Soils have the potential to sequester and store significant amounts of carbon, contributing towards climate change mitigation. Soil carbon markets are emerging to pay farmers for management changes that absorb atmospheric carbon, governed by codes that ensure eligibility, additionality and permanence whilst protecting against leakage and reversals. This paper presents the first global comparative analysis of farmland soil carbon codes, providing new insights into the range of approaches governing this global marketplace. To do this, the paper developed an analytical framework for the systematic comparison of codes which was used to identify commonalities and differences in approaches, methods, administration, commercialisation and operations for 12 publicly available codes from around the world. Codes used a range of mechanisms to manage additionality, uncertainty and risks, baselines, measurement, reporting and verification, auditing, resale of carbon units, bundling and stacking, stakeholder engagement and market integrity. The paper concludes by discussing existing approaches and codes that could be adapted for use in the UK and evaluates the need for an over-arching standard for soil carbon codes in the UK and internationally, to which existing codes and other schemes already generating soil carbon credits could be assessed and benchmarked. Graphical Abstract

Field experiments were conducted from April 2015 to September 2016 at the Royal Agricultural University, UK to explore the impact of drilling pattern and species mixtures on weed growth and forage yield. The bi-crops of spring field bean (Vicia faba) cv. Maris Bead and Fuego with spring wheat (Triticum aestivum) cv. Paragon were evaluated at four drilling patterns in a randomized complete block design with four replicates and compared against their respective sole crops. Weed DM was 59% higher in the sole cropping systems than the bi-cropping systems. The sole cropping systems outperformed the bi-cropping systems for wheat (in 2016 only) and for bean forage DM yield. However, the bi-cropping systems produced higher total forage DM yields than sole cropping systems. Weed DM was higher in broadcast than in alternate rows systems. Bean forage DM was 74% higher in treatments with alternate rows than in the broadcast treatment. Wheat forage DM was not affected by the drilling patterns. Maris Bead had higher forage DM than Fuego (in 2016 only). It was concluded that bi-cropping can increase land productivity per unit area over sole cropping, whilst improving forage DM yield and providing low cost integrated weed management. Alternate row drilling can improve bi-cropping productivity over the broadcast practice. Abbreviations: LER - Land Equivalent Ratio

In organic production systems, penalties in cereal forage yield and low crude protein (CP) concentration are mainly caused by limited soil nitrogen (N) availability, which can be addressed by using cereal/grain legume bi-cropping systems. To confirm this, a bi-cropping experiment with spring wheat cv. Paragon and faba beans cvs. Fuego and Maris Bead were conducted in 2 years, using a randomised complete block design and sowing the crops in a replacement design series. In 2016, the wheat forage yield in sole cropping exceeded that in bi-cropping by 58%. In 2015, the wheat forage harvest index (HI) in bi-cropping was 14% higher than that in sole cropping, but in 2016 it was 7% lower. In both years, bi-cropping increased the CP and the grain N uptake in the wheat compared with that sole cropping, by 25% and 17%, respectively. The chlorophyll concentration index (CCI) in the wheat was 2.2 times higher in bi-cropping than in sole cropping and 34% higher in the alternate rows systems compared with the broadcast system. In 2015, the efficiency of N use (NLER) in bi-cropping was 50.7% higher than that in sole cropping. Alternate row bi-cropping improved NLER over broadcast by 37.9%. Faba bean rust disease was more severe in Fuego than in Maris Bead. In conclusion, bi-cropping in uniform alternate row spacing can improve productivity and nutritional quality of wheat forage, compared with sole cropping. The bi-crop bean cultivars Fuego and Maris Bead can, improve wheat straw CP and reduce rust disease severity, respectively.

Field experiments from October 2010 to August 2012 were conducted at the Royal Agricultural University's organic Harnhill Manor Farm near Cirencester, UK to explore tillage and legume undersowing effects on dry matter (DM) of broadleaf and grass weed infestation in organic winter and spring wheat. The experiments were designed using a randomized complete block with split plot arrangements. Tillage treatments involved conventional tillage (CT), low residue non-inversion tillage (LRNiT) and high residue non-inversion tillage (HRNiT) as main plots with undersowing white clover (WC), black medic (BM) or non-undersown (N_us) as subplots. In both cropping seasons, among tillage treatments, HRNiT had significantly higher total weed DM than CT or LRNiT. The mid-season assessments for weed species indicated HRNiT as having significantly higher grass weed DM than CT or LRNiT for both the wheat types. Broadleaf weed DM was significantly higher under CT than under LRNiT or HRNiT for winter wheat after GS61, whereas for spring wheat, broadleaf weed DM was significantly higher under CT than under HRNiT throughout the growing season. Undersowing had a significant effect only in spring wheat. Among undersowing treatments, WC had significantly lower total weed DM than BM. The broadleaf weed DM was significantly lower under WC than under BM or N_us. On the basis of these results, increasing the levels of tillage intensity with complete (0%) or minimal (30%) dispersion of soil cover appears to have decreased grass weed and total weed DM. Among undersowing treatments, WC seems to be a more reliable option than BM for spring wheat.

Chemical contamination of soils due to military activity has become an urgent global concern, particularly in conflict-affected regions such as Ukraine. This study presents a methodology for the rapid identification and assessment of contaminated agricultural land using an integrated approach that combines open-source intelligence, geographic information systems (GIS), and remote sensing. The authors focused on military debris as a primary vector of soil contamination (by Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and utilized publicly available digital resources to geolocate fragments of destroyed equipment across farmlands in Kharkiv Oblast. To compensate for the limited availability of high-resolution, time-specific satellite imagery, the study employed free datasets from the European Space Agency. The emergence of soil tracks and field roads was used as a proxy indicator of ground disturbance and potential chemical impact. These signals guided field sampling campaigns, during which soil samples were collected in proximity to identified debris and analyzed in laboratory conditions for chemical pollutants. Analytical studies revealed that heavy metals at the impact site exceed maximum permissible concentrations and exhibit an increasing trend, particularly for cadmium, copper, lead, and zinc, with exceedances reaching up to 62 times the regulatory limits. All findings were systematically documented using a custom-designed GIS database, allowing the classification of contamination severity and spatial distribution. The resulting maps aim to support local authorities and farmers in decision-making and prioritising remediation measures. This approach provides a replicable framework for post-conflict environmental assessment and contributes to strengthening soil resilience in war-affected agricultural zones.

Field trials were conducted from October 2010 to August 2012 on land registered with the Soil Association, UK, for organic production on the Royal Agricultural University's Harnhill Manor Farm near Cirencester, UK, to compare the effects of conventional tillage (CT) involving maximum soil manipulation and 0% soil surface plant residues against conservation tillage strategy including low residue non-inversion tillage (LRNiT) involving minimal soil movements and 30% soil surface plant residues and also high residue non-inversion tillage (HRNiT) with least soil movements and maximum (>50%) retention of soil surface plant residues on organic winter and spring wheat performance. Establishment, growth and the yield response of organic winter and spring wheat for the three cultivation systems were assessed to determine the influence of these tillage treatments. Results showed that the plant establishment and tillers were significantly higher in CT than LRNiT and HRNiT in both cropping seasons. The total number of shoots, ear numbers, dry matter yield, 1000 grain weights and grain yield were significantly higher in the CT and LRNiT than HRNiT for winter wheat, whilst they were significantly higher in the CT than LRNiT or HRNiT for spring wheat. Crop establishment, growth and yield response were influenced by the weather conditions beyond the tillage treatments for the spring wheat compared with the winter wheat. On the basis of these results, a better alternative for CT could be LRNiT for winter wheat. Conversely, for spring wheat, CT had better crop establishment, growth and yield than other forms of cultivation.