Soil Acid Phosphomonoesterase Research Articles

Phosphatase activities and available nutrients in soil aggregates affected by straw returning to a calcareous soil under the maize–wheat cropping system

The objective of this study was to investigate the effects of different rates of straw returning on soil aggregate stability, phosphatase activities, and the available nitrogen (N) and phosphorus (P) within different soil aggregate sizes. The experiment included five treatments: 1) no straw returning and no chemical fertilizer, 2) chemical fertilizer only (150 kg N ha-1, 75 kg P ha-1, and 75 kg K ha-1), 3) 20% straw returning with chemical fertilizer, 4) 60% straw returning with chemical fertilizer, and 5) 100% straw returning with chemical fertilizer. Soil samples were collected 3.5 years after the start of the experiment and separated into four aggregate sizes (<0.25 mm, 0.25–1 mm, 1–2 mm, and 2–7 mm) using the dry sieving method. Soil acid phosphomonoesterase (AcP) and alkaline phosphomonoesterase (AlP); phosphodiesterase (PD); pyrophosphatase (PrA) activities; and soil NO3−−N, NH4+−N, and resin-P were determined within soil aggregates. The results showed that straw returning rates did not significantly impact soil aggregate distribution. However, straw returning increased soil AcP, AlP, and PD in <2 mm aggregates, and high rates of straw returning led to high enzyme activities. Soil phosphatase activities were also higher in 1–2 mm aggregates. All straw returning and chemical fertilization treatments increased soil NO3−−N and resin-P concentrations but had much less effect on soil NH4+−N concentrations. Additionally, the study revealed that soil pH, the concentrations of NH4+−N, NO3−−N, resin-P, and CaCO3 significantly influenced soil phosphatase activities, but their impact varied across different sizes of aggregates.

Distribution Characteristics and Influencing Factors of Soil Biological Indicators in Typical Farmland Soils

Soil biodiversity drives soil-based ecosystem services and is an important indicator of soil health. To understand the responses of important soil biological indicators to different farmland use contexts, 72 fields in three agricultural regions of China were used as research objects. The distribution characteristics and the factors influencing six indicators (carbon and nitrogen contents of soil microbial biomass (MBC, MBN, respectively), soil respiration (SR), soil catalase activity (CAT), soil acid phosphomonoesterase activity (APA), and soil earthworms) were investigated using field monitoring and indoor analysis. The MBC, SR, CAT, and APA indicators showed significant differences among the regions (p < 0.05). Correlation and redundancy analyses indicated that the important factors affecting MBC, MBN, and soil respiration were cation exchange capacity, total N, organic matter, hydrolytic N, and soil bulk density, whereas the important factors affecting APA and earthworms were total phosphorus, available phosphorus, and available potassium. None of these factors had a significant effect on CAT. Climatic conditions, soil types, and farmland practices all have complex impacts on soil biodiversity. The results showed that attention should be paid to improving the physical conditions of the soil and to increasing soil fertility levels when establishing sustainable farm management patterns.

Effects of nitrogen addition on the kinetic parameters of soil acid phosphomonoesterase in a Moso bamboo forest

Soil phosphatases are important in the mineralization of organophosphates and in the phosphorus (P) cycle. The kinetic mechanisms of phosphatases in response to nitrogen (N) deposition remain unclear. We carried out a field experiment with four different concentrations of N: 0 g N·hm-2·a-1(control), 20 g N·hm-2·a-1(low N), 40 g N·hm-2·a-1(medium N), and 80 g N·hm-2·a-1(high N) in a subtropical Moso bamboo forest. Soil samples were then collected from 0 to 15 cm depth, after 3, 5 and 7 years of N addition. We analyzed soil chemical properties and microbial biomass. Acid phosphatase (ACP) was investigated on the basis of maximum reaction velocity (Vm), Michaelis constant (Km), and catalytic efficiency (Ka). Results showed that N addition significantly decreased soil dissolved organic carbon (DOC), available phosphorus, and organophosphate content, but significantly increased soil ammonium, nitrate-N content, and Vm. There was a significant relationship between Vm and the concentrations of available phosphorus, organophosphate, and soil DOC. In general, N addition substantially increased Ka, but did not affect Km. The Km value in the high N treatment group was higher than that in the control group after five years of N addition. Km was significantly negatively associated with both available phosphorus and organophosphate. Medium and high N treatments had stronger effects on the kinetic parameters of ACP than low N treatment. Results of variation partition analysis showed that changes in soil chemical properties, rather than microbial biomass, dominated changes in Vm(47%) and Km(33%). In summary, N addition significantly affected substrate availability in Moso bamboo forest soil and modulated soil P cycle by regulating ACP kinetic parameters (especially Vm). The study would improve the understanding of the mechanisms underlying soil microorganisms-regulated soil P cycle under N enrichment. These mechanisms would identify the important parameters for improving soil P cycling models under global change scenarios.

Effects of Post-Thinning Precipitation on Soil Acid Phosphomonoesterase Activity in Larix principis-rupprechtii Mayr. Plantations

Soil phosphorus (P) is one of the essential macronutrients for plant growth. Phosphatase-mediated P mineralization in particular is critical for the biogeochemical cycling of P, and its activity reflects the organic P (Po) mineralization potential in soils. In recent years, global climate change has led to changes in precipitation, which inevitably has affected the P cycle as well. To study these effects of precipitation on soil acid phosphomonoesterase (AcPME) activity, the following combined thinning and precipitation treatments were conducted across Larix principis-rupprechtii Mayr. plantations in China: control (CK), light (LT), moderate (MT), and high thinning (HT). The precipitation treatments included natural precipitation (NP), 30% reduced precipitation (RP30), and 60% reduced precipitation (RP60). Soil moisture, microbial biomass carbon (MBC), and soil P fractions were also determined to link their effects on soil AcPME. The results show that soil AcPME activity was significantly higher in the rainy season, which is associated with higher microbial activity and increased P demand, than in the dry season. Generally, soil AcPME activity was found to increase with thinning intensity. In the dry season, the NP treatment was more conducive to improving soil AcPME activity. In the rainy season, the RP60 treatment inhibited soil AcPME activity under all thinning treatments. The RP30 treatment was only found to offer a significant boost for MT. These results indicate that the potential transformation rate of Po may be more dependent on water in the dry season than in the rainy season. If drought occurs, the Po mineralization rate would decrease for all L. principis-rupprechtii plantations, but excessive rainfall in the rainy season would also impact the turnover of Po into MT adversely.

Influence of individual and combined application of biochar, Bacillus megaterium, and phosphatase on phosphorus availability in calcareous soil

Phosphorus (P) in calcareous soil often needs to be replenished repeatedly. P-enriched biochar is expected to improve soil available P. However, the effect of acid biochar incorporated with other P activators on the P availability in calcareous soil is rarely reported. One soil incubation for 56 days was conducted to investigate the influence of individual application of acid biochar (B), phosphatase (E), Bacillus megaterium (M), and their combined application (BE, BM, EM, BEM) on soil P availability, based on analysis of Olsen-P, water-soluble P, P forms, acid phosphomonoesterase (AcP), alkaline phosphomonoesterase (AlP) activity, and pH after 7, 14, 28, and 56 days of incubation. Results indicated that individual application of B significantly increased soil Olsen-P and AcP compared with CK in the whole incubation period. Individual application of M significantly increased soil AcP and AlP on the 14th and 56th day of incubation, but decreased soil Olsen-P significantly in the whole incubation. Individual application of B was the best measure for improving P availability in calcareous soil, followed by application of BM. But individual application of E or M was not recommended. Further investigations are required to investigate the influence of acid biochar on P availability in calcareous soil at the field scale.

Effects of amendments on phosphorous status in soils with different phosphorous levels

Phosphate fertilizers are used in horticultural production to increase yields, but overuse can result in inefficient crop uptake and large loss of phosphorus (P). Soil amendments could potentially reduce the risk of P loss while maintaining high crop yield. The objective of this study was to investigate the effect of organic and inorganic amendments on P fractions in soils with different P levels (low, medium and high), and the underlying mechanisms. Five treatments were included: no amendment (CK), chemical fertilizers (CF), rice straw (FS), chicken manure compost (CM), and vermicompost (VM). Counterintuitively, the proportion of organic phosphorus (OP) tended to increase in the CF treatment, especially in soil with low P level. Results indicated that the change in the proportion of OP was mainly controlled by soil acid phosphomonoesterase, alkaline phosphomonoesterase and phosphate-solubilizing microorganisms. The proportion of available P increased in soil with low P level, but decreased in soil with high P level in the VM treatment. Non-labile P was preferentially formed in the VM treatment because of the high calcium content in vermicompost. Phosphates associated with aluminum (Al-P) were significantly higher in the CM treatment than in other treatments. This treatment also had a large presence of Pseudomonas and Streptomyces bacteria, which are capable of promoting the formation of Al-P. Our results indicated that mechanisms causing changes in soil P fractions were distinctly different among various amendments, and that vermicompost had the greatest potential to increase P supply in soil with low P level, and to decrease the risk of P loss in soil with high P level.

Impact of land use and nutrient addition on phosphatase activities and their relationships with organic phosphorus turnover in semi-arid grassland soils

Information on the relationships between phosphatase activities and organic phosphorus (P) turnover is fundamental to understanding soil P dynamics but remains poorly understood. An 8-year field study was conducted in a steppe and an abandoned cropland under semi-arid grasslands to explore the effects of nitrogen (N) and P additions on P composition in soil as determined by 31P nuclear magnetic resonance (NMR) and associated phosphatase activities. Results showed that the phosphate monoester content, soil acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase activities were higher in the steppe than in the abandoned cropland soil. Nitrogen addition significantly suppressed phosphatase activities. Phosphorus addition significantly increased acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase activities in the steppe but significantly decreased them in the abandoned cropland. Structural equation modeling revealed that both phosphodiesterase and alkaline phosphomonoesterase activities showed significant negative effects on diesters and monoesters in the steppe, but there were no significant effects of phosphatase activities on organic P composition in the abandoned cropland. Our findings highlight the variation of dominant mechanisms involved in organic P turnover with land use change. Phosphorus deficiency in the steppe appeared to promote the production of phosphatases and the subsequent biochemical mineralization of organic P. While in the abandoned cropland, previous cultivation resulted in a proportionally greater loss of soil organic carbon than that of organic P, indicating that organic P was mineralized as a result of biological mineralization of organic matter.

氮、磷添加对不同林型土壤磷酸酶活性的影响

Phosphorus( P) as a basic mineral nutrient is considered to constrain primary productivity in many tropical and subtropical forests. Soil phosphatase plays a very important role in P cycling in forest ecosystems because it catalyzes the hydrolysis of soil organic P compounds( e. g.,nucleic acids and phospholipids) into forms that are available to plants and soil microbes. Soil phosphatase activity is widely considered an effective indicator of the P demand of plants and microbes due to its ability to mediate plant and microbial nutrient acquisition from organic P compounds. In recent decades,increasing nitrogen( N) deposition due to human activity has been demonstrated to cause soil P deficiency and increase soil acid phosphomonoesterase activity( APA) in several tropical or subtropical forests. However,little is known about the effects of N deposition on soil APA in other forest types( e. g.,broadleaf forest and coniferous forest) or whether P addition may relieve soil P limitation in these forests. The present study investigated the responses of soil APA to N and P additions in a monsoon evergreen broadleaf forest( MEBF),a Pinus massoniana forest( PF),and a mixed broadleaf and pine forest( MF) in Dinghushan Mountain,Guangdong Province of southern China via a six- year fertilization experiment. The experiment used full factorial design,including four treatments: control( no fertilization),N addition( 150 kg N hm- 2a- 1),P addition( 150 kg P hm- 2a- 1),and combined N and P addition( 150 kg N hm- 2a- 1plus 150 kg P hm- 2a- 1).Each 5 m × 5 m plot was established with a surrounding buffer strip( 5 m wide). For each N and P application,NH4NO3 and Na H2PO4 solutions were applied below the canopy with a backpack sprayer,every other month from January 2007 to July 2013. In July 2013,soil samples were collected for analysis. Results showed that soil APA was significantly higher in MEBF(( 15. 83 ± 2. 46) μmol g- 1h- 1) than that in MF(( 10. 71 ± 0. 78) μmol g- 1h- 1) or PF(( 9. 12 ± 0. 38) μmol g- 1h- 1) soils,and a significant negative correlation existed between soil APA and soil available P contents in all forest types. N addition significantly increased soil APA in MEBF,while no statistical difference was found in MF or PF. P addition significantly decreased soil APA in MF and PF,but had no significant effect in MEBF. Combined N and P addition notably depressed soil APA in PF,but had no significant influence in MEBF and MF. Importantly,interactions between N and P additions were observed in MEBF. Based on our results,N deposition is expected to aggravate soil P deficiency in mature subtropical forest,while the N-induced P-limited state of these forests might be effectively relieved by P addition. In conclusion,the addition of P fertilizer may serve as an effective method for the sustainable future development of tropical and subtropical forests.

Proportion of root-derived acid phosphomonoesterase in total soil acid phosphomonoesterase in different forests

Enzyme acid phosphomonoesterase (APM) plays an important role in phosphorus mineralization in different type of terrestrial ecosystems. This enzyme is of great agronomic significance because it hydrolyses organic phosphorus to different forms of inorganic phosphorus which are assimilable by plants. APM may also indicate changes in the quantity and quality of phosphorylated substrates in soil and is a good indicator of its biological state as well as presence of pollutants. APM may be produced by plant roots and soil microorganisms and both of these sources may play different role in phosphorus mineralization in different ecosystems. The aim of this work was determine acid phosphomonoesterase (APM) activity location in soil of different forest ecosystems. The APM activity location determination was performed on the basis of root-derived and soil-derived APM and expression of proportion of those root-derived in total soil APM up to 13 cm depth. The results of this preliminary study showed that root-derived APM formed 21–34 % of total soil APM in pine and oak forest.

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation. Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems. A study of responses of soil APA to simulated N deposition was conducted in three succession forests of subtropical China. The three forests include a Masson pine (Pinus massoniana) forest (MPF)pioneer community, a coniferous and broad-leaved mixed forest (MF)transition community and a monsoon evergreen broad-leaved forest (MEBF)climax community. Four N treatments were designed for MEBF: control (without N added), low-N (50 kg N ha−1 year−1), and medium-N (100 kg N ha−1 year−1) and high-N (150 kg N ha−1 year−1), and only three N treatments (i.e., control, low-N, medium-N) were established for MPF and MF. Results showed that soil APA was highest in MEBF, followed by MPF and MF. Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N treatments. However, soil APA in MEBF exhibited negative responses to high N additions, indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem. Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

Soil phosphorus composition determined by 31P NMR spectroscopy and relative phosphatase activities influenced by land use

Land use can alter the phosphorus (P) pool in soil. Understanding detailed P changes derived from different land uses is important for sustainable development of soil resources. However, soil P composition and phosphatase activities under different land uses in temperate regions remain widely unknown. Soils from four types of land use, including cultivated (Maize and Paddy) and uncultivated (Woodland and Fallow) soils, in the same region were selected to characterize soil P composition using solution 31P nuclear magnetic resonance (31P NMR) spectroscopy. Four soil phosphatase activities, acid phosphomonoesterase (AcP), alkaline phosphomonoesterase (AlP), phosphodiesterase (PD) and pyrophosphatase (PY), were also considered. The results showed that the proportions of dominated inorganic orthophosphate were higher in cultivated soils than in uncultivated soils, while the opposite trend was observed for organic orthophosphate monoesters and diesters. Generally, soil phosphatase activities were higher in uncultivated soils than in cultivated soils. The multivariate analysis indicates that soil P composition as well as phosphatase activity was significantly influenced by land use. The correlation analysis showed that soil AcP and PY activities were positively correlated with soil monoester and pyrophosphate, respectively, and were negatively correlated with soil available P.

Soil acid phosphomonoesterase activity and phosphorus forms in ancient and post-agricultural black alder [Alnus glutinosa (L.) Gaertn.] woodlands

Black alder, an N-fixing tree is considered to accelerate the availability of phosphorus in soils due to the increased production of phosphatase enzymes, which are responsible for the P release from the litter. Acid phosphatase activity plays a pivotal role in organic P mineralization in forest soils and in making P available to plants. In order to check whether <em>Alnus glutinosa </em>stimulates acid phosphomonoesterase (PH<sub>ACID</sub>) activity, we compared enzyme activities, total P concentration (P<sub>TOT</sub>), plant-available P (P<sub>AVAIL</sub>), organic P (P<sub>ORG</sub>) and inorganic P (P<sub>INORG</sub>), and organic matter content in 27 ancient and 27 post-agricultural alder woods (the latter ones representing different age classes: 11-20, 21-40 and 41-60 years) of soil samples taken from the litter and the mineral layers. Phosphomonoesterase activity, organic matter, P<sub>TOT</sub>, P<sub>INORG</sub> and P<sub>ORG</sub> concentrations were significantly higher in ancient alder woods than in the soils of post-agricultural forests. Significant differences in the acid phosphatase activity, organic matter and P<sub>AVAIL</sub> concentration were noted between the litter and mineral layers within the same forest type. In recent stands the amount of organic matter and phosphatase activity increased significantly with the age of alder stands, although only in the mineral layer of their soils. Phosphomonoesterase activity, organic matter and P<sub>AVAIL</sub> content were higher in a litter layer and decreased significantly at a mineral depth of the soil. The acid phosphatase activity was significantly correlated with organic matter content in both ancient and recent stands. There was no significant relationship between PH<sub>ACID</sub> activity and any P forms.

Water Treatment Residuals and Biosolids Co‐applications Affect Phosphatases in a Semi‐arid Rangeland Soil

Co‐application of biosolids and water treatment residuals (WTR) land has not been extensively studied but may be beneficial by sorbing excess biosolid‐borne or soil phosphorus (P) onto WTR, reducing the likelihood of off‐site movement. Reduction of excess soil P may affect the role of specific P‐cleaving enzymes. The research objective was to understand the long‐term effects of single co‐applications and the short‐term impacts of repeated co‐applications on soil acid phosphomonoesterase, phosphodiesterase, pyrophosphatase, and phytase enzyme activities. Test plots were 7.5 × 15 m with treatments consisting of three different WTR rates with a single biosolids rate (5, 10, and 21 Mg WTR ha−1; 10 Mg biosolids ha−1) surface co‐applied once in 1991 or reapplied in 2002. Control plots consisted of those that received no WTR–biosolids co‐applications and plots that received only 10 Mg biosolids ha−1. Plots were sampled to a 5‐cm depth in 2003 and 2004, and soil phosphatases and phytase enzyme activities were measured. Soil phosphodiesterase activity decreased in WTR‐amended plots, and pyrophosphatase activity decreased with increasing WTR application rates. In contrast, acid phosphatase and phytase activity increased with WTR addition, with WTR application possibly triggering a deficiency response causing microorganisms or plants to secrete these enzymes. Biosolids and WTR co‐applications may affect enzymatic strategies for P mineralization in this study site. Reductions in phosphodiesterase activity suggest less P mineralization from biomass sources, including nucleic acids and phospholipids. Increased acid phosphatase and phytase activities indicate that ester‐P and inositol‐P may be important plant‐available P sources in soils amended with WTR.

Experimental approaches to the determination of acid phosphomonoesterase activity in soil

Quantitative methods used in measurements of soil acid phosphomonoesterase (EC 3.1.3.2) activity which may find use in ecological monitoring are reviewed.