Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from -9 to +26 °C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed.

Ecosystems provide multiple services to humans. However, agricultural systems are usually evaluated on their productivity and economic performance, and a systematic and quantitative assessment of the multifunctionality of agroecosystems including environmental services is missing. Using a long-term farming system experiment, we evaluated and compared the agronomic, economic, and ecological performance of the most widespread arable cropping systems in Europe: organic, conservation, and conventional agriculture. We analyzed 43 agroecosystem properties and determined overall agroecosystem multifunctionality. We show that organic and conservation agriculture promoted ecosystem multifunctionality, especially by enhancing regulating and supporting services, including biodiversity preservation, soil and water quality, and climate mitigation. In contrast, conventional cropping showed reduced multifunctionality but delivered highest yield. Organic production resulted in higher economic performance, thanks to higher product prices and additional support payments. Our results demonstrate that different cropping systems provide opposing services, enforcing the productivity-environmental protection dilemma for agroecosystem functioning.

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The impact of different arable farming practices on soil erosion is only partly resolved, and the effect of conservation tillage practices in organic agriculture on sediment loss has rarely been tested in the field. This study investigated rainfall-induced interrill sediment loss in a long-term replicated arable farming system and tillage experiment (the FAST trial) with four different cropping systems: (1) organic farming with intensive tillage, (2) organic farming with reduced tillage, (3) conventional farming with intensive tillage, and (4) conventional farming with no tillage. Measurements were carried out under simulated heavy rainfall events with runoff plots in 2014 (fallow land after winter wheat) and 2017 (during maize growth). Organic farming decreased mean sediment delivery compared to conventional farming by 30% (0.54 t ha −1 h −1). This study demonstrated that reduced tillage in organic farming decreased sediment delivery (0.73 t ha −1 h −1) compared to intensively tilled organic plots (1.87 t ha −1 h −1) by 61%. Nevertheless, the combination of conventional farming and no tillage showed the lowest sediment delivery (0.24 t ha −1 h −1), whereas intensively tilled conventional plots revealed the highest delivery (3.46 t ha −1 h −1). Erosion rates were much higher in June during maize growth (2.92 t ha −1 h −1) compared to those of fallow land after winter wheat (0.23 t ha −1 h −1). Soil surface cover and soil organic matter were the best predictors for reduced sediment delivery, and living plant cover from weeds in reduced organic treatments appeared to protect soil surfaces better than plant residues in conventional, no-tillage plots. Soil erosion rates were significantly lower when soil cover was above 30%. In conclusion, this study demonstrates that both organic farming and conservation agriculture reduce soil losses and showed for the first time that reduced tillage practices are a major improvement in organic farming when it comes to soil erosion control.

Soil erosion is a key threat to many ecosystems, especially in subtropical China where high erosion rates occur. While the mechanisms that induce soil erosion on agricultural land are well understood, soil erosion processes in forests have rarely been studied. Throughfall kinetic energy (TKE) is influenced in manifold ways and often determined by the tree’s leaf and architectural traits. We investigated the role of species identity in mono-specific stands on TKE by asking to what extent TKE is species-specific and which leaf and architectural traits account for variation in TKE. We measured TKE of 11 different tree species planted in monocultures in a biodiversity-ecosystem-functioning experiment in subtropical China, using sand-filled splash cups during five natural rainfall events in summer 2013. In addition, 14 leaf and tree architectural traits were measured and linked to TKE. Our results showed that TKE was highly species-specific. Highest TKE was found below Choerospondias axillaris and Sapindus saponaria, while Schima superba showed lowest TKE. These species-specific effects were mediated by leaf habit, leaf area (LA), leaf pinnation, leaf margin, stem diameter at ground level (GD), crown base height (CBH), tree height, number of branches and leaf area index (LAI) as biotic factors and throughfall as abiotic factor. Among these, leaf habit, tree height and LA showed the highest effect sizes on TKE and can be considered as major drivers of TKE. TKE was positively influenced by LA, GD, CBH, tree height, LAI, and throughfall amount while it was negatively influenced by the number of branches. TKE was lower in evergreen, simple leaved and dentate leaved than in deciduous, pinnated or entire leaved species. Our results clearly showed that soil erosion in forest plantations can be mitigated by the appropriate choice of tree species.