Soil bulk density pedotransfer functions of the humus horizon in arable soils

Abstract Soil bulk density is one of the main direct indicators of soil health, and is an important aspect of models for determining agroecosystem services potential. By way of applying multi-regression methods, we have created a distributed prediction of soil bulk density used subsequently for topsoil carbon stock estimation. The soil data used for this study were from the Slovakian partial monitoring system-soil database. In our work, two models of soil bulk density in an equilibrium state, with different combinations of input parameters (soil particle size distribution and soil organic carbon content in %), have been created, and subsequently validated using a data set from 15 principal sampling sites of Slovakian partial monitoring system-soil, that were different from those used to generate the bulk density equations. We have made a comparison of measured bulk density data and data calculated by the pedotransfer equations against soil bulk density calculated according to equations recommended by Joint Research Centre Sustainable Resources for Europe. The differences between measured soil bulk density and the model values vary from −0.144 to 0.135 g cm−3 in the verification data set. Furthermore, all models based on pedotransfer functions give moderately lower values. The soil bulk density model was then applied to generate a first approximation of soil bulk density map for Slovakia using texture information from 17 523 sampling sites, and was subsequently utilised for topsoil organic carbon estimation.

Download Full-text

Estimation of the density of the clay-organic complex in soil

International Agrophysics ◽

10.1515/intag-2015-0075 ◽

2016 ◽

Vol 30 (1) ◽

pp. 19-23 ◽

Cited By ~ 4

Author(s):

Ewa A. Czyż ◽

Anthony R. Dexter

Keyword(s):

Organic Matter ◽

Bulk Density ◽

Pore Space ◽

Organic Matter Content ◽

Soil Bulk Density ◽

Matter Content ◽

Gas Content ◽

Effective Density ◽

Organic Complex ◽

Arable Soils

Abstract Soil bulk density was investigated as a function of soil contents of clay and organic matter in arable agricultural soils at a range of locations. The contents of clay and organic matter were used in an algorithmic procedure to calculate the amounts of clay-organic complex in the soils. Values of soil bulk density as a function of soil organic matter content were used to estimate the amount of pore space occupied by unit amount of complex. These estimations show that the effective density of the clay-organic matter complex is very low with a mean value of 0.17 ± 0.04 g ml−1 in arable soils. This value is much smaller than the soil bulk density and smaller than any of the other components of the soil considered separately (with the exception of the gas content). This low value suggests that the clay-soil complex has an extremely porous and open structure. When the complex is considered as a separate phase in soil, it can account for the observed reduction of bulk density with increasing content of organic matter.

Download Full-text

Pedotransfer functions for Irish soils – estimation of bulk density (<i>ρ</i><sub>b</sub>) per horizon type

SOIL ◽

10.5194/soil-2-25-2016 ◽

2016 ◽

Vol 2 (1) ◽

pp. 25-39 ◽

Cited By ~ 15

Author(s):

B. Reidy ◽

I. Simo ◽

P. Sills ◽

R. E. Creamer

Keyword(s):

Bulk Density ◽

Soil Bulk Density ◽

Pedotransfer Functions ◽

Data Sets ◽

Density Data ◽

Soil Carbon Stock ◽

Packing Structure ◽

Core Method ◽

International Data ◽

Density Map

Abstract. Soil bulk density is a key property in defining soil characteristics. It describes the packing structure of the soil and is also essential for the measurement of soil carbon stock and nutrient assessment. In many older surveys this property was neglected and in many modern surveys this property is omitted due to cost both in laboratory and labour and in cases where the core method cannot be applied. To overcome these oversights pedotransfer functions are applied using other known soil properties to estimate bulk density. Pedotransfer functions have been derived from large international data sets across many studies, with their own inherent biases, many ignoring horizonation and depth variances. Initially pedotransfer functions from the literature were used to predict different horizon type bulk densities using local known bulk density data sets. Then the best performing of the pedotransfer functions were selected to recalibrate and then were validated again using the known data. The predicted co-efficient of determination was 0.5 or greater in 12 of the 17 horizon types studied. These new equations allowed gap filling where bulk density data were missing in part or whole soil profiles. This then allowed the development of an indicative soil bulk density map for Ireland at 0–30 and 30–50 cm horizon depths. In general the horizons with the largest known data sets had the best predictions, using the recalibrated and validated pedotransfer functions.

Download Full-text

Influence of ryegrass managements on the physical properties of a Haplohumox

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2018000800010 ◽

2018 ◽

Vol 53 (8) ◽

pp. 952-960 ◽

Cited By ~ 2

Author(s):

Bruno Vizioli ◽

Karina Maria Vieira Cavalieri-Polizeli ◽

Gabriel Barth

Keyword(s):

Organic Carbon ◽

Physical Properties ◽

Total Organic Carbon ◽

Bulk Density ◽

Block Design ◽

Soil Bulk Density ◽

Pedotransfer Functions ◽

Root Penetration ◽

Organic Carbon Content ◽

No Tillage

Abstract: The objective of this work was to evaluate the influence of ryegrass (Lolium multiflorum) managements on the physical properties of a Haplohumox, and on the yields of corn and of ryegrass cultivated in succession to corn. The experiment was carried out in a randomized complete block design, with three treatments and three replicates, in which treatments were the different managements of ryegrass under no-tillage for silage, soil cover, and grazing. After nine years of management, samples were collected at 0.00-0.05, 0.05-0.10, 0.10-0.20, and 0.20-0.30-m soil depths, to determine the following soil properties: texture, total organic carbon, soil bulk density, macroporosity, microporosity, total porosity, and resistance to root penetration. The index of structural stability was estimated from texture and total organic carbon data. Maximum soil bulk density and permanent wilting point were also estimated from pedotransfer functions. Corn and ryegrass dry matter yields were determined from plants harvested inside the plot area. Total organic carbon content increased as depth increased. The ryegrass managements in no-tillage system, in succession to corn, does not influence the soil physical properties of a Haplohumox, and maintains high corn and ryegrass yields.

Download Full-text