Soil Nutrient Accumulation Research Articles

Crop Rotation of Sainfoin on the Longzhong Loess Plateau Has a Positive Effect on Enhancing Soil Carbon Sequestration Potential

The impact of various crop rotation systems on the potential for soil carbon sequestration and stoichiometric characteristics is not yet fully understood, which poses challenges for effective land management and utilization. This study selected three typical crop rotation methods in the Longzhong Loess Plateau: maize–alfalfa rotation (MA), maize–sainfoin rotation (MS), and maize–wheat rotation (MW). Soil physical and chemical indices were measured, and the soil carbon density and soil stoichiometry were calculated and analyzed. The results show that the soil C/N of the surface soils was low across the rotation methods, indicating a rapid rate of organic matter decomposition and mineralization, which may hinder soil nutrient accumulation. The soil N/P was found to be lower than the national average of 8.0, indicating that nitrogen is a limited nutrient in the soil under the three crop rotation systems in this region. The soil total nitrogen content can be increased by rotation with leguminous forage. Sainfoin rotation can enhance the soil total carbon and organic carbon content, thereby improving the soil’s carbon sequestration potential. The research findings provide a theoretical foundation for the selection of appropriate rotation methods and the maintenance of the stability of agricultural ecosystems in semi-arid regions.

Impact of pine wilt disease infection on multiple ecosystem services and their trade-offs in subtropical Masson pine forests

Pine wilt disease (PWD) severely damages the health, stability, and functions of pine forests. However, empirical evidence regarding the impact of PWD on multiple ecosystem services in these forest ecosystems remains limited. This study investigated five ecosystem services, namely carbon sequestration, water conservation, soil nutrient accumulation, biomass nutrient accumulation and understory plant diversity in subtropical Masson pine (Pinus massoniana) forests, and quantified their trade-offs along varying ages of PWD infection (uninfected (0 years), 6, 10, and 16 years). The results showed that PWD infection significantly affected ecosystem services in Masson pine forests, with decreased carbon sequestration, water conservation, and biomass nutrient accumulation in 6 years of PWD infection forests. As the duration of PWD infection increased, the composite score of ecosystem services initially decreased, then increased, and finally decreased again. In contrast, soil conservation and understory plant diversity showed an initial increase, followed by a decline. Moreover, PWD infection increased the trade-offs among ecosystem services, with the highest trade-offs for 10 years of infected forests. PWD infection altered the trade-offs between understory plant diversity and other ecosystem services from low to high levels. Our results suggest that forest management should be strengthened to accelerate the recovery of ecosystem services while controlling PWD infection in these disturbed forests.

Organic substitution by pig manure combined with straw maintained reasonable content of soil available nutrients without productivity losses in autumn Chinese cabbage–spring pepper rotation system

Sustainable fertilization practices have been explored using both inorganic and organic nutrient sources. Replacing half of the inorganic nitrogen fertilizer with organic fertilizer still resulted in excess accumulation of available soil nutrients under continuous vegetable planting. In addition to substituting chemical fertilizer with pig manure (50 % pig manure+50 % chemical fertilizer, PMF) at a 50 % nitrogen rate, another treatment was added where pig manure was substituted with cereal straw (25 % straw+25 % pig manure+50 % chemical fertilizer, SMF) at a 25 % nitrogen rate. The agronomic and economic effects were compared with the fertilization solely with total chemical fertilizer (100 % chemical fertilizer, TCF) for a seven-year autumn Chinese cabbage-spring pepper rotation. Regardless of the crop, year, and key productivity parameters, the PMF treatment fully achieved half the fertilizer replacement values. In the spring pepper season, the marketable fresh yield, shoot biomass, gross output, and profits are significantly higher for the PMF treatment compared to the SMF and TCF treatments. Compared with the TCF treatment, the rapidly increasing NO3--N content was reduced under the PMF treatment, but the available phosphorus and potassium contents excessively accumulated to >300 mg kg-1 each in the soil. The available soil phosphorus and potassium increased and remained within a reasonable range without a loss of rotation productivity with the SMF treatment. The long-term study with optimized fertilization regimes revealed the basic laws of nutrient accumulation in soil and plants. The findings will be important in the use of combined fertilizer sources for vegetable production.

Exotic mangrove Laguncularia racemosa litter input accelerates nutrient cycling in mangrove ecosystems.

Exotic plant litter presents different chemical and physical properties relative to native plant litter and alters ecosystem processes and functions that may facilitate exotic plant dispersal. However, these effects are largely unknown, especially within wetland ecosystems. This study examines whether introducing litter from theexotic mangrove Laguncularia racemosa could result in (1) accelerated community litter decomposition rates and increased nutrient cycling rates and (2)microbial community structure changes in the invaded areas. A single decomposition experiment using litterbags was conducted to examine the short-term effects of L. racemosa litter in the native mangrove forest ecosystem. The soil nutrients and microbial communities of Rhizophora stylosa, L. racemosa, and mixed forests were also compared to explore the long-term cumulative effects of L. racemosa litter in native ecosystems. The results indicated that L. racemosa has lower-quality leaf litter than R. stylosa and a significantly faster decomposition rate. This may result from changes in the soil microbial community structure caused by L. racemosa leaf litter input, which favors the decomposition of its own litter. Both the short-term and cumulative effect experiments demonstrated that L. racemosa leaf litter significantly increased the relative abundance of microbes related to litter decomposition, such as Proteobacteria and Bdellovibrionota, and enhanced the alpha diversity of soil fungi, thus creating a microbial environment conducive to L. racemosa leaf litter decomposition. Moreover, the accumulation of soil nutrients was lower under L. racemosa than under R. stylosa over several years. This may be related to the more rapid growth of L. racemosa, which causes soil nutrient absorption and storage within the plant tissues, thereby reducing the soil nutrient content. Inputting exotic mangrove L. racemosa leaf litter reduced the soil blue carbon content, potentially adversely affecting global climate change. L. racemosa may employ a unique strategy to lower soil nutrient levels in native mangroves based on its low-quality leaf litter, thereby weakening the competitive ability of native plants that are intolerant to low-nutrient conditions and enhancing its own competitive advantage to further spread into these areas. In summary, the input of exotic L. racemosa leaf litter accelerates nutrient cycling in local mangroves.

Soil Nutrients Inversion in Open‐Pit Coal Mine Reclamation Area of Loess Plateau, China: A Study Based on ZhuHai‐1 Hyperspectral Remote Sensing

ABSTRACTSoil nutrients are crucial to assess land reclamation quality, and the use of various types of remote sensing data for soil nutrient inversion has been a key focus for soil monitoring. However, fewer studies have been conducted using satellite‐based hyperspectral remote sensing. To explore the potential of satellite‐based hyperspectral remote sensing in soil nutrient monitoring, this study selected soil organic matter, total nitrogen, available phosphorus, and available potassium content data from 83 sample sites using ZhuHai‐1 hyperspectral data. After spectral transformation and feature extraction, various inversion models were constructed, including partial least squares regression, support vector machine, recurrent neural network, and random forest. After verification by accuracy, the best spectral‐model combination was used for inversion. The results showed that the R‐squared range of the inversion models was 0.67748–0.78115. High content areas of soil organic matter and available potassium exhibited concentrated and contiguous features, while high content areas of total nitrogen and available phosphorus were more fragmented and fine‐grained. Alfalfa grassland plays a vital role in improving reconstructed soil in the early reclamation stage, and agricultural activities have differential impacts on soil nutrient accumulation. This study provides a theoretical basis for verifying the application capability of ZhuHai‐1 hyperspectral satellite data in soil monitoring.

Organic matter and nutrient content within putting green root zones in Tennessee

AbstractOrganic matter and soil nutrient accumulation within putting green root zones affects surface quality and performance. Research was conducted to explore differences in organic matter and nutrient content within creeping bentgrass (CBG; Agrostis stolonifera L.) and ultradwarf bermudagrass [UDBG; C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] putting greens. Sampling was conducted from January 30 to February 23, 2023, on 22 putting greens (11 CBG and 11 UDBG) in Tennessee. Forty cores (1.91‐cm diameter by 10‐cm depth) were randomly collected from each putting green and analyzed for total organic material (TOM; undisturbed cores) by profile depth (0–2 cm, 2–4 cm, and 4–6 cm), TOM throughout a 10‐cm core, soil organic matter (SOM; passed through sieve with 2 mm openings) throughout a 10‐cm core, and nutrient content. All organic matter measurements were determined via loss‐on‐ignition (LOI) testing, whereas nutrient content was determined by Mehlich‐3 extraction. LOI testing at 440°C resulted in greater TOM values than 360°C; however, values from both temperatures were closely related (R2 = 0.99). TOM values from UDBG greens were greater than those recorded on CBG at all profile depths. Greens established via no‐till conversion contained more TOM than those planted in a constructed sand‐matrix root zone. While TOM and SOM were associated (R2 = 0.62), removing verdure for SOM assessments reduced the amount of organic material in each sample by 38% and increased variability. Nutrient contents were lower than sufficiency level of available nutrients benchmarks but exceeded minimum levels for sustainable nutrition.

The development of terrestrial ecosystems emerging after glacier retreat.

The global retreat of glaciers is dramatically altering mountain and high-latitude landscapes, with new ecosystems developing from apparently barren substrates1-4. The study of these emerging ecosystems is critical to understanding how climate change interacts with microhabitat and biotic communities and determines the future of ice-free terrains1,5. Here, using a comprehensive characterization of ecosystems (soil properties, microclimate, productivity and biodiversity by environmental DNA metabarcoding6) across 46 proglacial landscapes worldwide, we found that all the environmental properties change with time since glaciers retreated, and thattemperature modulates the accumulation of soil nutrients. The richness of bacteria, fungi, plants and animals increases with time since deglaciation, but their temporal patterns differ. Microorganisms colonized most rapidly in the first decades after glacier retreat, whereas most macroorganisms took longer. Increased habitat suitability, growing complexity of biotic interactions and temporal colonization all contribute to the increase in biodiversity over time. These processes also modify community composition for all the groups of organisms. Plant communities show positive links with all other biodiversity components and have a key role in ecosystem development. These unifying patterns provide new insights into the early dynamics of deglaciated terrains and highlight the need for integrated surveillance of their multiple environmental properties5.

Agricultural waste-based modified biochars differentially affected the soil properties, growth, and nutrient accumulation by maize (Zea mays L.) plants

Biochar (BC) is an organic compound formed by the pyrolysis of organic wastes. Application of BCs as soil amendments has many benefits including carbon sequestration, enhanced soil fertility and sustainable agriculture production. In the present study, we acidified the different BCs prepared from rice straw, rice husk, wheat straw, cotton stalk, poultry manure, sugarcane press mud and vegetable waste; following which, we applied them in a series of pot experiments. Comparisons were made between acidified and non- acidified BCs for their effects on seed germination, soil properties (EC, pH) nutrient contents (P, K, Na) and organic matter. The treatments comprised of a control, and all above-described BCs (acidified as well as non-acidified) applied to soil at the rate of 1% (w/w). The maize crop was selected as a test crop. The results showed that acidified poultry manure BC significantly improved germination percentage, shoot length, and biomass of maize seedlings as compared to other BCs and their respective control plants. However, acidified BCs caused a significant decrease in nutrient contents (P, K, Na) of soil,maize seedlings, and the soil organic matter contents as compared to non- acidified BCs. But when compared with control treatments, all BCs treatments (acidified and non-acidified) delivered higher levels of nutrients and organic matter contents. It was concluded that none of the BCs (acidified and non-acidified) had caused negative effect on soil conditions and growth of maize. In addition, the acidification of BC prior to its application to alkaline soils might had altered soil chemistry and delivered better maize growth. Moving forward, more research is needed to understand the long-term effects of modified BCs on nutrient dynamics in different soils. In addition, the possible effects of BC application timings, application rates, particle size, and crop species have to be evaluated systemtically.

Rhizophagus intraradices and Azospirillum brasilense improve growth of herbaceous plants and soil biological activity in revegetation of a recovering coal-mining area.

We assessed, in a field experiment, the effects of arbuscular mycorrhizal fungi (Rhizophagus intraradices) and plant growth-promoting bacteria (Azospirillum brasilense) on the soil biological activity and the growth of key pioneer species used in the revegetation of coal-mining areas undergoing recovery. We applied four inoculation treatments to the pioneer plant species (Lablab purpureus, Paspalum notatum, Crotalaria juncea, Neonotonia wightii, Stylosanthes guianensis, Andropogon gayanus and Trifolium repens) used in the recovery process: NI (Control - Non-inoculated), AZO (A. brasilense), AMF (R. intraradices), and co-inoculation of AZO and AMF. On the 75th and 180th days, we measured plant dry mass, mycorrhizal colonization, N and P concentration, and accumulation in plant tissue. We collected soil to quantify glomalin content and soil enzyme activity. After 180 days, we did a phytosociological characterization of the remaining spontaneous plants.The both microorganisms, singly or co-inoculated, promoted increases in different fractions of soil glomalin, acid phosphatase activity, and fluorescein diacetate activity at 75 and 180 days. The inoculation was linked to higher plant biomass production (62-89%) and increased plant P and N accumulation by 34-75% and 70-85% at 180 days, compared with the non-inoculated treatment. Among the pioneer species sown Crotalaria juncea produced the highest biomass at the 75th and 180th days (67% and 76% of all biomass), followed by Lablab purpureus (3% and 0.5%), while the other species failed to establish. At 180 days, we observed twenty spontaneous plant species growing in the area, primarily from the Poaceae family (74%). That suggests that the pioneer species present in the area do not hinder the ecological succession process. Inoculation of R. intraradices and A. brasilense, isolated or combined, increases soil biological activity, growth, and nutrient accumulation in key pioneer plant species, indicating the potential of that technique for the recovery of lands degraded by coal mining.

Soil bacterial community structure and co‐occurrence networks in response to the succession of secondary forests in subtropical regions

AbstractA large amount of secondary successional vegetation (subtropical evergreen broadleaved forests) has formed after the extensive deforestation and cultivation of coniferous forests in Wuyi Mountain, Southeast China. However, we lack a detailed understanding of the dynamic changes in microbial community structure and its co‐occurrence network during succession. The features that are responsible for alterations in the soil bacterial community remain poorly defined. Therefore, we compared the soil physicochemical properties, enzyme activities, and bacterial diversity among three different forests (a coniferous forest [CF], early stage of succession; a mixed conifer‐broadleaf forest [CBMF], middle stage of succession; an evergreen broadleaf forest [EBF]; late stage of succession). Results indicated that the contents of soil organic carbon and microbial biomass carbon (MBC) in CBMF were higher compared with those in CF. The alpha diversity indices were the highest in CBMF. Functional annotation of prokaryotic taxa predicted the relative abundances of chemoheterotrophy and aerobic chemoheterotrophy were lower in CF than in the other two forests. Bacterial network topology was affected by forest succession, with CBMF having more complex bacterial networks. Mantel's test indicated the soil nitrate nitrogen content (P = 0.03) was the most important property that shaped the bacterial community composition, bacterial diversity was influenced by soil pH (P = 0.026), and the contents of available phosphorus (P = 0.04) and MBC (P = 0.022) during the succession process. In conclusion, the succession of secondary forests promoted soil nutrient accumulation and improved bacterial diversity and network complexity.

Fluvial avulsions influence soil fertility in the Pantanal wetlands (Brazil)

River avulsions drive important changes in the Pantanal wetlands, owing to their role in the hydro-sedimentology of the region. Although relevant to numerous ecosystem services, few studies have analyzed the influence of river avulsions on soil fertility in the Pantanal. Here, we use the largest ongoing avulsion in the Taquari River (Caronal region) to evaluate the effects on soil fertility, considering two factors: avulsion stage (1) and aquatic-terrestrial succession (2). Since both factors are influenced by macrophyte abundance, an incident map was created through tasseled cap indices from Sentinel 2 images to guide sampling efforts in flooded soils. The mapped area was split into two zones of alluvial processes, the first from the apex of the Caronal lobe corresponding to the Taquari River megafan (TRM), and the second as the distal Paraguay River floodplain (PRF). Soil macro- and micronutrient levels were evaluated from 42 surface samples (0–0.2 m) distributed across the two alluvial process zones. The macrophyte map's overall accuracy (OA) was analyzed by a confusion matrix using the Sentinel 2 imagery. Finally, we used Random Forest regressions to determine the influence of response variables on soil attributes, including tassel indices, distance from the Caronal crevasse, macrophyte density, and an existing soil fertility map. The macrophyte map obtained an OA of 93 %. Some parameters such as pH (r = −0.62; R2 = 0.57), effective cation exchange capacity (r = −0.49; R2 = 0.79), Mn (r = −0.71; R2 = 0.6), Zn (r = −0.69; R2 = 0.54), and base saturation (r = −0.7; R2 = 0.93) were influenced by the distance or level of maturation of the avulsion stage in the TRM. Our scattering of soil collections was insufficient to test the terrestrialization hypothesis (2). The study results show that river channel avulsions influence the accumulation of mineral and organic nutrients in tropical floodplain soils, which has implications for fertility and biodiversity.

Influence of nitrogen substitution at an equivalent total nitrogen level on bacterial and fungal communities, as well as enzyme activities of the ditch bottom soil in a rice-fish coculture system.

Rice-fish coculture system (RFS) operates through effectively utilizing water and land resources in a complementary form, but it requires more efficient utilization of fertilizer and feed without compromising rice yield. However, the knowledge of how to regulate the proportion of nitrogen (N) supplied from fertilizer and feed at an equivalent total N levelto improve the benefits of RFS remains limited. Therefore, four treatments (S0: RFS with 0% N fromfertilizer and 100% N from feed; S25: RFS with 25% N from fertilizer and 75% N from feed; S50: RFS with 50% N from fertilizer and 50% N from feed; S75: RFS with 75% N from fertilizer and 25% N from feed) were conducted to assess the variation of ditch bottom soil properties, microbial communities and enzyme activities, as well as to obtain the optimal ratio of N supplied from fish feed and fertilizer. The experiments showed that the contents of soil organic matter, total carbon and total N, and the activities of urease, N-acetyl-β-D-glucosaminidase, protease, β-1,4-glucosidase and catalase in the ditch bottom soil significantly reduced in S25 treatment, compared with the other three treatments. Ammonium N content decreased with increasing percentage of the basal fertilizer, whereas nitrate N content and pH value showed an adverse trend. However, the bacterial and fungal communities were unaffected by the ratio shifts between fertilizer-N and feed-N, but their dominant phyla were influenced by the ditch bottom soil N level. Moreover, the bacterial community composition was positively related to nitrate N, whereas fungal diversity was positively correlated with pH, ammonium N and nitrate N, and urease. We also found that the treatment of N input with 25% N from fertilizer and 75% N from feed can reduce N deposition in the ditch bottom soil in the rice-fish coculture system. Our findings indicate that under the equivalent total N input level, the relative higher ratio of N from fish feed increased (S0 treatment) or reduced (S25 treatment) the deposition of N in the ditch bottom soil, and improved fish production, but decreased rice yield; while the higher ratio of N from basal fertilizer increased the transportation of nutrients into the ditch bottom soil and rice yield, but reduced fish production. So when considering multi-balance and multiple benefits, we recommend that a selective substitution ratio within 50% ~ 75% from fish feed to substitute for the basal fertilizer under the equivalent total N input may achieve a good balance of rice and fish production improvement, and reduce nutrients wastage to the ditch bottom, as well as alleviate the potential of non-point source pollution. This study also provides an evidence for regulating and optimizing the ratio of N supplied from fertilizer and fish feed at an equivalent total N level through monitoring the nutrient accumulation in ditch bottom soil in the rice-fish coculture system. © 2024 Society of Chemical Industry.

Multi-ecosystem services differently affected by over-canopy and understory nitrogen additions in a typical subtropical forest.

Obtaining a holistic understanding of the impacts of atmospheric nitrogen deposition on multiple ecosystem services of forest is essential for developing comprehensive and sustainable strategies, particularly in heavy N deposition regions such as subtropical China. However, such impacts remain incompletely understood, with most previous studies focus on individual ecosystem function or service via understory N addition experiments. To address this knowledge gap, we quantified the effects of over-canopy and understory N additions on multiple ecosystem services based on a 7-year large-scale field experiment in a typical subtropical forest. Our results showed continued over-canopy N addition with 50 kg ha-1 year-1 over a period of 4-7 years significantly increased plant nutrient retention, but did not affect the services of soil nutrient accumulation, water yield, C sequestration (in plants and soil), or oxygen release. There were trade-offs between the soil and plant on providing the services of nutrient accumulation/retention and C sequestration under over-canopy N addition. However, without uptake and retention of tree canopy, the trade-off between soil and plant were more weaken under the understory N addition with 50 kg ha-1 year-1 , and their relationships were even synergetic under the understory N addition with 25 kg ha-1 year-1 . The results suggest that understory N addition cannot accurately simulate the effects of atmospheric N deposition on multiple services, along with mutual relationships. Interestingly, the services of plant N, P retention, and C sequestration exhibited a synergetic increase under the over-canopy N addition but a decrease under the understory N addition. Our results also found tree layer plays a primary role in providing plant nutrient retention service and is sensitive to atmospheric N deposition. Further studies are needed to investigate the generalized effects of forest canopy processes on alleviating the threaten of global change factors in different forest ecosystems.

The threat of groundwater pollution for petrifying springs; defining nutrient threshold values for an endangered bryophyte dominated habitat

Eutrophication by human activities is increasingly affecting ecosystem functioning and plant community composition. So far, studies mainly focus on the effects of atmospheric nitrogen deposition, surface water eutrophication or soil nutrient accumulation. Groundwater pollution of spring habitats, however, has received much less attention, although numerous papers report groundwater nutrient enrichment worldwide. This study presents a survey on groundwater pollution (with emphasis on nitrate and phosphate) and bryophyte composition in 51 ambient petrifying springs in 5 NW European countries, which were compared to published data from 173 other sites in 11 European countries.The reviewed dataset covers a broad range of unpolluted to heavily polluted springs with nitrate concentrations between 0.7 and 3227 μmol l−1. Most petrifying springs in the rural lowlands of NW Europe were found to have elevated concentrations of nitrate and phosphate with the most polluted springs occurring in The Netherlands.The cover of individual characteristic bryophyte species significantly correlates with groundwater nutrient concentrations indicating that nutrient pollution of spring waters affects bryophyte composition. Palustriella commutata, Eucladium verticillatum and Brachythecium rivulare prefer unpolluted petrifying springs whereas Cratoneuron filicinum and Pellia endiviifolia show a much broader tolerance to groundwater pollution. In order to sustain at least the basic conditions for the typical bryophyte composition of petrifying springs habitats, threshold values of 288 μmol (18 mg l−1) NO3− l−1 and 0.42 μmol (0.04 mg l−1) ortho-PO43- l−1 were defined.Data analysis of the spring water composition indicates that the main source for nutrient and nutrient induced base cation enrichment are nitrate losses from intensively used agricultural fields. The anthropogenically induced but regionally different chemical processes in subsoil and aquifers can result in different levels of nutrient pollution in springs.Further regulations for nitrate and phosphate application are required to conserve and restore groundwater fed ecosystems in Europe.

Long–term (25 years) continuous cotton cropping combined with residue incorporation affects the fungal communities in reclaimed saline soil

Soil fungi are essential in the degradation of crop residues in natural systems. However, how long–term continuous cropping combined with residue incorporation (CCRI) affects the fungal communities in reclaimed saline soils is still unclear. In this study, CCRI was implemented in a reclaimed salinized farmland for 0 (control group), 5, 10, 15, 20, and 25 years to explore the effects on soil properties and fungal communities. The results showed that CCRI reduced soil pH, electrical conductivity (EC), and available potassium (AK) by 2.6–8.3%, 24.0–71.4%, and 9.1–59.4%, respectively, and increased soil organ carbon (SOC), total nitrogen (TN), available phosphorus (AP), and microbial biomass carbon (MBC) by 36.0–117.2%, 84.2–173.4%, 18.5–344.8%, and 16.0–206.8%, respectively, compared with the control group (0–yr treatment). CCRI increased soil fungal species richness, but this effect decreased after 15–yr CCRI treatment; Ascomycota had the highest relative abundance (75.8–90.9%) in the CCRI soils. CCRI treatments significantly reduced the relative abundance of symbiotroph, saprotroph, and pathotroph; Especially, the relative abundance of plant pathogen fungi was significantly reduced by (25.5–36.7%), and that of arbuscular mycorrhizal fungi (AMF) was significantly increased (0.01–0.07%), compared with the control group. Besides, the main soil properties affecting soil fungal community were pH and AK. Overall, the 10 – 15 years CCRI treatment was most beneficial for soil nutrient accumulation and maintaining the richness and diversity of fungal communities. However, it also decreased the abundance of some beneficial fungi and increased soil pathogenic fungi. Therefore, the duration of CCRI can not exceed 15 years, and attention can be paid to maintaining the stability of soil fungal community by regulating soil pH and AK content to reduce the negative impact of long term CCRI. This study will have important guiding significance for soil health improvement in arid areas.

Sand-fixing measures improve soil particle distribution and promote soil nutrient accumulation for desert – Yellow River coastal ecotone, China

In the fragile desert ecosystems of the world, sand-fixing measures play an irreplaceable part in ecological restoration. However, it is unclear how the long-term establishment of sand-fixing measures affects soil particle distribution and soil nutrients for the desert – Yellow River coastal ecotone. Therefore, we selected sand-fixing measures that have been established for fifteen years: Pinus sylvestris (PS), Populus alba (PA), Elaeagnus angustifolia (EA), Hedysarum scoparium (HS), Salix psammophila (SC), Salix psammophila checkerboard barriers (SCSB), and mobile sandy land (LS). We analyzed soil physical properties, chemical properties, soil fractal dimension (D), and multi-fractal parameters in the top soil layer (0–20 cm). The results showed that the establishment of sand-fixing measures significantly increased the clay and silt, and decreased the sand (p < 0.05). Sand-fixing measures promote the heterogeneity of soil particle distribution and increase its dispersion. The soil nutrition content was significantly increased under different sand-fixing measures (p < 0.05), and soil organic carbon (SOC) and alkaline nitrogen (AN) changed significantly. The D value is between 2.18 and 2.39. The D value and multifractal parameters were driven by soil physicochemical properties and aboveground biomass (AGB). The regression model demonstrates a significant correlation between the D values and multi-fractal parameters (R2 = 0.58–0.77, p < 0.001). Therefore, we suggest that multifractal parameters can replace the D values as indicators of soil environmental changes in desertification. This study complements the information on the restoration of soils in the desert-Yellow River coastal ecotone by sand-fixing measures. In addition, we suggest that desert ecological management should be tailored to regional environmental differences to establish an integrated model of restoration of sand-fixing measures in the future. The results of this study scientifically provide a theoretical basis for the future reconstruction of ecologically fragile areas.

Functional genomic analysis of nutrient cycling of plant-soil continuum in the mossy biocrust in the Tengger Desert

The microbiome and metabolic processes occurring in the soil of the moss crust-soil continuum contribute to drive biogeochemical cycles. In this study, soil chemical properties of soil which was attached to bryophyte (BRS) and soil which was dropped from bryophyte (BBS) were analyzed. Differences in microbial species composition, metabolic pathways and related genes of these two different soil types were also analyzed. The results showed that the total organic carbon (TOC), total nitrogen (TN) and ammonium nitrogen (NH4+-N) content of BRS were significantly higher than those of BBS. The dominant phylum in the soil microbiome of the moss crust-soil continuum was Actinobacteria. Genes and metabolic pathways related to the carbon, nitrogen, phosphorus, and sulfur cycle differed between BRS and BBS. The carbon sequestration capacity of BRS was higher than that of BBS. The relative abundance of napA, narH and narI genes involved in denitrification and dissimilatory nitrate reduction in the BRS microbiome was significantly higher than that in the BBS microbiome, while the relative abundance of nasA, NR and nirA genes involved in assimilatory nitrate reduction in the BRS soil microbiome was significantly lower than that in the BBS soil microbiome. The relative abundance of glpQ genes encoding glycerophosphodiester phosphodiesterase in the BRS microbiome was significantly higher than that in the BBS microbime, while the relative abundance of pstS, pstA, pstC, pstB genes responsible for phosphate-specific transport systems in the BRS microbiome was significantly lower than that in the BBS microbiome. The abundance of the assimilatory sulfate-reducing metabolic pathway in the BRS microbiome was significantly higher than that in the BBS microbiome, while the dissimilatory sulfate-reducing metabolic pathway in the BRS microbiome was significantly lower than that in the BBS microbiome. The study found that the microbiome in the soil which was attached to bryophyte plays a more important role in the accumulation of soil nutrients in the Tengger Desert through biodiversity and metabolic activity.

Biological control of gentian spot blight by the combination of endophytic fungi fermentation broth and traditional Chinese medicine extractions

Gentian spot blight is a disease that decreases yields. Soil treatment can improve both plant growth and resistance to this disease. We investigated the effectiveness of endophytic fungi fermentation broth combined with traditional Chinese medicine (TCM) extractions in the biological control of gentian spot blight. We tested the anti-pathogen and growth-promoting properties of the endophytic fungi 3714, 272 fermentation broth, and 12 different TCM extractions in various solvents alone or in combination. The experiment was conducted in the field by treating gentian with various mixtures and examining their effect in controlling gentian spot blight. The combination of TCM water extractions and endophytic fungi fermentation broth, Anemarrhena asphodeloides Bge (ZM), ZM-272, Cnidium monnieri (L.). Cuss. (SCZ)-3714 and ZM-SCZ-3714 significantly controlled gentian spot blight at a control rate of more than 70%. Analyses of physiological and biochemical indexes, defense enzymes, soil enzymes, and soil properties suggest a mechanism for disease resistance and growth promotion. Specifically, different combination generally increases the number of microorganisms and soil enzyme activities in the rhizosphere of gentian, resulting in improvements in the accumulation of nutrients in soil, as well as the living environment of plants. The accumulation of nutrients in soil was improved by activating defense enzymes. The levels of secondary metabolites such as gentiopicrin increased, thus improving the disease resistance of gentian. Disease resistance was accomplished by directly suppressing the pathogen causing gentian spot blight on the surface of gentian plants and in the soil. These results provide a theoretical foundation for the biological control of gentian spot blight.

Increasing Calcium and Decreasing Nitrogen Fertilizers Improves Peanut Growth and Productivity by Enhancing Photosynthetic Efficiency and Nutrient Accumulation in Acidic Red Soil

Increasing Calcium and Decreasing Nitrogen Fertilizers Improves Peanut Growth and Productivity by Enhancing Photosynthetic Efficiency and Nutrient Accumulation in Acidic Red Soil

Afforestation Influences Soil Aggregate Stability by Regulating Aggregate Transformation in Karst Rocky Desertification Areas

Surface vegetation has a substantial impact on soil aggregate stability, which is an important indicator of soil quality. However, there is still limited research on the response of soil aggregate stability indicators and the organic carbon, total nitrogen, and total phosphorus content in soil aggregates for different vegetation patterns in rocky desertification fragile ecological areas. Therefore, in order to study the effects of different vegetation restoration models on soil aggregate stability and aggregate related nutrient content and their promoting relationships in the karst rocky desertification areas in southwest China, soil samples under three artificial restoration vegetation measures (Juglans regia L.-Rosa roxburghii Tratt., Rosa roxburghii Tratt.-Lolium perenne L., Juglans regia L.-Lolium perenne L.) were collected in 0–10 cm and 10–20 cm soil, and the traditional farmland (Zea mays L.) was used as the control, combined with dry and wet sieving experiments for the research and analysis. The results showed that there were significant differences in the distribution of aggregates and soil nutrients among the four types of plots. Compared with traditional agricultural land, artificial afforestation increased the content of soil large macroaggregates (LMAs) and decreased the proportion of microaggregates (MIAs) and silt+clay (SCA), which enhanced the soil aggregate stability and reduced the soil fragmentation and erodibility. The afforestation restoration increased the content of soil aggregate-related SOC, TN, and TP, and increased with the decrease in the aggregate particle size. Research has found that soil aggregate stability indicators are significantly influenced by the particle size distribution of soil aggregates. In the positive succession process of vegetation types, soil nutrient accumulation is controlled by changes in the soil aggregate particle size, which affects the soil aggregate stability and reduces soil erodibility, thereby protecting the soil nutrient loss. The composite management of forest and irrigation in degraded ecological areas has certain reference and indicative significance for ecological restoration in rocky desertification areas.