Organic phosphorus speciation in Australian Red Chromosols: stoichiometric control

Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.

2014 ◽  
Vol 11 (23) ◽  
pp. 6697-6710 ◽  
Author(s):  
A. W. Cheesman ◽  
B. L. Turner ◽  
K. R. Reddy

Abstract. Phosphorus (P) cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e., forms derived from biological activity) in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydrogeomorphic, and vegetation types. Total P concentrations ranged between 51 and 3516 μg P g-1, of which an average of 58% was extracted in a single-step NaOH–EDTA procedure. The extracts contained a broad range of P forms, including phosphomonoesters (averaging 24% of the total soil P), phosphodiesters (averaging 10% of total P), phosphonates (up to 4% of total P), and both pyrophosphate and long-chain polyphosphates (together averaging 6% of total P). Soil P composition was found to be dependant upon two key biogeochemical properties: organic matter content and pH. For example, stereoisomers of inositol hexakisphosphate were detected exclusively in acidic soils with high mineral content, while phosphonates were detected in soils from a broad range of vegetation and hydrogeomorphic types but only under acidic conditions. Conversely inorganic polyphosphates occurred in a broad range of wetland soils, and their abundance appears to reflect more broadly that of a "substantial" and presumably active microbial community with a significant relationship between total inorganic polyphosphates and microbial biomass P. We conclude that soil P composition varies markedly among freshwater wetlands but can be predicted by fundamental soil properties.


Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 564-567 ◽  
Author(s):  
Glen P. Murphy ◽  
David R. Shaw

Research was conducted in 1994 and 1995 to evaluate the field mobility of flumetsulam in three soils of varied texture and organic matter content but constant pH (pH = 6.0 ± 0.1). Flumetsulam was monitored to a depth of 122 cm at 28, 56, and 84 days after treatment (DAT). Flumetsulam concentrations were determined by cotton bioassay, with separate standard curves for various soil–depth combinations. Following a preemergence application of flumetsulam at 224 g ai ha−1, the herbicide was primarily limited to the upper 8 cm of soil, regardless of soil type, year, or DAT. Exceptions to this typically occurred following substantial rainfall amounts early in the season. Beyond 28 DAT, no significant concentrations of flumetsulam were detected below 15 cm. Results from this research suggest that leaching is not a significant route of flumetsulam dissipation in the field.


2011 ◽  
Vol 57 (No. 5) ◽  
pp. 228-234 ◽  
Author(s):  
G. Xu ◽  
J.N. Sun ◽  
R.F. Xu ◽  
Y.C. Lv ◽  
H.B. Shao ◽  
...  

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% &lt; 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO<sub>3</sub>-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios. &nbsp;


Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Chris H. Tingle ◽  
David R. Shaw ◽  
Patrick D. Gerard

Laboratory studies were conducted to evaluate14C-flumetsulam mobility in two Mississippi soils of varied texture and organic matter content following delays in irrigation. Mobility was evaluated using packed soil columns, 25 cm deep, under unsaturated–saturated flow conditions. Irrigation timings included 0, 3, and 5 d after flumetsulam application. Flumetsulam mobility (defined as the amount collected in leachate) decreased from 45% to no more than 20% of the applied in the Prentiss sandy loam soil when irrigation was delayed 3 or 5 d. With the Okolona soil, flumetsulam recovery in the leachate was 21, 14, and 6%, respectively when irrigation occurred 0, 3, and 5 d after application. Flumetsulam proved to be mobile when irrigation immediately followed application, with 6 to 45% recovered in the leachate from all soils evaluated. The Prentiss soil retained 6% of the applied flumetsulam in the upper 5 cm and the Okolona soil retained 22% when irrigation immediately followed flumetsulam application. When the irrigation interval was delayed at least 3 d, the Okolona soil retained 40% in the upper 5 cm, whereas the Prentiss soil retained 10%. Flumetsulam mobility was dependent on irrigation timing and soil type.


2010 ◽  
pp. 53-59
Author(s):  
Györgyi Kovács

Applying alternative soil cultivation methods based on reduced disturbance of the soil more favourable conditions can be created in order to increase the organic matter content of the soil and the availability of the nutrients for the crops. In complex soil tillage experiment – in 1997 was set on – at Karcag, as the element of the investigation of soil reduced and conventional tillage systems. There is close correlation between the degree and intensity of CO2-emission from the soil and the structural state and organic matter content of the soil. In order to quantify the increased CO2-emission from soil due to soil preserving cultivation systems, in situ CO2-emission of soil was measured by means of an ANAGAS 98 infrared gas analyser. The soil type of the investigated plot is meadow chernozem solonetz in the deeper layers, a soil type that is characteristicfor the Trans-Tisza Region of Hungary. In this paper the results gained from the measurement on different stubbles are published, as we consider stubbles the most suitable state when the effects of different soil cultivation systems on the microbiological activity of the soil can be compared. Experimental data provided information about the length of the time period when CO2 emission increasing effects of soil cultivation are observable. Studying the effect of different soil cultivation methods on the CO2 emission from chernozem soil is indisputably actual and needs more efforts as it can contribute to develop a more environmental friendly agricultural production. The main goal of these measurements was to determine the effect of soil cultivation technologies and certain agrotechnical elements on the factors of the soil carbon cycle.


2021 ◽  
Vol 22 (8) ◽  
Author(s):  
Munifatul Izzati ◽  
SRI HARYANTI ◽  
RINI BUDI HASTUTI

Abstract. Izzati M, Haryanti S, Hastuti RB. 2021. Effectivity of bulrush (Scirpus californicus) as a soil conditioner  increasing sandy and clay soil fertility. Biodiversitas 22: 3423-3429. Bullrush (Scirpus californicus) is a species of macrophytes that often populates lakesides. This aquatic plant was rarely studied and its use has not been explored yet. This study was carried out to determine the effects of soil conditioner made from bulrush on sandy and clay soil fertility. Collected bulrush from Rawa Pening lake was milled into a powder and used as a soil conditioner in a proportion of 1:1. After a week, soil fertility was evaluated including organic matter content, water retention, the ratio of C/N, and bacteria population. The study was designed using a Completely Randomized Design with two treatments and control. Resulted data were analyzed using a t-test to evaluate the difference between the two treatments. Results showed that bulrush powder application significantly increased sandy and clay soil fertility. The organic matter content significantly increased in both sandy (p<0,01) and clay soils (p<005). The water retention of sandy soil was increased by 74% (p<0,01), while in clay soil was reduced by 27% (p<0,01). The C/N ratio was significantly reduced in both sandy and clay soil (p<0,05), while the bacteria population significantly increased (p<0,01). It is suggested to use the bulrush as a soil conditioner particularly for sandy and clay soils.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ruilin Huang ◽  
Thomas W. Crowther ◽  
Yueyu Sui ◽  
Bo Sun ◽  
Yuting Liang

AbstractIrreversible climate change alters the decomposition and sequestration of soil carbon (C). However, the stability of C components in soils with different initial organic matter contents and its relationship with the response of major decomposers to climate warming are still unclear. In this study, we translocated Mollisols with a gradient of organic matter (OM) contents (2%–9%) from in situ cold region to five warmer climatic regions to simulate climate change. Soil C in C-rich soils (OM >5%) was more vulnerable to translocation warming than that in C-poor soils (OM ≤ 5%), with a major loss of functional groups like O-alkyl, O-aryl C and carboxyl C. Variations of microbial β diversity with latitude, temperature and precipitation indicated that C-rich soils contained more resistant bacterial communities and more sensitive fungal communities than C-poor soils, which led to strong C metabolism and high utilization ability of the community in C-rich soils in response to translocation warming. Our results suggest that the higher sensitivity of soils with high organic matter content to climate change is related to the stability and metabolic capacity of major bacterial decomposers, which is important for predicting soil-climate feedback.


1961 ◽  
Vol 12 (4) ◽  
pp. 612 ◽  
Author(s):  
CH Williams ◽  
J Lipsett

A study has been made of red-brown earth�s cultivated for wheat on a narrow rotation of fallow-wheat-volunteer pasture in the Ariah Park district of Xew South Wales. Surface soil samples from 55 cropped paddocks currently under fallow and from matched adjoining areas with no history of cultivation were examined in laboratory, pot culture, and field studies. Many of the soils had carried at least 20 crops since being brought under cultivation and had lost an average of 30% of their organic matter during this period. However, only 17% of the organic phosphorus had been mineralized. The mean ratio of carbon : nitrogen : sulphur : organic phosphorus in the uncultivated soils was 178.3 : 10 : 1.37 : 0.63 while that for the cultivated soils was 170.9 : 10 : 1.41 : 0.74. As a result of the decrease in organic matter content the cation exchange capacity decreased under cultivation. Losses of the exchangeable cations also occurred, but the relative proportions of the metal ions in the cultivated soils were the same as those in the uncultivated. Removal of cations in crops could not account for all of the losses observed. There had been a net loss of sulphur from the surface soils over and above that likely by crop removal. The nitrate content of the surface samples was insufficient to provide the nitrogen uptake by the crop either in pots or in the field. Evidence is presented suggesting that other sources, including leached nitrate, were utilized in the field. Mineralization of organic phosphorus and fertilizer addition had increased the amounts of inorganic, plant-available forms, but the total phosphorus was unchanged in the cultivated soils. However, the phosphorus status of' the cultivated soils was still extremely low and responses to phosphorus were obtained at all sites. There seems little prospect of reducing current superphosphate rates on these soils.


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