EFFECTS OF SOIL AND WATER CONSERVATION TECHNIQUES ON PHYSICAL AND CHEMICAL PROPERTIES OF SOIL IN THE SAVANNAH ECOLOGICAL ZONE

Abstract

Soil and water conservation technologies are practiced in Northern Ghana to help farmers reduce food insecurity and promote sustainable agriculture. This work seeks to understand the effects of soil and water conservation techniques on the physical and chemical properties of soils in the savannah ecological zone. Three and two communities in the Kumbungu district and Kasena Nankani East Municipality, respectively, were selected for the study. Rainfall data from 1977 to 2012 was analysed for erosivity using modified Fournier index and soil samples were collected and analysed for physical and chemical properties. Generally very rapid rate of infiltration occur, downstream whiles rapid infiltration occurs upstream. Bulk density, porosity, organic carbon, soil organic matter and carbon accumulation values ranged from 1.58g/cm3-1.72 g/cm3, 34 %-41 %, 4.6 g/kg- 6.4 g/kg, 0.79 g/kg-0.98 g/kg and 2.31 t/ha - 3.65 t/ha, respectively in the Tolan district. pH, Nitrogen, Phosphorus, potassium and CEC ranged from 5.27 - 5.56. 0.04 % - 0.05 %, 1.67 g/kg- 3.14 g/kg, 0.09 cmoi+/kg-0.17 cmol'zkg to 2.15 cmol'rkg- 5.21 cmol'vkg, respectively Kumbungu district. Bulk density, porosity, OC, SOM and Cc values ranged from 1.67g/cm3-1.83 g/cm3, 22 %-36 %, 5.3 g/kg- 7 g/kg, 0.91 g/kg-1.2 g/kg and 2.84 t/ha- 3.83 t/ha, respectively in the Kasena Nankani East Municipality. pH, Nitrogen, Phosphorus, potassium and CEC ranged from 4.92 - 5.62. 0.04 % - 0.05 %, 3.71 g/kg- 4.63 g/kg, 0.07 cmolf/kg-Ovl S cmol/kg to 2.13 cmol/kg- 8.36 cmol/kg, respectively Kasena Nankani East Municipality. Nutrient contents were generally low in soil sampled at the selected communities. Mean annual rainfall was 992 mm for 35 years, with highest rainfall occurring in 1999 with amount 1353 mm and lowest recorded 1995, with an amount of 688 mm for Kasena Nankani East Municipality, while 1147 mm for Tolan district the highest rainfall was recorded in 1999, with an amount of 1898.2 mm and the lowest occurring in 2005 with an amount of 749 mm. Mean Modified Fournier Index were 199 and 61 for Kasena Nankani East Municipality and Kumbugu district, respectively. In conclusion, soil nutrients were generally low among soils sampled at the selected communities as compared to the pre-data. It is recommended that farmers practice more of SW CT introduced by CPWF.