**6. References**


Rainfall produced by dripper-type rainfall simulator has been charcterized using piezoelectric transducers. The rainfall drop size distribution and kinetic energy has been measured in 10 second time interval. The rainfall micro-structure has been eveluated by the changes in the drop size distribution at each rainfall intensity. The soil splash erosion has been evaluated using splash cup method under five rainfall intensities ranges between 10 to 30 mm h-1. The rainfall kinetic energy was found to increase with the increase in large drops content (drops with diameter > 2.5). The splash soil loss was correlated with the large drop percentage which emphasize that the splash erosion is highly affected by the rainfall micro-

The authors thank Ms. Marreia Elamin Ugool for her help in rainfall simulator experiments. This study was financially supported by the Japan Society for the Promotion of Science

Abd Elbasit, M.A.M.; Yasuda, H. & Anyoji H. (2008). Development and application of digital

Abd Elbasit, M.A.M.; Yasuda, H., Salmi A. & Anyoji H. (2007). Characterization of rainfall

Abd Elbasit, M.A.M.; Yasuda, H., Salmi, A. & Anyoji, H. (2010). Characterization of rainfall

Al-Durrah, M.M. & Bradford J.M. (1982) The mechanism of raindrop splash on soil surfaces.

Auerswald, K.; Kainz, M., Wolfgarten, H. & Botschek, J. (1992). Comparison of German and

Cruse, R.M. & Francis, P.B. (1984). Shallow-layer soil water potential changes due to

Epema, G. F. & H. Th. Riezebos. (1983). Fall velocity of waterdrops at different heights as a

Central United States. *Transactions of the ASAE* 17(6): 1033-1037.

*simulation runoff and soil erosion*, Catena Supplement 4.

waterdrop impact. *Soil Science Society of America Journal* 48: 498-500.

elevation model rectification method in monitoring soil microtopography changes during rainfall. *Journal of Japan Society of Hydrology and Water Resources* 21(2): 114-

generated by dripper-type rainfall simulator using piezoelectric transducer. *Proceeding of the annual conference of Japan Society of Hydrology and Water Resources,*

generated by dripper-type rainfall simulator using piezoelectric transducer and its impact on splash soil erosion. *Earth Surface Processes and Landform* 35: 466-475. Abd Elbasit, M.A.M.; Yasuda, H. & Salmi A. (2011). Assessment of piezoelectric sensors for

rainfall erosivity under simulated rainfall. *Hydrological Science Journal* 56(1):187-194.

Swiss rainfall simulators - Influence of plot dimensions. *Zeitschrift für Pflanzenernährung und Bodenkunde*155: 493-497. DOI: 10.1002/jpln.19921550102 Carter, C.E.; Greer, J.D., Braud, H.J. & Floyd JM. (1974). Raindrop characteristics in South

factor influencing erosivity of simulated rain. In: DePloey, J. (Ed.): *Rainfall* 

**4. Conclusions** 

structure.

**5. Acknowledgments** 

**6. References** 

125.

Nagoya, Japan: 10-11.

DOI: 10.1080/02626667.2010.546359

*Soil Science Society of America Journal* 46: 1086-1090.


**9** 

**Soil Loss-Rainfall Duration Relations** 

Soil erosion, and its associated impacts, is a big environmental problem, globally. The resulting costs of this phenomenon are tremendous and originate from both on-site and ofsite effects of erosion (Morgan, 2005). On-site effects are particularly important on agricultural lands. The outcome includes loss of soil fertility and productivity, breakdown in soil structure, and at times loss of life and property. This decline in fertility leads to increased costly fertilizer use, affects food production and food security and substantial declines in land values. Off-site problems generally result in downstream or downwind

It is thus very important that new methods and practices for reducing and/or controlling erosion be developed and existing ones improved so as to combat this very important problem. There is also the need to encourage the use of existing agri-environmental management methods like the use of geotextiles and soil conditioners. Basically, all strategies for soil conservation include the following: providing a barrier against raindrop impact, increasing soil aggregate stability, increasing infiltration capacity of the soil to reduce runoff and/or increasing surface roughness to reduce velocity of runoff and wind

Peat is sometimes used as a source of organic matter for the soil. In Trinidad, peat is particularly used in nurseries, because unlike other organic materials like FYM, its incorporation is not accompanied by weeds infestation. Peat increases soil fertility and improves physical properties like saturated hydraulic conductivity (Ohu et al., 1985) and available water and reduces bulk density (Lebeau et al., 2003; Ekwue and Harrilal, 2010). Soil erosion by water consists of two basic processes: splash detachment and transport by raindrops and runoff. Splash erosion is the first step in the soil erosion process and control measures are best targeted at reducing it. Ekwue (1990, 1992) found that splash detachment by raindrops declined with increasing peat content of soils and noted that the relationship was negatively exponential over a range of organic matter content (1.50 – 18.23%). Peat was found to act as mulch and thereby protecting the soil surface from the direct impact of raindrops. Ekwue et al. (2009) further found that peat decreased soil transport by runoff or overland flow (wash erosion). However, it was not clear why peat

sedimentation. There is also the issue of pollution transfer from place to place.

**1. Introduction** 

(Morgan, 2005).

**as Affected by Peat Content, Soil** 

*Biosystems Engineering Programme, Faculty of Engineering* 

**Type and Compaction Effort** 

*The University of the West Indies, St. Augustine* 

E.I. Ekwue and S.D. Ramoutar

*Trinidad and Tobago* 

