Modeling the Relationship between Soil Bulk Density and the Hydraulic Conductivity Function

2006 ◽  
Vol 5 (2) ◽  
pp. 697-705 ◽  
Author(s):  
S. Assouline
Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1005 ◽  
Author(s):  
Lucia Toková ◽  
Dušan Igaz ◽  
Ján Horák ◽  
Elena Aydin

Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk density, porosity, saturated hydraulic conductivity, soil water content and selected soil water constants at the experimental site in Dolná Malanta (Slovakia) in 2019. Biochar was applied and re-applied at the rates of 0, 10 and 20 t ha−1. Nitrogen fertilizer was applied annually at application levels N0, N1 and N2. In 2019, these levels were represented by the doses of 0, 108 and 162 kg N ha−1, respectively. We found that biochar applied at 20 t ha−1 without fertilizer significantly reduced bulk density by 12% and increased porosity by 12%. During the dry period, a relative increase in soil water content was observed at all biochar treatments—the largest after re-application of biochar at a dose of 20 t ha−1 at all fertilization levels. The biochar application also significantly increased plant available water. We suppose that change in the soil structure following a biochar amendment was one of the main reasons of our observations.


Author(s):  
Yang Liu ◽  
Xiaoyu Liu ◽  
Ni Ren ◽  
Yanfang Feng ◽  
Lihong Xue ◽  
...  

Greenhouse cultivation consumes large volumes of freshwater, and excessive irrigation induces environmental problems, such as nutrient leaching and secondary salinization. Pyrochar (biochar from high-temperature pyrolysis) is an effective soil amendment, and researches have shown that pyrochar application could maintain soil nutrient and enhance carbon sequestration. In addition to pyrochar from pyrolysis, hydrochar from hydrothermic carbonization is considered as a new type of biochar and has the advantages of low energy consumption and a high productive rate. However, the effect of these two biochars on water evaporation in clayey soils under a greenhouse system has seldom been studied. The relationship between water evaporation and biochar properties is still unknown. Thus, in the present study, water evaporation under pyrochar and hydrochar application were recorded. Results showed that both pyrochar and hydrochar application could inhibit water evaporation in clayey soil under greenhouse cultivation. Pyrochar showed a better inhibition effect compared with hydrochar. Correlation analysis indicated that the water evaporation rate was significantly positively correlated with bulk density of biochar (p < 0.05). Overall, application of pyrochar or hydrochar could both reduce soil bulk density and inhibit soil evaporation, and be available for greenhouse cultivation. However, the inhibition effect depends on the properties of the biochar.


Bragantia ◽  
2014 ◽  
Vol 73 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Daniel Dias Valadão Junior ◽  
Aloísio Biachini ◽  
Franciele Caroline Assis Valadão ◽  
Rodrigo Pengo Rosa

This study aimed to evaluate the effect of penetration rate and the size of the cone base on the resistance to penetration under different soil moistures and soil bulk density. The experimental design was completely randomized in a 4x2x2x2 factorial arrangement, with the factors, soil bulk density of 1.0; 1.2; 1.4 and 1.6 Mg m-3, soil moisture at the evaluation of 0.16 and 0.22 kg kg-1, penetration rates of 0.166 and 30 mm s-1 and areas of the cone base of 10.98 and 129.28 mm² resulting in 32 treatments with 8 replicates. To ensure greater uniformity and similarity to field conditions, samples passed through cycles of wetting and drying. Only the interaction of the four factors was not significant. Resistance values varied with the density of the soil, regardless of moisture and penetration rate. Soil penetration resistance was influenced by the size of the cone base, with higher values for the smallest base independent of moisture and soil bulk density. The relationship between resistance to penetration and moisture is not always linear, once it is influenced by soil bulk density. Reduction in the area of the cone leads to an increase in the soil resistance to penetration.


2019 ◽  
Vol 38 (1) ◽  
pp. 59-68
Author(s):  
Hyeong-Jin Choi ◽  
Yong Choi ◽  
Seung-Whee Rhee

In bioreactor landfill, moisture content is one of the most important factors affecting the migration of leachate. The migration characteristics of leachate in the Sudokwon landfill site was estimated by examining relationships among self-loading weight of waste (waste weight load), bulk density, hydraulic conductivity and moisture content of the landfilled waste. Experimental zones in the Sudokwon landfill were divided into leachate recirculation zones (3-C and 4-C zone) and reference zone (3-D zone). The volume of the leachate recirculation was 207 m3 d-1 for 12 months in the 3-C zone and 190 m3 d-1 for 3 months in the 4-C zone. A logarithmic graph can describe the relationship between waste weight load and bulk density by moisture content. However, both the relationship between bulk density and hydraulic conductivity and the relationship between hydraulic conductivity and waste weight load can be expressed by an exponential graph. Through these relationships, generalised equations for hydraulic conductivity were established using moisture content and waste weight load. The hydraulic conductivity calculated from the generalised equation in the leachate recirculation zone was estimated to be 6.27 × 10-4 cm s-1 in the 3-C zone and 4.43 × 10-4 cm s-1 in the 4-C zone. The migration time of leachate in the leachate recirculation zone was estimated to be 64.2 days in the 3-C zone and 94.5 days in the 4-C zone, respectively.


2020 ◽  
Vol 3 (2) ◽  
pp. 51-55
Author(s):  
Muhammad Yakub ◽  
M. Faiz Barchia ◽  
Usman K.J. Suharjo

Salak (Zalacca edulis Gaertn. Voss) is one of the most populair native fruits of Indonesia, consumed as a table fruit by most Indonesians. However, the yield of salak pondoh grown in Bengkulu is still lower than that in their native soil Java, believed to have more suitable soil properties for growing salak pondoh. The objective of this research were to evaluate the relationship of soil bulk density, available K, and slope to the productivity of salak pondoh grown at Padang Jaya Regency, North Bengkulu. We did a survey to collect data on soil bulk density (BD), available K (K), and slope as well as the productivity of salak pondoh grown at Padang Jaya from November 2017 to May 2017. The results showed that there was a significant relationship between soil characteristics and salak productivity, as shown in a linear model of Y = 2.929 -1.070 BD + 0.069 K - 0.126 Slope. Soil K was positively correlated to salak productivity, suggesting that salak productivity increased with an increase in soil K.  On the other than, soil bulk density and slope were negatively correlelated to salak productivity, indicating that salak productity decreased with an increase in slope and in soil bulk density.


Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1063 ◽  
Author(s):  
G. J. Sheridan

Compaction of a silty clay loam forest soil was compared for 2 types of log-skidding equipment, a rubber-tyred skidder and a flexible-steel-tracked skidder. Experiments involved the loaded skidders traversing marked laneways at zero, 2, 4, and 10 passes. Compaction was quantified in terms of 3 parameters: (1) bulk density to 25 cm depth measured gravimetrically, (2) penetration resistance using a field penetrometer, and (3) saturated hydraulic conductivity using a field rainfall simulator. Results showed no substantial difference in soil bulk density between the experimental treatments, regardless of skidder type or number passes. Penetration resistance of the traversed laneways was significantly higher than the surrounding undisturbed areas; however, there was no difference between skidder type. Rainfall simulation showed that the saturated hydraulic conductivity of all treatments was strongly reduced by trafficking, although this did not differ with skidder type. The results from this study highlight the dangers in assuming that reduced machine static ground pressures will automatically lead to reduced soil impacts. It is important to note that while this study did not find differences between the 2 skidder types when operated in a similar manner, differences in the operation of the two skidders may also influence impacts on soil properties.


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