Attributes of Tasmanian ferrosols under different agricultural management

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 603 ◽  
Author(s):  
L. A. Sparrow ◽  
W. E. Cotching ◽  
J. Cooper ◽  
W. Rowley

Attributes of 25 Tasmanian ferrosols under 5 forms of management (low-input pasture, high-input pasture, intermittent cropping, continuous cropping, and pyrethrum production) were assessed using field and laboratory techniques, to see how these attributes changed as the intensity of land management increased. Among the most notable changes were soil organic carbon (C) in the top 150 mm, which was about 30% less in cropping and pyrethrum paddocks than pasture paddocks, and microbial biomass C, which was about 60% less. Earthworm numbers showed even greater differences, with virtually no earthworms under pyrethrum. Pasture soils had higher shear strength and water contents at the liquid limit in the top 150 mm, and more water-stable aggregates in the subsurface soil. Despite these differences, the absolute values of most attributes in cropping paddocks were of a magnitude, which suggests that Tasmanian ferrosols even under continuous cropping are still in good condition. This agreed with the views of the farmers, obtained by individual survey. The decrease in organic C in the cropped soils has not decreased the effective cation exchange capacity, probably because their higher pH due to liming has compensated. Because ferrosols with organic C contents of 1−2% elsewhere in Australia have been shown to have serious management limitations, we need to know by how much the organic C contents in Tasmanian ferrosols will continue to decrease under intensive cropping to predict whether they might suffer in a similar way.

Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 20 ◽  
Author(s):  
Nirmalendu Basak ◽  
Ashim Datta ◽  
Tarik Mitran ◽  
Satadeep Singha Roy ◽  
Bholanath Saha ◽  
...  

Rice-based cropping systems are the foundation of food security in countries of Southeast Asia, but productivity of such systems has declined with deterioration in soil quality. These systems are different from other arable systems because rice is grown under submergence, and this may require a different set of key soil attributes for maintenances of quality and productivity. A minimum dataset was screened for assessing quality of soils belonging to three Soil Orders (Inceptisols, Entisols and Alfisols) by using statistical and mathematical models and 27 physical, chemical and biological attributes. Surface soils were collected from farmers’ fields under long-term cultivation of rice–potato–sesame cropping systems. Most of the attributes varied significantly among the Soil Orders used. Four or five key attributes were screened for each Soil Order through principal component and discriminate analysis, and these explained nearly 80% and 90% of the total variation in each Soil Order dataset. The attributes were dehydrogenase activity (DHA), available K, cation exchange capacity (CEC) and pHCa for Inceptisols; organic C, pHCa, bulk density, nitrogen mineralisation (Nmin) and β-glucosidase for Entisols; and DHA, very labile C, Nmin and microbial biomass C for Alfisols. Representation of the screened attributes was validated against the equivalent rice yield of the studied system. Among the selected key soil attributes, DHA and CEC for Inceptisols, organic C for Entisols, and Nmin and very labile C for Alfisols were most strongly correlated with system yield (R2 = 0.45, 0.77 and 0.78). Results also showed that biological and chemical attributes were most sensitive for indicating the differences in soil quality and have a strong influence on system yield, whereas soil physical attributes largely varied but did not predict system yield.


2012 ◽  
Vol 36 (6) ◽  
pp. 649-664 ◽  
Author(s):  
João Bosco Vasconcellos Gomes ◽  
Marcelo Ferreira Fernandes ◽  
Antonio Carlos Barreto ◽  
José Coelho de Araújo Filho ◽  
Nilton Curi

This study evaluated the changes occurred in a set of soil attributes, particularly those related to the dynamics of soil organic carbon (SOC), as a function of the replacement of native forest for agricultural ecosystems of regional importance in the coastal tablelands of Northeastern Brazil (orange, coconut, eucalyptus and sugarcane). Six commercial sites under these agroecosystems were compared to neighboring areas of native forest in five areas along this region (Coruripe, Umbaúba, Acajutiba, Cruz das Almas and Nova Viçosa). Soil samples were taken from 0-5 and 5-20 cm depth and analyzed for particle size distribution, bulk density, organic C (OC), particulate organic matter, C in soil solution, microbial biomass C, total cation exchange capacity and water stable aggregates. Linear correlation and multivariate techniques were used for data analysis. The values of base saturation and Al saturation for the 0-20 cm depth layer were also calculated. In all the studied areas, soils under native forest presented better status of physical and chemical attributes than their agroecosystem counterparts, especially in the 0-5 cm layer. For both layers, OC content was the attribute most strongly correlated with the overall changes in all attributes. Unexpectedly, the OC content showed no significant correlation with the sum of silt and clay contents. The set of variables investigated in this study is sensitive to differentiate the quality of soils under perennial and semi-perennial land uses from their counterparts under natural vegetation in the landscapes of the coastal tablelands of Northeastern Brazil.


Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 345 ◽  
Author(s):  
G. D. Schwenke ◽  
D. R. Mulligan ◽  
L. C. Bell

At Weipa, in Queensland, Australia, sown tree and shrub species sometimes fail to establish on bauxite-mined land, possibly because surface-soil organic matter declines during soil stripping and replacement. We devised 2 field experiments to investigate the links between soil rehabilitation operations, organic matter decline, and revegetation failure. Experiment 1 compared two routinely practiced operations, dual-strip (DS) and stockpile soil, with double-pass (DP), an alternative method, and subsoil only, an occasional result of the DS operation. Other treatments included variations in stripping-time, ripping-time, fertiliser rate, and cultivation. Dilution of topsoil with subsoil, low-grade bauxite, and ironstone accounted for the 46% decline of surface-soil (0–10 cm) organic C in DS compared with pre-strip soil. In contrast, organic C in the surface-soil (0–10 cm) of DP plots (25.0 t/ha) closely resembled the pre-strip area (28.6 t/ha). However, profile (0–60 cm) organic C did not differ between DS (91.5 t/ha), DP (107 t/ha), and pre-strip soil (89.9 t/ha). Eighteen months after plots were sown with native vegetation, surface-soil (0–10 cm) organic C had declined by an average of 9% across all plots. In Experiment 2, we measured the potential for post-rehabilitation decline of organic matter in hand-stripped and replaced soil columns that simulated the DS operation. Soils were incubated in situ without organic inputs. After 1 year’s incubation, organic C had declined by up to 26% and microbial biomass C by up to 61%. The difference in organic C decline between vegetated replaced soils (Expt 1) and bare replaced soils (Expt 2) showed that organic inputs affect levels of organic matter more than soil disturbance. Where topsoil was replaced at the top of the profile (DP) and not ploughed, inputs from volunteer native grasses balanced oxidation losses and organic C levels did not decline.


Soil Research ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 296 ◽  
Author(s):  
D. Das ◽  
B. S. Dwivedi ◽  
V. K. Singh ◽  
S. P. Datta ◽  
M. C. Meena ◽  
...  

Decline in soil organic carbon (SOC) content is considered a key constraint for sustenance of rice–wheat system (RWS) productivity in the Indo-Gangetic Plain region. We, therefore, studied the effects of fertilisers and manures on SOC pools, and their relationships with crop yields after 18 years of continuous RWS. Total organic C increased significantly with the integrated use of fertilisers and organic sources (from 13 to 16.03gkg–1) compared with unfertilised control (11.5gkg–1) or sole fertiliser (NPKZn; 12.17gkg–1) treatment at 0–7.5cm soil depth. Averaged across soil depths, labile fractions like microbial biomass C (MBC) and permanganate-oxidisable C (PmOC) were generally higher in treatments that received farmyard manure (FYM), sulfitation pressmud (SPM) or green gram residue (GR) along with NPK fertiliser, ranging from 192 to 276mgkg–1 and from 0.60 to 0.75gkg–1 respectively compared with NPKZn and NPK+cereal residue (CR) treatments, in which MBC and PmOC ranged from 118 to 170mgkg–1 and from 0.43 to 0.57gkg–1 respectively. Oxidisable organic C fractions revealed that very labile C and labile C fractions were much larger in the NPK+FYM or NPK+GR+FYM treatments, whereas the less-labile C and non-labile C fractions were larger under control and NPK+CR treatments. On average, Walkley–Black C, PmOC and MBC contributed 29–46%, 4.7–6.6% and 1.16–2.40% towards TOC respectively. Integrated plant nutrient supply options, except NPK+CR, also produced sustainable high yields of RWS.


2000 ◽  
Vol 37 (3) ◽  
pp. 712-722 ◽  
Author(s):  
A Sridharan ◽  
H B Nagaraj

Correlating engineering properties with index properties has assumed greater significance in the recent past in the field of geotechnical engineering. Although attempts have been made in the past to correlate compressibility with various index properties individually, all the properties affecting compressibility behaviour have not been considered together in any single study to examine which index property of the soil correlates best with compressibility behaviour, especially within a set of test results. In the present study, 10 soils covering a sufficiently wide range of liquid limit, plastic limit, and shrinkage limit were selected and conventional consolidation tests were carried out starting with their initial water contents almost equal to their respective liquid limits. The compressibility behaviour is vastly different for pairs of soils having nearly the same liquid limit, but different plasticity characteristics. The relationship between void ratio and consolidation pressure is more closely related to the shrinkage index (shrinkage index = liquid limit - shrinkage limit) than to the plasticity index. Wide variations are seen with the liquid limit. For the soils investigated, the compression index relates better with the shrinkage index than with the plasticity index or liquid limit.Key words: Atterberg limits, classification, clays, compressibility, laboratory tests.


Author(s):  
Gazali Issah ◽  
Jeff Schoenau ◽  
J. Diane Knight

Termination by tillage is one strategy used for regenerating pasture stands. Yet, research gaps exist on how tillage affects carbon (C) and nitrogen (N) forms and amounts in western Canadian soils. We measured total soil organic C (SOC), dissolved organic C (DOC), total dissolved N (TDN), light fraction organic C (LFOC) and N (LFON), microbial biomass C (MBC) and N (MBN), and inorganic N as indicators of soil organic matter (SOM) dynamics. After tillage termination in fall 2018, we sampled soils (0‒10cm; 0‒15cm) under three legume species (alfalfa, cicer milkvetch and sainfoin) three times (spring, summer and fall of 2019) across three landscape positions. Legume species did not affect the measured parameters. Over time, tillage affected DOC, TDN, and inorganic N. Averaged across three pasture legumes and three landscape positions, tillage increased DOC 29% by summer. Fall-applied tillage led to 59% and 33% higher TDN in the succeeding summer and fall. Inorganic N increased by 14% and 40% across landscape positions and sampling after tillage. Averaged across landscape positions, MBC decreased by 31% from spring to summer and increased by 51% from summer to fall. However, MBN increased by 53% and decreased by 5% within the same period. The seasonal fluctuations in MBC/MBN reflected variations in moisture, temperature, and substrate quality. Total SOC, LFOC, and LFON increased on the upper slopes and fall sampling time. Although single intensive tillage did not affect total SOC, several tillage operations could accelerate SOM loss and reduced total C storage over time.


Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 323 ◽  
Author(s):  
CA Campbell ◽  
RJK Myers ◽  
KL Weier

The procedure of Stanford and coworkers was used to quantitatively relate net nitrogen mineralization in five Queensland semi-arid soils to temperature. The concentration of potentially mineralizable nitrogen (No) (1) ranged from 67 �g nitrogen g-1 for a red earth subsoil to 256 for a recently cultivated cracking clay surface soil, (2) was directly proportional to total soil carbon, (3) was greater in surface than in subsurface soil, and (4) was greater in subtropical than tropical soils. Expressed as a fraction of total nitrogen (No/Total N), it ranged between 8 and 21%, and was directly proportional to cation exchange capacity, perhaps implicating expanding lattice clays in stabilization of cell lysates and metabolites. The mineralization rate constant (k) was directly proportional to total carbon, the fuel for microbially mediated reactions in soil. The average k for surface soils was interpolated to be 0.058, 0.031, and 0.018 week-1, corresponding to half-lives of 11.9, 22.4 and 38.5 weeks, at 35�, 25� and 15�C, respectively; these values are similar to those reported for U.S.A. and Chilean soils. The Arrhenius relationship between k and temperature for surface soils (log k = 6.14-2285/T) was similar to that reported by Stanford for U.S.A. soils, and indicates that this relationship might be a general one.


1993 ◽  
Vol 44 (6) ◽  
pp. 1323 ◽  
Author(s):  
FA Robertson ◽  
RJK Myers ◽  
PG Saffigna

Nitrogen (N) limitation to productivity of sown perennial grass pastures on the brigalow lands of S.E. Queensland contrasts with adequate N supply to annual crops grown on the same soil. In order to understand this anomaly, the distribution of N and carbon (C) under permanent green panic pasture and under continuous cropping with grain sorghum was compared in an 18 month field study. Total soil N and organic C (0-10 cm) were, respectively, 0.37 and 3.20% under green panic and 0.23 and 2.31% under sorghum. Soil microbial biomass (0-28 cm) contained 246 kg N and 1490 kg C ha-1 under green panic and 147 kg N and 744 kg C ha-1 under sorghum. Enhanced microbial growth under pasture was attributed to the continuous input of available C from surface litter and roots. The C/N ratio of pasture residues was high (greater than 50) and conducive to immobilization of N. Availability of N under pasture was further reduced by approximately 50% of plant N being immobilized in standing dead tissue. Under sorghum, the microbial biomass was well supplied with N, but was limited by C availability. The soil under sorghum received a single large C input when crop residues were returned after harvest. The differences in N availability, and hence productivity, of these soils under cropping and permanent pasture were due primarily to differences in the timing and quality of C inputs.


2018 ◽  
Author(s):  
Natalia Andrea Osinaga ◽  
Carina Rosa Álvarez ◽  
Miguel Angel Taboada

Abstract. Abstract. The sub-humid Chaco region of Argentina, originally covered by dry sclerophyll forest, has been subjected to clearing since the end of the '70 and replacement of the forest by no till farming. Land use changes produced a decrease in aboveground carbon stored in forests, but little is known about the impact on soil organic C stocks. The aim of this study was to evaluate soil C stocks and C fractions up to 1 m depth in soils under different land use:  20 yr continuous cropping, warm season grass pasture and native forest in 32 sites distributed over the Chaco region. The organic C stock content up to 1 m depth expressed as equivalent mass varied as follows: forest (119.3 Mg ha−1) > pasture (87.9 Mg ha−1) > continuous cropping (71.9 and 77.3 Mg ha−1), with no impact of the number of years under cropping. The most sensitive organic carbon fraction was the coarse particle fraction (2000 μm–212 μm) at 0–5 cm and 5–20 cm depth layers. Resistant carbon (


2015 ◽  
Vol 39 (3) ◽  
pp. 643-653 ◽  
Author(s):  
Fabrício de Araújo Pedron ◽  
Rodrigo Bomicieli de Oliveira ◽  
Ricardo Simão Diniz Dalmolin ◽  
Antonio Carlos de Azevedo ◽  
Ricardo Vargas Kilca

Despite numerous studies conducted on the lower limit of soil and its contact with saprolite layers, a great deal of work is left to standardize identification and annotation of these variables in the field. In shallow soils, the appropriately noting these limits or contacts is essential for determining their behavior and potential use. The aims of this study were to identify and define the field contact and/or transition zone between soil and saprolite in profiles of an Alisol derived from fine sandstone and siltstone/claystone in subtropical southern Brazil and to subsequently validate the field observations through a multivariate analysis of laboratory analytical data. In the six Alisol profiles evaluated, the sequence of horizons found was A, Bt, C, and Cr, where C was considered part of the soil due to its pedogenetic structure, and Cr was considered saprolite due to its rock structure. The morphological properties that were determined in the field and that were different between the B and C horizons and the Cr layer were color, structure, texture, and fragments of saprolite. According to the test of means, the properties that support the inclusion of the C horizon as part of the soil are sand, clay, water-dispersible clay, silt/clay ratio, macroporosity, total porosity, resistance to penetration, cation exchange capacity, Fe extracted by DCB, Al, H+Al, and cation exchange capacity of clay. The properties that support the C horizon as a transition zone are silt, Ca, total organic C, and Fe extracted by ammonium oxalate. Discriminant analysis indicated differences among the three horizons evaluated.


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