Effect of short-term legume residue decomposition on soil acidity

Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 561 ◽  
Author(s):  
G. P. Sparling ◽  
C. D. A. McLay ◽  
C. Tang ◽  
C. Raphael

The accumulation of organic matter has been suggested to be one of the causes of soil acidification. We examined the effect of applying clover shoots, clover roots, and lupin leaves which differed in concentrations of N and excess cations/ash alkalinity on the pH of 2 acidic soils from Western Australia over a 28-day incubation period. Addition of the legume residues at rates of 1·54 and 3·08 g/kg soil increased soil pH by up to 0·6 units at Day 0 and 0·7 units at Day 28 after incubation. The increase in soil pH was the greatest with addition of lupin leaves, followed by clover shoots, and the least with clover roots. The increase in pH correlated well with the amounts of ash alkalinity added as plant materials. Ammonium concentrations were generally increased by addition of the plant materials, but with time the concentrations decreased in the Kojonup soil and increased in the Moora soil. Nitrate concentrations were similar between the treatments, and increased with time. Addition of legume residues slightly increased the pH buffer capacity of both soils at Day 0 but not at Day 28. After 28 days, 37–51% of clover shoots and 36–51% of lupin leaf had decomposed compared with 22-38% of clover roots. The results suggest that rapid changes in soil pH following application of plant materials are related to the concentration of excess cations and decomposition of the material and that the application of legume shoot residues, which usually have high concentrations of excess cations, is not the likely cause of soil acidification.

1991 ◽  
Vol 31 (3) ◽  
pp. 321 ◽  
Author(s):  
WJ Slattery ◽  
AM Ridley ◽  
SM Windsor

The export of farm produce from farming systems results in the removal of excess cations over anions from the soil. This removal of bases from the soil will eventually cause an increase in the acidity of the soil. Ash alkalinity data for a range of farm products are presented in this paper and lime replacement values calculated. Of produce from mixed farming enterprises in north-eastern Victoria, hay required the greatest amount of lime (270-1260 kg CaCO3/ha.year) to replace lost alkali from the soil. By comparison, removal of cereal produce required much less lime (7-20 kg CaCO3/ha.year) to replace lost alkali, as did removal of wool and lamb (0.8 and 6.0 kg CaCO3/ha.year respectively). Management strategies that include a lime replacement value for exported farm produce should be considered in overall farm management strategies to reduce soil acidification.


2011 ◽  
Vol 52 (No. 3) ◽  
pp. 137-140 ◽  
Author(s):  
F. Nourbakhsh

Carbon and nitrogen transformations in soil are microbially mediated processes that are functionally related. The fate of C and N was monitored in a clay-textured soil (Typic Haplocambid) which was either unamended (control) or amended with various plant materials at the rate of 10 g residue C/kg soil. To evaluate C mineralization, soils were incubated for 46 days under aerobic conditions. Nitrogen mineralization/immobilization was evaluated at the end of eight-week incubation experiment. All CO<sub>2</sub> evolution data conformed well to a first-order kinetic model, C<sub>m&nbsp;</sub>= C<sub>0</sub> (1 &ndash; e<sup>&ndash;Kt</sup>). The product of K and C<sub>0 </sub>(KC<sub>0</sub>) was significantly correlated with some chemical and biochemical properties of the plant residues, including N concentration (r = 0.83, P &lt; 0.001), C:N (r = &ndash;0.64, P &lt; 0.05) and lignin:N (r = &ndash;0.81, P &lt; 0.001). Among the plant residue composition characteristics, N concentration (r = 0.96, P &lt; 0.001), C:N (r = &ndash;0.69, P &lt; 0.01) and lignin:N (r = &ndash;0.68, P &lt; 0.01) were significantly correlated with the net rates of N mineralization/immobilization (N<sub>m/i</sub>).


2014 ◽  
Vol 4 ◽  
Author(s):  
Verónica Asensio Fandiño ◽  
Flora A. Vega ◽  
Rubén Forján ◽  
Emma F. Covelo

The sorption capacity for Ni, Pb and Zn of mine tailings soil with and without reclamation treatment (tree planting and waste amendment) was evaluated using the batch adsorption technique. It is important to determine the capacity of waste-amended soils to retain Ni, Pb and Zn, as the sludges used usually have high concentrations of these metals. The results obtained in the present study showed that the untreated mine tailings soil had a low capacity for Ni, Pb and Zn retention. The sorption capacity for Pb increased significantly in all of the treated soils, without any significant differences between them. The treatment that most increased the sorption capacity for Ni and Zn was planting with trees and amending with waste simultaneously, as this increased the concentration of both organic and inorganic carbon, exchangeable calcium, soil pH and effective cation exchange capacity


1998 ◽  
Vol 49 (1) ◽  
pp. 53 ◽  
Author(s):  
C. Tang ◽  
L. Barton ◽  
C. Raphael

The capacity of subterranean clover (Trifolium subterraneum L. cv. Clare), medic (Medicago murex Willd. cv. Zodiac), serradella (Ornithopus sativus Brot. line SP1/13), biserrula (Biserrula pelecinus L. line Mor99), and woolly clover (Trifolium tomentosum L.) to acidify soil under N2 fixation was compared in a pot experiment using a poorly buffered sandy soil. The amount of acid produced per kg shoot dry matter (specific acid production) varied betweefin species and with growth stages, ranging from 44 to 128 cmol/kg shoot. Subterranean clover and serradella acidied soil to a greater extent than woolly clover and medic, whereas biserrula acidified soil least. Irrespective of pasture species and growth stage, specific acid production correlated well with concentrations of excess cations and calcium in shoots. Furthermore, total excess cation, ash alkalinity, and calcium in shoots were all good indicators of total acid production across all of the species.


Soil Research ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 183 ◽  
Author(s):  
M. J. McLaughlin ◽  
K. G. Tiller ◽  
M. K. Smart

Fifty commercial potato crops and associated soils were sampled. Soil solutions were extracted from rewetted soils by centrifugation, and solution composition was related to Cd concentrations in tubers. Soils were also extracted with 0·01 M Ca(NO3)2 and 0·01 M CaCl2 solutions, and Cd2+ activities in the extracts were calculated by difference using the stability constants for formation of CdCl2-nn species. The soils had saline solutions (>4 dS/m), and Cl- and SO2-4 in solution markedly affected the speciation of Cd in soil solution, with chloro-complexes, in particular, dominating. While low soil pH was associated with high (>25 nM) concentrations of Cd in soil solution, chloro-complexation also led to high concentrations of Cd in solution, even at neutral to alkaline soil pH values. Tuber Cd concentrations were not related to activities of Cd2+ in soil solution or to activities in dilute salt extracts of soil. Tuber Cd concentrations were related to the degree of chloro-complexation of Cd in solution. The relationship of tuber Cd concentrations to chloro-complexation in soil solution suggests that Cd species other than the free Cd2+ ion are involved in the transport through soil and uptake of Cd by plants.


Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 509 ◽  
Author(s):  
A. D. Noble ◽  
I. P. Little ◽  
P. J. Randall

Soil acidification and related land degradation issues are assuming increasing importance in Australia and challenging the concept of sustainability of current land management systems. In this study, the impacts of tree plantations of 2 species and permanent pasture on soil chemical properties are compared. Soil samples were collected from the top 50 cm (0–5, 5–10, 10–15, 15–20, 20–30, and 30–50 cm depths) from 3 adjacent sites carrying pasture and monocultures of Pinus radiata (radiata pine) and Quercus suber (cork oak) on a deep-surfaced yellow podzolic soil, and differences in soil pH and other soil chemical properties were examined. In the surface 0–5 cm, pH was similar at all 3 sites. Below that depth, soil pH was significantly lower and exchangeable Al greater under the cork oak stand than at the other 2 sites. Consistent with a decrease in soil pH there was significantly less exchangeable Ca under cork oak. Also, less clay was observed under the cork oak stand and this is taken as evidence of the degradational impact of soil acidification. An estimate of Ca in the top 50 cm of the soil implies considerable loss of Ca under oak, probably by leaching and loss of litter down the slope. Evidence is presented to show that there has been more Fe and Al movement under oak than under pasture and pine, this being ascribed in part to the greater Al and Fe mobilising capacity of the water-soluble component extracted from freshly fallen leaf litter of oak. The Fe and Al composition of the oxalate extract from concretionary material at 10–30 cm under oak is consistent with a process similar to podzolisation. Pseudogleying of Fe and Al may have accompanied the leaching of bases from the system and a reduction of pH.


1976 ◽  
Vol 22 (10) ◽  
pp. 1648-1654 ◽  
Author(s):  
B F Howell ◽  
S Margolis ◽  
R Schaffer

Abstract Methods are described for detection of lactate dehydrogenase (LDH) inhibitors in preparations of reduced nicotinamide adenine dinucleotide. They are (a) comparison of values by kinetic methods with those measured for highly purified NADH and (b) examination of Lineweaver-Burk plots. Chromatographic inhomogeneities are correlated with deviant values for the kinetic constants of NADH preparations. Lineweaver-Burk plots that curve upward at the high concentrations or have a larger or smaller than normal slope may indicate the presence of inhibitor. As determined in bicarbonate buffer (0.11 mol/liter, pH 7.9) by use of 0.600 mmol/liter pyruvate and NADH freshly separated from impurities by chromatography on diethyl-aminoethyl-cellulose, the Km (apparent) of NADH at 25 degrees C has the value 8.11 +/- 0.71 mumol/liter (SD, n = 28) with LDH-1 (pig heart, 2.48 +/- 0.05 U per milliliter of reaction mixture, or 41.3 +/- 0.8 nmol/liter per second). Under similar conditions, the Km (apparent) of NADH has the value of 8.57 +/- 1.58 mol/liter (SD, n = 21) with LDH-5 (pig muscle, 1.77 +/- 0.03 U/ml of reaction mixture), or 29.4 +/- 0.6 nmol/liter per second). At infinite substrate concentrations with the same pH, buffer, and temperature, the Km (apparent) for NADH was 26.0 +/- 0.63 mumol/liter with LDH-1 and 23.2 +/- 4.6 mumol/liter with LDH-5.


Soil Research ◽  
2008 ◽  
Vol 46 (1) ◽  
pp. 17 ◽  
Author(s):  
F. C. B. Vieira ◽  
C. Bayer ◽  
J. Mielniczuk ◽  
J. Zanatta ◽  
C. A. Bissani

Cropping systems and N fertilisation affect soil acidification mainly due to the removal of alkaline plant material from the field and nitrate leaching. The study evaluated the acidification of a subtropical soil under no till cropping systems with different C and N addition rates for 19 years. The contributions of leguminous and non-leguminous crops (fallow/maize, black oat/maize, black oat + vetch/maize, black oat + vetch/maize + cowpea, lablab + maize, pigeon pea + maize, and digitaria) and mineral N fertiliser (0 and 180 kg N/ha.year as urea) to total acidification were estimated. Cropping systems and N fertilisation significantly affected soil pH, which ranged from 4.3 to 5.1. The presence of leguminous species and mineral N promoted greater decreases in soil pH and net soil acidification, which resulted in increases in exchangeable Al content and Al saturation. Black oat + vetch/maize with N fertilisation promoted the highest soil net acidification rate (2.65 kmol H+/ha.year), while digitaria had the lowest (1.07 kmol H+/ha.year). Leguminous species and N fertilisation increased soil acidification through changes in the C cycle associated with the removal of alkaline plant material by grains. Leguminous-based cropping systems promoted higher maize yields than those comprising essentially gramineous species, indicating an opportunity for a reduction in N fertiliser rates. With N application, however, maize yield did not differ among cropping systems, despite differences in soil pH and exchangeable Al.


1991 ◽  
Vol 42 (3) ◽  
pp. 391 ◽  
Author(s):  
DR Coventry ◽  
WJ Slattery

Soil pH decline and net acidification inputs were determined for a long-term crop rotation experiment at Rutherglen in north-eastern Victoria. The rotations utilized were continuous wheat (WW), a 1 : 1 wheat-lupin sequence (WL) and continuous lupins (LL), and each rotation was cropped from 1975-1989. The soil at the site had an initial pH (0.01 mol/LCaCl2) of 6.0 (0-10 cm depth), sandy loam texture, and had a past use of grape vines and then lucerne pasture. The soil pH (0-10 cm) declined for each rotation with time (1977/78-1988/89), decreasing by about 0.8 units for WW and further decreasing with the inclusion of lupin in the rotation. Compared with the WW soil, the WL soil pH was 0.7 and 0.4 units lower at 5-10 cm and 10-15 cm depth and the LL soil pH was 1.0 and 0.8 units lower at 5-10 and 10-15 cm depth. There was no difference in pH between WW and WL below 20 cm depth, but the LL soil had a significantly lower pH to 40 cm depth. Acidification rates were calculated for the period of cropping and for the 3 rotations, with rates of 3.22, 4.11 and 5.26 kmols H+/ha.yr as net acid input for WW, WL and LL rotations. These values represent a rapid rate of soil acidification. The removal of alkalinity in grain accounted for between 15-21% of the overall calculated acidification rate for the 3 rotations. Therefore, it is likely in this cropping system that the acidification largely results from progressive nitrate leaching.


1986 ◽  
Vol 16 (6) ◽  
pp. 1389-1391 ◽  
Author(s):  
David G. Brand ◽  
Paul Kehoe ◽  
Maureen Connors

The soil pH under 20 coniferous plantations on abandoned farmland at the Petawawa National Forestry Institute was remeasured after 46 years and showed a significant decrease. Soils under white spruce (Piceaglauca (Moench) Voss) showed the greatest degree of acidification, with the average pH in 13 plantations decreasing by 1.28.


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