Crop and Soil Response to Tillage and Crop Residue Application in a Tropical Ferralsol in Sub-humid Western Kenya

2012 ◽  
pp. 41-57
Author(s):  
J. Kihara ◽  
J. Mukalama ◽  
F. O. Ayuke ◽  
S. Njoroge ◽  
B. Waswa ◽  
...  
Keyword(s):  
Crop Residue ◽  
Western Kenya ◽  
Soil Response

Impact of reduced tillage and crop residue management on soil properties and crop yields in a long-term trial in western Kenya

Soil Research ◽  
2016 ◽  
Vol 54 (6) ◽  
pp. 719 ◽  
Author(s):  
Jeremiah M. Okeyo ◽  
Jay Norton ◽  
Saidou Koala ◽  
Boaz Waswa ◽  
Job Kihara ◽  
...  
Keyword(s):  
Crop Residue ◽  
Crop Yields ◽  
Smallholder Farmers ◽  
Sub Saharan Africa ◽  
Residue Management ◽  
Microbial Biomass C ◽  
Reduced Tillage ◽  
Western Kenya ◽  
Entry Points ◽  
The Impact

Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in Sub-Saharan Africa. Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) compared with conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an 8-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced soil physical quality through increased macroaggregate (>2000µm) proportions and mean weight diameter. Similarly, lower respiratory quotient values indicate that soil microbes under RT have better substrate-use efficiency than those under CT. Nevertheless, soil organic carbon (C), potentially mineralisable C, microbial biomass C and mineral nitrogen contents were all higher under CT with crop residue incorporated into the soil. Maize grain yield and aboveground biomass were also higher under CT. Thus, despite RT showing potential to improve soil physical properties, CT performed better. A stepwise approach is proposed towards the practice of conservation agriculture under resource-constrained smallholder farming conditions, starting with increased biomass production to provide crop residue for soil cover, followed by RT approaches.

Crop residue disappearance and macrofauna activity in sub-humid western Kenya

2014 ◽  
Vol 102 (1) ◽  
pp. 101-111 ◽  
Author(s):  
J. Kihara ◽  
C. Martius ◽  
A. Bationo
Keyword(s):  
Crop Residue ◽  
Western Kenya

Soil Response during Globally Drained and Undrained Freeze–Thaw Cycles under Deviatoric Loading

2021 ◽  
Vol 147 (2) ◽  
pp. 06020030
Author(s):  
Sang Yeob Kim ◽  
Junghee Park ◽  
Wonjun Cha ◽  
Jong-Sub Lee ◽  
J. Carlos Santamarina
Keyword(s):  
Soil Response ◽  
Freeze Thaw

Soil response to chemicals used in a field experiment

2013 ◽  
Vol 27 (2) ◽  
pp. 151-158 ◽  
Author(s):  
S. Jezierska-Tys ◽  
A. Rutkowska
Keyword(s):  
Alkaline Phosphatase ◽  
Enzymatic Activity ◽  
Field Experiment ◽  
Soil Microorganisms ◽  
Block Design ◽  
Soil Samples ◽  
Alkaline Phosphatases ◽  
Soil Response ◽  
Negative Effect ◽  
Set Up

Abstract The effect of chemicals (Reglone 200 SL and Elastiq 550 EC) on soil microorganisms and their enzymatic activity was estimated. The study was conducted in a field experiment which was set up in the split-block design and comprised three treatments. Soil samples were taken six times, twice in each year of study. The results showed that the application of chemicals generally had no negative effect on the number of soil microorganisms. The application of Reglone 200 SL caused an increase of proteolytic and ureolytic activity and affected the activity of dehydrogenases, acid and alkaline phosphatases in the soil. The soil subjected of Elastiq 550 EC was characterized by lower activity of dehydrogenases, protease, urease and alkaline phosphatase.

Determination and prediction of the stress-strain state of pipeline, taking into account soil changes during operation

2020 ◽  
Vol 10 (4) ◽  
pp. 372-378
Author(s):  
Aydar К. Gumerov ◽  
◽  
Rinat M. Karimov ◽  
Robert М. Askarov ◽  
Khiramagomed Sh. Shamilov ◽  
...  
Keyword(s):  
Strain State ◽  
Mathematical Framework ◽  
Equilibrium Equations ◽  
Stress Strain ◽  
Optimal Method ◽  
Initial Stress State ◽  
Soil Response ◽  
Stress Strain State ◽  
Support Reaction ◽  
Key Factor

The key factor determining the strength, reliability, service life and fail-safe operation of the main pipeline is its stress-strain state. The purpose of this article is to develop a mathematical framework and methodology for calculating the stress-strain state of a pipeline section laid in complex geotechnical conditions, taking into account all planned and altitude changes and impacts at various points of operation, as well as during repair and after its completion. The mathematical framework is based on differential equations reflecting the equilibrium state of the pipeline, taking into account the features of the sections (configuration, size, initial stress state, acting forces, temperature conditions, interaction with soil, supports, and pipe layers). The equilibrium equations are drawn up in a curvilinear coordinate system – the same one that is used for in-pipe diagnostics. According to the results of the solution, all stress components are determined at each point both along the length of the pipeline and along the circumference of any section. At the same time, transverse and longitudinal forces, bending moments, shearing forces, pipeline displacements relative to the ground and soil response to displacements are determined. As an example, a solution is given using the developed mathematical framework. During the course of calculation, the places where the lower form of the pipe does not touch the ground and the places where the support reaction becomes higher than a predetermined limit are determined. A comparative analysis was accomplished, and the optimal method for section repair has been selected.

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