Search Results (16)

Soil erosion on sloping farmland impairs cultivated land quality, food security, and watershed ecological sustainability across China. Vegetation serves as a core erosion buffer, yet how nitrogen–phosphorus (N-P) stoichiometry shapes coordinated maize growth to regulate multi-stage runoff–sediment coupling remains underexplored. This study reveals the complete mechanistic chain linking N-P ratios, crop growth synchrony, and hillslope erosion dynamics via 60 mm·h⁻¹ simulated rainfall experiments at three key summer maize stages, with six N/P gradients (0–3.75) in an eastern China brown soil zone. An N/P ratio of 2 optimized maize biomass, canopy cover, and root soil-binding capacity, yielding the lowest sediment concentrations. Excess nitrogen (N/P = 3.75) triggered spindly, mechanically weak maize growth, elevating runoff volume and sustaining high-variability sediment transport. High-frequency runoff–sediment signals maintained a consistent positive correlation, while mid/low-frequency components decoupled under imbalanced N-P supply. Moderate balanced N-P fertilization (N/P = 1–2) stabilized hillslope hydrological-erosion processes throughout the growing cycle, whereas surplus nitrogen induced asynchronous erosion responses. This research delivers quantitative evidence for coordinated high-yield and erosion-control nutrient management. Full article

Excessive basal and tillering nitrogen (BTN) application in rice production causes substantial N losses and environmental costs, yet practical soil fertility thresholds to guide safe BTN reduction (RBTN) have not been established. This study combined meta-analysis with field experiments to determine these thresholds and elucidate underlying mechanisms. The meta-analysis showed that the BTN yield response was negatively correlated with soil total nitrogen (STN) and soil organic matter (SOM), with no significant RBTN yield penalty above 2.0 g kg⁻¹ STN or 30 g kg⁻¹ SOM. Field experiments in soils exceeding these thresholds demonstrated that zero BTN with optimized panicle N (90 kg ha⁻¹ for indica; 120 kg ha⁻¹ for japonica) increased indica yield by 3.6% while reducing N input by 62%, and maintained japonica yield with 50% less N. Nitrogen recovery efficiency rose from 35.5% to 86.1% in indica and from 42.0% to 55.8% in japonica. These improvements were physiologically underpinned by sufficient indigenous soil N supply for productive tiller formation and improved synchrony between panicle N application and crop demand. Collectively, these findings establish quantifiable soil fertility thresholds for safe early N reduction and demonstrate that BTN can be substantially reduced or even omitted in high-fertility soils without compromising yield—offering a simplified, efficient N management strategy for intensive rice production systems. The divergent compensatory pathways between indica and japonica rice further highlight the need for cultivar-specific calibration in future applications. Full article

The synchronization between nitrogen sources and carbohydrate fractions represents a critical factor for optimizing microbial protein synthesis and overall ruminant performance. This systematic review, conducted according to PRISMA 2020 guidelines, comprehensively evaluated the interactions between different nitrogen sources (true protein, urea, controlled-release urea, and bypass amino acids) and carbohydrate fractions (rapidly degrading soluble, slowly degrading soluble, fibrous, non-fibrous, and Van Soest fractions) in ruminant nutrition. A comprehensive search across PubMed, ScienceDirect, Web of Science, and Scopus databases identified 1855 records, of which 164 studies met the eligibility criteria for qualitative synthesis and 89 for quantitative meta-analysis. The review reveals that synchronization effectiveness varies significantly depending on the nitrogen source–carbohydrate combination, with controlled-release urea showing superior synchrony with slowly degrading carbohydrates, while conventional urea performs better with rapidly degrading sources. Meta-analytical results indicate that optimal nitrogen–carbohydrate synchronization can improve microbial protein synthesis by 18–34%, reduce urinary nitrogen excretion by 12–28%, and enhance feed efficiency by 8–15%. These findings provide evidence-based recommendations for precision nutrition strategies in ruminant production systems. Full article

The convergence of food insecurity, water scarcity, and environmental degradation has intensified the global search for sustainable agricultural models. Integrated Microalgal–Aquaponic Systems (IAMS) have emerged as a novel multi-trophic platform that unites aquaculture, hydroponics, and microalgal cultivation into a closed-loop framework for resource-efficient food production and water recovery. This critical review synthesizes empirical findings and engineering advancements published between 2008 and 2024, evaluating IAMS performance relative to traditional agriculture and recirculating aquaculture systems (RAS). Reported under controlled laboratory and pilot-scale conditions, IAMS have achieved nitrogen and phosphorus recovery efficiencies exceeding 95% while potentially reducing water consumption by up to 90% compared to conventional farming. The integration of microalgal photobioreactors enhances nutrient retention, may contribute to internal carbon capture, and enables the generation of diversified co-products, including biofertilizers and protein-rich aquafeeds. Nevertheless, significant barriers to commercial scalability persist, including the biological complexity of maintaining multi-trophic synchrony, high initial capital expenditure (CAPEX), and regulatory ambiguity regarding the safety of waste-derived algal biomass. Technical challenges such as photobioreactor upscaling, biofouling control, and energy optimization are critically discussed. Finally, the review evaluates the alignment of IAMS with UN Sustainable Development Goals 2, 6, and 13, and outlines future research priorities in techno-economic modeling, automation, and policy development to facilitate the transition of IAMS from pilot-scale innovations to viable industrial solutions. Full article

This three-year field study evaluated the agronomic and physiological responses of Tritordeum to nitrogen fertilisation strategies under Mediterranean conditions using an integrated approach combining GDD-aligned phenological monitoring, UAV-based multispectral imaging, and soil analysis. Treatments included conventional urea, urea with a nitrification inhibitor (U+NI; DMPP-based), and urea with a urease inhibitor (U+UI; NBPT-based), compared to an unfertilised control. All nitrogen treatments significantly increased grain yield, reaching up to 2319 kg ha⁻¹ under the nitrification inhibitor treatment (26% higher than the control), and protein content, which peaked at 16.04% under urea. Temporal analysis revealed that urea with nitrification inhibitors consistently enhanced plant height, canopy greenness, and pigment retention during flowering to ripening stages, with NDVI and MCARI peaking under U+NI in 2025. In contrast, urea with urease inhibitor promoted greater early-season biomass and height. Soil nitrogen retention was slightly improved under both EEF treatments, with no adverse effects on pH or salinity. The strong alignment between UAV-derived indices and agronomic traits supports their use for monitoring nitrogen response. These findings demonstrate the benefits of a stage-specific fertilisation strategy, deploying urea with nitrification inhibitor early and urea with urease inhibitor during peak vegetative growth, to improve nitrogen synchrony with crop demand and support sustainable crop management in Tritordeum. Full article

Alfalfa silage has a high proportion of rumen-degradable protein content. Increasing dietary rumen-degradable starch (RDS) can enhance ruminal microbial protein synthesis. This study was conducted to investigate the influence of RDS levels in substrates with alfalfa silage on in vitro rumen fermentation and nitrogen (N) utilization. Rumen fluid was collected and dispensed into anaerobic fermentation bottles, each containing 1 g of substrate and 60 mL of rumen fluid–buffer mixture. The substrate was composed of 40% alfalfa silage and five different RDS levels: 14.85% RDS, 16.40% RDS, 18.67% RDS, 20.21% RDS, and 21.62% RDS. For each RDS level, three replicates were prepared. Each substrate was then incubated at 39 °C for 3, 6, 12, and 24 h. After incubation, the following parameters were measured: gas production, pH, α-amylase activity, ammonia nitrogen (NH₃-N), bacterial protein (BCP), and short-chain fatty acid (SCFA) concentrations were measured. Total gas production increased linearly with increasing RDS levels from 3 to 10 h of incubation (p < 0.01), with no difference observed among five levels after 11 h. At 3 h of incubation, pH decreased linearly with increasing RDS levels (p < 0.05). BCP concentrations and α-amylase activity increased linearly or quadratically with increasing RDS levels (p < 0.01), while the R4 group had the highest concentrations of BCP and the R5 group had the highest activity of α-amylase (p < 0.01). At 6 h of incubation, the NH₃-N concentration decreased linearly or quadratically with increasing RDS levels (p < 0.05), and the α-amylase activity, acetate, propionate, and total SCFA concentrations increased linearly (p < 0.01). The R4 group had the highest activity of α-amylase (p < 0.01), and the R5 group had the highest concentrations of acetate (p < 0.05) and propionate (p < 0.01). At 12 h of incubation, BCP, NH₃-N, and propionate concentrations, as well as α-amylase activity, increased linearly or quadratically with increasing RDS levels (p < 0.05). At 24 h of incubation, the α-amylase activity increased linearly with increasing RDS levels (p < 0.05). The highest multiple-factor associative effects index was observed in the 20.21% RDS substrate, indicating that an RDS level of 20.21% in the alfalfa silage substrate resulted in a desirable rumen N utilization. Full article

The number of livestock farms decreased by 40% in Europe over the last 10-year period. Stockless organic cropping systems started to dominate in many intensive agricultural regions in Europe. Developing the sustainable management of an organic stockless agroecosystem is related to guaranteeing self-sufficiency in nitrogen (N) supply, maintaining high grain yields, and promoting carbon (C) sequestration in the soil. The aim of this study was to investigate if the processed legume green manures can be an alternative to granulated cattle manure and direct ploughing of legume biomass in order to develop the sustainability of the stockless organic cropping system. The decomposition rate and C and N release were observed for green manures made of fermented red clover and composted red clover with wheat straw. Fresh red clover biomass and granulated cattle manure were used for the comparison. Results of the 3-year field experiment showed that technologically processed legume biomass had a positive effect on the productivity of crops at least two years in rotation. Fermented red clover and red clover compost increased N use efficiency by 15% and biomass output efficiency by 16% compared with fresh red clover biomass. Processed legume green manures significantly increased the synchronisation index between crop N demand and N supply. In autumn, incorporated fresh red clover biomass lost 65.6% of its initial C and 37.6 kg ha⁻¹ (50.1%) of its initial N under decomposition in the first non-growing season. It also increased mineral N losses deeper into the subsoil by 52.7%. Meanwhile, fermented red clover and red clover compost released 43% of its N during the first crop growing season, sustained at least one year slower C release to the soil, promoted ecosystem productivity, prevented mineral N losses to subsoil and gained high N synchrony indexes. The best N synchrony was achieved using fermented red clover, with a higher decomposition rate positively significantly correlated (r = 0.47–0.78, p < 0.05) with grain yield, total biomass, protein content and total N accumulated in the plant of spring wheat and spring barley. Full article

Densification of ashy biochar into tablet can enhance the handling and conveyance efficiencies of biochar. It was hypothesized that fertilizer-embedded biochar tablets can slowly release embedded nutrients in synchrony with optimum nutrient uptake by crops. The objectives of this research were to determine the effects of biochar tablets with and without embedded fertilizer on soil chemical properties and nutrient use efficiency of Zea mays (sweet corn). The biochar tablet (BT) was produced by blending a biochar mixture with starch followed by densification using a single punch tablet press whereas the fertilizer embedded biochar tablet (BF) was prepared using the same procedure except that NPK fertilizer was added during blending. A pot experiment with five fertilization treatments including control was carried out in an open field located in Perlis, Malaysia. Co-application of biochar and fertilizer increased soil total carbon, nitrogen, but it reduced soil electrical conductivity (EC). Additionally, the BF significantly increased leaf chlorophyll content, dry root weight, and total plant nutrient use efficiency of sweet corn. The findings suggest that BF can serve as a slow release fertilizer to improve crop nutrient use efficiency. Therefore, embedding fertilizer in biochar tablets is recommended for sweet corn production following a long term field study to confirm the findings of this pot study. Full article

The study analyzes the long-term trends (1998–2019) of concentrations of the air pollutants ozone (O₃) and nitrogen oxides (NO_x) as well as meteorological conditions at forest sites in German midrange mountains to evaluate changes in O₃ uptake conditions for trees over time at a plot scale. O₃ concentrations did not show significant trends over the course of 22 years, unlike NO₂ and NO, whose concentrations decreased significantly since the end of the 1990s. Temporal analyses of meteorological parameters found increasing global radiation at all sites and decreasing precipitation, vapor pressure deficit (VPD), and wind speed at most sites (temperature did not show any trend). A principal component analysis revealed strong correlations between O₃ concentrations and global radiation, VPD, and temperature. Examination of the atmospheric water balance, a key parameter for O₃ uptake, identified some unusually hot and dry years (2003, 2011, 2018, and 2019). With the help of a soil water model, periods of plant water stress were detected. These periods were often in synchrony with periods of elevated daytime O₃ concentrations and usually occurred in mid and late summer, but occasionally also in spring and early summer. This suggests that drought protects forests against O₃ uptake and that, in humid years with moderate O₃ concentrations, the O₃ flux was higher than in dry years with higher O₃ concentrations. Full article

The use of black soldier fly frass fertilizer (BSFFF) is being promoted globally. However, information on nitrogen (N) fertilizer equivalence (NFE) value and synchrony of N mineralization for crop production remains largely unknown. Comparative studies between BSFFF and commercial organic fertilizer (SAFI) were undertaken under field conditions to determine synchrony of N release for maize uptake. The BSFFF, SAFI, and urea fertilizers were applied at the rates of 0, 30, 60, and 100 kg N ha⁻¹. The yield data from urea treated plots were used to determine the NFE of both organic inputs. Results showed that maize from BSFFF treated plots had higher N uptake than that from SAFI treated plots. High N immobilization was observed throughout the active growth stages of maize grown in soil amended with BSFFF, whereas soil treated with SAFI achieved net N release at the silking stage. Up to three times higher negative N fluxes were observed in SAFI amended soils as compared with BSFFF treated plots at the tasseling stage. The BSFFF applied at 30 and 60 kg N ha⁻¹ achieved significantly higher NFE than all SAFI treatments. Our findings revealed that BSFFF is a promising and sustainable alternative to SAFI or urea for enhanced maize production. Full article

Sediment transport in coastal regions is regulated by the interaction of river discharge, wind, waves, and tides, yet the role of vegetation in this interaction is not well understood. Here, we evaluated these variables using multiple acoustic and optical sensors deployed for 30–60 days in spring and summer/fall 2015 at upstream and downstream stations in Mike Island, a deltaic island within the Wax Lake Delta, LA, USA. During a flooding stage, semidiurnal and diurnal tidal impact was minimal on an adjacent river channel, but significant in Mike Island where vegetation biomass was low and wave influence was greater downstream. During summer/fall, a “vegetated channel” constricted the water flow, decreasing current speeds from ~13 cm/s upstream to nearly zero downstream. Synchrony between the upstream and downstream water levels in spring (R² = 0.91) decreased in summer/fall (R² = 0.84) due to dense vegetation, which also reduced the wave heights from 3–20 cm (spring) to nearly 0 cm (summer/fall). Spatial and temporal differences in total inorganic nitrogen and orthophosphate concentrations in the overlying and sediment porewater were evident as result of vegetation growth and expansion during summer/fall. This study provides key hourly/daily data and information needed to improve the parameterization of biophysical models in coastal wetland restoration projects. Full article

Kura clover (Trifolium ambiguum) is a perennial living mulch species that can be used in conjunction with zone tillage to reduce nitrogen pollution, maintain ground cover, and provide nitrogen to crops. In such systems, kura clover is maintained between crop rows by limiting tillage only to within-row areas. However, the effect of zone-tilled living mulches on soil quality and nutrient cycling in these distinct regions is relatively unexplored. We examined three pools of labile soil organic matter (SOM): microbial biomass, particulate organic matter (POM), and permanganate oxidizable carbon (POXC). Soil samples were collected from both within-row and between-row locations of a zone-tilled kura clover living mulch at three time points per year: before spring zone tillage, approximately ten days after spring zone tillage and corn (Zea mays) planting, and at corn harvest in 2015 and 2016. In 2016, POM and POXC decreased within rows relative to between-row regions after tillage, suggesting that zone till management stimulated decomposition of readily available SOM to effectively localize nutrient cycling in this region and slow mineralization between rows where living kura clover remained. This work shows that zone-tilled living mulches may be a promising avenue for enhancing the synchrony of nutrient mineralization specifically within crop rows, while maintaining year-round ground cover between rows. Full article

Latin America is an important contributor to the worldwide beef business, but in general, there are limited studies considering strategies to reduce nitrogen contamination in their production systems. The study’s goal was to assess the effect of two nutritional strategies to balance energy and protein supply in fattening heifers on performance, ruminal metabolism, and carcass characteristics. A total of 24 crossbred heifers (initial body weight ’BW ’of 372 ± 36 kg) were used to create two blocks (based on live weight) of two pens each, that were equipped with individual feeders. Within each block, half of the animals were assigned to a diet based on tabular Crude Protein (CP) requirements denominated Crude Protein Diet ‘CPD’ but without a ruminal degradable protein balance. The other half received a diet denominated Metabolizable Protein Diet ‘MPD’, formulated with the metabolizable protein system, balanced for the ruminal degradable protein. Both diets had the same ingredients and as well as similar synchrony indexes (0.80 and 0.83, respectively). For nitrogen concentration in feces and urine as well as microbial crude protein synthesis, a total of 12 heifers (three per pen) were randomly selected to collect samples. The dataset was analyzed as a randomized complete block design with a 5% significance. No diet × time interaction was observed for Average Daily Gain ’ADG’ (p = 0.89), but there was an effect of the time on ADG (p ≤ 0.001). No differences were observed neither for final weight, dry matter intake ’DMI’, and feed conversion rate (p > 0.05). Heifers fed with CPD showed greater cold carcass weight (p = 0.041), but without differences in ribeye area, backfat thickness, pH, dressing %, and marbling (p > 0.05). Differences between diets were observed for the in vitro parameters as well as for the Total Volatile Fatty Acids ’VFA’ and NH₃ (p < 0.05). Total N concentrations (urine + feces) of heifers fed with MDP was lower than in those fed with the CPD (p < 0.01), but no differences were observed in microbial protein, purine derivatives, and creatinine (p > 0.05). We conclude that the combination of synchrony and the metabolizable protein system achieve greater efficiency in the use of nitrogen, without negatively affecting animals’ performance or the quality of the carcass. Full article

Synchrony of energy and nitrogen release in rumen has been proposed to maximize ruminal microbial fermentation. However, the information regarding bacterial community composition and its metabolism under a higher or lower degree of synchronization is limited. In our study, a 0 to 6 h post-feeding infusion (first half infusion, FHI), 6 to 12 h post-feeding infusion (second half infusion, SHI), and 0 to 12 h post-feeding infusion (continuous infusion, CI) of maltodextrin were used to simulate varying degrees of synchronization of energy and nitrogen release in a rumen simulation system. In addition, the bacterial community, metabolite, enzyme activity, and microbial protein synthesis (MPS) were evaluated. Compared with the FHI and CI, the relative abundance of Fibrobacter, Ruminobacter, BF311, and CF231 decreased in the SHI, but that of Klebsiella and Succinivibrio increased in the SHI. The NH₃-N and branched-chain volatile fatty acids were significantly higher, but propionate content and activities of glutamate dehydrogenase (GDH) and alanine dehydrogenase were significantly lower in the SHI than those in the FHI and CI. The SHI had lower MPS and less efficiency of MPS than the FHI and CI, which indicated that the SHI had a lower degree of synchronization. Correlation analysis showed that MPS was positively related to GDH activity and relative abundance of Fibrobacter but negatively related to NH₃-N and relative abundance of Klebsiella. Therefore, a higher degree of synchronization of energy and nitrogen release increased MPS partly via influencing the bacterial community, metabolism, and enzyme activities of ammonia assimilation in the in vitro fermenters. Full article

Synchrony between soil mineral nitrogen (N) supply and crop N demand is important for optimal plant growth. Excessively wet conditions expose poorly drained soils to an increased potential of N loss and reduced N use efficiency. A two-year experiment with wheat (Triticum aestivum L.) was initiated in 2014 and concluded in 2016 in northeastern Missouri in the United States (USA). The objective of this experiment was to evaluate the effects of nitrapyrin and pronitridine nitrification inhibitors (NI) applied as an early or late-split application timing (40:60%) of 79 kg N ha⁻¹ or 112 kg N ha⁻¹ on winter wheat soil and plant N status, as well as grain yield. Both NIs had no effect (p = 0.3917) on yield, while there was an interaction between year and the urea ammonium nitrate (UAN) rate on grain yield. Yields were similar (3550 kg ha⁻¹ to 3686 kg ha⁻¹) in 2015 between UAN application rates. UAN at 112 kg N ha⁻¹ resulted in a 551 kg ha⁻¹ greater yield than UAN at 79 kg N ha⁻¹ in 2016. Nitrapyrin and pronitridine did not significantly affect soil ammonium or nitrate–N concentrations at depths of 0–15 cm and 16–30 cm compared to the absence of NI over the period of three months after application. Nitrapyrin with UAN at 112 kg N ha⁻¹ had the highest grain test weight. Further testing of these NIs in combination with UAN for winter wheat production is needed under different climatic and environmental conditions to develop comprehensive management recommendations. Full article