ABSTRACT Selenium (Se) is essential for human health, and agronomic biofortification of food crops offers a direct strategy to address global dietary Se deficiency. Plants exhibit pronounced interspecific variation in Se sensitivity, yet whether this differential susceptibility enables concurrent crop biofortification and weed suppression remains unexplored. Garlic (Allium sativum L.) possesses exceptional Se-accumulating capacity due to its sulfur-rich metabolism, whereas Veronica didyma—a pernicious speedwell that heavily infests garlic fields and requires repeated herbicide sprayings – lacks this specialization. Here we demonstrate that foliar Na2SeO3 spraying elicits a sharply divergent hormetic response between these species. At 225 g hm−2, Se significantly promoted garlic growth. Chlorophyll increased 24.01%, photosynthetic parameters (Pn, Tr, and Gs) enhanced by 29.45–39.77%, and Ci reduced by 23.10%. Antioxidant enzyme activities rose, proteins, sugars, amino acids, and glutathione were markedly elevated, while malondialdehyde (MDA) and proline decreased by 21.08% and 25.94%. In contrast, the same treatment induced phytotoxicity in the co-cultivated speedwell. Biomass was inhibited, chlorophyll declined by 20.24%, and photosynthetic parameters (Pn, Tr, and Gs) significantly decreased, while Ci significantly increased. Antioxidant enzymes were suppressed, proline and MDA increased by 20.46% and 21.86%. The tissue Se concentration in speedwell and garlic increased significantly with increasing foliar spray concentration. Higher concentrations (450–675 g hm−2) could induce oxidative stress responses in both plants. Our findings establish a discrete Se spraying window where the element simultaneously acts as a biofortifying biostimulant for garlic and a selective phytotoxic agent against speedwell, eliminating separate herbicide applications and transforming Se fertilization into an integrated crop management tool.

ABSTRACT Nitrogen (N) management in Ethiopian lowland rice systems relies on outdated, suboptimal practices, leading to low N use efficiency (NUE) and significant environmental losses. A two-year field experiment was conducted across four sites to evaluate the effects of N application rate and timing on grain yield, NUE, chlorophyll content (SPAD), and economic returns. The study employed a factorial randomized complete block design with three N rates (92, 138, and 184 kg N ha−1) and five application schedules (two-, three-, and four-split regimes). Results showed that both N rate and timing significantly influenced productivity and efficiency, though their interaction was not significant, suggesting that optimal timing remains consistent regardless of the total N dose. The three-split strategy (1/3 basal +1/3 mid-tillering +1/3 panicle initiation) proved superior, achieving a maximum grain yield of 7.70 t ha−1 and biomass of 16.96 t ha−1 at the 184 kg N ha−1 rate. This strategy optimized sink-source dynamics and maintained higher SPAD values (36.3), while simultaneously enhancing agronomic N use efficiency by 20–30% compared to other regimes. Economic analysis revealed that while 184 kg N ha−1 yielded the highest net return (238,336 ETB ha−1), the 138 kg N ha−1 rate provided the greatest investment efficiency, with a Value-Cost Ratio of 8.7 and a Marginal Rate of Return of 765.8%. These findings demonstrate that synchronizing N supply with key growth stages maximizes both biological potential and economic stability. We recommend 184 kg N ha−1 in three splits for high-input systems, while 138 kg N ha−1 in three splits is the optimal recommendation for resource-constrained farmers to maximize profitability and minimize environmental risks. Future research should focus on sensor-guided and model-based precision N management to further refine these recommendations for Ethiopia’s lowland rice systems.

ABSTRACT Inland wetlands offer numerous ecosystem services, including water filtration and storage, habitat for migratory birds, and support for diverse wildlife. In the semiarid landscapes of Mongolia, isolated patches of permafrost beneath these wetlands play a crucial role in maintaining these services. They also serve as essential water sources and forage pastures for livestock and agricultural activities. This study examines the effects of anthropogenic activities (mainly livestock grazing) on vegetation and soil properties in permafrost-affected wetlands and adjacent upland grasslands in the Khurkh River Valley. The composition and coverage of vegetation at 35 study sites were assessed through triplicate quadrat harvests, clipped at the soil surface. Pasture degradation was classified as non-degraded, slightly degraded, or moderately degraded based on the proportion of deterioration indicator species. To analyze spatial variability in soil properties, samples were collected from 43 cores (0–30 cm) and analyzed for physicochemical characteristics. The effects of pasture degradation on surface soils varied by reference soil groups, including Phaeozems, Kastanozems, Chernozems, Cryosols, and Histosols. In Phaeozems and Kastanozems, livestock trampling and compaction in moderately degraded pastures tended to decrease water infiltration and accelerate organic matter loss, although these effects were not statistically significant. As a result, soil carbon and nitrogen pools may decrease as degradation intensifies. By contrast, Cryosols underlain by permafrost experienced strong freeze–thaw processes, which promote organic matter accumulation even in pasture-degraded conditions. These differing responses among soil groups highlighted the importance of soil-specific management strategies, including pasture rotation regimes of different durations, to conserve the valuable wetland and grassland ecosystems.

ABSTRACT Risks of food insecurity are being aggravated by degradation of soil and environment, and the attendant closure of the Strait of Hormuz, which is a critical shipping route for the transport of fertilizers, food, and energy. Use of modern war also pollutes soil, water, and air, and destroys the agricultural infrastructure. As much as 20% to 45% of critical food inputs and 25% of global fertilizers are dependent on this route. Thus, the number of food-insecure people may increase by an additional 45 million. Gulf countries import 70% of their food through this checkpoint. Furthermore, a complete closure of this shipping route would need to replace 87 M kg of food per day to minimize the risks of food shortage in Gulf Countries. Hunger and desperateness may aggravate risks of political instability because of an increase in human miseries and desperateness. War has 3 parties: two are those which are at war with one another. The third party is the land on which or about which they fight. While different nations or organizations support one party or the other, but no one cares about the land/soil which has been cratered, compacted, polluted, contaminated, and rendered unfit for food production for decades or generations. Thus, the best strategy would be to minimize the risks of such events through political dialogue and empowerment of the United Nations and other organizations to encourage and promote peace and stability. There must also be a soil/environment restoration and rehabilitation plan agreed upon by both parties involved. War and its consequences, human-made tragedies, have dire long-term effects. Destroying soil and polluting environments are crime against nature, which are neither bearable nor acceptable. These acts of violence against nature must be forbidden.

ABSTRACT Selenium (Se) is an essential micronutrient for human and animal health; however, its soil concentrations exhibit significant variability due to environmental and land-use influences. Thus, this study examined selenium distribution, fractionation, and bioavailability across 84 vegetable cultivation sites in four provinces of western central Thailand, sampling soils at three depth intervals and the associated edible vegetables. Soil physicochemical properties were determined, and the Se fractions were assessed using a five-step sequential extraction and flow hydride generation atomic absorption spectrophotometry. Total Se in edible plant parts was also analyzed. The results showed that parent material and soil properties, particularly organic matter content, mineral composition, and texture, play key roles in controlling Se fractionation. Soils rich in organic matter and Fe–Mn oxides tended to retain Se in less mobile forms, whereas coarse-textured soils with low organic matter exhibited higher proportions of relatively labile Se. With increasing soil depth, the concentrations of labile Se fractions decreased, while the proportion of residual Se increased. Among the studied crops, Chinese cabbage and other Brassicaceae species showed higher Se accumulation, whereas Solanaceae crops (chili and tomato) contained markedly lower concentrations. A significant relationship was observed between plant Se concentrations and the relatively labile soil Se fractions, indicating that bioavailable Se, rather than total Se, is a more reliable predictor of plant uptake. These findings highlight the importance of site-specific Se management strategies to improve crop nutritional quality and support sustainable agricultural practices in the region.

ABSTRACT Associations between soybean yield and soil chemical properties in Japan have largely been examined using regional-scale surveys. However, none of the previous studies in Japan modeled the strong regional heterogeneity inherent in these datasets. This study aims to reanalyze the cross-regional dataset of Takamoto, Takahashi, and Nira (2020) using a linear mixed-effects model (LMM) to identify soil chemical properties associated with soybean yield after accounting for hierarchical structure (random intercepts for prefecture and site nested within prefecture). The dataset comprised 214 sites across 16 prefectures in Japan and included soybean yield and six soil variables: total N, available P, soil pH, and exchangeable K, Ca, and Mg. Fixed effects initially included all variables and all their first-order interactions, and an exhaustive all-subsets search then selected the final fixed effect set. Random effects explained approximately 60% of the variance in yield, whereas the selected fixed effects explained less than 5%. The selected LMM retained only two fixed effects: exchangeable Ca (β = +0.24, p < 0.001) and exchangeable Mg (β = −0.22, p < 0.001). These coefficients were significantly larger in the high-yield group than in the low-yield group (groups defined by prefectural mean yields). Although soil chemical properties contribute little to soybean yield at a national scale, exchangeable Ca and Mg represent broadly applicable factors for yield improvement and may help to overcome the long-term stagnation in soybean yields in Japan.

ABSTRACT Denitrification is a key process in the nitrogen cycle that reduces nitrate and nitrite to nitric oxide, nitrous oxide (N2O), and dinitrogen gas. Denitrification is also a key reaction involved in nitrogen loss from agricultural soils and emission of the greenhouse gas N2O. In recent years, significant findings have been reported regarding the diversity, function, and ecology of the microorganisms responsible for denitrification. This review provides an overview of the ecological and functional characteristics of various microorganisms involved in soil denitrification, as well as technologies for controlling denitrification. Genomic and metagenomic analyses of the denitrification enzymes nitrite reductase (Nir) and nitric oxide reductase (Nor) in soil revealed that denitrifying bacteria exhibit niche partitioning based on soil properties. In addition to canonical denitrifying bacteria, non-denitrifying N2O-reducing bacteria exist in the soil, and three clades of the nitrous oxide reductase gene (nosZ) have been identified. Furthermore, many denitrifying bacteria possess only partial sets of denitrification enzymes, suggesting that denitrification is driven by modular processes in the environment. Meanwhile, fungi have been known to be capable of denitrification. Effective primers were designed to detect the fungal denitrification enzyme genes NirK and cytochrome P450 nitric oxide reductase (P450nor). Metagenomic and isotopomer analyses with these primers demonstrated that fungal denitrification functioned as a major pathway in some soil environments. Denitrifying activity has also been found among microorganisms involved in the carbon, sulfur, and iron cycles, indicating the coupling of nitrogen and other biogeochemical cycles. Although actinomycetes and archaea have been shown to possess denitrification metabolic pathways, further investigation is needed to determine their actual contributions to soil denitrification capacity. The development of diverse technologies for controlling denitrification has been promoted. Approaches utilizing N2O-reducing bacteria and soybean rhizobia with enhanced Nos activity have successfully mitigated N2O at the field level. Furthermore, N2O mitigation has been demonstrated by improving soil physical properties with biochar. The use of chemicals to inhibit denitrification specifically has been demonstrated at the laboratory level.

ABSTRACT The history of pedology in Japan is younger than that in Europe, the United States, and Russia. In late 19th century, the Meiji government initiated national soil surveys under Max Fesca, producing Agronomic Maps for Japan. 1930s onward, pedological studies began, focusing on soil profiles and genesis. As a result, in volcanic ash soils (Andosols), allophane was discovered in 1913 and imogolite in 1962, respectively, and Japanese pedologist have made significant contributions to increasing global recognition of Andosols. Regarding Red-Yellow soils, the theory that Red-Yellow soils are zonal soils has been questioned, and it has been revealed that they are paleosols formed during a warm geological period. In the case of paddy soils, they are formed under alternating redox conditions due to artificial flooding and drainage management practiced during long-term rice cultivation, which in some cases exceeds 1500 years. In Japan, classification based on unique redox-driven soil formation so called the concept of ‘Aquarization’ was introduced. Post-World War II, National projects for cultivated and forest lands (1947–1982) produced detailed soil maps. Also, National Land Survey (1951–2006) integrated cultivated and forest soils for the first time. Regarding Classification Systems, Unified Soil Classification System for Japan was proposed in 1986, revised in 2003, and integrated into the latest version in 2017. On the other hand, Comprehensive Soil Classification System (2011) are harmonized cultivated and forest soil classification systems. In addition, the Soils of Japan (2021) consolidates current knowledge and international comparisons. Japanese pedology evolved from practical land management to advanced science, influencing global soil taxonomy, especially through research on volcanic ash and paddy soils.

ABSTRACT Soil fertility drives crop productivity, with integrated organic-chemical fertilization effectively boosts soil organic carbon (SOC), nutrient availability, and microbial activity, especially in low-fertility soils like Vertisol in the Huaibei Plain. However, the role of labile organic carbon (LOC) fractions in driving yield under diversified fertilization remains unclear. Through a long-term field experiment comparing no fertilizer (NF), chemical fertilizer alone (CF), chemical fertilizer with low or high straw, pig or cattle manure (CFLS, CFHS, CFP, CFC), we demonstrate that organic-chemical treatments significantly increased SOC, LOC, carbon pool management index (CPMI), and nutrients versus NF, with cattle manure (CFC) exhibiting the strongest improvement. Partial least squares path model (PLS-PM) revealed that LOC strongly influenced soil nutrients and microbial traits, while soil nutrients were the strongest predictor of crop yield, explaining 73% of yield variance. Microbial traits had a marginally negative effect on yield, suggesting potential nutrient competition. Therefore, integrating cattle manure with chemical fertilizers optimizes soil quality and crop yield by enhancing LOC-mediated nutrient availability, demonstrating superior efficacy among organic amendments.