Quantifying the contribution from the soil microbail biomass to the extractable P levels of fresh and air-dried soils

Soil Research ◽  
1985 ◽  
Vol 23 (4) ◽  
pp. 613 ◽  
Author(s):  
GP Sparling ◽  
KN Whale ◽  
AJ Ramsay
Keyword(s):  
Microbial Biomass ◽  
Inorganic Phosphorus ◽  
Microbial Biomass C ◽  
Air Drying ◽  
P Values ◽  
Extractable P ◽  
P Content ◽  
Microbial P ◽  
Drying Treatment ◽  
Substrate Induced Respiration

Levels of P extractable in 0.5 M NaHCO3 and the microbial biomass C were measured on a range of 15 New Zealand pasture soils, with and without an air-drying treatment. The microbial biomass C, estimated using a modified substrate-induced-respiration method, was decreased 11-68% by air-drying. Two soils showed no increase in extractable inorganic phosphorus (P) levels after air-drying, but increases for the other 13 soils ranged over 14-184%. In general, the biomass C was not related to the overall P, levels of moist or air-dried soils. However, the increase in P, after air-drying was related to the microbial P content of the moist soil, estimated by CHCl3 fumigation, and the proportion of the biomass C killed by air-drying. A comparison of the actual measured Pi levels of dried soils and those estimated allowing for the microbial contribution, showed excellent agreement, strongly suggesting that the whole of the Pi increase on air-drying of soils was derived from killed microbial cells. The microbial contribution to Pi levels in NaHCO3 extracts of dried soils ranged over 4-76% and was therefore a significant large proportion in some soils. A large microbial contribution to Pi in extracts is most likely on air-dried soils from under pasture with >2% organic matter and NaHCO3-extractable P values of <20 �g g-1.

Relationship between phosphorus fractions and properties of highly calcareous soils

Soil Research ◽  
2007 ◽  
Vol 45 (4) ◽  
pp. 255 ◽  
Author(s):  
Ebrahim Adhami ◽  
Hamid Reza Memarian ◽  
Farzad Rassaei ◽  
Ehsan Mahdavi ◽  
Manouchehr Maftoun ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Hydroxylamine Hydrochloride ◽  
Inorganic Phosphorus ◽  
Influential Factor ◽  
Sequential Fractionation ◽  
Inorganic P ◽  
Soil P ◽  
Fractionation Procedure ◽  
Extractable P ◽  
P Content

Inorganic phosphorus (P) sequential fractionation schemes are applicable techniques to interpret soil P status. The present study was initiated to determine the origin of various P fractions in highly calcareous soils. Inorganic P forms were determined by a sequential fractionation procedure extracting with NaOH (NaOH-P), Na citrate-bicarbonate (CB-P), Na citrate 2 times (C1-P and C2-P), Na citrate-ascorbate (CAs-P), Na citrate-bicarbonate-dithionite (CBD-P), Na acetate (NaAc-P), and HCl (HCl-P). Results showed that NaOH-P was negatively correlated with active iron oxides. CB-P was positively correlated with silt content and negatively related to citrate-bicarbonate-dithionite extractable Fe (Fed). This result illustrates the weathering effect on Ca-P, with Ca-P content declining as a consequence of weathering. A negative correlation was observed between C1-P and citrate ascorbate extractable Fe (FeCAs). Second citrate extractable P (C2-P) was negatively related to calcium carbonate equivalent and positively related to hydroxylamine-hydrochloride and neutral ammonium acetate-hydroquinone extractable Mn (Mnh and Mnq). Fine silt (Fsilt) was the most influential factor affecting CAs-P. It seemed citrate-dithionite-bicarbonate extractable Al (Ald), Mnh, and Mnq have been sinks for CBD-P, while free iron oxide compounds (Feo, Fec, and FeCAs) were a major contributing factor for the formation of NaAc-P. Stable P compounds (HCl-P) of highly calcareous soils originated from coarse silt (Csilt) and hydroxylamine-hydrochloride extractable Mn (Mnh).

Changes in carbon content, respiration rate, ATP content, and microbial biomass in nitrogen-fertilized pine forest soils in Sweden

1989 ◽  
Vol 19 (3) ◽  
pp. 323-328 ◽  
Author(s):  
H.-Ö. Nohrstedt ◽  
K. Arnebrant ◽  
E. Bååth ◽  
B. Söderström
Keyword(s):  
Microbial Biomass ◽  
Carbon Content ◽  
Respiration Rate ◽  
Microbial Biomass C ◽  
Absolute Amount ◽  
Fertilizer Treatment ◽  
Atp Content ◽  
Area Basis ◽  
Substrate Induced Respiration ◽  
And Control

Carbon content and indices of microbial biomass and activity were determined in 1985 in different soil horizons of two nitrogen-fertilized pine forests in Sweden. The Kroksbo site was fertilized in 1974 with 150 and 600 kg N•ha−1 using NH4NO3 or urea, while the Nissafors site was fertilized in 1977 and 1984 with 150 kg NH4NO3-N•ha−1 The absolute amount of C per square metre of forest floor increased in fertilizer treatments compared with the control (by 10–26%, depending on the site or fertilizer treatment). Respiration rate, ATP content, and microbial biomass C, measured with the substrate-induced respiration technique, decreased in all horizons when expressed per gram of C. The decrease was most evident with NH4NO3, and at the highest level of fertilization. However, on an area basis there were no differences between fertilizer and control treatments. A calculated increase in litter fall in the fertilized plots could not explain all the increase in the amount of C per square metre compared with the control. Decreased microbial activity per gram of C therefore appeared to be an important factor in the increase in C content in fertilized plots.

scholarly journals Rhizosphere priming of two near-isogenic wheat lines varying in citrate efflux under different levels of phosphorus supply

2019 ◽  
Vol 124 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Qiao Xu ◽  
Xiaojuan Wang ◽  
Caixian Tang
Keyword(s):  
Microbial Biomass ◽  
Root Exudates ◽  
Root Exudation ◽  
Mineral Dissolution ◽  
Microbial Biomass C ◽  
Inorganic N ◽  
Organic C ◽  
Extractable P ◽  
Water Extractable ◽  
Citrate Efflux

Abstract Backgrounds and Aims The rhizosphere priming effect (RPE) has been explained from the perspective of microbial responses to root exudates and nutrient availability. This study introduced a chemical process that could also contribute to RPE: root exudates (organic acid ligands) could liberate mineral-protected carbon (C) in soil for microbial degradation. Methods Wheat (Triticum aestivum L.) near-isogenic lines varying in citrate efflux were grown for 6 weeks in a C4 soil supplied with either low (10 μg g–1) or high P (40 μg g–1). Total below-ground CO2 was trapped and partitioned for determination of soil organic C decomposition and RPE using a stable isotopic tracing technique. Mineral dissolution was examined by incubating soil with citric ligand at a series of concentrations. Key Results High P increased RPE (81 %), shoot (32 %) and root biomass (57 %), root-derived CO2-C (20 %), microbial biomass C (28 %) and N (100%), soil respiration (20 %) and concentrations of water-extractable P (30 %), Fe (43 %) and Al (190 %), but decreased inorganic N in the rhizosphere. Compared with Egret-Burke, wheat line Egret-Burke TaMATE1B with citrate efflux had lower inorganic N, microbial biomass C (16 %) and N (30 %) in the rhizosphere but greater RPE (18 %), shoot biomass (12 %) and root-derived CO2-C (low P 36 %, high P 13 %). Egret-Burke TaMATE1B also had higher concentrations of water-extractable P, Fe and Al in the rhizosphere, indicating the release of mineral-protected C. In addition, citrate ligand facilitated Fe and Al release from soil, with their concentrations rising with increasing ligand concentration and incubation time. Conclusions While high P supply increased microbial growth and RPE possibly due to higher total root exudation, citrate efflux from the root might have facilitated the liberation of mineral-bound C, leading to the higher RPE under Egret-Burke TaMATE1B. Mineral dissolution may be an important process that regulates RPE and should be considered in future RPE research.

Soil microbial biomass carbon and phosphorus as affected by frequent drying–rewetting

Soil Research ◽  
2016 ◽  
Vol 54 (3) ◽  
pp. 321 ◽  
Author(s):  
Hao Chen ◽  
Lu Lai ◽  
Xiaorong Zhao ◽  
Guitong Li ◽  
Qimei Lin
Keyword(s):  
Microbial Biomass ◽  
Nutrient Management ◽  
Microbial Biomass Carbon ◽  
Arable Land ◽  
Experimental Period ◽  
Microbial Biomass C ◽  
Organic C ◽  
Soil Microbial ◽  
Drying And Rewetting ◽  
Extractable P

Drying and rewetting (DRW) events are very common in arable land. However, it is not clear how the frequency of DRW stress history influences soil carbon (C) and phosphorus (P) dynamics under field conditions. In this study, an arable loam calcareous soil was treated with simulated farming practices that included wheat straw and nitrogen incorporation and three DRW cycles at intervals of 14 days during a 90-day experimental period of incubation at 25°C. The DRW events significantly increased cumulative CO2-C evolution, but the increase rate of cumulative CO2-C evolution declined with increasing DRW cycles. Microbial biomass C (MBC) and P (MBP) decreased by 9–55% and 9–29%, respectively, following each DRW event, but recovered to the level before DRW treatment within 7 days. Frequent drying and rewetting caused significant increases in both extractable organic C and NaHCO3-extractable P, by 10–112% and 10–18%, respectively. The fluctuation of the tested parameters became less with increasing frequency of DRW cycles. Changes in microbial biomass, either MBC or MBP, were poorly correlated with those of extractable organic C and NaHCO3-extractable P. Overall, frequent DRW cycles had much stronger and longer lasting impact on soil biomass P dynamics than biomass C. These findings may imply certain links among soil moisture, microbial activity and nutrient bioavailability that are important in water and nutrient management.

scholarly journals Nitrogen Immobilisation and Microbial Biomass Build-Up Induced by Miscanthus x giganteus L. Based Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Triticum Aestivum L ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Miscanthus X Giganteus ◽  
Organic Fertilisers ◽  
Biomass N ◽  
Set Up

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.

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