scholarly journals Influence of soil physical factors on productivity of herbaceous forage species in Kivaa and Ntugi rangelands in Eastern Kenya

2020 ◽  
Vol 1 (1) ◽  
pp. 17-24
Author(s):  
E. Karugia ◽  
F. Kariuki ◽  
J. Mwaniki
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Texture ◽  
Soil Bulk Density ◽  
Cyperus Rotundus ◽  
Grass Species ◽  
Physical Factors ◽  
Forage Species ◽  
Experimental Plots

Rangelands are extensive tracts of land with natural vegetation which is the main forage resource for domestic and wild ungulates. This study investigated the influence of soil texture, bulk density, and moisture content on the production of herbaceous forage species biomass in Kivaa and Ntugi rangelands in Eastern Kenya. Stratified random sampling was used where one out of four blocks of the target rangelands was picked and three belt transects established. Along the belt transects, ten experimental plots of 5 metres by 5 metres were established at intervals of 5 metres. Key forage species were identified using a structured questionnaire administered to key informants. Soil samples were collected from the experimental plots and analyzed for soil texture, bulk density and moisture content. Forage samples were collected and dry matter weight determined. The data collected were analyzed using both descriptive and inferential statistics especially tabulation and regression respectively. The study identified the most valuable forage species namely, Dichanthium annulatum, Themeda triandra, Cenchrus ciliaris, Rhynchelytrum repens, Digitaria abyssinica, Chloris roxburghiana and Cyperus rotundus. Soils in Ntugi ranged from clay loam to sandy clay while those from Kivaa ranged from silty loam to sandy loam. There was higher moisture content in soils in Ntugi than soils in Kivaa (t = 7.71, P ≤ 0.05). Soil moisture content had significant influence on herbage production in both Kivaa (R= 0.968, P ≤ 0.05) and Ntugi (R = 0.962, P ≤ 0.05). Soil bulk density significantly influenced forage grass species herbage production in Ntugi in 2014 (R= 0.513, P ≤ 0.05) and in 2016 ((R = 0.632, P ≤ 0.05). This study concluded that soil texture, bulk density and moisture content significantly influenced herbaceous forage production in the two rangelands. The study recommends use of rotational grazing systems combined with proper stocking rates to maintain moderate soil bulk density and good levels of soil moisture for the herbaceous forage species to continue producing adequate biomass while maintaining residual foliage for continued primary production.

scholarly journals Machinery-Induced Damage to Soil and Remaining Forest Stands—Case Study from Slovakia

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1289
Author(s):  
Zuzana Dudáková (Allmanová) ◽  
Michal Allman ◽  
Ján Merganič ◽  
Katarína Merganičová
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Moisture Content ◽  
Soil Bulk Density ◽  
Forest Stands ◽  
Forest Operations ◽  
Factorial Anova ◽  
Size Type ◽  
The Impact

The paper deals with the damage of the remaining stand and soil caused by harvesting using three ground-based forest operations methods (harvester-forwarder/cable skidder/animal-tractor). It compares the impact of the most common harvesting technologies applied in Slovakia and in Central Europe and thus contributes with valuable information to the knowledge on the suitability of their application in forests stands dominated by broadleaved tree species. Harvesting was performed in five forest stands located at the University Forest Enterprise of Technical University in Zvolen in central Slovakia from August to October 2019. Damage to remaining trees was assessed from the point of its size, type, and position of damage along stem. We expected lower damage of remaining trees in stands where harvesters were used because of the applied cut-to-length short wood system and fully mechanized harvesting system. In addition, we examined soil bulk density and soil moisture content in ruts, space between ruts, and in undisturbed stand to reveal the impact of harvesting machinery on soil. We expected greater soil bulk densities and lower soil moisture content in these stands due to the greatest weight of harvesters and in ruts created by machinery compared with undisturbed stand soil. The highest percentage of damaged remaining trees equal to 20.47% and 23.36% was recorded for harvester forest operations, followed by skidder (19.44%) and animal forest operations with 19.86% and 14.47%. Factorial ANOVA confirmed significant higher soil compaction in stands where harvesters were used (higer bulk density) than in stands where skidding was performed with the skidder and animal power. Higher soil moisture content was recorded in ruts created by harvesters and the skidder. The lowest soil moisture content was in undisturbed stands irrespective of the applied forest operation method.

scholarly journals Data Grouping Method for the Purpose of Forecasting the Mechanical Strength of Plastic Soils

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 578
Author(s):  
Dariusz Błażejczak ◽  
Jan Jurga ◽  
Jarosław Pytka
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Field Measurements ◽  
Penetration Resistance ◽  
Soil Bulk Density ◽  
Regression Equations ◽  
Soil Penetration Resistance ◽  
Small Set ◽  
Data Grouping

The aim of this work was to develop a method of data grouping (DGM) that enables the selection of regression equations for forecasting soil penetration resistance based on an easily available and small set of input data: soil moisture content, soil bulk density and the grain size distribution of the soil. Models for forecasting the penetration resistance were created by selecting regression equations for specific intervals of granulometric variability of soil fractions. A field measurements campaign was conducted and soil samples were taken from the subsoil on 43 profiles, at depths of 25–30, 35–40, 45–50 and 55–60 cm. It was found that the dry bulk density is much less useful for predicting the penetration resistance of plastic soils than soil moisture. The study also showed that it is possible to forecast the soil penetration resistance on the basis of the gravimetric moisture content and the soil specific surface.

scholarly journals Effect of Biochar on Soil Temperature under High Soil Surface Temperature in Coal Mined Arid and Semiarid Regions

2020 ◽  
Vol 12 (19) ◽  
pp. 8238
Author(s):  
Jibing Xiong ◽  
Runhua Yu ◽  
Ejazul Islam ◽  
Fuhai Zhu ◽  
Jianfeng Zha ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Surface Temperature ◽  
Soil Temperature ◽  
Bulk Density ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Bulk Density ◽  
High Soil ◽  
Soil Surface Temperature

High soil surface temperature and loosened soil are major limiting factors of plant productivity in arid and semi-arid coal mining areas of China. Moreover, the extensive and illegitimate burning of crop residues is causing environmental pollution; whereas, these residues could be converted to biochar to benefit soil quality. In this study, the effect of wheat straw biochar (WSB) at rates of 0% (control, CK), 1% (low, LB), 2% (medium, MB) and 4% (high, HB) on soil temperature at different depths (5, 10, 15, and 20 cm) and moisture levels (10 and 20%) was investigated under high soil surface temperature of 50 °C and air humidity of 40%. Our data suggested that soil bulk density was inversely, and soil moisture was directly corelated with soil thermal parameters. Moreover, the increasing rate of WSB addition linearly decreased the soil thermal properties. The maximum decrease in soil bulk density at both moisture levels (10% and 20%) was measured in HB treatment compared to respective CKs. The highest decrease in soil thermal conductivity (59.8% and 24.7%) was found under HB treatment in comparison to respective controls (CK10% and CK20% moisture). The soil volumetric heat capacity was also strongly corelated with soil moisture content (r = 0.91). The WSB treatments displayed differential responses to soil temperature. Under 10% soil moisture, temperature of LB, MB and HB treatments was higher as compared to CK at 5–20 cm depth, and MB treated soil had the smallest increase in temperature. At the 15-cm depth, the MB treatment decreased the temperature by 0.93 °C as compared to the CK20%. Therefore, the effect of WSB on soil temperature was influenced by soil moisture content, soil depth and WSB application rates. It suggested that MB treatment could be a useful farming practice for mitigating soil temperature fluctuation.

FIELD CALIBRATION OF A NEUTRON PROBE

1986 ◽  
Vol 66 (1) ◽  
pp. 173-176 ◽  
Author(s):  
D. S. CHANASYK ◽  
R. H. McKENZIE
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Texture ◽  
Calibration Curve ◽  
Soil Moisture Content ◽  
Field Calibration ◽  
Neutron Probe ◽  
Probe Calibration

A study near Lethbridge, Alberta examined the effect of soil texture and bulk density on the calibration of a neutron probe and explored the feasibility of using only one calibration curve for measuring soil moisture. The effect of soil texture was found to be negligible. Bulk density did affect calibration, but not enough to warrant calibration based on bulk density. A calibration curve derived using all data was adequate for estimating soil moisture content and moisture changes, but the manufacturer’s curve was highly inappropriate for determination of either. Key words: Neutron probe, calibration, texture, bulk density

scholarly journals Influence of Saturated Organic Matter on the Accuracy of In-Situ Measurements Recorded with a Nuclear Moisture and Density Gauge

2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Eric R. Labelle ◽  
Dirk Jaeger
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Forest Soils ◽  
Mineral Soil ◽  
Soil Bulk Density ◽  
Organic Layer ◽  
Correction Factors ◽  
Non Destructive

The impact of machines on forest soils is regularly assessed and quantified using absolute bulk density, which is most frequently obtained by soil cores. However, to allow for repeated measurements at the exact same locations, non-destructive devices are increasingly being used to determine soil bulk density and moisture content in field studies. An example of such a device is a nuclear moisture and density gauge (NMDG), originally designed as a control measurement for soil bulk density and moisture content in geotechnical applications. Unlike road construction or foundation projects that use mineral soil or gravel, forest soils have complex structures and the presence of organic matter, which can skew moisture and density readings from a NMDG. To gain further knowledge in this respect, we performed controlled tests in a sandbox to quantify the influence of varying amounts of saturated organic matter (3, 5, 10, and 15%) mixed with mineral soil in different layers (0–5, 0–10, 0–20 and 0–40 cm) on the accuracy of soil moisture content obtained by a NMDG and soil theta probe at varying depths. Main results illustrated that the presence of saturated organic matter per se was not problematic but moisture content overestimations and related underestimation of dry bulk density occurred when the tested measurement depth was below the created organic layer. Since forest soils often exhibit higher organic matter contents in the upper horizon, correction factors are suggested to minimize the moisture content variations between NMDG and reference method. With the use of correction factors, NMDG can present a non-destructive, fast, and accurate method of measuring soil moisture and bulk density in forestry applications.

A generally applicable pedotransfer function that estimates field capacity and permanent wilting point from soil texture and bulk density

2008 ◽  
Vol 88 (5) ◽  
pp. 761-774 ◽  
Author(s):  
J. A. P. Pollacco
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Bulk Density ◽  
Soil Texture ◽  
The United States ◽  
Pedotransfer Functions ◽  
Pedotransfer Function ◽  
Data Set ◽  
Wide Range ◽  
Fitting Parameters

Hydrological models require the determination of fitting parameters that are tedious and time consuming to acquire. A rapid alternative method of estimating the fitting parameters is to use pedotransfer functions. This paper proposes a reliable method to estimate soil moisture at -33 and -1500 kPa from soil texture and bulk density. This method reduces the saturated moisture content by multiplying it with two non-linear functions depending on sand and clay contents. The novel pedotransfer function has no restrictions on the range of the texture predictors and gives reasonable predictions for soils with bulk density that varies from 0.25 to 2.16 g cm-3. These pedotransfer functions require only five parameters for each pressure head. It is generally accepted that the introduction of organic matter as a predictor improves the outcomes; however it was found by using a porosity based pedotransfer model, using organic matter as a predictor only modestly improves the accuracy. The model was developed employing 18 559 samples from the IGBP-DIS soil data set for pedotransfer function development (Data and Information System of the International Geosphere Biosphere Programme) database that embodies all major soils across the United States of America. The function is reliable and performs well for a wide range of soils occurring in very dry to very wet climates. Climatical grouping of the IGBP-DIS soils was proposed (aquic, tropical, cryic, aridic), but the results show that only tropical soils require specific grouping. Among many other different non-climatical soil groups tested, only humic and vitric soils were found to require specific grouping. The reliability of the pedotransfer function was further demonstrated with an independent database from Northern Italy having heterogeneous soils, and was found to be comparable or better than the accuracy of other pedotransfer functions found in the literature. Key words: Pedotransfer functions, soil moisture, soil texture, bulk density, organic matter, grouping

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