Combining slow-release fertilizer and plastic film mulching reduced the carbon footprint and enhanced maize yield on the Loess Plateau.

Agricultural practices significantly contribute to greenhouse gas (GHG) emissions, necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production. Plastic film mulching is commonly used in the Loess Plateau region. Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity. Combining these techniques represents a novel agricultural approach in semi-arid areas. However, the impact of this integration on soil carbon storage (SOCS), carbon footprint (CF), and economic benefits has received limited research attention. Therefore, we conducted an eight-year study (2015-2022) in the semi-arid northwestern region to quantify the effects of four treatments [urea supplied without plastic film mulching (CK-U), slow-release fertilizer supplied without plastic film mulching (CK-S), urea supplied with plastic film mulching (PM-U), and slow-release fertilizer supplied with plastic film mulching (PM-S)] on soil fertility, economic and environmental benefits. The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions (≥71.97%). Compared to other treatments, PM-S increased average grain yield by 12.01%-37.89%, water use efficiency by 9.19%-23.33%, nitrogen accumulation by 27.07%-66.19%, and net return by 6.21%-29.57%. Furthermore, PM-S decreased CF by 12.87%-44.31% and CF per net return by 14.25%-41.16%. After eight years, PM-S increased SOCS (0-40 cm) by 2.46%, while PM-U decreased it by 7.09%. These findings highlight the positive effects of PM-S on surface soil fertility, economic gains, and environmental benefits in spring maize production on the Loess Plateau, underscoring its potential for widespread adoption and application.

Effects of silicate stabilizers on cadmium reduction and the quality of rice grains in acidic paddy soil.

Silicate has been proven to be highly-effective at immobilizing soil heavy metals, but the effects of silicate stabilizers on rice grain cadmium (Cd) reduction and rice quality under field conditions are not clear. In this study, a field experiment was conducted over three consecutive years was conducted to examine the Cd reduction in rice grains and to reveal the potential effects of silicate stabilizers on rice grain nutrients, by setting different amounts of bentonite (B), silica‒calcium fertilizer (SC) and zeolite powder (ZP). The results revealed that the application of the B, SC and ZP significantly decreased the soil CaCl2‒Cd concentration (> 39%) and significantly reduced the grain Cd concentration in both early rice (> 70%) and late rice (> 18%) under field conditions; the silicate stabilizers reduced the soil available iron (Fe) but did not limit rice grain Fe nutrition. Additionally, the three silicates promoted rice yield and improved the rice grain Ca and Mg contents; and the application of B increased the amylose concentration of the late rice grains. In conclusion, high amounts of silicate stabilizers did not adversely influence the soil conventional nutrient indices, rice minerals or rice taste, but changes in rice selenium content need attention. Overall, in comparison with lime, silicate stabilizers can improve not only the safety of rice but also the nutritional and taste qualities of rice and are more eco-friendly for long-term use in soil.

Dynamics of growth, physiology, radiation interception, production, and quality of autumn black gram (Vigna mungo (L.) Hepper) as influenced by nutrient scheduling.

To analyse the effect of nutrient management on the growth, physiology, energy utilization, production and quality of black gram, a field trial on black gram was conducted at eastern Indian Gangetic alluvium during the autumn of 2020 and 2021. Treatments were two soil applications of cobalt (Co) and foliar spray of potassium (K) and boron (B) in five combinations. All treatments were arranged in a split-plot design and repeated three times. Two soil applications of cobalt (Co) were assigned in the main plots and foliar spray of potassium (K) and boron (B) in five combinations were assigned in sub-plots. Applications of Co in soil and foliar K+B facilitated significantly higher (p≤0.05) values for aerial dry matter (ADM), leaf area index (LAI), nodules per plant, total chlorophyll, net photosynthetic rate and nitrate reductase content in both 2020 and 2021, with a greater realization of photosynthetically active radiation interception, and use efficiency (IPAR and PARUE respectively), seed yield, seed nutrients and protein contents. Differences in LAI exhibited positive and linear correlation with IPAR explaining more than 60% variations in different growth stages. The innovative combination of soil Co (beneficial nutrient) application at 4 kg ha-1 combined with foliar 1.25% K (macronutrient) + 0.2% B (micronutrient) spray is a potential agronomic management schedule for the farmers to sustain optimum production of autumn black gram through substantial upgradation of growth, physiology, energy utilization, production and quality in Indian subtropics.

Influence of potassium addition on phosphorus availability and heavy metals immobility of biochar derived from swine manure.

Pyrolysis of animal manure at high temperature is necessary to effectively immobilize heavy metals, while the available phosphorus (P) level in biochar is relatively low, rendering it unsuitable for use as fertilizer. In this study, the pretreatment of swine manure with different potassium (K) sources (KOH, K2CO3, CH3COOK and C6H5K3O7) was conducted to produce a biochar with enhanced P availability and heavy metals immobility. The addition of all K compounds lowered the peak temperature of decomposition of cellulose in swine manure. The percentage of ammonium citrate and formic acid extractable P in biochar increased with K addition compared to undoped biochar, with CH3COOK and C6H5K3O7 showing greater effectiveness than KOH and K2CO3, however, water- extractable P did not exhibit significant changes. Additionally, the available and dissolved Si increased due to the doping of K, with KOH and K2CO3 having a stronger effect than CH3COOK and C6H5K3O7. X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that K addition led to the formation of soluble CaKPO4 and silicate. In addition, the incorporation of K promoted the transformation of labile copper (Cu) and znic (Zn) into the stable fraction while simultaneously reducing their environmental risk. Our study suggest that the co-pyrolysis of swine manure and organic K represents an effective and valuable method for producing biochar with optimized P availability and heavy metals immobility.

Sewage sludge fertilization affects microbial community structure and its resistome in agricultural soils.

Global sewage sludge production is rapidly increasing, and its safe disposal is becoming an increasingly serious issue. One of the main methods of municipal sewage sludge management is based on its agricultural use. The wastewater and sewage sludge contain numerous antibiotic resistance genes (ARGs), and its microbiome differs significantly from the soil microbial community. The aim of the study was to assess the changes occurring in the soil microbial community and resistome after the addition of sewage sludge from municipal wastewater treatment plant (WWTP) in central Poland, from which the sludge is used for fertilizing agricultural soils on a regular basis. This study used a high-throughput shotgun metagenomics approach to compare the microbial communities and ARGs present in two soils fertilized with sewage sludge. The two soils represented different land uses and different physicochemical and granulometric properties. Both soils were characterized by a similar taxonomic composition of the bacterial community, despite dissimilarities between soils properties. Five phyla predominated, viz. Planctomycetes, Actinobacteria, Proteobacteria, Chloroflexi and Firmicutes, and they were present in comparable proportions in both soils. Network analysis revealed that the application of sewage sludge resulted in substantial qualitative and quantitative changes in bacterial taxonomic profile, with most abundant phyla being considerably depleted and replaced by Proteobacteria and Spirochaetes. In addition, the ratio of oligotrophic to copiotrophic bacteria substantially decreased in both amended soils. Furthermore, fertilized soils demonstrated greater diversity and richness of ARGs compared to control soils. The increased abundance concerned mainly genes of resistance to antibiotics most commonly used in human and animal medicine. The level of heavy metals in sewage sludge was low and did not exceed the standards permitted in Poland for sludge used in agriculture, and their level in fertilized soils was still inconsiderable.

Planting pattern and nitrogen management strategies: positive effect on yield and quality attributes of Triticum aestivum L. crop.

Wheat (Triticum aestivum L.) is a staple food crop that plays a crucial role in global food security. A suitable planting pattern and optimum nitrogen (N) split management are efficient practices for improving wheat production. Therefore, an experiment was performed to explore the effect of N split management and sowing patterns on wheat at the Agronomy Research Farm, The University of Agriculture Peshawar, during rabi season 2020-21 and 2021-22. The treatments consisted of different nitrogen rates of 0, 80, 120, and 160 kg ha- 1 and planting patterns of W, M, broadcast and line sowing. The pooled analysis of both cropping seasons showed that application of 120 kg N ha- 1 increased spikelets spike- 1, grains spike- 1, 1000 grains weight, grain yield, grain N content, evapotranspiration and water use efficiency by 21.9, 16.7, 21.8, 70, 13, 19.9 and 40% as compared to control, respectively. In addition, W and M were observed the best management practices among all planting patterns. The M planting pattern enhanced chlorophyll a, b, carotenoids and evapotranspiration while W plating pattern improved yield components and yield of wheat as compared to broadcast planting patterns. The principal component analysis biplot showed a close association of M and W planting patterns with 120 kg N ha- 1 in most of the studied traits. Hence, it is concluded that split application of 120 kg N ha- 1 in W and M sowing patterns enhanced growth, biochemical traits and water use efficiency, reducing N fertilization from 160 to 120 kg ha- 1 while increasing grain yield of wheat. Hence, it is recommended that application of 120 kg N ha⁻¹ in combination with W and M planting patterns offer a sustainable approach to enhancing wheat production in the alkaline soil conditions of the Peshawar valley.

Effect of combined application of inorganic nitrogen and phosphorus to an organic-matter poor soil on soil organic matter cycling.

Background: Sequestering carbon dioxide (CO2) in agricultural soils promises climate change mitigation as well as sustainable ecosystem services. In order to stabilize crop residues as soil carbon (C), addition of mineral nutrients in excess to crop needs is suggested as an inevitable practice. However, the effect of two macronutrients i.e., nitrogen (N) & phosphorus (P), on C cycling has been found contradictory. Mineral N usually decreases whereas mineral P increases the soil organic C (SOC) mineralization and microbial biomass. How the addition of these macronutrients in inorganic form to an organic-matter poor soil affect C cycling remains to be investigated. Methods: To reconcile this contradiction, we tested the effect of mineral N (120 kg N ha-1) and/or P (60 kg N ha-1) in presence or absence of maize litter (1 g C kg-1 soil) on C cycling in an organic-matter poor soil (0.87% SOC) in a laboratory incubation. Soil respiration was measured periodically during the incubation whereas various soil variables were measured at the end of the incubation. Results: Contrary to literature, P addition stimulated soil C mineralization very briefly at start of incubation period and released similar total cumulative CO2-C as in control soil. We attributed this to low organic C content of the soil as P addition could desorb very low amounts of labile C for microbial use. Adding N with litter built up the largest microbial biomass (144% higher) without inducing any further increase in CO2-C release compared to litter only addition. However, adding P with litter did not induce any increase in microbial biomass. Co-application of inorganic N and P significantly increased C mineralization in presence (19% with respect to only litter amended) as well as absence (41% with respect to control soil) of litter. Overall, our study indicates that the combined application of inorganic N and P stabilizes added organic matter while depletes the already unamended soil.

A review on fungal-based biopesticides and biofertilizers production.

The escalating use of inorganic fertilizers and pesticides to boost crop production has led to the depletion of natural resources, contamination of water sources, and environmental crises. In response, the scientific community is exploring eco-friendly alternatives, such as fungal-based biofertilizers and biopesticides, which have proven effectiveness in enhancing plant health and growth while sustainably managing plant diseases and pests. This review article examines the production methodologies of these bioproducts, highlighting their role in sustainable agriculture and advancing our understanding of soil microorganisms. Despite their increasing demand, their global market presence remains limited compared to traditional chemical counterparts. The article addresses: 1) the production of biofertilizers and biopesticides, 2) their contribution to crop productivity, 3) their environmental impact and regulations, and 4) current production technologies. This comprehensive approach aims to promote the transition towards more sustainable agricultural practices.

Effect of graphene oxide on carbon and nitrogen metabolism and growth of kidney bean at flowering stage.

Graphene oxide (GO) is a novel nanomaterial being applied in different fields, but was less used as foliar fertilizer in agriculture. We conducted a pot experiment to analyze the effects of foliar spraying GO from 0 (control), 50 (T1), 100 (T2), 150 (T3) and 200 mg·L-1 (T4) on the morphogenesis and carbon and nitrogen metabolism of kidney bean plants during the initiation of flowering to clarify the physiological effects of foliar spraying GO. The results showed that dry matter accumulation, the content of photosynthetic pigments, soluble sugars of T1 to T4 treatments, were significantly increased by 40.7%-43.4%, 10.4%-80.7%, 6.4%-9.1% in kidney bean plants compared with CK treatment, respectively. T3 treatment performed the best. Meanwhile, the activities of sucrose phosphate synthase, acid converting enzyme and neutral converting enzyme of T3 and T4 treatments were increased by 25.7%-45.5%, 17.4%-28.6%, and 14.7%-20.1%, and the activities of nitrate reductase, glutamine synthetase, and glutamate synthetase of T2 and T3 treatments were increased by 8.1%-15.2%, 11.5%-25.0%, and 89.7%-93.1%, respectively. In conclusion, foliar spraying of appropriate GO in early flowering stage of kidney bean could increase the content of photosynthetic pigments, improve the level of photosynthetic carbon and nitrogen metabolism, and increase dry matter accumulation. T3 treatment (150 mg·L-1) was the most effective in this study.

[Effects of water and nitrogen management on photosynthetic matter production and yield of wheat]. / æ°´æ°®è¿ç­¹å¯¹å°éº¦å ‰åˆç‰©è´¨ç”Ÿäº§å’Œäº§é‡çš„å½±å“.

The shortage of water resources and the irrational application of nitrogen fertilizer restrict the synergistic enhancement of yield and water- and fertilizer-use efficiencies of wheat in the Huang-Huai-Hai region. In this study, we conducted an experiment following two-factor split zone design with three irrigation levels and four nitrogen application rates. The relative water content of the 0-40 cm soil layer was supplemented to 65% (W1), 75% (W2), and 85% (W3) of field water capacity at the jointing and anthesis stages of wheat. The rates of nitrogen application were 0 (N0), 150 (N1), 180 (N2), and 210 (N3) kg·hm-2. We analyzed the effects of these different managements on post-anthesis photosynthetic matter production, yield, and water- and nitrogen-use efficiencies. The results showed that yield first increased with increases in the levels of irrigation and nitrogen application, peaking under the W2N2 treatment (9103.53 kg·hm-2). However, further increases in water and nitrogen input did not have further enhancement of wheat yield. Under the same nitrogen application condition, compared with W1 treatment, the canopy light interception rate, chlorophyll relative content and actual photochemical efficiency after anthesis increased by 4.5%-6.0%, 19.7%-28.2%, and 7.5%-9.8% in response to the W2 treatment, respectively, without any difference between the W2 and W3 irrigation levels. At the same irrigation level, post-anthesis dry matter accumulation in repose to the N2 treatment increased by 80.1%-88.9% and 16.7%-22.2% compared with N0 and N1 treatments, respectively, without significant difference between the N2 and N3 treatments. Both the irrigation water-use efficiency (IWUE) and the nitrogen partial factor productivity declined with increases in the levels of irrigation and nitrogen application. Under the W1, W2, and W3 treatments, the values obtained for IWUE were 16.23, 11.01, and 7.91 kg·hm-2·m-3, respectively, whereas in response to the N1, N2, and N3 treatments, N partial factor productivity was 50.8%, 48.4%, and 42.5%, respectively. In all, based on soil moisture measurements and assessments of wheat yield and water- and nitrogen-use efficiencies, the optimal water and nitrogen management strategy for enhancing wheat yield in the Huang-Huai-Hai region is supplementation of water content of 0-40 cm soil layer at the jointing and anthesis stages to 75% field capacity combined with the application of 180 kg·hm-2 nitrogen (W2N2). This approach could achieve high yield and efficiency and promote conservation of water and fertilizer.

[Construction effect of fertile cultivated layer in albic soil â Effects of inversion tillage with organic mate-rials on the redistribution of organic matter in surface layer of albic soil]. / 白浆土肥沃耕层构建效应â .不同有机物料深混对白浆土有机质在表层土壤中再分布的影响.

Soil organic matter serves as a crucial indicator for soil quality. Albic soil, characterized by a barrier layer, exhibits limitations in organic matter content, which can adversely affect crop growth and development. To elucidate the impact of deep mixing of various organic materials on the redistribution of organic matter in the surface soil of albic soil could provide theoretical and technical insights for establishing suitable plough layers for albic soil in Northeast China. We conducted a two-year positioning experiment in Shuangyashan, Heilongjiang Province with five treatments, conventional shallow tillage (0-15 cm, CK), inversion tillage (0-35 cm) without or with straw return (T35 and T35+S), inversion tillage with cattle manure (T35+M) and cattle manure plus maize straw (T35+S+M). The results showed that soil fertilization via deep mixing of organic materials to a depth of 35 cm significantly increased maize yield in albic soil, with the T35+S+M treatment demonstrating the most pronounced effect, yielding an average production of 2934.76 kg·hm-2. Compared to CK, the T35 treatment resulted in a significant 8.4% decrease in organic matter content in the tillage layer, a significant 7.6% increase in organic matter in the sub-tillage layer, and a relative richness degree of soil organic matter in the sub-tillage layer increased by 17.5%. Deep mixed return of organic materials following deep ploughing markedly increased organic matter content of the plough layer, with organic matter conversion ranging from 16.3% to 31.0%. In comparison to the T35 treatment, there was no significant increase in soil organic matter content in the T35+S tillage layer and sub-tillage layer. Conversely, soil organic matter content increased by 4.6% and 6.9% in the T35+M and T35+S+M treatments, with corresponding increase of 11.2% and 15.4% in sub-tillage layer, respectively. Additionally, the soil organic matter richness index in sub-tillage layer increased by 2.5% and 5.1%, respectively. There was a significant positive correlation between organic matter content in the entire plough layer and maize yield, with a contribution rate of 17.5%. Therefore, the utilization of organic fertilizer or a combination of organic fertilizer and straw deep mixing can quickly fertilize albic soil by increasing soil organic matter content in both the whole tillage layer (0-35 cm) and the sub-tillage layer (15-35 cm).

[Effects of Streptomyces pactum Act12 on root morphogenesis and medicinal quality of Codonopsis pilosula]. / 密旋链霉菌Act12å¯¹å šå‚æ ¹ç³»å½¢æ€åŠè¯æå“è´¨çš„å½±å“.

As a kind of tonic Chinese medicine with dual use in medicine and food, there is a large market demanding for Codonopsis pilosula. Taking one-year-old C. pilosula seedlings as materials, we conducted a field experiment to examine the effect of compound fertilizer (750 kg·hm-2), organic fertilizer (15 t·hm-2) and Streptomyces pactum Act12 agent (9 t·hm-2 Act12+10 t·hm-2 organic fertilizer) treatments on root morphology, secondary metabolite content and expression level of lobetyolin metabolic pathway gene of C. pilosula, to clarify the effects of three fertilizers on the root morphology and medicinal quality. Compared to the control (10 t·hm-2 organic fertilizer, conventional fertilization), three fertilization treatments could promote root growth and formation. All fertilization treatments promoted the accumulation of C. pilosula polysaccharides and secondary metabolites. Act12 agent significantly increased the content of lobetyolin, atractylenolideIII, and 5-hydroxymethylfurfural. The qRT-PCR analysis indicated that three fertilization treatments increased the expression level of lobetyolin metabolic pathway genes, with Act12 agent treatment showing the most significant effect. Pearson correlation analysis demonstrated that the expression level of CpHCT and CpFAD genes was significantly positively correlated with atractylenolide III content. In conclusion, three fertilization treatments could effectively improve the yield and quality of C. pilosula. Among the three treatments, Act12 agent performed better than that of compound fertilizer and organic fertilizer, which was an effective measure to increase the yield and quality of C. pilosula.

Role of reactive nitrogen species in changing climate and future concerns of environmental sustainability.

The nitrogen (N) cycle is an intricate biogeochemical process that encompasses the conversion of several chemical forms of N. Given its role in food production, the need for N for life on Earth is obvious. However, the release of reactive nitrogen (Nr) species throughout different biogeochemical processes contributes to atmospheric pollution. Several human activities generate many species, including ammonia, nitrous oxide (N2O), nitric oxide, and nitrate. The primary reasons for this change are the use of nitrogen-based fertilizers, industrial activities, and the burning of fossil fuels. N2O poses a significant threat to environmental sustainability on our planet, with its global warming potential approximately 298 times greater than that of CO2. It has direct or indirect impacts on the environment, agroecosystem, and human life on earth. Solar, hydroelectric, geothermal, and wind turbines must be used to reduce Nr emissions. In addition, enterprises should install catalytic converters to minimize nitrogen gas emissions. To reduce Nr emissions, strategic interventions like fertilizer balancing are needed. This work will serve as a comprehensive guide for researchers, academics, and policymakers. Additionally, it will also assist social workers in emphasizing the Nr issue to the public in order to raise awareness within worldwide society.

RNA-seq reveals the gene expression in patterns in Populus × euramericana 'Neva' plantation under different precision water and fertilizer-intensive management.

BACKGROUND: Populus spp. is a crucial fast-growing and productive tree species extensively cultivated in the mid-latitude plains of the world. However, the impact of intensive cultivation management on gene expression in plantation remains largely unexplored. RESULTS: Precision water and fertilizer-intensive management substantially increased key enzyme activities of nitrogen transport, assimilation, and photosynthesis (1.12-2.63 times than CK) in Populus × euramericana 'Neva' plantation. Meanwhile, this management approach had a significant regulatory effect on the gene expression of poplar plantations. 1554 differential expression genes (DEGs)were identified in drip irrigation (ND) compared with conventional irrigation. Relative to ND, 2761-4116 DEGs, predominantly up-regulated, were identified under three drip fertilization combinations, among which 202 DEGs were mainly regulated by fertilization. Moreover, drip irrigation reduced the expression of cell wall synthesis-related genes to reduce unnecessary water transport. Precision drip and fertilizer-intensive management promotes the synergistic regulation of carbon and nitrogen metabolism and up-regulates the expression of major genes in nitrogen transport and assimilation processes (5 DEGs), photosynthesis (15 DEGs), and plant hormone signal transduction (11 DEGs). The incorporation of trace elements further enhanced the up-regulation of secondary metabolic process genes. In addition, the co-expression network identified nine hub genes regulated by precision water and fertilizer-intensive management, suggesting a pivotal role in regulating the growth of poplar. CONCLUSION: Precision water and fertilizer-intensive management demonstrated the ability to regulate the expression of key genes and transcription factor genes involved in carbon and nitrogen metabolism pathways, plant hormone signal transduction, and enhance the activity of key enzymes involved in related processes. This regulation facilitated nitrogen absorption and utilization, and photosynthetic abilities such as light capture, light transport, and electron transport, which faintly synergistically regulate the growth of poplar plantations. These results provide a reference for proposing highly efficient precision intensive management to optimize the expression of target genes.

Enhanced nitrous oxide emission factors due to climate change increase the mitigation challenge in the agricultural sector.

Effective nitrogen fertilizer management is crucial for reducing nitrous oxide (N2O) emissions while ensuring food security within planetary boundaries. However, climate change might also interact with management practices to alter N2O emission and emission factors (EFs), adding further uncertainties to estimating mitigation potentials. Here, we developed a new hybrid modeling framework that integrates a machine learning model with an ensemble of eight process-based models to project EFs under different climate and nitrogen policy scenarios. Our findings reveal that EFs are dynamically modulated by environmental changes, including climate, soil properties, and nitrogen management practices. Under low-ambition nitrogen regulation policies, EF would increase from 1.18%-1.22% in 2010 to 1.27%-1.34% by 2050, representing a relative increase of 4.4%-11.4% and exceeding the IPCC tier-1 EF of 1%. This trend is particularly pronounced in tropical and subtropical regions with high nitrogen inputs, where EFs could increase by 0.14%-0.35% (relative increase of 11.9%-17%). In contrast, high-ambition policies have the potential to mitigate the increases in EF caused by climate change, possibly leading to slight decreases in EFs. Furthermore, our results demonstrate that global EFs are expected to continue rising due to warming and regional drying-wetting cycles, even in the absence of changes in nitrogen management practices. This asymmetrical influence of nitrogen fertilizers on EFs, driven by climate change, underscores the urgent need for immediate N2O emission reductions and further assessments of mitigation potentials. This hybrid modeling framework offers a computationally efficient approach to projecting future N2O emissions across various climate, soil, and nitrogen management scenarios, facilitating socio-economic assessments and policy-making efforts.

The efficiency of adjusting nutrient solution renewal frequency on physicochemical properties and microbial community of cucumber exudates under closed cultivation tank.

The closed nutrient solution management method allows for the recycling and utilization of nutrient solutions, improving the efficiency of water and fertilizer utilization. This study was conducted to investigate the effects of changing the frequency of nutrient solution renewal and method of nutrient supply on the microbial communities composition, yield, and quality in closed soilless systems by using high-throughput sequencing technology and combining the physicochemical properties of root exudate solution. The results showed that different nutrient solution management modes had a significant impact on the structure and diversity of root exudate solution microbial communities. The abundance and diversity of microorganisms in inorganic perlites were correlative with EC. The abundance and diversity of bacterial communities in the root exudate solution of open liquid supply (CK) were higher than that of closed liquid supply, while the abundance and diversity of fungal communities in the root exudate solution of closed liquid supply (T1, T2, T3) were higher than that of open liquid supply. As the frequency of nutrient solution interval decreased, the accumulation of salt in root exudate solution and the richness and diversity of the fungal community also decreased, especially increasing the K+, Ca2+, and Mg2+ contents, which were positively correlated with potential beneficial Candidatus_Xiphinematobacter, Arachidicoccus, Cellvibrio, Mucilaginibacter, Taibaiella communities and decreasing the content of soluble protein, Vitamin C content, but not significantly increased cucumber yield.

Fertilization regulates global thresholds in soil bacteria.

Global patterns in soil microbiomes are driven by non-linear environmental thresholds. Fertilization is known to shape the soil microbiome of terrestrial ecosystems worldwide. Yet, whether fertilization influences global thresholds in soil microbiomes remains virtually unknown. Here, utilizing optimized machine learning models with Shapley additive explanations on a dataset of 10,907 soil samples from 24 countries, we discovered that the microbial community response to fertilization is highly dependent on environmental contexts. Furthermore, the interactions among nitrogen (N) addition, pH, and mean annual temperature contribute to non-linear patterns in soil bacterial diversity. Specifically, we observed positive responses within a soil pH range of 5.2-6.6, with the influence of higher temperature (>15°C) on bacterial diversity being positive within this pH range but reversed in more acidic or alkaline soils. Additionally, we revealed the threshold effect of soil organic carbon and total nitrogen, demonstrating how temperature and N addition amount interacted with microbial communities within specific edaphic concentration ranges. Our findings underscore how complex environmental interactions control soil bacterial diversity under fertilization.

Tracing Nitrogen Flows Associated with Beef Supply Chains: A Consumption-Based Assessment.

While highly connected food chains provide numerous benefits, they lack traceability and transparency. As such, understanding the spatial heterogeneity in their environmental burdens is critical for targeted interventions. This is especially important for nutrient-related impacts such as nitrogen since the release of reactive nitrogen has been linked to loss of biodiversity and decrease in water quality in different parts of the world. Animal feed production is heavily dependent on synthetic fertilizers, and the consumption of beef products, in particular, is associated with high nitrogen footprints. Although there is a rich body of work on nutrient footprints of beef production, there is a gap in understanding the spatial distribution of the nutrient releases throughout the beef supply chain in the U.S. We present an optimization-based framework to trace supply chain networks of beef products at the county level. Using publicly available data, we construct a weighted network of nutrient flows based on mass balance, including synthetic fertilizers, manure production, and crop uptake and residues. The results show that beef consumption in a county can be associated with nitrogen losses in hundreds of counties. One year worth of beef consumption in the United States released approximately 1.33 teragrams (Tg) of N to the environment, and most of it as diffuse pollution during the feed production phase. Analysis also revealed the huge disparity between consumption-based and production-based impacts of beef and the need for considering consumption-based accounting in discourse around the environmental sustainability of food systems.

Improving semi-arid agroecosystem services with cover crop mixes.

Winter wheat (Triticum aestivum, L.) production in the semi-arid US Northern High Plains (NHP) is challenged by frequent droughts and water-limited, low fertility soils. Composted cattle manure (compost) and cover crops (CC) are known to provide agroecosystem services such as improved soil health, and in the CC case, increased plant diversity, and competition with weedy species. The main concern of planting CC in winter wheat fallow rotation in regions that are more productive than the NHP, however, is the soil moisture depletion. It is unknown however, whether addition of CC to compost-amended soils in the NHP will improve soil properties and agroecosystem health without compromising already low soil water content. The main objective of this study was to assess the effects of four CC treatments amended with compost (45 Mg ha-1) or inorganic fertilizer (IF) (.09 Mg ha-1 mono-ammonium phosphate, 11-52-0 and 1.2 Mg ha-1ammonium sulfate, 21-0-0) on the presence of weeds, soil and plant total carbon (C), nitrogen (N), and biological dinitrogen (N2) fixation (BNF). Mycorrhizal Mix (MM), Nitrogen Fixer Mix (NF), Soil Building Mix (SB), a monoculture of phacelia (Phacelia tanacetifolia Benth L.) (PH), and a no CC control (no CC) were grown in native soil kept at 7% soil moisture in a greenhouse for a period of nine weeks. When amended with compost, MM was the most beneficial (48 g m-2 BNF and 1.7% soil C increase). SB had the highest germination, aboveground biomass, and decreased weed biomass by 60%. It also demonstrated the second highest amount of BNF (40 g m-2) and soil C increase by 1.5%. On contrary, IF hindered BNF by almost 70% in all legume-containing CC treatments and reduced soil C by 15%.

Effects of humic acid fertilizer on the growth and microbial network stability of Panax notoginseng from the forest understorey.

Humic acid (HA) can substantially enhance plant growth and improve soil health. Currently, the impacts of HA concentrations variation on the development and soil quality of Panax notoginseng (Sanqi) from the forest understorey are still unclear. In this study, exogenous HA was administered to the roots of Sanqi at varying concentrations (2, 4, and 6 ml/L). Subsequently, the diversity and community structure of bacteria and fungi were assessed through high-throughput sequencing technology. The investigation further involved analyzing the interplay among the growth of sanqi, soil edaphic factors, and the microbial network stability. Our finding revealed that moderate concentrations (4 ml/L) of HA improved the fresh/dry weight of Sanqi and NO3--N levels. Compared with control, the moderate concentrations of HA had a notable impact on the bacterial and fungal communities compositions. However, there was no significant difference in the α and ß diversity of bacteria and fungi. Moreover, the abundance of beneficial bacteria (Bradyrhizobium) and harmful bacteria (Xanthobacteraceae) increased and decreased at 4 ml/L HA, respectively, while the bacterial and fungal network stability were enhanced. Structural equation model (SEM) revealed that the fresh weight of Sanqi and bacterial and fungal communities were the factors that directly affected the microbial network stability at moderate concentrations of HA. In conclusion, 4 ml/L of HA is beneficial for promoting Sanqi growth and soil quality. Our study provides a reference for increasing the yield of Sanqi and sustainable development of the Sanqi-pine agroforestry system.