Soil Alkaline Phosphatase Research Articles

Natural degradation process of Salix psammophila sand barriers regulates desert soil microbial biomass C:N:P stoichiometry and homeostasis

The Salix psammophila sand barrier is widely used to control wind-sand disasters in desert areas. Importantly, the means through which the natural degradation of the sand-buried section of these sand barriers contributes to the community-level microbial elemental homeostasis of desert soils remains elusive. In this study, we conducted long-term field in situ sampling experiments over a nine-year period in a typical study area in the desert region of northwest China. Chloroform fumigation and high-throughput sequencing were used to determine soil microbial biomass and the diversity of fungi and bacteria. Combined with sand barrier decay characteristics, soil physicochemical factors, and extracellular enzyme activities, we explored the dynamic balance of soil microbial element ratios and key driving factors. The results show that natural degradation of S. psammophila sand barriers increased microbial biomass C and N contents in desert soil, with seven years being the most important turning point. The consistent increase in the soil microbial C:N:P stoichiometry ratios was primarily directly caused by an increase in the mass loss and changes in the fungal diversity. Microbial C:N and N:P ratios were well limited over time, suggesting homeostatic regulation of microorganisms, but the C:P ratio was not homogenized at the community level. The higher microbial C:P and N:P ratios indicated that microorganisms were limited by P after five years of sand barrier degradation. This was primarily related to a decrease in the soil alkaline phosphatase activity. However, microorganisms mitigated P limitation by altering the fungal community structure. These results constitute new evidence in our understanding of the relationships between S. psammophila sand barriers and soil element stoichiometry and the subsequent effects on microorganisms and community-level elemental homeostasis. This work advances the current understanding of artificial interventions in ecological restoration and desertification control.

Grazing promotes soil phosphorus cycling by enhancing soil microbial functional genes for phosphorus transformation in plant rhizosphere in a semi-arid natural grassland

Soil microorganisms play a key role in soil P transformation and cycling in grassland ecosystems, while the microbial mechanisms of animal grazing mediating soil P processes are not fully understood. We conducted a grazing experiment in a typical steppe grassland in Inner Mongolia, to explore the responses of microbial communities in rhizosphere and bulk soils to grazing intensity for understanding the mechanisms of grazing affecting P cycling. We determined soil physico-chemical properties and alkaline phosphatase activities, and measured soil microbial diversity and the relative abundance of microbial P-transformation genes by metagenomics in the rhizosphere and bulk soils of a Stipa grandis dominated grassland under three grazing intensities (no-, moderate, and heavy grazing). We found that (i) grazing significantly increased soil available P concentration and soil alkaline phosphatase activity; (ii) grazing increased the abundance of bacterial, but not fungal communities, and the enhanced abundance of rhizosphere bacteria promotes the P-cycling potential; (iii) grazing increased the relative abundance of the genes responsible for microbial P-uptake and transport, and inorganic P solubilization and organic P mineralization in rhizosphere soil, but not in bulk soil; (iv) grazing reduced the node degree of the network of the genes involved in P-transformation, but it increased the node degree of the genes encoding alkaline phosphatase and the C–P lyase multi-enzyme complex in the rhizosphere soil. The grazing-induced changes in the abundance of microbial functional genes are beneficial to P-solubilization and mineralization. Our results indicate a divergent effect of grazing on soil microbial communities and their functional genes involved P-transformation in rhizosphere and bulk soils, and represent an important progress towards the understanding of the mechanisms of microbial regulation of P cycling in grassland ecosystems.

Changes in soil properties and the phoD-harboring bacteria of the alfalfa field in response to phosphite treatment.

- Phosphite and phosphate increase the total phosphorus and available phosphorus.- The pH was the dominant factor influencing the phoD-harboring bacterial community under phosphite fertilizer.- The response of soil properties and phoD-harboring bacterial community to phosphate and phosphite fertilizers differed in the alfalfa field.

Metagenomic insights into the effects of organic and inorganic agricultural managements on soil phosphorus cycling

Microbes play important roles in regulating soil phosphorus (P) cycling in agroecosystems. However, little is known about how P-cycling microbes respond to organic and inorganic agricultural managements in terms of their functional and phylogenetic traits. Here, metagenomics was used to determine effects of P-cycling functional genes and taxa on soil P availability in a forage (Broussonetia papyrifera) monoculture ecosystem under organic (inoculating arbuscular mycohrrizal fungi (AMF) and intercropping legume (Medicago sativa)) and inorganic (adding chemical nitrogen (N) and P fertilizers) managements. The results showed that soil available P (AP) in plots with both legume and AMF addition was increased by 54.3 % compared with the control and was1.6–2.4 times higher than in plots with N or P fertilization. The abundance of ppa involved in inorganic-P solubilization was significantly increased after adding both legume and AMF compared with P-addition treatment. Soil alkaline phosphatase activity increased with P fertilizer addition and was positively correlated with soil AP. The abundances of phoA and phnI involved in organic-P mineralization were significantly higher under P fertilization treatment than under N fertilization treatment. Soil total N and AP were the key drivers on interactions among P-transportation genes, organic-P mineralization genes and taxa related to P-transportation. Overall, organic agricultural management increases soil P availability by increasing the potential of inorganic-P solubilization, while inorganic agricultural management regulates P availability via altering the potential of organic-P mineralization. These findings could provide a better understanding of the mechanisms that drive soil P availability under organic and inorganic agricultural managements.

Potential Application of Paenibacillus sp. C1 to the Amelioration of Soda Saline-Alkaline Soil

In this study, a saline-alkaline-tolerant bacterial strain named Paenibacillus sp. C1 was screened and isolated, and its basic properties were characterized. Its phosphorus dissolution, organic acid production, and application on ameliorating soda saline-alkaline soil were studied, and the changes of microbial communities after adding strain C1 with or without rice straws, (NH4)2SO4 and Ca3(PO4)2 were investigated. The results demonstrated that when the nitrogen, carbon, and phosphorus sources were (NH4)2SO4, glucose, and Ca3(PO4)2, respectively, strain C1 was in the best phosphorus-dissolving condition. The strain had good characteristics of acid production and phosphorus dissolution under the condition of high salinity and alkalinity. It could secrete cellulases, decompose rice and corn straws, and produce polysaccharides effectively. Strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could increase the content of available phosphorus (AP), organophosphorus (OP), total organic carbon (TOC), and polysaccharide (PS) and the activity of alkaline phosphatase (ALP) in saline-alkaline soil. Furthermore, adding strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could alter the bacterial flora of soil to make it adapt to high salinity and alkalinity better. Our study can be an important step toward the application of Paenibacillus sp. C1 to the amelioration of soda saline-alkaline soil and the investigation of its deep mechanisms.

Long-term high-P fertilizer input shifts soil P cycle genes and microorganism communities in dryland wheat production systems

Phosphorus (P) fertilizer input influences crop yield, soil P cycling, and phosphate-solubilizing microorganism (PSM) communities, which play a key role in obtaining soil available phosphorus. However, the responses of soil P cycle genes and PSM communities to long-term high-P fertilizer application are less known in the Chinese Loess Plateau. In this study, metagenomics was used to explore the shifts in the abundance and compositions of soil P cycle genes and PSM communities at a long-term (14 years) trial site with four P fertilization rates. Long-term high-P (200 kg P2O5 ha−1 year−1) inputs resulted in a decrease in the abundance of the P-starvation response genes (phoR and phoP), the high-affinity phosphate-specific transporter (pst), the inorganic P-solubilization, and organic P-mineralization genes (gcd, pqq, and phoD). Long-term P inputs increased the abundance of phosphate-solubilizing bacteria but decreased the abundance of phosphate-solubilizing fungi and weakened the relationship of relevant key soil P genes. Soil total P, inorganic P, available P (AP), dissolved organic C contents, and alkaline phosphatase (ALP) activity were significantly related to soil P cycle genes and PSM community structure. In conclusion, the changes in soil P cycle genes and microbial P solubilization capacity under long-term P input conditions were mainly regulated by soil AP content and ALP activity, while long-term high-P inputs increased soil mineral P immobilization by altering the expression of soil P cycle genes and the PSM functional profiles. These consequences provide a new view for the study of soil P cycles in agricultural ecosystems with P inputs.

Intercropping regulation of soil phosphorus composition and microbially-driven dynamics facilitates maize phosphorus uptake and productivity improvement

Intercropping is a powerful way that promote a more diversified plant community in croplandas. It is important to understand how this practice regulates phosphorus (P) footprint and trade-off in plant-soil system which influences crop productivity. Herein, a field-based experiment was conducted to investigate the effects of intercropping of maize with legumes (peanut and soybean) and non-legumes (gingelly and sweet potato) on maize productivity and P transformation and regulation. Compared with the monoculture, intercropping treatments increased maize yield, P use efficiency (PUE), P partial factor productivity (PFPP), and aboveground P uptake by 13.3–34.4%, 6.2–41.2%, 13.6–68.2%, and 10.3–20.1%, respectively. Intercropping treatments significantly reduced the cumulative losses of total P, dissolved P, and particulate P by 4.7–60.1%, 3.2–67.1%, and 2.7–64.7%, respectively. Maize/peanut and maize/soybean systems showed a better advantage in improving maize productivity and mitigating P runoff loss than the maize/gingelly and maize/sweet potato. Compared with the monoculture, intercropping increased the contents of soil labile-P, stable-P, solution-P, hydrolysable-P, and exchangeable-P by 3.1–7.8%, 18.7–63.2%, 8.4–35.5%, 0.2–28.3%, and 38.6–637.1%, respectively. The potential activities of soil alkaline and acid phosphatase in intercropping treatments increased respectively by 15.3–173.7% and 5.6–215.2% compared with the monoculture. Maize productivity components (crop yield, PFPP, and PUE, and plant P uptake) were positively correlated with soil P composition and bioavailability, microbial biomss P, and phosphatase activity, while negatively correlated with P runoff loss (P < 0.05). Those findings highlight the importance in understanding how soil P composition and microbially-driven P dynamics mediates plant P uptake to determine the consequences of intercropping for maize productivity. • Intercropping increased maize yield and PUE by 13–34% and 6–41%, respectively. • Intercropping decreased the runoff loss of TP, DP, and PP by 5–60%, 3–67%, and 3–65%. • Intercropping increased soil phosphatase activities by 6–215% with maize development. • Increased productivity was related to soil P composition, bioavailability, and dynamics. • Intercropping-driven plant-soil P trade-off contributed to maize productivity improvement.

Plastic mulching significantly improves soil enzyme and microbial activities without mitigating gaseous N emissions in winter wheat-summer maize rotations

Plastic mulching is an important agricultural practice to increase crop yield by increasing soil temperature and moisture. Plastic mulching can also affect soil greenhouse gas emissions [e.g., N 2 O emissions and NH 3 volatilization] and soil characteristics such as soil enzyme and microbial activities, but the simultaneous effects of plastic mulching on these parameters and the potential links between them are rarely evaluated. Here, we conducted a field study to investigate the concurrent responses of N 2 O emissions, NH 3 volatilization, soil enzyme and microbial activities, soil dissolved organic C (DOC) and N (DON), and crop yield to plastic mulching (mulching) and no mulching (ambient) under consecutive winter wheat–summer maize rotation cycles in China’s Loess Plateau. The mulching treatment significantly increased soil water-filled pore spaces (WFPS) and soil temperature during growing cycle 1 (2018–2019 winter wheat and 2019 summer maize) and cycle 2 (2019–2020 winter wheat and 2020 summer maize). Averaged across both growing cycles, the mulching treatment significantly increased winter wheat yield by 31.8 %, summer maize yield by 36.4 %, soil NO 3 – -N content by 18.2 %, NH 4 + -N content by 27.4 %, cumulative N 2 O emissions by 34.0 % and NH 3 volatilization by 50.6 %, relative to the ambient treatment. Moreover, the mulching treatment significantly enhanced soil alkaline phosphatase, invertase, catalase, and urease activities and soil microbial biomass C and N contents in the 0–10 cm soil layer across both growing cycles. This study revealed a tradeoff, with plastic mulching significantly improving crop yields and soil enzyme and microbial activities but not mitigating N 2 O emissions or NH 3 volatilization. Our results highlight that simultaneously documenting gaseous N emissions and changes in soil properties under plastic mulching can advance the understanding of sustainable agriculture in semi-arid areas. • Soil water-filled pore spaces and soil temperatures differed highly in plastic mulching and no mulching. • Plastic mulching had higher grain yield and soil mineral N content than no mulching. • Plastic mulching significantly improved soil enzyme and microbial activities. • Plastic mulching increased NH 3 volatilization and N 2 O emissions.

Soil properties and fine root morphological traits in relation to soil particle-size fractions in a broad-leaved beech (Fagus orientalis Lipsky) forest

Soil particle-size fractions play an important influence soil physico-chemical properties, microbial biomass processes as well as fine roots morphological traits in beech forest ecosystem. The objectives of study were to determine how soil texture interacts with soil physico-chemical properties and microbial biomass as well as fine roots traits in oriental beech forest in Guilan province, northern Iran. Five subplots of 400 m2 were randomly selected at a plot of 1 ha. At five different locations, soil samples were collected at depth of 0–20 cm and fine root samples were also taken from beech trees. Results indicated that clay content was positively correlated with carbon, carbon/nitrogen (C/N) ratio, and moisture, but negatively correlated with nitrogen (N) and phosphorous (P). Silt values had significant positive correlation with C/N, and negative correlation with N and P. The microbial biomass carbon/carbon (MBC/C) ratio in soil increased significantly with clay, but microbial biomass nitrogen (MBN) decreased significantly with increasing clay. The MBC/C ratio decreased significantly with sand values in soil at depth 0–20 cm. Results showed that silt value of soil profile was negatively correlated with MBN, but positively with MBN/N ratio. Soil acidic phosphatase concentration was negatively correlated with clay content, but soil alkaline phosphatase was positively correlated with silt. Clay and sand contents were positively correlated with fine root density, fine root biomass, fine root length, and surface root area. Sand content was negatively correlated with fine root volume. The results of research, considering the correlation between soil particle-size fractions and some soil characteristics as well as fine root traits, show that soil texture in oriental beech forest can play an important role in forest stand dynamics.

The Effect and Influence Mechanism of Soil Salinity on Phosphorus Availability in Coastal Salt-Affected Soils

Soil salinization is a problem that arouses the world’s attention. Soil salinity is an important limitation for agriculture production in coastal area. Phosphorus is a very important nutrient element in the process of plant growth, and its effectiveness affects plant growth to a great extent. In this study, soil available phosphorus and its component in Hedley phosphorus classification were found to be affected by soil salinity in coastal areas of Jiangsu Province. Several key environmental factors changed under the saline environment of the coastal areas, such as soil salinity, soil pH, and soil alkaline phosphatase activity. These environmental factors were significantly correlated with soil available phosphorus. Results showed that there were significant correlations between soil salinity and other environmental factors, and soil salinity and alkaline phosphatase activity were the main influencing factors of soil available phosphorus in this study. Significant positive correlation was found between alkaline phosphatase activity and soil salt content, and soil salinity was considered as the most important impact factor for soil available phosphorus as it affected the surrounding environment, and the soil alkaline phosphatase could be considered as the direct influencing factor for soil available phosphorus. Analysis between the soil alkaline phosphatase activity and phosphorus component showed that soil alkaline phosphatase activity could increase the proportion of active inorganic phosphorus and medium active inorganic phosphorus in soil phosphorus pool, which explained the effect of soil alkaline phosphatase activity on soil available phosphorus.

Effects of Organic Fertilizer Combined with Chemical Fertilizer on Nutrients, Enzyme Activities, and Rice Yield in Reclaimed Soil

ABSTRACT A field experiment was conducted to explore the effects of combined application of organic and chemical fertilizers (organic-chemical fertilizers) on reclaimed soil fertility and rice yield. The experiment involved five treatments: no nitrogen (N) fertilizer (CK1), 100% chemical fertilizer N (CK2), 40% chicken manure N + 60% chemical fertilizer N (T1), 40% vermicompost N + 60% chemical fertilizer N (T2), 40% rapeseed meal fertilizer N + 60% chemical fertilizer N (T3). Organic-chemical fertilizers maintained or increased rice yield. Rice yields of T2 and T3 increased by 6.7% and 8.9%, respectively, as compared with CK2. T1 showed similar value of rice yield with CK2. Organic-chemical fertilizers application increased contents of soil organic C (SOC), total N (TN), alkali-hydrolyzable N (AN), NH4 +-N, NO3 –N, available phosphorus (AP), available potassium (AK) as well as CEC by 10.5%~15.9%, 8.9%~39.3%, 16.9%~74.5%, 38.1%~77.2%, 18.3%~136.5%, 27.7%~75.0%, 16.1%~24.7% and 7.2 ~ 26.0%. T3 had highest soil TN, AN, NH4 +-N, NO3 –N, CEC as well as T2 showed the highest contents of soil AP and AK. Organic-chemical fertilizers application increased soil sucrase (S-SC), urease (S-UE) and catalase (S-CAT) activities. The highest soil S-SC activity was detected in T3, and the highest soil S-UE and soil alkaline phosphatase (S-AKP) activities were observed in T2. Rice yield was positively related to SOC, TN, AN, NH4 +-N, NO3 –N, AP and AK as well as S-SC, S-UE and S-AKP activities. In conclusion, 40% organic N + 60% chemical N application could improve soil fertility and rice yield in reclaimed soils, with rapeseed meal fertilizer the most effective organic N source, followed by vermicompost and chicken manure.

Changes in soil phosphorus fractions associated with altered vegetation and edaphic conditions across a chronosequence of revegetated dunes in a desert area

Revegetation through the establishment of woody vegetation on bare active dunes is an effective approach to restore degraded dune systems. Revegetation can affect soil inorganic and organic phosphorus (Pi and Po) cycling and storage by modifying biotic and abiotic conditions (vegetation characteristics and soil properties, respectively). However, how shrub revegetation and revegetation age affect soil P fractions and how biotic and abiotic factors interact to mediate revegetation effects on P fractions are poorly understood. To address these questions, we conducted a field survey in an artificially established chronosequence of revegetated dunes in a desert area of China, with five differently aged revegetated sites (19, 32, 46, 55, and 63 years) and an adjacent non-revegetated control site. We investigated changes in soil Pi and Po fractions of decreasing lability (labile P: resin Pi and NaHCO3-extractable Pi/Po; moderately labile P: NaOH-extractable Pi/Po; recalcitrant P: HCl-extractable Pi/Po and residual P) and vegetation and edaphic properties as predictors. Boosted regression trees analysis was used to evaluate the contributions of individual predictors to variability in P fractions, and structural equation modeling was used to determine the interactive effects of multiple predictors. Concentrations of soil P fractions were 65–114% greater in revegetated sites compared with the non-revegetated control, but the magnitude of this effect varied with revegetation age. Furthermore, soil total P and its fraction concentrations increased with revegetation age, but the accumulation rates of total P and most P fractions were greatest during the first 19 years after revegetation. Revegetation-induced soil total and available P increases were caused by multiple factors, including enhanced P inputs from dust deposition and plants due to increased vegetation cover and surface litter and root biomass, and enhanced Po and Pi mobilization due to increased soil alkaline phosphatase activity and decreased soil pH. Edaphic properties exerted greater controls over the spatiotemporal dynamics of soil P than vegetation changes, but the key influential factors differed among P fractions. We conclude that revegetation significantly increased the labile, moderately labile, and non-labile P pools and that the effects of revegetation were fraction- and time-dependent, with important implications for managing soil P cycling in revegetated desert ecosystems.

Organic amendment plus inoculum drivers: Who drives more P nutrition for wheat plant fitness in small duration soil experiment.

Functioning of ecosystems depends on the nutrient dynamics across trophic levels, largely mediated by microbial interactions in the soil food web. The present study investigated the use of phosphate solubilizing bacteria (PSB) and poultry manure (PM) for maintaining labile P in the soil for an extensive fertility enhancement and as a substitution of chemical fertilizers. Based on the different P solubilizing capabilities of Bacillus and Pseudomonas, a quadruple consortium of Bacillus subtilis, Bacillus cereus, Bacillus thuringiensis and Pseudomonas fluorescens, and their grazer nematodes (soil free living) supplemented with PM were studied. This study was carried out on the trophic levels of soil communities to assess the growth and availability of P to the wheat plants. Experiment was performed for 90 days. Comparing the unamended and amended predator results showed that nematode addition beyond bacterial treatment substantially increased the net available P by ≈2 times, and alkaline phosphatase (ALP) activity by 3.3 times. These results demonstrated the nematodes association with increasing nutrient availability or P mineralization. The interactive effect of PM as substrate and biological drivers was more noticeable on plant dry biomass (1.6 times) and plant P concentration (3.5times) compared to the similar unamended treatment. It is concluded that the biological drivers significantly enhanced the soil ALP and available P while the substrate and biological drivers enhanced dry biomass and plant P concentration. Bacterivore nematodes enhanced the effect of PSB for P mineralization via microbial loop and could be used for the enhancement of wheat production.

Application of humic acid compound fertilizer for increasing sweet potato yield and improving the soil fertility

Combined application of humic acid (HA) and multi-nutrient fertilizer improve nutrient utilization and increase crop yield. To give insight about the application of HA compound fertilizer in sweet potato production, a field experiment was conducted the effect of humic acid-nitrogen, phosphorus, and potassium compound fertilizer (HA-NPK) on soil nutrient contents, soil enzyme activity, soil microorganism community structure and yield of sweet potato. Results showed that compared to nitrogen, phosphorus, and potassium compound fertilizer (NPK) treatment, the activated humic acid- nitrogen, phosphorus, and potassium compound fertilizer (HA-NPK1) and non-activated humic acid- nitrogen, phosphorus, and potassium compound fertilizer (HA-NPK2) treatment significantly increased the plant biomass and storage root yield. Increase in yield from application of HA-NPK1 was significantly larger than those from HA-NPK2. The HA-NPK1 treatment greatly increased the content of readily available phosphorus, potassium and soil organic matter, enhanced the enzyme activity of soil urease, invertase, alkaline phosphatase and catalase. The numbers of soil bacteria, fungi and actinomycetes in the HA-NPK1 treatment were significantly higher than the NPK treatment. In conclusion, the application of the activated HA-NPK in sweet potato production could be used effectively to increase soil quality, facilitate the growth of sweet potato and increase its yield under similar conditions to this work.

Interactions between phosphorus availability and microbes in a wheat–maize double cropping system: A reduced fertilization scheme

Mechanisms controlling phosphorus (P) availability and the roles of microorganisms in the efficient utilization of soil P in the wheat–maize double cropping system are poorly understood. In the present study, we conducted a pot experiment for four consecutive wheat–maize seasons (2016–2018) using calcareous soils with high (30.36 mg kg−1) and low (9.78 mg kg−1) initial Olsen-P content to evaluate the effects of conventional P fertilizer application to both wheat and maize (Pwm) along with a reduced P fertilizer application only to wheat (Pw). The microbial community structure along with soil P availability parameters and crop yield were determined. The results showed that the Pw treatment reduces the annual P input by 33.3% without affecting the total yield for at least two consecutive years as compared with the Pwm treatment in the high Olsen-P soil. Soil water-soluble P concentrations in the Pw treatment were similar to those in the Pwm treatment at the 12-leaf collar stage when maize requires the most P. Furthermore, the soil P content significantly affected soil microbial communities, especially fungal communities. Meanwhile, the relative abundances of Proteobacteria and alkaline phosphatase (ALP) activity of Pw were significantly higher (by 11.4 and 13.3%) than those of Pwm in soil with high Olsen-P. The microfloral contribution to yield was greater than that of soil P content in soil with high Olsen-P. Relative abundances of Bacillus and Rhizobium were enriched in the Pw treatment compared with the Pwm treatment. Bacillus showed a significant positive correlation with acid phosphatase (ACP) activity, and Rhizobium displayed significant positive correlations with ACP and ALP in soil with high Olsen-P, which may enhance P availability. Our findings suggested that the application of P fertilization only to wheat is practical in high P soils to ensure optimal production in the wheat and maize double cropping system and that the soil P availability and microbial community may collaborate to maintain optimal yield in a wheat–maize double cropping system.

Long-term fertilization lowers the alkaline phosphatase activity by impacting the phoD-harboring bacterial community in rice-winter wheat rotation system

PhoD-harboring bacteria and the secreted alkaline phosphatases (ALP) are crucial in the regulation of soil phosphorus (P) cycling. However, the influential factors of these crucial indicators and their internal interactions remain controversial. Here, a long-term field experiment containing different fertilization regimes was conducted (chemical, organic, and no fertilizer applied). The results indicated that the richness and diversity of phoD-harboring bacterial community were significantly decreased after long-term fertilization. The applied fertilizer promoted the growth of competitive species, while phoD-harboring bacteria lost the advantage to outcompete other microorganisms after long-term fertilization. The decreased ALP activity was caused by the declined phoD gene abundance, which is attributed to the comprehensive effects of soil organic C (SOC), total nitrogen (TN), and various forms of P. The random forest models identified SOC, TN, and available P (AP) to be the dominant environmental factors in shaping the phoD-harboring bacterial community. In addition, some other forms of P such as organic P (Po), inorganic P (Pi) or total P (TP) also exerted significant effects. Different fertilization regimes changed the keystone genera that contributed significantly to soil ALP activities, while Pseudolabrys and Pseudomonas were predicted to be the most important genera regardless of different fertilization regimes. This study extends the understanding of the main process and mechanisms of P mobilization in response to different fertilization regimes.

Application of cotton straw biochar and compound Bacillus biofertilizer decrease the bioavailability of soil cd through impacting soil bacteria

BackgroundCd seriously threatens soil environment, remedying Cd in farmland and clearing the response of soil environment to modifiers in Cd-contaminated soils is necessary. In this study, the effects of cotton straw biochar and compound Bacillus biofertilizer used as modifiers on the biochemical properties, enzyme activity, and microbial diversity in Cd-contaminated soils (1, 2, and 4 mg·kg−1) were investigated.ResultsThe results showed that both cotton straw biochar and compound Bacillus biofertilizer could improve the soil chemical characteristics, including the increase of soil C/N ratio, electrical conductance (EC) and pH, and the most important decrease of soil available Cd content by 60.24% and 74.34%, respectively (P < 0.05). On the other hand, adding cotton straw biochar and compound Bacillus biofertilizer in Cd stressed soil also improved soil biological characteristics. Among them, cotton straw biochar mainly through increasing soil alkaline phosphatase activity and improve bacteria abundance, compound Bacillus biofertilizer by increasing soil invertase, alkaline phosphatase, catalase, and urease activity increased bacterial community diversity. On the whole, the decrease of soil available Cd was mainly caused by the increase of soil pH, C/N, urease and alkaline phosphatase activities, and the relative abundance of Acidobacteria and Proteobacteria.ConclusionsIn summary, the applications of cotton straw biochar and compound Bacillus biofertilizer could decrease soil available Cd concentration, increase soil bacterial community diversity and functions metabolism, and reduce the damage of Cd stress, compared with cotton straw biochar, compound Bacillus biofertilizer was more effective in immobilizing Cd and improving soil environmental quality.

Plastic film mulching with ridge planting alters soil chemical and biological properties to increase potato yields in semiarid Northwest China

BackgroundThe growth of potato (Solanum tuberosum L.) is severely affected by the complex and variable soil environment, and film mulching has been widely used for potato growth in semiarid areas of western China. However, there are few studies on the effects of film mulching on soil quality and tuber yield in potato fields.MethodsThe effects of four mulching patterns (flat plot without film mulching, FP; flat plot with film mulching, FPM; ridge planting with half mulch, RPHM; ridge planting with full mulch, RPFM) on soil chemical and biological properties and potato tuber yield were investigated during two growing seasons (2018 and 2019) in the field.ResultsThe results showed that compared with FP, the mulching treatments significantly increased the tuber yield of potato, with an increase of 3.7–20.77% and 7.89–26.35% in 2018 and 2019, respectively, and the yield of RPFM was higher than that of other treatments. In both growing seasons, RPFM significantly increased the contents of alkali-hydrolyzed N and available P, and the activities of soil urease, catalase, alkaline phosphatase, and sucrase. Bacterial and actinomycete counts were significantly higher in RPFM than those in the other treatments. Furthermore, RPFM significantly increased large potatoes and decreased small potatoes. Pearson’s correlation analysis revealed that soil alkaline dissolved nitrogen and actinomycete populations were the main factors affecting potato yield formation.ConclusionsThese results indicate that RPFM can improve the soil environment and further increase potato tuber yield, which is a viable option for potato production in semiarid areas.Graphical

内蒙古典型草原不同地形单元放牧对土壤微生物量磷及磷酸酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 内蒙古典型草原不同地形单元放牧对土壤微生物量磷及磷酸酶活性的影响 DOI: 10.5846/stxb202102200477 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金应急项目（21025120） Effect of grazing on soil microbial biomass phosphorus and phosphatase activities on different topographic unit of a typical steppe Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤微生物量磷和磷酸酶在土壤磷的有效化过程中起着极为重要的作用。过度放牧干扰微生物主导的草原土壤磷的有效化过程，地形也会驱动土壤磷的形态转化和积累。然而，地形与放牧强度的交互作用对土壤微生物参与磷活化过程的影响尚不明确，它们对不同地形单元放牧强度的响应可能存在差异。基于十年定位不同地形单元（坡地和平地）放牧试验，研究不同地形单元放牧对土壤磷酸酶活性和微生物量磷（SMBP）的影响。结果表明，地形而不是放牧显著影响土壤全磷（TP）、有机磷（PO）、有效磷（Olsen-P）含量。坡地SMBP含量显著低于平地，平地重牧（G7.5-G9.0）显著提高了SMBP含量，而坡地放牧则对其没有显著影响。土壤碱性磷酸酶（ALP）和磷酸二酯酶（PD）活性的变化只受放牧影响，而酸性磷酸酶活性（ACP）受地形驱动。平地土壤PD、ALP活性与土壤理化性质间存在复杂的联系，且与放牧强度呈负相关关系，而坡地则只保留了土壤PD活性与磷、全氮（TN）的联系。平地和坡地的土壤ACP活性与土壤化学性质无关。土壤含水量（WC）驱动了平地和坡地SMBP和磷酸酶活性的差异，其中WC、PO、TP、TN驱动平地土壤变化，而坡地土壤则受到WC、PO、TOC的影响。综上，地形驱动SMBP和土壤磷酸酶活性对放牧的响应。本研究表明在平地放牧和坡地放牧是通过不同的方式影响的微生物活化磷的过程，并且土壤含水量起到关键作用。 Abstract:Overgrazing interferes the grassland soil process of phosphorus (P) availability which is dominated by microorganisms, and topography also drives the P transformation and accumulation in soil. Soil microbial biomass phosphorus (SMBP) and enzymes involved phosphorus mineralization played important roles in soil P transformation. However, the effect of the interaction between topography and grazing rate on the participation of soil microorganisms in phosphorus activation process is not clear. In this study, the effects of grazing on the activities of soil alkaline phosphatase (ALP), acid phosphatase (ACP), phosphodiesterase (PD), and SMBP were investigated based on a ten-year grazing experiment (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/hm2) on two topography treatments (slope and flat). This study hypothesized that 1) due to the soil water content (WC) of slope treatment is lower than the flat treatment, and so do soil nutrient properties, so the effect of slope treatment on SMBP is stronger than flat soil; 2) due to the slope soil lack of phosphorus than flat soil, so the activities of ALP, ACP, PD are higher than flat soil; 3) slope soil is facing higher nutrient limit caused by the difference of parent material, and water limit caused by topography, so, there may be different environmental factor driving the change of SMBP and enzymes. The results showed that topography, not grazing, significantly affected soil TP, PO and Olsen-P. SMBP in slope treatment was significantly lower than that in flat treatment. SMBP was significantly increased by heavy grazing on flat treatment, but not on slope treatment. ALP and PD activities were only affected by grazing, while the activities of ACP were driven by topography. There was a complex relationship between the activities of PD, ALP and soil physical and chemical properties in the flat group, and there was a negative correlation between the activities of PD, ALP and grazing rate, while only the relationship between PD activities, phosphorus and TN was maintained in the slope group. The ACP activity of flat group and slope group was not related to soil chemical properties. Soil water content drives the difference between flat land and sloping land. Considering topographic factors, soil water content, PO, TP and TN drive the change of flat soil, while slope soil is affected by soil water content, PO and TOC. In conclusion, topography drives the response of SMBP phosphorus and phosphatase activity to grazing. This article indicates that, under grazing, the process of soil microorganism activities phosphorus is affected by different factors on flat and slope grazing treatments, and soil water content plays an important role. 参考文献 相似文献 引证文献

The importance of rare versus abundant phoD-harboring subcommunities in driving soil alkaline phosphatase activity and available P content in Chinese steppe ecosystems

The alkaline phosphatase-harboring community (the phoD community hereafter) plays an important role in organic P mineralization. Here, we comparatively studied the biogeographical patterns of abundant and rare phoD subcommunities and their roles in mediating soil phosphatase (ALP) activity and available P content in three representative steppe regions in China, namely the Inner Mongolian Plateau, the Loess Plateau, and the Qinghai-Tibetan Plateau. The results indicated that soil ALP activity, available P content, soil and microbial biomass C:P, N:P ratios varied significantly among steppe regions. Significant differences in diversity, metabolic energy and assembly processes were observed between abundant and rare phoD subcommunities. First, richness of the rare taxa was significantly higher than that of the abundant subcommunities. Second, testing of metabolic theory of ecology showed that rare subcommunities had a higher metabolic activation energy than the abundant taxa. Thirdly, deterministic other than stochastic processes dominated in the community assembly of both subcommunities. Soil pH was the key environmental determinant in community assembly processes for both subcommunities. The relationships among P-cycling parameters and between these parameters and phoD diversity were scale-dependent. The phylogenetic beta diversity of the rare phoD taxa had higher correlations with P-cycling parameters than that with the abundant taxa. More rare than abundant genera were significantly correlated with P limitation and ALP activity at different spatial scales. The rare Frankia was the key genus detecting P limitation, producing ALP and enhancing soil available P in Qinghai-Tibet.