Effect of basin irrigation system on soil physio-chemical properties under fertilized and unfertilized lowland rice in Tochi irrigation scheme
Namulindwa, Penina Kisaakye
MetadataShow full item record
Irrigation practices often impact soil properties and other parameters negatively and this could be as result of irrigation method of application, water quality and nature of scheme soil. There is limited information about effect of basin irrigation system on soil physio-chemical properties under fertilized and unfertilized lowland rice in Tochi irrigation scheme. This study was conducted to study the relationship of soil physio-chemical properties and effect of basin irrigation practices of lowland rice production on the soil physio-chemical properties of soils at Tochi Irrigation Scheme, Oyam district, in northern Uganda. Soil samples were taken at depths 0-20 cm, from the lowland rice fields at the area of study and were analysed for physical property (soil texture) and chemical parameters (pH, Available P, Total N, SOC, SOM, K and Na). From the results no significant differences (p>0.05) were observed in the parameters. The soil pH was very acidic (very low) and pH ranges (5.2±0.08 to5.5±0.08) of the soils studied and this explains the low amount of available P in the basin irrigation in Tochi irrigation scheme. The SOM content was higher than the recommended range 3.0%)in all the plots possibly due to water logging conditions causing the decline in soil oxygen levels hence poor aeration or anaerobic conditions which cannot favor soil microorganisms to break down organic matter. The total nitrogen in the soil was very low and it ranged from 0.165-0.177 % which was below the 0.2%N threshold for crop production. The available P in the study was observed to be very low and the mean value ranged from (1.79-2.79) ppm which were below the critical limit of 15ppm but significantly higher in fertilized plots (p<0.05) Exchangeable potassium was low yet K fertilizer has been pplied and it ranged from (0.09 - 0.12cmol/kg below the critical limit of 0.4 cmol/kg. Sodium was found to be (0.1620-0.228 cmol/kg) which was above the critical limit of sodium in the soil which is 0.01cmol/kg thus soils are regarded as potentially sodic soils. Overall, the fertilization did not have significant effect on soil properties except for phosphorus suggesting that irrigated systems also retain some applied nutrients for next season especially phosphorus.