Abstract:
Soil fertility plays a key role in crop production. However, due to intensive and continuous
cultivation of agricultural land in Ethiopia, soil fertility has been decline. Therefore, the
objective of this study was to assess the impact of wheat based cropping system on soil fertility in
Hetosa Woreda. To achieve the objective a composite soil samples were collected from five
cultivation fields, with three replication and two depths (0-15, 15-30cm). Totally, 30 soil samples
were brought to laboratory from wheat rotated with legumes and cereals fields with simple
random sampling system. The two-way ANOVA were used to compare the effects of wheat based
cropping systems at different soil sampling depth with their interaction on selected soil
physicochemical properties at P<0.05. There was a significantly (P<0.05) higher value of soil
BD in wheat-wheat and wheat-barley than wheat-bean and wheat-pea cropping system. The
wheat-wheat and wheat-barley cropping systems didn’t pose any changes in the values of pH,
SOM, Av.P, CEC, PBS and basic cations. Similarly, mean comparison for wheat-bean and
wheat-pea cropping system reveal that there were no significant changes in the value of pH,
SOM, TN, Av.P, CEC, Ca2+, Mg2+, K+
, ex.Na+ and PBS while soil pH in wheat-maize was
significantly different from the entire cropping systems. As compared to the adjacent continuous
wheat cultivation, wheat-barley, wheat-bean, and wheat-maize cropping system increased SOM
by 0.5%, 19.5%, and 3.7% and TN by 5%, 20% and 5%, respectively. Similarly, the value of
Av.P, pH and CEC is increased by 39.6%, 12.3% and 19. 9% at the surface layer of wheat-bean
while decreased by 15.4%, 0.9%, and 5.5% in the subsurface, respectively. The BD, sand and
clay were significantly higher (P < 0.05) in wheat-maize cropping system at the subsurface
whereas the pH, SOM, Av.P, ex.Ca2+, ex.Mg2+, CEC, and PBS were higher in wheat-bean
cropping system at the surface. Generally, the cultivation of wheat-bean and wheat-pea cropping
systems improve the selected properties of soil while wheat-barley and wheat-maize in
comparison with continuous wheat cropping systems had adverse effects on the soil
physicochemical properties of the study area. Therefore, it is recommended to include grain
legume in wheat based cropping system for sustaining the soil fertility level.
Key words: Cereal, Crop rotation Grain legume, Soil fertility, Soil properties.
