Search Results (637)

Rice is a priority crop in Cuba, and bacterial inoculants could help sustain productivity under reduced mineral fertilizer inputs. However, evidence describing the main stages involved in developing these bioproducts in the country remains limited. This study aimed to evaluate the suitability of a bacterial strain as the active microbial ingredient of a prototype rice inoculant for application under reduced nitrogen fertilization. Three promising bacterial strains were evaluated for their effects on rice yield components under field conditions at 60% of the recommended N fertilization rate. The taxonomic affiliation of the selected strain was assessed by multilocus phylogenetic analysis of the recA, rpoB, and glnII genes. The microbiological stability of inoculant formulations supplemented with CaCl₂ or sodium alginate was evaluated during storage at 4 °C and room temperature for 231 days. Inoculant production was scaled up to working volumes of 30 and 300 L, and the resulting prototype was evaluated in a second field experiment at 30% of the recommended N fertilization rate. Among the inoculated treatments, strain Rpd16 produced the highest numbers of panicles per square meter and total and filled grains per panicle. This strain was selected as the active microbial ingredient and was phylogenetically affiliated with the Agrobacterium pusense lineage. After 231 days at 4 °C, all formulations contained viable cell concentrations above 10⁸ CFU mL⁻¹. Compared with the uninoculated treatment receiving the same N fertilization rate, seed bio-priming with the prototype inoculant, provisionally named Azofert-A, was associated with higher tiller number (5.6%), plant height (10.7%), flag leaf length (9.9%), flag leaf dry weight (41.2%), and grain yield (20.4%), providing preliminary evidence of its agronomic potential under reduced N fertilization. This study integrates the main stages involved in developing a prototype bacterial inoculant for rice under Cuban conditions. Full article

Alpine agroecosystems face fertilizer-induced nutrient imbalances, including early nitrogen accumulation and late-season nitrate residue. While organic substitution is promoted as a sustainable practice, different substitution ratios may generate contrasting responses among nutrient availability, rhizosphere function, and SOC temporal stability. We established a field experiment in Tibetan highland barley with five treatments at equivalent N, P, and K rates: 100% NPK, 75% NPK + 25% cattle manure (CM), 50% NPK + 50% CM, 25% NPK + 75% CM, and 100% CM, plus an unfertilized control. Soils were sampled from 0–10 cm bulk soil, 10–20 cm bulk soil, and rhizosphere soil (0–10 cm) at booting, filling, and maturity. Stoichiometric ratios in the 0–10 cm layer changed mainly at maturity, whereas responses in the 10–20 cm layer and rhizosphere were weaker, indicating stage- and compartment-dependent treatment responses. The treatments showed three response modes: mineral fertilizer-dominated nutrient pulses, manure-dominated late-season nitrate residue and surface SOC stability, and partial substitution patterns with comparatively balanced nutrient responses. No single substitution ratio optimized all measured indicators. We therefore propose these modes as a framework for organizing treatment-specific nutrient responses and as candidates for further multi-year and multi-site testing, rather than as ready-to-apply fertilization prescriptions. Full article

In this work, LTA-type zeolite synthesized from kaolin was successfully modified via ion exchange with Zn²⁺ and Cu²⁺ ions followed by thermal treatment at 550 °C and 650 °C, leading to the formation of ZnO–CuO/zeolite composites (ZA550ZnCu and ZA650ZnCu). The structural and physicochemical properties of the catalysts were investigated using XRD, SEM, EDS, XPS, TEM, and zeta-potential analysis, confirming the successful incorporation of metal oxides while preserving the zeolitic framework, particularly at moderate calcination temperature. The catalytic performance of the prepared materials was evaluated in the heterogeneous catalytic ozonation of methylene blue (MB) in aqueous solution. The results demonstrated a strong synergistic effect between adsorption on the zeolite surface and ozone activation by ZnO and CuO species, leading to the generation of reactive oxygen species (•OH, O₂^•−) responsible for rapid methylene blue degradation. Among the tested catalysts, ZA550ZnCu exhibited superior activity compared to ZA650ZnCu, attributed to better dispersion of active phases and higher structural stability. Operational parameters, including pH, catalyst dosage, and initial MB concentration, significantly influenced the decolorization efficiency. Alkaline conditions (pH 11) strongly enhanced MB removal due to increased hydroxyl radical formation. Kinetic analysis showed that the degradation process follows a pseudo-first-order model, with higher rate constants in the presence of the catalyst. The electronic structure and local reactivity of methylene blue were investigated through DFT calculations and used to support the identification of potentially reactive sites and to propose plausible initial oxidation steps. The most reactive sites were identified as the dimethylamino nitrogen atoms, the central sulfur and nitrogen centers, and certain carbon atoms of the conjugated framework using frontier molecular orbital analysis, global reactivity descriptors, Hirshfeld charges, condensed Fukui functions, and the dual descriptor. These results are consistent with an initial N-demethylation, oxidative attack on the heterocyclic chromophore, C–N and C–S bond cleavage, hydroxylation, and aromatic-ring opening followed by mineralization. The study highlights the effectiveness of natural-source zeolite-based bimetallic catalysts as promising and sustainable materials for wastewater treatment via catalytic ozonation. Full article

Comparative evidence on the performance of urea and ammonium nitrate within integrated organo-mineral fertilization systems in acidic Luvisols under humid subtropical kiwifruit production remains limited. This study evaluated compost (30 t ha⁻¹ + P₁₅₀K₁₂₀) combined with urea or ammonium nitrate (0, 90, 120, and 150 kg N ha⁻¹) in non-degraded (ND) and moderately degraded (MD) acidic Luvisols during a three-year field experiment (2022–2024) arranged in a randomized complete block design (RCBD) with five fertilization treatments and four replications. Integrated fertilization significantly increased soil organic carbon (SOC), water-stable aggregates (WSA), and nutrient availability. Stepwise regression showed that NO₃⁻–N explained 72.9% of yield variation, while inclusion of P₂O₅, SOC, and K₂O increased explained variation to 93.8%. In ND soil, yield increased from 7004 to 20,139 kg ha⁻¹ under Base + N150, but the increase over Base + N120 was small and non-significant. Urea generally resulted in higher yield and greater NUE than ammonium nitrate, whereas effects on fruit quality were less consistent. The highest NUE occurred under Base + N120 with urea (0.99) and declined at higher N rates. Overall, Base + N120, particularly with urea, provided the most favorable balance between soil improvement, kiwifruit productivity, and nitrogen use efficiency. Full article

This study evaluated the interaction between energy supplementation and pre-grazing sward height on grazing behavior, nutrient intake, digestion, and nitrogen metabolism of cattle. Eight rumen-cannulated Nellore steers (24 mo; 343 ± 7.4 kg BW) grazed palisade grass (Urochloa brizantha cv. Marandu) managed at 25 or 35 cm pre-grazing height until a 15 cm post-grazing target. Treatments were arranged in a 2 × 2 factorial structure: two sward heights and two supplementation levels (mineral supplement only or ground corn at 0.6% BW, DM basis). The experiment was conducted as two replicated 4 × 4 Latin squares, with eight animals, four treatments, and four experimental periods. An interaction (p = 0.02) showed that supplementation reduced grazing time only at 35 cm. Steers grazing 25 cm swards spent less time grazing, rested more, took fewer steps, had higher bite rates, and consumed more forage (p < 0.05). Supplementation reduced forage intake but increased total DM intake, improved forage NDF and total DM digestibility, increased microbial protein synthesis, enhanced nitrogen retention, reduced ruminal ammonia-N, urinary N losses, and the acetate:propionate ratio (p ≤ 0.05). Steers grazing 25 cm swards also exhibited greater ruminal ammonia-N, urinary N excretion, and nitrogen retention. Managing pastures at 25 cm improved forage harvesting efficiency, while energy supplementation enhanced rumen fermentation, nitrogen utilization, and overall grazing efficiency, with potential environmental benefits. Full article

The black soil region of Northeast China is a major grain-producing area, where excessive nitrogen (N) fertilizer application is common in maize production. Optimizing N application rates and developing fertilization strategies that balance high yield, N-use efficiency, and environmental sustainability are therefore critical for green maize production. Based on a two-year stationary field experiment, this study systematically evaluated the effects of different N application rates on maize yield, N-use efficiency, N cycling and balance within the soil–crop system, and greenhouse gas emissions from farmland. Four treatments were established: no N control (N0, 0 kg N ha⁻¹), low N (N1, 120 kg N ha⁻¹), medium N (N2, 180 kg N ha⁻¹), and high N (N3, 240 kg N ha⁻¹). Among the N-fertilized treatments, N2 provided the best overall balance between maize yield, N-use efficiency, and environmental performance; N1 failed to achieve the high-yield target, whereas N3 increased potential environmental risks despite further yield gains. Compared with N1 and N3, N2 increased maize yield by 14.6% and 4.1%, N recovery efficiency (NRE) by 2.6% and 26.8%, and N agronomic efficiency (NAE) by 9.8% and 51.8%, respectively. Although N1 exhibited the highest partial factor productivity of applied N (PFPN), its PFPN was 27.2% and 68.7% higher than those of N2 and N3, respectively. Increasing N application significantly increased soil N residues and greenhouse gas emissions. After the 2025 autumn harvest, mineral N residues in the 0–80 cm soil profile were 82.7, 138.9, 172.5, and 207.9 kg N ha⁻¹ under N0, N1, N2, and N3, respectively, and declined with soil depth. Compared with N3, N2 reduced apparent N loss, soil mineral N residue, apparent N surplus, nitrous oxide (N₂O) and carbon dioxide (CO₂) efflux by 47.8%, 17.0%, 26.2%, 25.5%, and 23.1%, respectively. Collectively, these results provide a theoretical and technical basis for high-yield, high-efficiency, and sustainable maize production in the black soil region of Heilongjiang Province. Full article

Fruits play a vital role in global agriculture, yet the greenhouse gas (GHG) balance of orchard ecosystems remains poorly constrained due to the lack of integrated assessments of soil organic carbon (SOC) sequestration and non-CO₂ emissions. Given China’s substantial share of global fruit production, resolving this gap is critical for advancing low-carbon agricultural strategies. Here, we provide the first data-driven, system-level quantification of GHG balance in Chinese orchards by explicitly integrating SOC sequestration and nitrous oxide (N₂O) emissions within a unified analytical framework. A comprehensive database containing 170 observations of SOC change and 82 observations of N₂O emissions was compiled, and nonlinear relationships between environmental/management drivers and GHG fluxes were captured using random forest models, which showed robust predictive performance (R² = 0.71 and 0.66 for SOC and N₂O, respectively). Organic matter input and SOC content were identified as the most influential predictors for the SOC and N₂O models, respectively. Model simulations estimated that in 2021, Chinese orchards sequestered 4.53 Tg C in the standardized 0–20 cm soil layer, with an average sequestration rate of 0.34 t C ha⁻¹ yr⁻¹, while emitting 89.37 Gg N₂O, corresponding to an emission intensity of 6.76 kg N₂O ha⁻¹. The net GHG balance of Chinese orchards was estimated at 7.78 Tg CO₂-eq, with stone fruit and citrus orchards identified as the main contributors to net positive GHG emissions. Scenario analysis revealed that replacing 20% of mineral nitrogen fertilizer with organic fertilizer could shift the net GHG balance from a source to a sink (–1.03 Tg CO₂-eq), while a 50% substitution scenario could achieve a net carbon sink of up to –14.37 Tg CO₂-eq. These findings redefine the relative roles of SOC sequestration and N₂O mitigation in perennial systems and highlight organic matter management as a pivotal pathway toward carbon neutrality in orchard agriculture. Full article

Global modeling of soil net nitrogen mineralization rates (Nmin) is challenging due to the absence of an integrated system that accurately quantifies their magnitude and spatial distribution. This study addresses this gap by analyzing the spatial variability of Nmin using a comprehensive dataset of 1347 Nmin measurements from 291 studies, combined with high-resolution climate and soil data. Our global maps reveal average Nmin rates of 1.68, 5.17, and 1.71 mg N kg⁻¹ day⁻¹ for cropland, forest, and grassland soils, respectively. Integrating projected climate scenarios, we also explore potential shifts in Nmin patterns under future varying environmental conditions. Key factors influencing Nmin include mean annual precipitation, soil pH, total nitrogen, carbon-to-nitrogen ratio, and microbial biomass nitrogen, with microbial biomass nitrogen playing a particularly significant role. These findings underscore the potential of global-scale Nmin modeling to support informed decision-making, facilitating optimal fertilizer use and management practices that promote soil health and sustained productivity. Full article

Organic systems rely on nitrogen (N) supplied through organic sources that must be mineralized before uptake. The timing and rate of N release are often difficult to synchronize with crop demand, especially for short-duration crops like bok choy. We evaluated the response of bok choy to N rates in Florida sandy soils using five N rates (0, 56, 112, 168, and 224 kg N ha⁻¹) in a randomized complete block design. Yield, N uptake, apparent N recovery, N balances, and in-season crop indicators (SPAD, sap nitrate) were measured across three years. N applications significantly increased yield in 2023 and 2025 (with no significant differences in yield above 112 kg N ha⁻¹), but not in 2024, highlighting the variability in crop response, likely due to environmental conditions. Higher N rates increased plant N accumulation but reduced N recovery and increased N surpluses, indicating a greater potential for N losses. SPAD and sap nitrate measurements were positively related to yield and could be used as rapid indicators of in-season crop N status, with SPAD having the advantage of being non-destructive. Overall, these findings help to optimize N management to better match crop demand in organic leafy green production systems, improving productivity while minimizing environmental costs. Full article

An important component of sustainable agriculture is the development of strategies that reduce the use of mineral fertilizers while maintaining high crop productivity. One promising approach is the application of plant growth-promoting bacteria (PGPB), which may support plant development and improve nutrient use efficiency. A field experiment with winter wheat was conducted in south-western Poland during two growing seasons, 2023–2024 and 2024–2025, to evaluate the effect of inoculation with Priestia sp. KR219 under different nitrogen fertilization regimes. The experiment included three levels of nitrogen: 70, 91, and 130 kg N ha⁻¹ (54%, 70%, and 100% of the full spring nitrogen fertilization rate) with and without bacterial application. Soil chemical and biological properties, photosynthetic pigment content, plant morphological traits, grain yield, as well as grain chemical composition and amino acid profile were evaluated. The inoculated treatments showed higher soil dehydrogenase activity in the second growing season and higher contents of selected photosynthetic pigments, particularly chlorophyll a, under reduced nitrogen fertilization. Bacterial inoculation was also associated with numerical increases in grain yield in most treatment combinations, although these differences were not statistically significant. Differences among treatment combinations involving nitrogen fertilization were more pronounced for grain chemical composition and amino acid profile than differences between inoculated and non-inoculated treatments at the same nitrogen level, with the full nitrogen rate generally resulting in the highest protein content and higher contents of several essential and non-essential amino acids. Overall, the responses observed following Priestia sp. KR219 inoculation included changes in selected soil and physiological parameters, while responses in grain yield and quality varied between growing seasons. Further studies under diverse environmental conditions are required to determine its agronomic potential. Full article

Improving nitrogen (N) use efficiency while reducing environmental losses remains a major challenge in crop production. Zeolites, due to their high cation exchange capacity, have been proposed as carriers for ammonium-based fertilizers, potentially modifying N retention and release in soils. However, the effect of varying ammonium-loaded zeolite application rates, while supplying equal amounts of zeolite-derived nitrogen, on soil N dynamics is not well understood. In this study, a greenhouse pot experiment with spring wheat was conducted to investigate the effects of ammonium-loaded zeolite applied at different rates (30, 36, 42 and 48 g pot⁻¹; Zeo30–Zeo48), each supplying 700 mg zeolite-derived N pot⁻¹ in addition to a basal ammonium sulfate application, on N leaching, plant growth and N recovery. Nitrogen leaching was strongly influenced by the amount of zeolite applied. Lower application rates (Zeo30 and Zeo36) resulted in higher nitrate and ammonium leaching losses, particularly during early growth stages, whereas higher application rates (Zeo42 and Zeo48) significantly reduced total N losses. Despite these differences, total aboveground plant N uptake and N recovery (68–71%) did not differ significantly among treatments. However, increasing zeolite application rates tended to improve grain and straw yields and influenced nitrogen partitioning within the plant, as reflected by differences in grain-to-straw N ratios. Residual soil ammonium decreased with increasing zeolite application rate, indicating differences in ammonium retention and release among zeolite treatments. Overall, the results indicate that under the conditions of this greenhouse pot experiment, the amount of zeolite carrier material influenced nitrogen retention patterns and leaching losses. Together, these findings suggest that the effectiveness of ammonium-loaded zeolite depends on the balance between ammonium loading and zeolite mass, although the absence of an equivalent mineral-N control limits the separation of zeolite effects from effects of total N supply. Full article

Integrated organic–inorganic soil amendments have been proposed as a strategy to improve soil fertility while maintaining crop productivity, yet their effects on seasonal nutrient dynamics and chile (Capsicum annuum L.) performance remain unclear. Two chile cultivars (‘NuMex Odyssey’, ‘NuMex Sandia Select’) were tested to evaluate the effects of organic and inorganic amendments on soil nutrient dynamics, chile vegetative growth, and fruit yield and dimensions across key growth stages. The amendments included an unamended control (CK), half-rate (CF) and full-rate (CFCF) chemical fertilizer, and three integrated amendments consisting of composted manure–biochar blend (CFMB), composted manure (CFM), and pea residues (CFP) applied at a 1:1 ratio with chemical fertilizer on a plant-available nitrogen (PAN) basis. CFCF produced the highest early-season availability of N, P, and K, whereas CFP and CFM provided a more gradual nutrient release pattern, maintaining PAN comparable to CFCF through flowering and sustaining P and K availability through harvest. ‘NuMex Sandia Select’ exhibited greater yield responsiveness to soil amendments, while ‘NuMex Odyssey’ produced fewer but higher dimension fruits. CFP maintained fruit yields comparable to CFCF while producing lower vegetative biomass. Correlation analyses showed that significant nutrient–plant relationships were concentrated at harvest, with soil NO₃⁻-N associated with fruit number and NH₄⁺-N with fruit dimensions. These findings indicate that partial substitution of mineral fertilizer with organic amendments may sustain nutrient availability and chile productivity while providing a more gradual nutrient release throughout the growing season. Full article

Erosion affects soil health, nutrient cycling, and ecosystem productivity. Although the physical manifestations of erosion are well known, further research is needed to understand how its biochemical consequences interact to limit soil functionality and plant productivity. We investigated this in erosion-threatened chernozem soils of the Czech Republic using a pot experiment and a synthetic soil quality index (SQI) with Festuca rubra under varying nitrogen fertilization rates (0–250 kg N ha⁻¹). Erosion significantly degraded soil biochemical quality, reducing soil organic carbon content from 1.40% to 0.78% (p < 0.001) and total nitrogen content from 0.15% to 0.13%. Microbial functions were severely disrupted, as evidenced by a 57% decrease in dehydrogenase activity (p < 0.001) and a 35% decrease in urease activity (p < 0.001). From a production perspective, erosion significantly reduced plant biomass (p = 0.004) across all treatment groups. While nitrogen fertilization significantly stimulated biomass production up to an intermediate rate of 50 kg N ha⁻¹ (p < 0.001), higher application rates led to a strict yield plateau. These results demonstrate that erosion-induced deterioration of the soil’s biochemical complex acts as a primary constraint on crop growth, which cannot be compensated for by increasing doses of mineral nitrogen fertilizer. Full article

To verify the growth-promoting effects of Bacillus amyloliquefaciens on silage maize (Zea mays L.), optimize its application dosage, and elucidate rhizosphere microecological responses, this study executed field experiments in both conventional and saline-alkali soils. We comprehensively assessed how varying biofertilizer dosages (0, 300, and 600 kg ha⁻¹) influenced crop phenotypes, soil physical and chemical attributes, and rhizosphere microbial communities. Results demonstrated that applying B. amyloliquefaciens substantially enhanced biomass and crude protein accumulation in silage maize, without compromising its ideal carbohydrate profile and fermentation characteristics. The observed growth stimulation was likely linked to efficient mobilization of native soil nutrients. Following biofertilizer application, significant surges in available potassium, available phosphorus, and inorganic nitrogen were recorded at both locations, coupled with successful pH buffering in the saline-alkali plots. Microbial analysis indicated a notable expansion of the copiotrophic Proteobacteria phylum, with the bio-inoculant displaying dose-dependent shifts. Specifically, Xanthobacteraceae was heavily recruited in standard agricultural soils to hasten nutrient mineralization, while stress-tolerant bacterial groups like Nitrosomonadaceae were stimulated under saline-alkali conditions. Furthermore, comprehensive phenotypic and nutritional evaluations demonstrated that, among the tested doses, an application rate of 300 kg ha⁻¹ effectively optimizes crop performance. Higher doses do not yield proportional biological benefits, likely due to the carrying capacity limits of the rhizosphere microecology. In summary, B. amyloliquefaciens can support high-yield and high-quality silage maize production by activating soil nutrients and remodeling the core rhizosphere microbiome in a habitat-specific manner. Among the tested doses, 300 kg ha⁻¹ showed the best performance, but further studies with lower doses and longer durations are needed to determine the true optimal application rate and to assess its economic and environmental sustainability. Full article

To address the issues of low mechanical rock-breaking efficiency and severe tool wear in hard rock, this study investigates the mechanical deterioration and abrasivity response of granite subjected to rapid flame-jet heating followed by liquid nitrogen cooling, with rock pre-treatment in thermal-assisted rock breaking as the background. Fine-grained granite specimens were heated by flame jet to temperatures ranging between 200 and 600 °C and then subjected to natural cooling or sudden liquid nitrogen cooling. Physical parameter measurements, uniaxial compression tests, Brazilian splitting tests, and CERCHAR abrasivity tests were conducted using national standards to investigate the evolution of thermal damage and the effect of cooling path. The results show that the damage degree of granite continuously increases with increasing heating temperature, and the damage induced by liquid nitrogen cooling is greater than that induced by natural cooling. Visible cracks begin to appear on the specimen surface after 300 °C, while crack propagation and structural deterioration become more pronounced at 500–600 °C. Among the measured physical parameters, P-wave velocity is the most sensitive to damage, with a maximum attenuation rate of 60.6%. The deterioration of the physical structure further reduces the load-bearing capacity and deformation performance of granite. After liquid nitrogen cooling at 600 °C, the uniaxial compressive strength, tensile strength, and elastic modulus decrease to 92.6 MPa, 1.42 MPa, and 17.4 GPa, respectively, corresponding to reductions of 56.0%, 87.7%, and 69.3% compared with the untreated specimens. The tensile strength is the most sensitive mechanical parameter to liquid nitrogen cooling. The CERCHAR abrasivity index decreases from 3.81 to 2.12. Liquid nitrogen cooling advances the transition of granite abrasivity from high to medium from 400–500 °C to 300–400 °C. The integrated analysis indicates that the non-uniform temperature field generated by rapid flame-jet heating and the differences in thermal deformation among minerals promote the initiation of initial cracks. The additional shrinkage stress induced by liquid nitrogen cooling further drives crack propagation and coalescence, eventually leading to the coupled reduction in the strength, stiffness, and abrasivity of granite. The results provide laboratory-scale evidence for evaluating granite pre-treatment under rapid flame-jet heating and liquid nitrogen cooling and offer a reference for thermal-assisted mechanical rock breaking and standardized abrasivity reduction. However, the relationship between CAI and actual tool wear still requires further verification. Full article