Search Results (571)

Excessive planting density and heavy rainfall weather threatens global agriculture, particularly affecting maize. Biochar is an environmentally friendly soil amendment that has a yield-increasing effect. However, the regulatory mechanism of biochar frequency on crop internode development and photosystem II photosynthetic efficiency remains unknown. A total of nine treatments were followed in this experiment. Three applications of biochar were as follows: no biochar application (B0); biochar application at 4.2 t ha⁻¹ year⁻¹ (B1); and biochar application at 8.4 t ha⁻¹ 2 year⁻¹ (B2), alongside three nitrogen (N) fertilizer rates (0, N0; 180 kg ha⁻¹, N1 and 225 kg ha⁻¹, N2). The results showed that the internode thickness of the 2nd to 5th nodes under N2B2 treatment increased by 17.7%, 16.0%, 19.7%, and 21.7%, respectively, compared to N0B0. Annual biochar application had a higher stem diameter coefficient for the 1st to 3rd nodes than no biochar (B0) and treatments applied every two years (B2). Annual biochar application had the highest dry weight of internodes and plant height compared with B0 and B2. The relative chlorophyll content of leaves was significantly increased by biochar combined with N fertilizer or by N fertilizer alone. Biochar combined with N fertilizer significantly reduced NPQt and ΦNPQ, which were reduced by 59% and 50%, respectively, under N2B1 treatment compared with N0B0. The N2B1 treatment increased ΦII by 30% compared to N0B0. Stem diameter coefficient was significantly negatively correlated with NPQt and ΦNPQ and significantly positively correlated with ΦII and Fv/Fm. Compared to B1, B2 increased the maize yield. Annual biochar application combined with N fertilizer reduced stem collapse and enhanced post-flowering photosynthesis. Overall, considering the yield traits, 8.4 t ha⁻¹ biochar application combined with 180 kg ha⁻¹ N fertilizer treatment was the best. This study will provide reference data for cultivation regulation to enhance maize’s resistance to collapse and maintain photosynthetic capacity. Full article

Excessive fertilizer use not only harms agricultural sustainability but also leads to massive energy waste and carbon emissions. Under China’s carbon peaking and carbon neutrality goals, using social networks to spread better fertilization practices and reduce excessive application can deliver real wins for both energy savings and emission cuts. This paper examines whether farmers’ social network positions affect their fertilizer use. We analyze 14 years of data from 206 farm households in Gansu, China, using fixed effects models that incorporate degree, betweenness, and closeness centrality. Our results reveal that centrally positioned farmers substantially reduce fertilizer application: each 0.1 unit rise in standardized degree, betweenness, and closeness centrality corresponds to reductions of 1.26%, 0.84%, and 0.78%, which translate to actual reductions and carbon emission reduction of 1.06, 0.71, and 0.66 kg/mu; 9.52, 6.38, and 5.93 kg CO₂e/mu. The effects are stronger for farmers with more education, higher off-farm income, and tighter network connections. The effect of degree centrality on fertilizer reduction increased by 7.2 percentage points after 2018. Extension services should build on existing social networks and use key node farmers to drive other farmers in the village to reduce fertilizer use. It helps reduce carbon emissions from fertilizer production and promote sustainable agricultural development. Full article

Excessive nitrogen (N) fertilization is widely used to increase rice yield, but it often leads to lodging by weakening culm strength. This study aimed to elucidate the structural and molecular mechanisms underlying nitrogen-induced changes in culm lodging resistance in rice. Field and pot experiments with two nitrogen levels were conducted using a randomized design with three biological replicates to evaluate the effects of high nitrogen application on culm mechanical properties, secondary cell wall development, and associated metabolic pathways. Mechanical measurements and microscopic analysis revealed that high nitrogen significantly reduced culm rigidity and impaired sclerenchyma development. To investigate the underlying mechanisms, integrated transcriptomic and proteomic analyses were performed on developing internodes. Differentially expressed genes and proteins were predominantly enriched in carbohydrate metabolism and phenylpropanoid biosynthesis pathways. Notably, key enzymes involved in lignin biosynthesis were consistently downregulated at the protein level under high-nitrogen conditions. In contrast, genes and proteins related to cellulose and hemicellulose biosynthesis exhibited transient inhibition at early stages followed by recovery or upregulation at later stages. Consistent with these findings, histochemical staining and quantitative assays demonstrated a significant reduction (14–16%) in lignin content in the fourth internode, whereas cellulose content showed no substantial change. Furthermore, lignin biosynthetic genes (OsCAD2, Os4CL3, and OsCOMT) were persistently suppressed during critical stages of secondary wall formation, while cellulose synthase genes (OsCESA4, OsCESA7, and OsCESA9) displayed more variable and less sustained expression patterns. Collectively, these results demonstrate that excessive nitrogen application weakens rice culms primarily by inhibiting lignin accumulation rather than cellulose deposition. The preferential suppression of the phenylpropanoid pathway and disruption of secondary cell wall formation provide a mechanistic basis for nitrogen-induced lodging susceptibility in rice. Full article

The excessive use of chemical fertilizers in rice cultivation has contributed to soil degradation, creating a need for sustainable biological alternatives. This study examined the functional diversity of three indigenous nostocalean cyanobacterial strains (UP1, UP2, and UP3) isolated from forest and paddy field ecosystems by comparing the effects of their cellular biomass and extracellular polymeric substances (EPS) on rice seedling growth and soil properties. Morphological observations and partial 16S rRNA sequence analysis indicated that strains UP1 and UP2 were affiliated with the genus Ahomia, whereas UP3 was placed within the genus Nostoc. Together, these results placed all three isolates within the heterocystous cyanobacterial order Nostocales. The strains were further characterized based on EPS production and its degree of polymerization. Seed germination and seedling vigor assays were conducted to select the most effective biomass and EPS treatments, which were subsequently evaluated in 21-day pot experiments. Fresh biomass from strain UP2 most effectively enhanced rice growth, whereas EPS from strain UP3 promoted root development. EPS application from strain UP3 significantly increased root elongation to 13.44 cm, while high biomass levels of UP2 increased total sugar and free amino acid contents, indicating distinct plant response patterns. Soil analyses revealed differential responses between biomass- and EPS-based applications, with biomass generally producing stronger effects. Biomass from all strains was associated with higher physical soil function index (PSFI) values (up to 1.35). In contrast, improvements in chemical soil function index (CSFI) were observed across treatments, with variable responses and relatively higher values recorded in biomass from strain UP3 (up to 1.24). These findings suggest strain- and form-dependent response patterns of nostocalean cyanobacteria with potential for enhancing rice growth and improving soil functionality under the controlled conditions. Full article

Excessive fertilizer application is a common practice in agricultural production in the North China Plain. To determine an optimal fertilization strategy for summer maize with nitrogen-fixing bacterial inoculation, we conducted a two-year field experiment (2022–2023) using the conventional fertilization rate (600 kg ha⁻¹ NPK; N:P₂O₅:K₂O = 28:8:10; 100F by default) as a control and examined the effects of fertilizer reduction (at 90%, 80%, 62.5%, and 50% of 100F) combined with Azotobacter chroococcum inoculation on maize plants and soil. Although fertilizer reduction increased free amino acid content, soluble sugars, proteins, and fatty acids contents were reduced. However, bacterial inoculation significantly enhanced all the above nutritional indices in maize leaves. Bacterial inoculation under fertilizer reduction conditions can enhance the activity of key nitrogen metabolism enzymes (i.e., GS and GOGAT), which further supports nitrogen, sugar, and lipid metabolism in maize plants. Additionally, bacterial inoculation promoted root development, biomass accumulation, and grain nutritional value while significantly increasing yield under reduced fertilizer conditions. The highest yield (11,454 kg ha⁻¹) was achieved with bacterial inoculation at approximately 87F (≈522 kg ha⁻¹ NPK), while the non-inoculated control reached a peak yield (11,032 kg ha⁻¹) only at around 90.5F (≈543 kg ha⁻¹). The complementary effects of bacterial inoculation with fertilizer reduction resulted in improved nutrient supply and modulation of soil microbial diversity. Inoculation of A. chroococcum increased soil ammonium and nitrate levels and decreased soil pH, though it was associated with a decline in overall bacterial richness, which may have persistent and adverse effects on the soil. Both fertilizer reduction and bacterial inoculation significantly altered microbial community structure, with notable interannual variation. Collectively, our findings suggest that moderate fertilizer reduction (9.5–13%) combined with nitrogen-fixing bacteria inoculation can support sustainable maize production by maintaining higher yield, enhancing nutrient use efficiency, and improving soil health. However, due to pH-lowering effects, long-term monitoring is necessary to assess the ecological impact of nitrogen-fixing bacteria inoculation on soil microbial balance. Full article

Under conditions of limited irrigation and excessive fertilizer application in the arid regions of Xinjiang, it is essential to adopt well-coordinated strategies to improve yield and crop water productivity (WP). In this study, a comparative experiment was conducted with three irrigation levels, T1 (100% crop evapotranspiration, ET_c), T2 (75% ET_c), and T3 (50% ET_c), combined with three potassium application rates, K1 (540 kg ha⁻¹), K2 (360 kg ha⁻¹), and K3 (180 kg ha⁻¹). The objective was to investigate their effects on the yield, quality, and economic benefits of jujube trees. Limited irrigation amounts significantly affected the photosynthetic characteristics, growth parameters, and ET_c of jujube trees, whereas potassium fertilizer levels primarily regulated fruit development and yield formation. Compared with full irrigation, mild deficit irrigation caused a moderate yield reduction but significantly enhanced economic returns due to the improved water productivity and fruit quality. In contrast, severe water deficit led to substantial decreases in growth parameters and economic benefits by 12.87–45.70% and 81.69%, respectively. Potassium application demonstrated a significant threshold effect, with the K2 treatment showing greater improvements in fruit quality indices, including reducing sugars, vitamin C, and other key quality parameters, compared to the K3 treatment. Based on hierarchical–grey relational analysis, the combination of 75% ET_c and 300 kg K ha⁻¹ was identified as the optimal water–potassium management strategy. The net profit was 29,199 CNY. The benefit–cost ratio increased to 3.63, and the WP improved by 16.17% compared to full irrigation. Thus, this study provides an important theoretical basis and technical support for water-saving and quality-improving cultivation of jujube trees in arid regions. Full article

At the current stage, water resource shortages and significant regional disparities in resource distribution severely restrict China’s food security. Existing research primarily focuses on resource use efficiency, while lacking a systematic framework to distinguish between equality and equity in the coupled distribution of irrigation water, grain production, and nitrogen pollution across major river basins. The core objective of this study is to utilize the Concentration Index (CI) to construct a unified equity assessment framework, quantify the evolution of equality and equity in irrigation water use, grain production, and nitrogen loss to surface water in different river basins in China from 1992 to 2017, and determine the key influencing factors. For positive production resources, a distribution that benefits low-income groups is equity, while for pollution burdens, this distribution pattern is inequity. The results show that water shortages in Northern China have intensified, and higher income groups have obtained excessive benefits. The distribution of grain production has shifted from favoring higher income groups to favoring low-income groups, with the Concentration Index changing from 0.214 to −0.052, indicating an enhancement in equity. Irrigation water use has shown a certain degree of improvement, with the CI dropping from 0.023 to 0.017. However, nitrogen loss to surface water has exacerbated environmental inequality, with the CI dropping from 0.10 to 0.03, indicating that pollution burdens have shifted to low-income groups. Changes in equity across the country are driven by a small number of high-intensity grain production areas, and the key influencing factors include food security policies, urbanization, population size, and nitrogen fertilizer application. An asymmetric coupling relationship exists between water resource shortages and equity, and the regional economic foundation determines the formation of synergy or trade-offs. The findings underscore the necessity of transitioning from efficiency-focused to equity-focused agricultural governance in China. Targeted policies should include cross-basin ecological compensation mechanisms, differentiated technology promotion strategies, and integrated water–food-pollution management systems to balance food security, environmental protection, and social justice. Full article

Freshwater scarcity limits agricultural production in southern Xinjiang, China, while saline groundwater utilized for direct irrigation adversely affects soils and crops. Excessive nitrogen fertilizer is often applied to compensate for these adverse effects, potentially jeopardizing soil environmental quality. A two-year field experiment was conducted to assess the impact of decreased nitrogen application on cotton growth, nitrogen use efficiency, and yield under different irrigation water salinity levels, with the addition of biofertilizer. The experiment was undertaken on drip-irrigated cotton fields in southern Xinjiang, China, during 2021 and 2022. Three salinity concentrations of irrigation water were quantified: W₁ (1 g L⁻¹), W₂ (3 g L⁻¹), and W₃ (7 g L⁻¹). Under all three salinity levels, conventional fertilization (F1) served as the control, and F0, a no-nitrogen treatment, was also utilized. A total of 18 treatments were assessed using four nitrogen fertilizer application rates in conjunction with biofertilizer: no nitrogen (B₀), 100% conventional nitrogen rate (B₁), 85% conventional nitrogen rate (B₂), and 70% conventional nitrogen rate (B₃). The findings showed that adding biofertilizer considerably increased cotton output under both freshwater and brackish water irrigation regimes when compared to traditional nitrogen fertilization. In just two years, the yield of seed cotton grew by 6.15–10.56% (W₁) and 6.49–11.81% (W₂). In 2021, lint yield climbed by 11.79% (W₁), and in two years, it increased by 6.69–15.51% (W₂). Although internal nitrogen use efficiency (iNUE) initially rose and subsequently fell with escalating nitrogen rates, the application of lower nitrogen combined with biofertilizer significantly enhanced agronomic nitrogen use efficiency (aNUE) and diminished soil nitrogen residue. Recommended nitrogen application rates for cotton, utilizing 1200 kg ha⁻¹ of biofertilizer, were established for diverse irrigation water qualities to achieve optimal nitrogen reduction, maximum iNUE, and peak yield: 283.21–322.95 kg ha⁻¹ under freshwater irrigation (W₁), 281.00–328.14 kg ha⁻¹ under brackish water (W₂) irrigation, and ≥326.28 kg ha⁻¹ under saline irrigation (W₃). These findings recommend the optimization of fertilizers across various irrigation conditions and facilitate the efficient utilization of saline water resources. Full article

Excessive nitrogen fertilizer application in the black soil region of Northeast China leads to nitrate leaching and gaseous nitrogen loss, posing environmental risks. This study aimed to evaluate the effectiveness of controlled-release urea (CRU) mixed with conventional urea in synchronizing nitrogen fertilizer supply with maize nitrogen requirements, improving nitrogen fertilizer use efficiency (NUE), and increasing economic benefits. A two-year field trial (2023–2024) tested six nitrogen fertilizer application strategies, all with a total nitrogen application rate of 168 kg N ha⁻¹, including no nitrogen fertilizer application (CK), conventional fractionated urea application (C0), and four controlled-release urea–urea mixed application schemes, where CRU supplied 100%, 70%, 50%, and 30% of the total nitrogen (C100, C70, C50, and C30). The results showed that the C70 treatment had the highest maize grain yield and protein yield, at 12,502.92 kg ha⁻¹ and 1567.65 kg ha⁻¹, respectively, and NUE increased by 10.07% in 2024 compared to the C0 treatment. The C70 strategy also reduced nitrate concentrations in deeper soil layers, decreasing nitrogen loss by 29.04–31.21% compared to the C0 treatment. Furthermore, the C70 strategy yielded the highest net benefit, reaching $2817 ha⁻¹. These results indicate that in black soil systems, a single basal application of C70 mixed fertilizer is an effective strategy for increasing maize yield, improving nitrogen fertilizer use efficiency, and reducing environmental risks. Full article

Reproductive efficiency in female cattle is significantly influenced by micronutrient status, particularly the availability and balance of essential trace minerals. Selenium, copper, zinc, cobalt, and iron serve as critical components of enzymatic systems, antioxidant defense networks, hormone synthesis, and cellular metabolism, collectively sustaining reproductive health. This review integrates current research evidence on the physiological functions and molecular mechanisms through which these five trace minerals regulate reproductive performance in female cattle, with a specific focus on iron—an often overlooked element—highlighting the novelty of this synthesis. Both deficiency and excess of these minerals impair key reproductive outcomes such as estrous cyclicity, conception rate, and embryonic survival. Furthermore, complex interactions among minerals influence their bioavailability and physiological responses. Advances in mineral supplementation strategies, particularly the application of organic minerals and precision feeding technologies, offer promising solutions to improve reproductive performance. Elucidating these interrelationships provides a theoretical foundation for optimizing trace mineral nutrition, thereby enhancing female cattle fertility, reducing metabolic disorders and promoting the sustainable development of beef and dairy industries. Full article

The rapid expansion of coastal dredging projects has resulted in the accumulation of large volumes of dredged sediments, creating significant environmental and land-use challenges. Conventional disposal methods, such as landfilling and marine dumping, not only waste valuable resources but also pose risks, including heavy metal contamination and excessive salinity. In this study, dredged sediment from the former sedimentation area of Huanghua Port was systematically examined for its potential reuse as greening soil through a three-stage approach: desalination, amendment with additives, and composting. Water-washing experiments were conducted to optimize desalination parameters, with a focus on the effects of solid-to-liquid ratios and washing solution concentrations on electrical conductivity reduction. Biochar, fly ash, and wood vinegar were then applied as amendments to evaluate their impacts on soil properties, including pH, organic matter, electrical conductivity, and cation exchange capacity. In addition, co-composting experiments with dredged sediment and crop straw were designed to investigate composting dynamics and changes in physicochemical characteristics under different mixing ratios. The results showed that two washes with a 0.3% NaCl solution effectively reduced electrical conductivity to acceptable levels. Subsequent amendment and composting treatments markedly enhanced soil fertility and ecological suitability. In particular, the combination of 1000-fold diluted wood vinegar and straw-to-sediment composting at a 1:3 weight ratio enabled the amended sediment to meet the Chinese standards for Planting Soil Green. Overall, this study establishes a scientific basis and practical strategy for the sustainable recycling of dredged sediments, supporting their application in urban greening and ecological restoration. Full article

To mitigate the exhausting of phosphate rock (PR) reserves and the widespread water eutrophication due partially to excessive phosphorus (P), efficient adsorbents are valuable. Calcium (Ca) and aluminum (Al) containing layered double hydroxides (CaAl-LDHs) showed high P adsorption capacity and potential as slow-release P fertilizers, which merits further investigation. Two P proportions (5% and 10%) of P-adsorbed CaAl-LDHs (P-LDHs) were prepared, and its effects on various soil P contents and oilseed rape (Brassica napus L.) growth were evaluated. The main components of 5%P-LDH were P-intercalated CaAl-LDH and brushite, while 10%P-LDH mainly consisted of brushite. The proportions of P were extracted from 10%P-LDH and increased in the order of 4.9% (deionized water) < 48.9% (Olsen method) < 63.5% (Bray method) < 67.4% (citric acid), which suggested that 10%P-LDH could be citrate-soluble P fertilizer. 10%P-LDH showed similar effects on soil available P with single superphosphate (SSP). Both 5%- and 10%P-LDHs showed comparable improvement with SSP on aboveground dry weight of oilseed in the red soil, while being inapparent in the Fluvo-aquic soil. The CaAl-LDH appeared capable of providing Ca for rape growth in the low initial P concentration red soil, which showed the highest dry weight when combined with SSP. The recycled P-LDHs, especially 10%P-LDH, could supply P in a comparable manner with SSP for oilseed rape P uptake. Based on trials conducted under controlled conditions, our study suggested a promising production route of commercial P fertilizer alternatives via water P removal by CaAl-LDH. Further validations with realistic wastewater P removal by CaAl-LDH and via field scale growth trials are still needed before wide application of the alternative P fertilizer production procedure reported in the present study. Full article

Cannabis sativa, a species within the Cannabaceae family, produces a diverse range of phytochemicals, notably cannabinoids and terpenoids, with significant physiological and pharmacological relevance. Among its phytochemicals, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most studied for their psychoactive and medicinal properties. However, emerging evidence indicates that chronic or excessive exposure to these phytocannabinoids may adversely affect male fertility. This review synthesizes current knowledge on the influence of C. sativa and its constituents on the male reproductive system, with emphasis on spermatogenesis, sperm function, hormonal regulation, and the role of the endocannabinoid system (ECS). Experimental and clinical studies demonstrate that cannabinoids interact with CB1 and CB2 receptors expressed in the testes, epididymis, and spermatozoa, thereby modulating testosterone synthesis, sperm motility, morphology, and capacitation. THC, in particular, disrupts the hypothalamic–pituitary–gonadal (HPG) axis, leading to reduced luteinizing hormone and testosterone levels, impaired mitochondrial activity, and abnormal sperm morphology. Although CBD exhibits anti-inflammatory and antioxidant properties, its long-term impact on reproductive function remains uncertain. The review further highlights the complex interplay between exogenous cannabinoids and the endogenous ECS in maintaining reproductive homeostasis. Understanding these molecular mechanisms is critical for balancing the therapeutic potential of Cannabis-derived products with their reproductive risks. This knowledge could inform safe medicinal applications and contribute to the development of targeted cannabinoid-based therapies for male infertility. Full article

Saline soil represents an important reserve of cultivated land in China, yet poor soil conditions and low-nitrogen use efficiency constrain crop production. Biochar has been widely applied to improve soil properties; however, its interactive effects with nitrogen fertilization in saline soils remain unclear. A pot experiment using coastal saline soil collected from the northern Jiangsu province was conducted to evaluate the combined effects of biochar (0%, 4%, and 8% w·w⁻¹) and nitrogen fertilizer (0, 150, and 200 mg·kg⁻¹) on the growth performance, photosynthetic indices, yield, quality, and nitrogen use efficiency of water spinach (Ipomoea aquatica Forssk.). Moderate biochar application significantly improved vegetative growth of water spinach, as indicated by higher plant height, stem diameter, leaf area index, and SPAD values. In addition, biochar substantially enhanced photosynthetic performance, dry matter accumulation, and yield, whereas excessive biochar or nitrogen application generally inhibited plant performance. The combined application of 4% biochar with 150 mg·kg⁻¹ nitrogen consistently produced the highest yield and nitrogen partial factor productivity, while simultaneously increasing soluble protein, soluble sugar, and vitamin C contents and reducing nitrite accumulation. These research results demonstrated a clear synergistic interaction between biochar and nitrogen fertilization. In coastal saline soils, reducing the usage of nitrogen fertilizer moderately and adding approximately 4% of biochar is an effective strategy. Full article

The excessive use of chemical fertilizers raised concerns regarding environmental sustainability and soil degradation, prompting increasing interest in biofertilizers as eco-friendly alternatives. Among these, a compound that is effective in stimulating root and plant growth is indole-3-acetic acid (IAA). In our study, we evaluated IAA production by the halotolerant bacterium Vreelandella titanicae under different and varying nutritional conditions, such as tryptophan availability, temperature, pH, salinity, etc. The bacterium showed significant IAA production under a broad range of conditions and a dependence on the presence of tryptophan for IAA biosynthesis. High salinity (1.0 M NaCl), slightly alkaline pH (8.0–9.0), and temperatures of 34 °C increased IAA production, while optimal growth occurred in the absence of NaCl at a range of temperatures of 25–28 °C, suggesting a stress-responsive regulation of its biosynthesis. Easily metabolizable carbon sources, such as glucose and mannitol, enhanced IAA yield again, whereas additions of 1.0 g L⁻¹ NH₄NO₃ and KH₂PO₄ in the basal medium, poor in these salts, inhibited both the growth of the bacterium and IAA production. Notably, V. titanicae produced relevant amounts of IAA in seawater (24.57 ± 11.28 μg⋅mL⁻¹) when used as growth medium and dairy whey (15.68 ± 2.42 μg⋅mL⁻¹), highlighting its suitability for low-cost and circular bioprocessing strategies. In conclusion, V. titanicae is a promising Plant Growth-Promoting Rhizobacterium (PGPR) candidate for sustainable IAA production and potential application in saline or marginal agricultural soils. Its ability to synthesize IAA in different growth media could allow its exploitation in environmentally friendly bioprocesses. Full article