed the impact of different soil management practices on entomopathogenic nematodes (EPN), which have great potential as biological control agents against root-feeding insects. Soils were sampled during spring and autumn 2013 in all 96 plots of a long-term Swiss field trial (DOK experiment). By combining a traditional insect-baiting technique and real-time qPCR analyses, we identified and quantified over 20 soil-dwelling species (or genera). This allowed us to investigate how communities of natural EPN populations and their associated natural enemies and competitors are affected by ( i ) three crop types (wheat, maize and grass-clover ley) and ( ii ) farming systems, i.e. conventional, organic and biodynamic, which differed in fertilization, and pesticide use. We also determined the effects on soils’ microbial biomass in terms of carbon (C mic ) and nitrogen (N mic ) and applied spatial distribution analysis (SADIE) to uncover patterns of aggregations and associations of the study organisms. Although manure based farming systems increased microbial biomass, the systems did not influence the presence of EPN or their antagonists. EPN was more abundant in winter-wheat plots than in maize and grass-clover ley plots. Overall, very low numbers of EPN were recorded, implying that their natural presence would not be sufficient to have a satisfactory suppressive effect on root-feeding pests and the application of EPN would therefore be an appropriate measure to protect yields in case of root pest outbreaks. [ABSTRACT FROM AUTHOR]

Abstract: The scarcity of non-renewable resources such as soils and fertilizers and the consequences of climate change can dramatically influence the food security of future generations. Mutualistic root microorganisms such as plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) can improve plant fitness. We tested the growth response of wheat (Triticum aestivum [L.]), rice (Oriza sativa [L.]) and black gram (Vigna mungo [L.], Hepper) to an inoculation of AMF and PGPR alone or in combination over two years at seven locations in a region extending from the Himalayan foothills to the Indo-Gangetic plain. The AMF applied consisted of a consortium of different strains, the PGPR of two fluorescent Pseudomonas strains (Pseudomonas jessenii, R62; Pseudomonas synxantha, R81), derived from wheat rhizosphere from one test region. We found that dual inoculation of wheat with PGPR and AMF increased grain yield by 41% as compared to un-inoculated controls. Yield responses to the inoculants were highest at locations with previously low yields. AMF or PGPR alone augmented wheat grain yield by 29% and 31%, respectively. The bio-inoculants were effective both at Zero and at farmers’ practice fertilization level (70 kg N ha−1, 11 kg P ha−1 in mineral form to wheat crop). Also raw protein (nitrogen × 5.7) and mineral nutrient concentration of wheat grains (phosphorus, potassium, copper, iron, zinc, manganese) were higher after inoculation (+6% to +53%). Phosphorus use efficiency of wheat grains [kg P grain kg−1 P fertilizer] was increased by 95%. AMF and PGPR application also improved soil quality as indicated by increased soil enzyme activities of alkaline and acid phosphatase, urease and dehydrogenase. Effects on rice and black gram yields were far less pronounced over two cropping seasons, suggesting that AMF and PGPR isolated from the target crop were more efficient. We conclude that mutualistic root microorganisms have a high potential for contributing to food security and for improving nutrition status in southern countries, while safeguarding natural resources such as P stocks. [Copyright &y& Elsevier]

Activated charcoal (AC) amendments have been suggested as a promising, cost-effective method to immobilize organic contaminants in soil. We performed pot experiments over two years with cucumber (Cucumis sativus L.) grown in agricultural soil with 0.07 mg kg¿1 of weathered dieldrin and 0, 200, 400, and 800 mg AC per kg soil. Dieldrin fresh weight concentrations in cucumber fruits were significantly reduced from 0.012 to an average of 0.004 mg kg¿1, and total uptake from 2 to 1 ¿g in the 800 mg kg¿1 AC treatment compared to the untreated soil. The treatment effects differed considerably between the two years, due to different meteorological conditions. AC soil treatments did neither affect the availability of nutrients to the cucumber plants nor their yield (total fruit wet weight per pot). Thus, some important prerequisites for the successful application of AC amendments to immobilize organic pollutants in agricultural soils can be considered fulfilled. [Copyright &y& Elsevier]

Organochlorine pesticides (OCP) are still found in food and feed crops although they were applied about 40 years ago. There is a considerable knowledge gap concerning the extent of soil and crop contamination by OCP. We performed two surveys in 2002 and 2005 to assess the loads of OCP in 41 Swiss horticultural fields under organic and conventional production and corresponding Cucurbitaceae fruits (cucumbers, zucchini, and pumpkin), whereas these fields stay for intensive agricultural production in Europe. In addition, soil organic carbon, texture, and pH were measured also. OCP were detected in 27 out of 41 fields (65.9%). The farming practice had no influence on the contamination or level of OCP in soil. The sum of OCP-loads per field ranged from <0.01 to 1.3mgkg−1 dry soil and pentachloroaniline (PCA, 2.1mgkg−1), p,p′-DDT (0.5mgkg−1), and p,p′-DDE and dieldrin (0.4mgkg−1) were the most detected pesticides over all investigated soils. PCA (up to 0.02mgkg−1), dieldrin (up to 0.04mgkg−1), α-chlordane and cis-heptachloroepoxide (<0.01mgkg−1) were detected in five cucumber samples out of 41 Cucurbitaceae samples. Statistical analysis revealed no significant influence of the measured soil properties on the OCP-load of soils and cucumbers, although there is evidence that the bioavailability of OCP in soils to Cucurbitaceae plants was influenced by the sorption of the compounds to soil organic matter and by the polarity of the pesticide molecules. It is suggested, that OCP contamination is widespread in all European regions with intensive plant production and associated pesticide use, and deserves more attention with respect to save food production. [Copyright &y& Elsevier]

Long-term sustainability and high resource use efficiency are major goals for high quality baking wheat production throughout the world. Present strategies are low input systems such as organic agriculture or improved conventional systems (integrated). The fertilisation level and strategy, crop protection as well as preceding crop effects may modulate system performance with respect to wheat grain yield, quality and environmental performance of the systems. Our aim was to evaluate data of winter wheat ( Triticum aestivum L.) performance from the DOK long-term systems experiment in Switzerland comparing two mixed organic (biodynamic and bioorganic: BIODYN and BIOORG) and a mixed conventional cropping system (CONFYM) using mineral fertilisers and farmyard manure at two fertilisation intensities (level 1: 50% of standard fertilisation, level 2: standard fertilisation) since 1978. A conventional system was fertilised exclusively minerally at level 2 (CONMIN) and a control remained unfertilised (NOFERT). We compared crop yields, baking quality parameters, the nitrogen use efficiency and the effect of maize and potatoes as preceding crops obtained between 2003 and 2010 along with long-term soil sustainability parameters. The mean grain yields across both fertiliser levels of the organic cropping systems (BIODYN and BIOORG) were 64% of CONFYM, whereas crude protein contents were 79% of CONFYM at fertilisation level 2 and achieved 90% at level 1. The main driving factor of lower yields was a reduction of the numbers of ears per m 2 and the thousand kernel weight. The apparent nitrogen use efficiency decreased with increasing N fertilisation. Doubling the organic fertilisation in the organic systems only slightly improved wheat grain yields but was not able to improve grain baking quality, due to low mineral N additions via slurry and farmyard manure. In contrast the effects of the preceding crop potatoes in comparison with preceding silage maize outperformed the organic fertilisation effects, resulting in 33% higher yields and 11% higher crude protein contents. The yield components recorded in the case of preceding potatoes demonstrated a more synchronised nutrient supply throughout the wheat development. Over all low input systems and both fertilisation levels in the conventional mixed farm system at half standard fertilisation (level 1) performed best with distinctly higher grain yields and crude protein contents than in the organic systems with standard fertilisation. However, all systems, organic and conventional, with the low or zero organic fertiliser inputs performed poorly considering the long-term soil quality parameters, indicating a degradation of soil quality. The DOK long-term experiment allows an integrated view on the performance of baking wheat production and long-term sustainability. The results emphasise the importance of a sufficient supply of soils with organic fertilisers as well as the need to improve the availability of organic nitrogen and synchrony between nutrient supply and demand in organic baking wheat production, beside the selection of a suitable preceding crop. [ABSTRACT FROM AUTHOR]

Intercropping is a sustainable agroecological tool known to provide multiple benefits to farmers. Several studies have shown that arbuscular mycorrhizal fungi (AMF) play a key role for the improved grain yields in intercropping systems through facilitative nutrient and water uptake via the common mycorrhizal network (CMN), yet little is known on the rate of hyphal spread. Here we hypothesized that AMF species differ in the rate of extraradical hyphae to spread from one plant to another, thereby affecting the growth of the intercropped plants. To test our hypothesis, we established experimental microcosms in the greenhouse, in which one pigeon pea (Cajanus cajan) and two finger millet (Eleusine coracana) plantlets were kept in separate pots, connected by soil bridges of 5 or 12 cm length, inaccessible to roots but accessible to fungal hyphae. The pigeon pea plants were pre-inoculated with Claroideoglomus etunicatum , Rhizophagus fasciculatus or Rhizophagus irregularis. All three AMF species led to a strong growth promotion compared to uninoculated control of the short microcosms and more than doubled the biomass of pigeon pea. The biomass as well the phosphorus content of finger millets connected by AMF to the pigeon pea differed with the length of the soil bridge and the species of AMF. By applying 15N isotopes to the soil of pigeon pea pots we revealed that in both lengths of the microcosms R. fasciculatus and C. etunicatum transported nitrogen from pigeon pea to finger millet across distances of up to 12 cm but R. irregularis did not. Furthermore, by destructive sampling, we estimated a hyphal spread of 4.1 mm d−1 by C. etunicatum across a 12 cm soil bridge. We conclude that the row distance between the crops and the choice of AMF species play a crucial role for the application of AMF as biofertilizer. • Growth promotion and P uptake differed by length of the soil bridge and AMF species. • Hyphae of C. etunicatum spread at a rate of 4.1 mm d−1 across a 12 cm soil bridge. • AMF species differed in their ability to facilitate nitrogen transport across a soil bridge. [ABSTRACT FROM AUTHOR]

Abstract Wheat is a staple food crop and a major source of both the essential micronutrient zinc (Zn) and the toxic heavy metal cadmium (Cd) for humans. Since Zn and Cd are chemically similar, increasing Zn concentrations in wheat grains (biofortification), while preventing Cd accumulation, is an agronomic challenge. We used two Swiss agricultural long-term field trials, the "Dynamic-Organic-Conventional System Comparison Trial" (DOK) and the "Zurich Organic Fertilization Experiment" (ZOFE), to investigate the impact of long-term organic, mineral and combined fertilizer inputs on total and phytoavailable concentrations of soil Zn and Cd and their accumulation in winter wheat (Triticum aestivum L.). "Diffusive gradients in thin films" (DGT) and diethylene-triamine-pentaacetic acid (DTPA) extraction were used as proxies for plant available soil metals. Compared to unfertilized controls, long-term organic fertilization with composted manure or green waste compost led to higher soil organic carbon, cation exchange capacity and pH, while DGT-available Zn and Cd concentrations were reduced. The DGT method was a strong predictor of shoot and grain Cd, but not Zn concentrations. Shoot and grain Zn concentrations correlated with DTPA-extractable and total soil Zn concentrations in the ZOFE, but not the DOK trial. Long-term compost fertilization led to lower accumulation of Cd in wheat grains, but did not affect grain Zn. Therefore, Zn/Cd ratios in the grains increased. High Zn and Cd inputs with organic fertilizers and high Cd inputs with phosphate fertilizers led to positive Zn and Cd mass balances when taking into account atmospheric deposition and fertilizer inputs. On the other hand, mineral fertilization led to the depletion of soil Zn due to higher yields and thus higher Zn exports than under organic management. The study supports the use of organic fertilizers for reducing Cd concentrations of wheat grains in the long-term, given that the quality of the fertilizers is guaranteed. Graphical abstract Unlabelled Image Highlights • Impact of fertilization on Zn and Cd in wheat was studied in long-term field trials. • DGT and DTPA were used to measure plant-available soil metals. • DGT-available soil Cd positively correlated with wheat shoot and grain Cd. • Wheat grain Cd but not Zn was reduced by long-term organic fertilization. [ABSTRACT FROM AUTHOR]

Abstract Soil suppressiveness to pathogens is defined as the capacity of soil to regulate soil-borne pathogens. It can be managed by agricultural practices, but the effects reported so far remain inconsistent. Soil suppressiveness is difficult to predict and for this reason different soil properties have been linked to it with the aim to find informative indicators, but these relationships are not conclusive. The objectives of this study were i) to test if soil suppressiveness is affected by long-term agricultural management such as tillage and organic matter (OM) addition; ii) to understand the direct and indirect relationships between soil suppressiveness and labile organic carbon fractions; and iii) to understand the relationship between soil suppressiveness and other chemical, physical and biological soil quality indicators. We measured soil suppressiveness with a bioassay using Pythium ultimum - Lepidium sativum (cress) as a model system. The bioassay was performed in soils from 10 European long-term field experiments (LTEs) which had as main soil management practices tillage and/or organic matter addition. We found that the site had a stronger influence on soil suppressiveness than agricultural practices. Reduced tillage had a positive effect on the suppressive capacity of the soil across sites using an overall model. Organic farming and mineral fertilization increased soil suppressiveness in some LTEs, but no overall effect of OM was found when aggregating the LTEs. Soil suppressiveness across LTEs was linked mainly to microbial biomass and labile carbon in the soil, but not to total soil organic matter content. From structural equation modelling (SEM) we conclude that labile carbon is important for the maintenance of an abundant and active soil microbial community, which is essential for the expression of soil suppressiveness. However, soil suppressiveness could only partly (25%) be explained by the soil parameters measured, suggesting that other mechanisms contribute to soil suppressiveness such as the presence and the activity of specific bacterial and fungal taxa with high biocontrol activity. Highlights • We assessed soil suppressiveness in 101 soil samples from 10 long-term field experiments. • Reduced tillage, and, at some sites, also organic farming and mineral fertilization increased soil suppressiveness. • Labile carbon promoted soil suppressiveness through positive effects on microbial biomass. • Soil suppressiveness could only partly be explained by the soil parameters measured. [ABSTRACT FROM AUTHOR]

Highlights • We analysed topsoils from 10 European long-term field experiments. • Reduced tillage and high organic matter input increased labile soil carbon. • POXC and POMC were the most sensitive to tillage and organic matter additions. • POXC was highly correlated with chemical, physical and biological soil parameters. • POXC has the potential to be used as a comprehensive soil quality indicator. Abstract Soil quality is defined as the capacity of the soil to perform multiple functions, and can be assessed by measuring soil chemical, physical and biological parameters. Among soil parameters, labile organic carbon is considered to have a primary role in many soil functions related to productivity and environmental resilience. Our study aimed at assessing the suitability of different labile carbon fractions, namely dissolved organic carbon (DOC), hydrophilic DOC (Hy-DOC), permanganate oxidizable carbon (POXC, also referred to as Active Carbon), hot water extractable carbon (HWEC) and particulate organic matter carbon (POMC) as soil quality indicators in agricultural systems. To do so, we tested their sensitivity to two agricultural management factors (tillage and organic matter input) in 10 European long-term field experiments (LTEs), and we assessed the correlation of the different labile carbon fractions with physical, chemical and biological soil quality indicators linked to soil functions. We found that reduced tillage and high organic matter input increase concentrations of labile carbon fractions in soil compared to conventional tillage and low organic matter addition, respectively. POXC and POMC were the most sensitive fractions to both tillage and fertilization across the 10 European LTEs. In addition, POXC was the labile carbon fraction most positively correlated with soil chemical (total organic carbon, total nitrogen, and cation exchange capacity), physical (water stable aggregates, water holding capacity, bulk density) and biological soil quality indicators (microbial biomass carbon and nitrogen, and soil respiration). We conclude that POXC represents a labile carbon fraction sensitive to soil management and that is the most informative about total soil organic matter, nutrients, soil structure, and microbial pools and activity, parameters commonly used as indicators of various soil functions, such as C sequestration, nutrient cycling, soil structure formation and soil as a habitat for biodiversity. Moreover, POXC measurement is relatively cheap, fast and easy. Therefore, we suggest measuring POXC as the labile carbon fraction in soil quality assessment schemes in addition to other valuable soil quality indicators. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

There is an urgent need to identify and evaluate management practices for their biophysical potential to maintain productivity under climate change while mitigating greenhouse gas (GHG) emissions from individual cropping systems under specific pedo-climatic conditions. Here, we examined, through DayCent modeling, the long-term impact of soil management practices and their interactions on soil GHG emissions and GHG intensity from Swiss cropping systems. Based on experimental data from four long-term experimental sites in Switzerland (Therwil, Frick, Changins, and Reckenholz), we robustly parameterized and evaluated the model for simulating crop productivity, soil C dynamics and soil N 2 O emissions across a range of management practices and pedo-climatic conditions. Net soil GHG emissions (NSGHGE) were derived from changes in soil C, N 2 O emissions and CH 4 oxidation. Soils under conventional management acted as a net source of soil GHG emissions (1361–1792 kg CO 2 eq ha −1 yr −1 ) and NSGHGE were dominated by N 2 O (50–63%). Reduced tillage and no-tillage reduced long-term NSGHGE by up to 31 and 58%, respectively. Organic farming, represented by organic fertilization, reduced NSGHGE by up to 31% compared to systems based solely on mineral fertilization. Replacement of slurries with a composted FYM led to an additional reduction in NSGHGE by 46%, although our approach considered only soil GHG emissions and thus did not take into account GHG emissions from the composting process. Cover cropping did not significantly influence NSGHGE, however vetch tended to reduce NSGHGE (-19%). The highest mitigation potential was associated with organic farming plus reduced tillage management, it reduced long-term NSGHGE by up to 128%. Soil C sequestration accounted, on average, for 89% of GHG mitigation potentials, consequently N 2 O dominated NSGHGE across all treatments and sites (60 − 80%). This indicates that these mitigation potentials are time limited and reversible, if the management is not maintained, in contrast to the reduction in N 2 O emissions, which is considered permanent. Not all the management practices sustained crop yields. Nevertheless, composting of organic manures, reduced tillage and no-tillage effectively reduced NSGHGE and GHG intensity without a noticeable yield reduction. Our results suggest that implementation of the above soil management practices in Swiss cropping systems have a considerable potential for climate change mitigation, although time-limited. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) plays a vital role for soil quality, sustainable food production and climate change mitigation. It is common knowledge that SOM consists of different pools with varying qualities, quantities, and turnover times. However, it is still poorly understood how mineral and organic fertilization affects the formation and stabilization of mineral-associated organic matter (MAOM) and how long it can remain there. Here, we report on the long-term effects of different farming systems on the stability and turnover of the fine silt and clay-sized MAOM fraction (<6.3 μm) of a Haplic Luvisol (0–20 cm) in the DOK long-term trial (Switzerland). We compared three farming systems with contrasting fertilization (CONMIN = pure mineral, CONFYM = mineral + organic, BIODYN = pure organic) with an unfertilized control (NOFERT) between 1982 and 2017. We performed specific surface area (SSA) measurements on fractionated MAOM samples (<6.3 μm) from 1982 to 2017, before and after removal of OM, measured the 14C activity of all samples during the entire period and estimated the mean residence time (MRT) with a model taking into account 'bomb 14C' and radioactive decay. We found constant MAOM-C contents under organic fertilization. Results of SSA analysis indicate best conditions for MAOM-C stabilization under organic fertilization and different sorption mechanisms in MAOM between farming systems with and without organic fertilization. The modelled MRTs were significantly higher in NOFERT (238 ± 40 yrs) and CONMIN (195 ± 27 yrs), compared to CONFYM (138 ± 18 yrs) and BIODYN (140 ± 19 yrs), implying a high C turnover (i.e. more active MAOM) at high C contents under organic fertilization. Our findings show that MAOM is not the dead OM but corroborates the concept of 'dynamic stability'. Continuous OM inputs from organic fertilizers and their rapid and constant turnover are needed to stabilize the "stable" MAOM-C fraction. • SSA analysis reveals improved aggregate stability under organic fertilization. • Significantly shorter MRT of MAOM-C under organic fertilization. • Highest MAOM-C turnover (i.e. more active MAOM) under organic fertilization. • Constant OM input and turnover is vital for maintenance of MAOM-C contents. [ABSTRACT FROM AUTHOR]

N 2 O is a major greenhouse gas and the majority of anthropogenic N 2 O emissions originate from agriculturally managed soils. Therefore, developing N 2 O mitigation strategies is a key challenge for the agricultural sector and biochar soil treatment is one reported option. Biochar's capacity to increase soil pH and to foster activity of specialized N 2 O reducers has been proposed as possible mechanisms for N 2 O mitigation. An experiment was undertaken to investigate whether changes in the community composition of N 2 O reducers was observed under field conditions after biochar application. The study objective was to assess the abundance and taxonomic composition of the functional marker genes nosZ and nosZ –II across a vegetation period of Zea mays L. after biochar or lime addition compared to an untreated control. After fertilization, biochar amendment resulted in a significant increase of nosZ gene copy numbers compared to the control and the lime treatment. Simultaneously a shift in community composition of nosZ-II bearing bacteria was observed in the biochar treatment that went beyond the sole liming effect. This study broadens our understanding of the functional impact of biochar on N 2 O emissions and emphasizes the possibility to shape the functioning of the N 2 O reducing microbial community through the addition of biochar at a field scale. [ABSTRACT FROM AUTHOR]

N 2 O is a potent greenhouse gas with an atmospheric lifetime of 114 years which also contributes to ozone layer destruction. Mitigating N 2 O emissions is especially challenging to the agricultural sector that is responsible for the majority of anthropogenic N 2 O release. In order to develop effective mitigation strategies, a detailed understanding of drivers for N 2 O production and reduction in agriculturally managed soils is needed. Denitrification is recognized as one of the most important source processes for N 2 O emissions from soils. However, the last step in denitrification, the reduction of N 2 O to N 2 is the only known sink for N 2 O in soil. Although the impact of single parameters on denitrification is quite well documented, there is still a knowledge gap when it comes to the impact of complex farming systems on N 2 O production and reduction. In this experiment, we incubated soil samples from the DOK long term field trial in Therwil/Switzerland comparing organic (BIOORG) and conventional (CONMIN) farming systems with an a non-fertilized control (NOFERT). Soil samples were incubated under 90% WFPS after fertilization with NH 4 15 NO 3 equivalent to a moderate fertilization event in the field with 40 kg N ha −1 . In order to assess soil's potential for N 2 O production and reduction, we combined direct measurements of denitrification end products N 2 O and N 2 with molecular analysis of functional denitrifying communities involved in NO 2 − and N 2 O reduction on DNA and mRNA levels. In order to monitor N cycling processes under the chosen conditions, stable isotope tracing was employed to quantify nitrification and NO 3 − consumption rates. Results revealed increased NO 3 − consumption and greatest potential for N 2 O emissions in BIOORG as a result of increased soil organic carbon contents. Production of N 2 was similar in BIOORG and CONMIN and significantly lower in NOFERT, most likely due to significantly decreased pH inhibiting N 2 O reduction. This caused the greatest N 2 O/(N 2 O + N 2 ) ratios in NOFERT (0.88 ± 0.02) followed by BIOORG (0.79 ± 0.01) and CONMIN (0.68 ± 0.02) (p < 0.001). Lowest N 2 O/(N 2 O + N 2 ) ratios in CONMIN were reflected by lowest N 2 O emissions and coincided with elevated nosZ transcript copies in the beginning of incubation. Although highest N 2 O emissions in BIOORG were detected, the incubation setup cannot directly be translated to field conditions. Nevertheless, our results emphasize that farming system induced changes on soil geochemical parameters like soil pH and soil organic carbon affect microbial N 2 O production and reduction processes during denitrification. [ABSTRACT FROM AUTHOR]

Conservation agriculture is arising as an alternative to conventional agriculture with the aim to have a reduced impact on the environment. This includes the use of cover crops to conserve soil quality by limiting soil erosion, adding organic matter, and enhancing soil nutrient content, as well as water availability, which are all factors that can greatly influence the presence of soil organisms. In the current study, we investigated whether winter cover crops can enhance the persistence of entomopathogenic nematodes (EPN) over the winter season. In a first trial we augmented EPN populations in plots without (bared) and with the cover crops, pea ( Pisum sativum ) or mustard ( Brassica juncea ). In late autumn, individual mini-plots in each of the three treatments were supplemented with infective juveniles (IJs) of either Heterorhabditis bacteriophora or Steinernema feltiae . In a second trial we studied naturally occurring EPN in plots without (bared) and with the cover crop pea ( Pisum sativum ) followed by planting of winter wheat. To identify and quantify EPN, we analyzed soil samples using quantitative real time PCR (qPCR) at three time points over the winter season. We also measured the activity of augmented EPN by baiting the soil with wax moth larvae, Galleria mellonella . In addition, we used the qPCR method to investigate the presence of nematophagous fungi (NF), free-living nematodes (FLN) and ectoparasitic bacteria, all of which can interfere with EPN performance. Numbers of naturally occurring EPN in the investigated fields were very low (< 1 EPN per 100 g of soil). The cover crops only had a significant positive effect on the numbers of augmented S. feltiae found in early winter. No striking effect was found for H. bacteriophora . Yet, augmentation was found to enhance the insect-suppressiveness of the soil, as the recorded EPN infectivity after the winter was slightly higher than what was observed in autumn, one month after application. The numbers of FLN, which compete for insect cadavers, was higher in spring than in early winter. These FLN and other antagonists may be important in reducing EPN numbers. In conclusion, the effect of cover crops on EPN persistence was only evident during early-winter and was only significant in the plots augmented with S. feltiae . Moreover, we found that higher numbers of EPN in agricultural soils do not necessarily translate into high infectivity, which is the key factor determining their effectiveness in controlling soil pests. [ABSTRACT FROM AUTHOR]

Organic reduced tillage aims to combine the environmental benefits of organic farming and conservation tillage to increase sustainability and soil quality. In temperate climates, there is currently no knowledge about its impact on greenhouse gas emissions and only little information about soil organic carbon (SOC) stocks in these management systems. We therefore monitored nitrous oxide (N 2 O) and methane (CH 4 ) fluxes besides SOC stocks for two years in a grass-clover ley – winter wheat – cover crop sequence. The monitoring was undertaken in an organically managed long-term tillage trial on a clay rich soil in Switzerland. Reduced tillage (RT) was compared with ploughing (conventional tillage, CT) in interaction with two fertilisation systems, cattle slurry alone (SL) versus cattle manure compost and slurry (MC). Median N 2 O and CH 4 flux rates were 13 μg N 2 O-N m −2 h −1 and −2 μg CH 4 C m −2 h −1 , respectively, with no treatment effects. N 2 O fluxes correlated positively with nitrate contents, soil temperature, water filled pore space and dissolved organic carbon and negatively with ammonium contents in soil. Pulse emissions after tillage operations and slurry application dominated cumulative gas emissions. N 2 O emissions after tillage operations correlated with SOC contents and collinearly to microbial biomass. There was no tillage system impact on cumulative N 2 O emissions in the grass-clover (0.8–0.9 kg N 2 O-N ha −1 , 369 days) and winter wheat (2.1–3.0 kg N 2 O-N ha −1 , 296 days) cropping seasons, with a tendency towards higher emissions in MC than SL in winter wheat. Including a tillage induced peak after wheat harvest, a full two year data set showed increased cumulative N 2 O emissions in RT than CT and in MC than SL. There was no clear treatment influence on cumulative CH 4 uptake. Topsoil SOC accumulation (0–0.1 m) was still ongoing. SOC stocks were more stratified in RT than CT and in MC than SL. Total SOC stocks (0–0.5 m) were higher in RT than CT in SL and similar in MC. Maximum relative SOC stock difference accounted for +8.1 Mg C ha −1 in RT-MC compared to CT-SL after 13 years which dominated over the relative increase in greenhouse gas emissions. Under these site conditions, organic reduced tillage and manure compost application seems to be a viable greenhouse gas mitigation strategy as long as SOC is sequestered. [ABSTRACT FROM AUTHOR]

Organic farm management through farmyard manure application is associated with soil organic carbon sequestration facilitated by more balanced nutrient stoichiometry of macro- and micronutrients. Quantitative information on micronutrients within the soil microbial biomass is lacking. Using soils from a 40-year old long-term field trial (DOK), we investigated if fertilisation differences (farmyard manure equivalent to 0.7 or 1.4 livestock units per hectare and mineral fertilisation) and farm management (biodynamic, organic, conventional) changed the soil microbial ionome and stoichiometry and if this is related to microbial community shifts. Soil (15% sand, 70% silt and 15% clay) from the top 20 cm was analysed for microbial biomass carbon, nitrogen and phosphorus. Further elements were assessed via an adapted chloroform-fumigation extraction procedure. Abundances of bacteria, archaea, and fungi were determined (q PCR). Farmyard manure increased microbial biomass by approximately two-fold and the contribution of bacteria and archaea by up to approximately five-fold. Microbial biomass phosphorus and magnesium increased with mineral fertilisation (from 7 to 14 μg g−1 soil) and farmyard manure (from 0.5 to 2.7 μg g−1 soil), respectively. The microbial biomass carbon to potassium ratio remained similar, at around 47:1, revealing stoichiometric control. Microbial biomass manganese was reduced from 3.5 to 2.2 μg g−1 soil with lower availability due to raised pH in biodynamic management. The microbial stoichiometry and ionome were mainly affected by nutrient input and soil chemical properties; direct links between microbial (micronutrient-) stoichiometry and microbial community changes cannot be established with certainty due to potential confounding effects of pH changes. • Soil microbial biomass K, Mg, Zn, Mn, Cu measured in situ via chloroform-fumigation. • Homeostatic (K, Cu) as well as plastic stoichiometry (Mg, Zn, Mn) was found. • pH exerted control over available elements which influenced microbial stoichiometry. • Farmyard manure increased bacterial and archaeal contribution to community. [ABSTRACT FROM AUTHOR]

In 2007 two long-term trials were established in Kenya to contribute research-based evidence to the global debate on the productivity, economic viability and sustainability of different agricultural production systems. These trials compare conventional (Conv) and organic (Org) farming systems at high and low input levels at two locations, i.e. Chuka, with Humic Nitisols, high inherent soil fertility and rainfall, and Thika, with Rhodic Nitisols with low soil fertility and rainfall. The high input systems (High) represent commercial-scale, export-oriented production that uses the recommended amounts of fertilisers, pesticides and irrigation water to generate high yields, whilst the low input systems (Low) represent local smallholder practices, using relatively few fertilisers and pesticides and operating under rain-fed conditions. The conventional systems received synthetic fertilisers and organic manure, whilst the organic systems only received organic inputs. The trials so far have consisted of a 6-season, 3-year, crop rotation with maize ( Zea mays L.) planted in the long rainy seasons (March-September), and vegetables in the short rainy seasons (October – February). Generally, there were no significant differences in the dry matter yields and nutrient uptake by maize, baby corn or beans between the conventional and organic systems at either site. Similar maize grain and baby corn yields were also obtained at Chuka. However, at Thika, maize grain yields in Org-High in 2007 (at conversion) were lower than the yields in Conv-High, but the yields became similar in 2010 (after conversion). At the same site the yields of maize grain under sole cropping in Org-Low were 3.2 times lower than the yields in Conv-Low in 2007 and 1.7 times lower in 2010. When intercropped with beans the yields of the two systems were similar. In the first two years profits from Conv-High were 0.5–1.8 times and 0.2–2.4 times higher than in Org-High when selling the produce at local (Chuka and Thika) and regional markets (Nairobi), but thereafter the profit from the two was similar, even when organic produce was sold at regular market prices. From the fifth year onwards Org-High attracted a price premium of 20 to 50% and this made it 1.3 to 4.1 times more profitable than Conv-High when selling on local and regional markets (in Chuka, Thika and Nairobi). Compared to Conv-High, partial N and K balances at the two sites were positive and higher in Org-High, except for N at Chuka. Our findings demonstrate that Org-High is productive, economically viable, resource-conserving and can contribute to sustainable agriculture production in Kenya depending on regional conditions and the crops cultivated. [ABSTRACT FROM AUTHOR]

Under the United Nations Framework Convention on Climate Change (UNFCCC), industrialized countries and countries with economies in transition (so called Annex 1 countries) are encouraged to move towards more sophisticated approaches for national greenhouse gas reporting. To develop a model-based approach for estimating nitrous oxide (N 2 O) emissions from agricultural soils, model calibration is one of the first important steps. Extensive multisite field observations are necessary for this purpose, as agricultural management in Western Europe is complex (e.g. , diverse crop rotations, different types of fertilizer and soil tillage). In the present study, we used ca. 24,000 daily N 2 O flux observations from six cropland sites, two in France and four in Switzerland, to conduct an automatic data-driven calibration of the biogeochemical model DayCent. This model is planned to be used for greenhouse gas reporting in the entire European Union as well as in Switzerland. After a site-specific calibration, a leave-one-out (LOO) cross-evaluation was conducted to assess the model's ability to predict N 2 O emissions for sites it was not calibrated for. Mean observed N 2 O fluxes for 54 interactions of crop cycles, field studies and treatments were used to evaluate the model. The LOO cross-evaluation resulted in a R 2 of 0.63 for the prediction of mean N 2 O fluxes per crop cycle, compared to an R 2 of 0.51 obtained with default parameterization. Our results showed that the improvement in N 2 O predictions was associated with the adjustment of only seven parameters controlling the N cycle in soil (e.g. , the maximum daily nitrification amount and the inflection point for the effect of water-filled pore space on denitrification) out of several hundred parameters. These parameters showed a wide range of values between sites, revealing an important challenge for calibration-based improvement of N 2 O simulations. Despite the remaining uncertainty, our model-based estimates of N 2 O emission per crop cycle (2.64 kg N ha-1) were clearly closer to measurements (2.67 kg N ha-1) than commonly used emission factor approaches (1.60–1.71 kg N ha-1). Based on extensive field observations, our results suggest that, after data-driven calibration of only few N cycle parameters, DayCent simulations are useful for reporting N 2 O emissions of complex cropland management. These model based-estimates were more accurate, because they consider key drivers that are disregarded by simpler approaches. Moving towards more complex methods of N 2 O reporting, is therefore expected to improve the accuracy and additionally allows to assess mitigation options. • Model estimates of N 2 O emissions can improve national greenhouse gas reporting. • Calibration based on field data is a critical first step for modeling N 2 O emissions. • N 2 O observations from six sites were used to test DayCent's performance. • The model's performance could be improved by calibrating only few N cycle parameters. • DayCent simulations were clearly more accurate than emission factor approaches. [ABSTRACT FROM AUTHOR]

Conventional high-input farming systems in Europe are often regarded as unsustainable with severe environmental impacts on biodiversity, soils, water and climate. Low-input farming approaches, such as organic farming, have been proposed to reduce environmental impacts while further improving soil properties such as soil organic matter content and aggregate stability. Whether these changes also influence ecohydrological properties and improve the water relations of organically grown crops remains unclear. In this study we assessed the long-term effects of conventional and organic farming systems on the water relations of soils and crops in the "DOK" (bio-Dynamic, bio-Organic & 'Konventionell' = conventional) trial. In particular, we tested if organic and conventional farming lead to marked differences in soil moisture, soil water evaporation, as well as root water uptake depth and stomatal conductance of winter wheat and soybean during the growing seasons 2017 and 2018. Stable isotope analyses and ecophysiological measurements revealed that organic compared to conventional farming did not affect soil water evaporation or root water uptake depths. Instead, we found higher soil moisture in the rooting zone and reduced stomatal conductance (g s) in organically grown wheat. Treatment effects on soil moisture and g s of soybean were smaller but showed similar tendencies as observed in wheat. Also, leaf area, and grain and straw yield of wheat decreased under organic farming while yields of soybean were not affected by the treatments. Based on our data we suggest that reduced plant water use observed under organically managed farming lead to the observed higher soil moisture in organically compared to conventionally managed farming systems in the DOK trial. These results suggest advantages of organic farming regarding agronomic water use as well as for the resistance of farming systems to current or future drought scenarios. • Organic farming had no effect on soil water evaporation and root water uptake depths. • Organic farming reduced grain and straw yield of winter wheat but not of soybean. • Organic farming generally increased soil moisture and reduced stomatal conductance. • Organically grown winter wheat showed lower leaf area. • Our results suggest that organic farming can reduce total water use. [ABSTRACT FROM AUTHOR]

Communities of arbuscular mycorrhizal fungi (AMF) are strongly affected by land use intensity and soil type. The impact of tillage practices on AMF communities is still poorly understood, especially in organic farming systems. Our objective was to investigate the impact of soil cultivation on AMF communities in organically managed clay soils of a long-term field experiment located in the Sissle valley (Frick, Switzerland) where two different tillage (reduced and conventional mouldboard plough tillage) and two different types of fertilization (farmyard manure & slurry, or slurry only) have been applied since 2002. In addition, a permanent grassland and two conventionally managed croplands situated in the neighborhood of the experiment were analyzed as controls. Four different soil depths were studied including top-soils (0-10 and 10-20 cm) of different cultivation regimes and undisturbed sub-soils (20-30 and 30-40 cm). The fungi were directly isolated from field soil samples, and additionally spores were periodically collected from long-term trap culture (microcosm) systems. In total, >50,000 AMF spores were identified on the species level, and 53 AMF species were found, with 38 species in the permanent grassland, 33 each in the two reduced till organic farming systems, 28-33 in the regularly plowed organic farming systems, and 28-33 in the non-organic conventional farming systems. AMF spore density and species richness increased in the top-soils under reduced tillage as compared to the ploughed plots. In 10-20 cm also the Shannon-Weaver AMF diversity index was higher under reduced tillage than in the ploughed plots. Our study demonstrates that AMF communities in clay soils were affected by land use type, farming system, tillage as well as fertilization strategy and varying with soil depth. Several AMF indicator species especially for different land use types and tillage strategies were identified from the large data set. [ABSTRACT FROM AUTHOR]

Highlights: [•] Unexplained yield depression is a main issue in organic legume production. [•] A robust test system to narrow down causes of yield depression was established. [•] Soils from 22 sites with unexplained pea yield losses were evaluated. [•] Biotic causes were identified as the primary cause of yield depressions. [•] Either oomycetes or a multitude rather than a single group of pathogens was involved. [ABSTRACT FROM AUTHOR]

It is anticipated that organic farming systems provide benefits concerning soil conservation and climate protection. A literature search on measured soil-derived greenhouse gas (GHG) (nitrous oxide and methane) fluxes under organic and non-organic management from farming system comparisons was conducted and followed by a meta-analysis. Up to date only 19 studies based on field measurements could be retrieved. Based on 12 studies that cover annual measurements, it appeared with a high significance that area-scaled nitrous oxide emissions from organically managed soils are 492±160kg CO2 eq. ha−1 a−1 lower than from non-organically managed soils. For arable soils the difference amounts to 497±162kg CO2 eq. ha−1 a−1. However, yield-scaled nitrous oxide emissions are higher by 41±34kg CO2 eq. t−1 DM under organic management (arable and use). To equalize this mean difference in yield-scaled nitrous oxide emissions between both farming systems, the yield gap has to be less than 17%. Emissions from conventionally managed soils seemed to be influenced mainly by total N inputs, whereas for organically managed soils other variables such as soil characteristics seemed to be more important. This can be explained by the higher bioavailability of the synthetic N fertilisers in non-organic farming systems while the necessary mineralisation of the N sources under organic management leads to lower and retarded availability. Furthermore, a higher methane uptake of 3.2±2.5kg CO2 eq. ha−1 a−1 for arable soils under organic management can be observed. Only one comparative study on rice paddies has been published up to date. All 19 retrieved studies were conducted in the Northern hemisphere under temperate climate. Further GHG flux measurements in farming system comparisons are required to confirm the results and close the existing knowledge gaps. [ABSTRACT FROM AUTHOR]

Abstract: Organic farming may contribute substantially to future agricultural production worldwide by improving soil quality and pest control, thereby reducing environmental impacts of conventional farming. We investigated in a comprehensive way soil chemical, as well as below and aboveground biological parameters of two organic and two conventional wheat farming systems that primarily differed in fertilization and weed management strategies. Contrast analyses identified management related differences between “herbicide-free” bioorganic (BIOORG) and biodynamic (BIODYN) systems and conventional systems with (CONFYM) or without manure (CONMIN) and herbicide application within a long-term agricultural experiment (DOK trial, Switzerland). Soil carbon content was significantly higher in systems receiving farmyard manure and concomitantly microbial biomass (fungi and bacteria) was increased. Microbial activity parameters, such as microbial basal respiration and nitrogen mineralization, showed an opposite pattern, suggesting that soil carbon in the conventional system (CONFYM) was more easily accessible to microorganisms than in organic systems. Bacterivorous nematodes and earthworms were most abundant in systems that received farmyard manure, which is in line with the responses of their potential food sources (microbes and organic matter). Mineral fertilizer application detrimentally affected enchytraeids and Diptera larvae, whereas aphids benefited. Spider abundance was favoured by organic management, most likely a response to increased prey availability from the belowground subsystem or increased weed coverage. In contrast to most soil-based, bottom-up controlled interactions, the twofold higher abundance of this generalist predator group in organic systems likely contributed to the significantly lower abundance of aboveground herbivore pests (aphids) in these systems. Long-term organic farming and the application of farmyard manure promoted soil quality, microbial biomass and fostered natural enemies and ecosystem engineers, suggesting enhanced nutrient cycling and pest control. Mineral fertilizers and herbicide application, in contrast, affected the potential for top-down control of aboveground pests negatively and reduced the organic carbon levels. Our study indicates that the use of synthetic fertilizers and herbicide application changes interactions within and between below and aboveground components, ultimately promoting negative environmental impacts of agriculture by reducing internal biological cycles and pest control. On the contrary, organic farming fosters microbial and faunal decomposers and this propagates into the aboveground system via generalist predators thereby increasing conservation biological control. However, grain and straw yields were 23% higher in systems receiving mineral fertilizers and herbicides reflecting the trade-off between productivity and environmental responsibility. [Copyright &y& Elsevier]

Assessing soil microbial functionality has the potential to reveal meaningful effects of soil management on soil processes influencing soil quality. We used MicroResp™ to assess microbial respiration upon the addition of six carbon substrates (glucose, alanine, aminobutyric acid, N -acetyl glucosamine, alpha-ketoglutaric acid, and lignin). From this, we calculated the multiple substrate induced respiration (MSIR), the microbial catabolic profile expressed as absolute and relative utilization rate, and the Shannon microbial functional diversity index (H′). We tested the effect of tillage (reduced vs. conventional) and organic matter addition (high vs. low) on these microbial parameters in soil from 10 European long-term field experiments (LTEs), and investigated their relationships with labile organic carbon fractions and various soil parameters linked to soil functions. Reduced tillage and high organic matter input increased MSIR compared to conventional tillage and low organic matter input. In addition, reduced tillage resulted in a small but significant increase in functional diversity compared to conventional tillage. An increase in soil management intensity (CT-Low > CT-High > RT-Low > RT-High) was associated with lower utilization of all the substrates expressed as absolute utilization rate, and a proportionately higher utilization of alpha-ketoglutaric acid compared to the other substrates. More intensive management systems also showed lower soil quality as measured by various soil parameters, in particular total and labile organic carbon, basal respiration, and microbial biomass nitrogen. The present work shows for the first time the key role of labile organic carbon, as affected by soil management, in determining microbial functional diversity. Aggregating results from 10 European arable LTEs, making use of a comprehensive dataset, MicroResp™ showed that reduced tillage and increased organic matter addition created a more favourable habitat for the microbial community to utilize different carbon substrates and, thereby, the potential for nutrient cycling. • We tested the effects of tillage and organic matter addition on soil microbial catabolic profiles. • Soil management effects on catabolic profiles were derived from 10 long-term arable field experiments. • Reduced tillage and high organic matter addition increased substrate utilization rate. • Reduced tillage, but not organic matter addition, increased microbial functional diversity (H′). • H′ was best explained by soil labile carbon (POMC) and pH. [ABSTRACT FROM AUTHOR]

• The fate of C and N were quantified and modelled in two long term experiments. • STICS model was improved to simulate organic farming (OF) systems. • STICS reproduced crop production, N surplus and change in SON stocks. • OF did not systematically differ from conventional in N surplus, N losses and GHG. • N losses and GHG was related to N surplus. Although organic cropping systems are promoted for their environmental benefits, little is known about their long-term impact on nitrogen (N) fate in the soil–plant-atmosphere system. In this paper, we analyze two long-term experiments: DOK in Switzerland (39-yr) and Foulum organic in Denmark (19-yr). Four treatments were considered in each experiment: two conventional treatments with (CONFYM) or without manure (CONMIN), organic with manure (BIOORG) and unfertilized treatment (NOFERT) at DOK; conventional (CGL-CC+IF) and three organic treatments, one with cover crops only (OGL+CC-M) and two including cover crops and grass-clover with (OGC+CC+M) or without manure (OGC+CC-M), at Foulum. STICS model was used to simulate crop production, N surplus, nitrate leaching, gaseous N losses and changes in soil organic N. It was calibrated in the conventional treatments and tested in organic systems. The crop production, N surplus and soil organic N stocks were satisfactorily predicted. The mean N surplus greatly differed between treatments at DOK, from −58 (NOFERT) to +21 kg N ha−1 yr−1 (CONFYM), but only from −9 (OGL+CC-M) to +21 kg N ha−1 yr−1 (OGC+CC+M) in Foulum. Soil N pools declined continuously in both sites and treatments at a rate varying from −18 to −78 kg N ha−1 yr−1, depending on fertilization and crop rotation. The decline was consistent with the observed N surpluses. Although not all simulations could be tested against field observations and despite of prediction uncertainties, simulations confirm the hypothesis that environmental performances resulting from C and N cycles depend more on specificities of individual than nominal treatments. Significant correlations appeared between long-term N surplus and soil N storage and between total N fertilization and total N gaseous losses. Results showed in both experiments that arable organic systems do not systematically have lower N surplus and N losses than conventional ones, providing opportunity for increasing N use efficiency of these systems. [ABSTRACT FROM AUTHOR]

Annual changes in soil organic carbon stocks of eleven experimental field sites in Switzerland in response to a large range of different agricultural practices. • Changes in soil organic carbon (SOC) were assessed in Swiss long-term experiments. • Topsoils lost SOC despite practices expected to enhance SOC stocks. • C inputs to soil were insufficient and some sites were affected by former land-use. • Efforts to sequester soil C need to be intensified and new approaches applied. Soil carbon sequestration (SCS) is one of the cheapest and technically least demanding carbon dioxide (CO 2) removal (CDR) or negative CO 2 emission technologies. For a realistic assessment of SCS, it is critical to evaluate how much carbon (C) can be stored in soil organic matter under actual agricultural practices. This includes typical crop rotations and fertilization strategies, depends on resources that are available (e.g. farmyard manure (FYM)) and are affordable for farmers. Furthermore, it is important to assess SCS based on given climatic and soil conditions. Here, we evaluate changes in soil C storage for Switzerland using data from eleven long-term field experiments on cropland and permanent grassland that include common local practices. At all sites, changes in soil organic carbon (SOC) stocks were measured in topsoil (∼0-0.2 m) in response to a total of 80 different treatments including different types of mineral or organic fertilization (e.g. FYM, slurry, peat, compost) or soil management (tillage vs. no-till). The treatments were applied to different, diverse crop rotations or grass mixtures that are representative for Switzerland. We found that topsoils lost C at an average rate of 0.29 Mg C ha−1 yr−1, although many of the investigated treatments were expected to lead to SOC increases. Based on a linear mixed effects model we showed that SOC change rates (ΔSOC) were driven by C inputs to soil (harvest residues and organic fertilizer), soil cover and initial SOC stocks. The type of land use or soil tillage had no significant effect. Our analysis suggests that current efforts to manage soils sustainably need to be intensified and complemented with further techniques if Switzerland wants to achieve the goal of the 4 per 1000 initiative. [ABSTRACT FROM AUTHOR]