Effects of soil and water conservation practices on soil physicochemical properties in Gumara watershed, Upper Blue Nile Basin, Ethiopia

Abstract

Background: Soil erosion is among the foremost causes of declining soil resources in Ethiopia, which in turn affect agricultural productivity. To limit this problem, for the last two decades in Gumara watershed, soil and water conservation measures have been practiced through free labor community mass-mobilization. However, their effect on soil fertility has not been evaluated. This study investigated the impact of implemented soil and water conservation measures on fertility improvement in the Gumara watershed. Both composite and core soil samples were taken from upstream, midstream, and downstream adjacent conserved and non-conserved cultivated and grazing plots. Selected soil fertility indicators were analyzed using standard laboratory procedures. Results: Soil and water conservation practices have resulted in a statistically significantly higher mean values of total nitrogen, exchangeable Na + and Mg 2+ at p < 0.01, and of soil organic carbon and organic matter at p < 0.05 in the watershed. The clay content, soil reaction, cation exchange capacity, and exchangeable K + showed nonsignificant, but higher mean values in conserved plots. Furthermore, the effects of conservation practices on soil properties were found more effective in cultivated land uses as compared to that of grazing land uses. This is because conservation treatments had significant effects on organic carbon, total nitrogen, exchangeable Na + and Mg 2+ in cultivated land uses but only on exchangeable Na + in grazing land uses. The interaction effect of treatments and land uses did not reach a statistically significant result for any of the soil properties considered in this study. Conclusion: Conservation measures have important implications for improving soil fertility in the Gumara watershed. Therefore, proper guidance and follow-up, use of agro-forestry and grass strips, and maintenance are required for the watershed's sustainability and good soil conditions.

Soil erosion risk and sediment yield assessment with universal soil loss equation and GIS: in Dijo watershed, Rift valley Basin of Ethiopia

“…The result is consistent with the finding of Bekele et al (2019) in the Karesa watershed south west Ethiopia who found a comparable result ranging from 0 to 25 ton/ha/year. The finding was also consistent with the finding of Belayneh et al (2019), who estimated the annual soil loss ranges from 0.01 to 442.92 ton/ha/year. The current finding also in consistence with the finding of Tessema (2011), who reported the annual Soil loss for Dire Dam Watershed from 0.00 to 263.25 ton/ ha/year, Amsalu and Mengaw(2014), reported the annual soil loss in Jabi Tehinan Woreda ranges from nearly 0 in south and central parts of the area to 504.6 ton/ha/year in steeply sloping mountainous areas of the north and northeastern parts of the catchments.…”

Runoff and soil loss responses of cultivated land managed with graded soil bunds of different ages in the Upper Blue Nile basin, Ethiopia

“…Haplic alisols cover the dominant portion (43.76%) of the watershed. The soil in the area is characterized by heavy clay content on average approximately 65% (Belayneh et al 2019b). The dominancy of clay soils than sand and silts can cause high runoff and sediment loss (Bashari et al ).…”

“…Currently nearly, 90% of the local population relies on subsistence based agricultural activities with a population density of over 185 persons per square kilometer. This might be the case that the soil in the Gumara watershed is characterized by low organic carbon and total nitrogen contents (Belayneh et al 2019b).…”

“…Particularly in cultivated fields, within a few years of construction, either erosion sediments or farmers while plowing nearly totally filled furrow depressions. It has been a usual practice in the Gumara watershed, UBNB (Belayneh et al 2019b), and most parts of Ethiopia at large.…”

Major Constraints of Watershed Management Practices in Ethiopia and Ways Forward

“…In 1970s various soil and water conservation measures have been implemented by Ministry of Agriculture in Ethiopia [15, 16, 17, 18 19]. Since then, many efforts were given to conserve the natural resources under watershed management [19]. There are success stories of watershed management in many districts of Ethiopia [8,14,20,21].…”