Bob Rees

Scotland's Rural College | SRUC · Carbon crop and soils

Soybean-based rotations have long proven beneficial for increasing subsequent crop productivity and nitrogen (N) use efficiency (NUE) under low chemical N inputs. Despite this, importance of soil microbial community and enzymes in N cycling processes has not been well investigated. As well, optimal fertilizer-N that achieve high yield and NUE with...

The future of reactive nitrogen (N) for subtropical lowland rice to be characterised under diverse N-management to develop adequate sustainable practices. It is a challenge to increase the efficiency of N use in lowland rice, as N can be lost in various ways, e.g., through nitrous oxide (N2O) or dinitrogen (N2) emissions, ammonia (NH3) volatilizati...

CONTEXT The UK Climate Change Committee has recommended a 64% reduction in greenhouse gas emissions from the agriculture and land-use sector to meet the 2050 Net Zero target in the UK. However, it is unclear how this reduction can be achieved at a farm level. OBJECTIVE Using detailed real farm data and novel modelling approaches, we investigated t...

While wheat domestication is reported to influence the soil microbial community, few studies have evaluated the influence of cultivar replacement in modern breeding on both bacterial and fungal communities. Especially, few studies reported the bacterial-fungal interkingdom association by analysis of taxa co-occurrence or co-exclusion between differ...

Crop residues are important inputs of carbon (C) and nitrogen (N) to soils and thus directly and indirectly affect nitrous oxide (N2O) emissions. As the current inventory methodology considers N inputs by crop residues as the sole determining factor for N2O emissions, it fails to consider other underlying factors and processes. There is compelling...

Fossil fuel supplies are becoming scarce as a result of the growing world’s population. The increasing use of fossil fuels also pose a threat to ecosystem. Renewable energy sources should be revived in order to meet future energy demands, and minimize the adverse effects on environment. Biofuels and biochemicals can be made from a wide variety of l...

The vast majority of agri-food climate-based sustainability analyses use GWP100 as an impact assessment, usually in isolation; however, in recent years, discussions have criticised the ‘across-the-board’ application of GWP100 in Life Cycle Assessments (LCA), particularly of food systems which generate large amounts of methane (CH4) and considered w...

Context: The North China Plain (NCP) is China’s largest peanut producing area, where winter-wheat summerpeanut is an important double cropping system. Excessive nitrogen (N) applications are widely used leading to declined N use efficiency (NUE) and biological N fixation (BNF). However, the influence of excessive fertilizer N inputs on yield and BN...

Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However, agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely ackno...

Citation: Pashaei, R.; Sabaliauskaitė, V.; Suzdalev, S.; Balčiūnas, A.; Putna-Nimane, I.; Rees, R.M.; Dzingelevičienė, R. Assessing the Occurrence and Distribution of Microplastics in Surface Freshwater and Wastewaters of Latvia and Lithuania. Toxics 2023, 11, 292. Abstract: Microplastic concentrations in surface water and wastewater collected from...

Nitrous oxide (N2O) emissions occur as a consequence of the turnover of soil nitrogen (N), but gross N transformations and N2O production are often not studied in combination, so the relationships are poorly understood. Here, we quantified gross N transformations and the N2O production pathway of alkaline fluvo-aquic soils under different fertiliza...

The optimization of nitrogen (N) fertilization has become an ever more important global challenge with the aim of achieving high crop yields and high N use efficiency (NUE) with low environmental risks. The North China Plain (NCP) is China’s most important wheat (Triticum aestivum Linn.) production region, and a global hotspot for N fertilizer use....

Enhancing soil organic carbon (SOC) while concurrently reducing greenhouse gas (GHG) emissions and without compromising yield is a contemporary challenge for many agricultural sectors across the globe. In China, resolving this apparent contradiction is a key pillar of government policies aimed at constraining “Peak Carbon” and delivering “Carbon Ne...

Pharmaceuticals, microplastics, and oil spills are the most hazardous contaminants in aquatic environments. The COVID-19 pandemic enhanced pharmaceutical and microplastic contamination in aquatic environments. The present study aimed to investigate the prevalence of pharmaceutical and microplastic pollution on a global scale. This study assessed th...

Most nitrogen (N) lost to the environment from grazed grassland is produced as a result of N excreted by livestock, released in the form of nitrous oxide (N 2 O) emissions, nitrate leaching and ammonia volatilisation. In addition to the N fertiliser applied, excreta deposited by grazing livestock constitute a heterogeneous excess of N, creating spa...

Agriculture is committed to large reductions in greenhouse gas emissions in order to achieve policy commitments needed to deliver net zero targets. Accounting for and mitigating these GHG emissions is crucial in reducing the industry's overall carbon footprint. This is especially true for the dairy industry with the associated GHG emissions from th...

The effects of cattle farming systems and individual management practices on GHG emissions have been studied by applying a screening method on eight European countries totalizing 60 dairy farms and four seasonal measurements. This method is based on indoor and outdoor CO2, CH4, and N2O concentration measurements and on a questionnaire developed to...

List> ● Virtual joint centers on N agronomy were established between UK and China. ● Key themes were improving NUE for fertilizers, utilizing livestock manures, and soil health. ● Improved management practices and technologies were identified and assessed. ● Fertilizer emissions and improved manure management are key targets for mitigation. Tw...

Achieving a pathway for green development is a critically important challenge for agriculture in China and beyond. The current study evaluates the effects of a range of management interventions including planting, fertilizer nitrogen (N) rate optimization and increasing farm size to promote agricultural green development across the North China Plai...

Ammonia (NH3) and nitrous oxide (N2O) are two important air pollutants that have major impacts on climate change and biodiversity losses. Agriculture represents their largest source and effective mitigation measures of individual gases have been well studied. However, the interactions and trade-offs between NH3 and N2O emissions remain uncertain. H...

This position paper summarizes the current understanding of biological nitrification inhibition (BNI) to identify research needs for accelerating the development of BNI as a N2O mitigation strategy for grazed livestock systems. We propose that the initial research focus should be on the systematic screening of agronomically desirable plants for the...

Crop residues are of crucial importance to maintain or even increase soil carbon stocks and fertility, and thereby to address the global challenge of climate change mitigation. However, crop residues can also potentially stimulate emissions of the greenhouse gas nitrous oxide (N2O) from soils. A better understanding of how to mitigate N2O emissions...

The present review article will outline alternative uses of sugar beet pulp residue produced during the preparation of sugar from sugar beet. Traditionally, sugar beet pulp has been used as cattle fodder and was not considered to have much potential to be utilised in other competitive industries such as bio-energy, polymer composites, water purific...

The effects of pharmaceuticals on the nitrogen cycle in water and soil have recently become an increasingly important issue for environmental research. However, a few studies have investigated the direct effects of pharmaceuticals on the nitrogen cycle in water and soil. Pharmaceuticals can contribute to inhibition and stimulation of nitrogen cycle...

Nitrogen, being an integral part of proteins, DNA, RNA, chlorophyll, enzymes, and several other biomolecules, is vital for life on earth. About 50% of global food production is dependent on mineral N fertilizers; hence, it is essential for food security and economic development. Its excessive and inefficient use, however, results in several environ...

Quantifying the fate of nitrogen (N) fertilizer is essential to develop more sustainable agricultural N management practices. However, our understanding of N losses, particularly in low fertility soils remains incomplete. We evaluated the fate and N use efficiency of N fertilizer under different long-term fertilization regimes, i.e., no N; syntheti...

Crop residue incorporation is a common practice to increase or restore organic matter stocks in agricultural soils. However, this practice often increases emissions of the powerful greenhouse gas nitrous oxide (N2O). Previous meta-analyses have linked various biochemical properties of crop residue to N2O emissions, but the relationships between the...

Hot moments of nitrous oxide (N2O) emissions induced by interactions between weather and management make a major contribution to annual N2O budgets in agricultural soils. The causes of N2O production during hot moments are not well understood under field conditions, but emerging evidence suggests that short-term fluctuations in soil oxygen (O2) con...

The use of green manures contributes to sustainable soil and nutrient management in agriculture; however, the responses of soil microbial communities to different fertilization regimes at the regional scale are uncertain. A study was undertaken across multiple sites and years in Hunan, Jiangxi, Anhui, Henan, Hubei, and Fujian provinces of South Chi...

Well-managed legume-based food systems are uniquely positioned to curtail the existential challenge posed by climate change through the significant contribution that legumes can make toward limiting Green House Gas (GHG) emissions. This potential is enabled by the specific functional attributes offered only by legumes, which deliver multiple co-ben...

Life Cycle Assessment (LCA) of dairy herds of different genetic merit and diets. Differences in outcomes when the mass and economic allocation methods, and land use functional units were considered. This resulted in the performance ranking of the dairy systems changing, with larger footprints resulting from mass allocation.

Soil Quality or Soil Health are terms adopted by the scientific community as a metaphor for the effects of differing land management practices on the properties and functions of soil. Many other terms and metaphors are in use that defy neat quantification: human health, for example. Our challenge is to understand the importance of using such metaph...

Introducing legumes to crop rotations could contribute toward healthy and sustainable diet transitions, but the current evidence base is fragmented across studies that evaluate specific aspects of sustainability and nutrition in isolation. Few previous studies have accounted for interactions among crops, or the aggregate nutritional output of rotat...

Identification of yield deficits early in the growing season for cereal crops (e.g., Triticum aestivum) could help to identify more precise agronomic strategies for intervention to manage production. We investigated how effective crop canopy properties, including leaf area index (LAI), leaf chlorophyll content, and canopy height, are as predictors...

New agronomic and management approaches are urgently required to meet the challenges of improving resource use efficiency and crop yields in intensive agricultural systems. Here we report the fertilizer N use efficiency (FNUE), fate of fertilizer N and N budgets in newly designed cropping systems as compared with conventional winter wheat-summer ma...

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), w...

Carbon (C) quality and quantity and nitrogen (N) availability are known to play a crucial role in influencing diazotroph community structure in soils and they are commonly affected by crop residue management and fertilizer application. However, a full understanding of how C and N interactions contribute to shaping soil diazotroph communities remain...

Soil organic carbon (SOC) sequestration across agroecosystems worldwide can contribute to mitigate the effects of climate change by reducing levels of atmospheric CO2. Stabilisation of organic carbon (OC) in the fine soil fraction (< 20 µm) is considered an important long-term store of SOC, and the saturation deficit (difference between measured OC...

Enhanced efficiency nitrogen fertilizers (EENFs), including nitrification inhibitors (NIs) and slow-release fertilizer (SRF), are considered promising approaches for mitigating nitrous oxide (N2O) emissions while improving crop yield. This study investigated the combined application of EENFs with improved water and fertilizer management in an inten...

The present study determined the dynamic changes of enzyme activity and bacterial community in rice straw (RS) and milk vetch (MV) co-decomposing process. Results showed that mixing RS and MV promoted decomposition. The mixture enhanced β-glucosidase and β-cellobiohydrolase activities relative to its monospecific residue during the mid-late stage o...

Rice–rice–green manure rotations in south China are characterized by high efficiency and good environmental performance, and the application of green manure plays an important role in N management. Nitrification is a key process in N cycling and is highly correlated with the N utilization of crops and with leaching losses. As a potential N loss pat...

A potential strategy for mitigating nitrous oxide (N2O) emissions from permanent grasslands is the partial substitution of fertilizer nitrogen (Nfert) with symbiotically fixed nitrogen (Nsymb) from legumes. The input of Nsymb reduces the energy costs of producing fertilizer and provides a supply of nitrogen (N) for plants that is more synchronous t...

Purpose There is an imperative to accurately assess the environmental sustainability of crop system interventions in the context of food security and climate change. Previous studies have indicated that the incorporation of legumes into cereal rotations could reduce overall environmental burdens from cropping systems. However, most life cycle asses...

Nitrous oxide (N2O) emissions are highly episodic in response to nitrogen additions and changes in soil moisture. Automated gas sampling provides the necessary high temporal frequency to capture these emission events in real time, ensuring the development of accurate N2O inventories and effective mitigation strategies to reduce global warming. This...

Strategies for achieving environmental sustainability of protein production vary regionally. In this study, a framework was applied that would quantify a region-specific contribution to global protein supply with a special focus on protein quality i.e. essential amino acid composition. The framework was applied in Scotland and showed that high-qual...

Grasslands are an important component of the global carbon (C) cycle, with a strong potential for C sequestration. However, an improved capacity to quantify grassland C stocks and monitor their variation in space and time, particularly in response to management, is needed in order to conserve and enhance grassland C reservoirs. To meet this challen...

Managed grasslands are extensive terrestrial ecosystems that provide a range of services. In addition to supporting the world’s various livestock production systems they contain climatically significant amounts of carbon (C). Understanding and quantifying the C dynamics of managed grasslands is complicated yet crucial.This presentation describes a...

Soil organic carbon (SOC) sequestration across agroecosystems worldwide can contribute to mitigate the effects of climate change by reducing levels of atmospheric CO2. Mineral associated organic carbon (MAOC) is considered an important long-term store of SOC and the saturation deficit (difference between measured MAOC and estimated maximum MAOC) is...

Improved utilization of rice (Oryza sativa L.) straw and Chinese milk vetch (Astragalus sinicus L., vetch) has positive effects on rice production. So far, few studies have investigated the productivity of vetch under different residue management practices in double-rice cropping system. The effects of rice straw on the growth and nutrient accumula...

Leaf area index (LAI) estimates can inform decision-making in crop management. The European Space Agency’s Sentinel-2 satellite, with observations in the red-edge spectral region, can monitor crops globally at sub-field spatial resolutions (10–20 m). However, satellite LAI estimates require calibration with ground measurements. Calibration is chall...

A critical step in determining soil‐to‐atmosphere nitrous oxide (N2O) exchange using non‐steady‐state chambers is converting collected gas concentration versus time data to flux values using a flux calculation (FC) scheme. It is well documented that different FC schemes can produce different flux estimates for a given set of data. Available schemes...

Nitrous oxide (N2O) emission factors (EFs) were calculated from measurements of emissions from livestock manures applied to UK arable crops and grassland as part of a wider research programme to reduce uncertainty in the UK national agricultural N2O inventory and to enhance regional inventory reporting through increased understanding of processes a...

In sustainable agriculture crop residues management should consider the interactions between soil and residue properties which can affect the decomposition and global greenhouse gases (GHGs) emission. Through a laboratory experiment, we investigated the effect of the management (incorporation and surface placement) of wheat and faba bean residues o...

Process‐based models are useful for assessing the impact of changing management practices and climate on yields and greenhouse gas (GHG) emissions from agricultural systems such as grasslands. They can be used to construct national GHG inventories using a Tier 3 approach. However, accurate simulations of nitrous oxide (N2O) fluxes remain challengin...

Nitrous oxide emissions make up a significant part of agriculture’s contribution to greenhouse gas emissions in farming systems. There is an urgent need to identify new approaches to the mitigation of these emissions with new and emerging technologies offering potentially novel approaches. The need to reduce nitrous oxide emissions is particularly...

Cattle excreta deposited on grazed pastures are responsible for one fifth of the global anthropogenic nitrous oxide (N2O) emissions. One of the key nitrogen (N) sources is urine deposited from grazing animals, which contributes to very large N loadings within small areas. The main objective of this plot study was to establish whether the applicatio...