Assessment Of Horizontal Wind Erosion And Wind Erosivity And Their Interrelationship In Gozalhalag Area, River Nile State, Sudan
This work was conducted in a bare land in River Nile State to assess the intensity of wind erosion measured by horizontal traps (IWEh) and wind erosivity (Wr) and their interrelationship for two climatic seasons during (August 2008-March 2009, August 2009-March 2010). IWEh was measured monthly in four directions, namely; West (W), North West (NW), North (N), and North East (NE). Wr computed by analyzed mean monthly climatic data. In two seasons the results showed that the IWE and Wr varied in frequency and direction even within the same climatic season. The following results of the first season will be presented as an example, the mean IWEh ranged from 99.9 (W) to 109.8 (NE) with a mean of 104.4 tons ha-1 day-1, a standard deviation (STD) of 4.13 tons ha-1 day-1 and a coefficient of variation (CV) of 4%. The mean IWEh values for the main month effect ranged from 260 (Sept.) to 2.1 (Nov.) with a mean of 104.4 tons ha-1 day-1, a STD of 97.49 tons ha-1 day-1 and a CV of 93.4%. Wr ranged from 0 (Nov., 2008) to 745.7 (Mar. 2009) with a mean of 310.4 (m/s)3 and a CV of 66.7%. Wr decreased in the following order: Mar.> Feb.>Jan.> Oct.>Aug.>Dec.>Sept.>Nov. Wr accounted for about 42% of the variability of the IWE. In two seasons March as an example for winter season gave the higher Wr caused mainly by NW (27.6)%, and N (46.4)% directions respectively. Furthermore the higher percentage contribution of erosive winds in summer season (August) blowing mainly from SW (75% & 65.3%) for first and second season respectively. The IWEh and Wr measured in the second season was much lower than that in the first season; the overall mean IWEh and Wr values in the second season was 44% and 93% of that in the first season respectively, due to the higher monthly variability of Wr. Regression between IWEh and Wr gave a highly significant polynomial relationship, (P< 0.05, r=0.649 and R2=42%) and (P< 0.05, r=0.681 and R2=46%) for first and second seasons respectively.
Key words- Horizontal wind erosion, wind erosivity, Soil traps, climatic seasons and River Nile State.