Abstract:
Parkland agroforestry woody species are prominent features in many landscapes worldwide,
and their ecological, social and economic importance is widely acknowledged. Farmers have
different objectives for retaining trees on their farm. This study was conducted to assess
woody species diversity and evaluate the effect of selected tree species on sorghum yield
components. For woody species inventory in the farmland with diameter at breast height
(DBH) ≥5 cm were identified and measured in each 50 m*50 m plot size. Saplings below 5 cm
were counted within the major plots, five subplots of 10 m*10 m, at four corners and one in
the center. A total of 29 woody species, belonging to 19 families were recorded in the PAF of
the study area. Among the families, Fabaceae and Euphorbiaceae were the first and second
more diverse species represented by 7 and 3 respectively. The sorghum yield experiment had
three factors which were distances from tree trunk with three levels; at radius of 2.5m, edge
crown radius and at five times total crown radius away from tree trunk (open field) which was
used as control, and two locations. Collected data were analyzed by two-way ANOVA and
mean separation was done with LSD at 5%. The highest value of sorghum grain yield
were under F. albida (2052.05), followed by C. africana (1738.10), C. machrostachyus (1857.
00) and A. tortilis (1835.78) kg/ha, at the distance of 2.5 m away from the trunk in Yabeta
lencha and Bereka kebeles at Kersa district. The grain yield of sorghum (sorghum bicolor)
were significantly higher (P<0.05) under canopy of four trees species as compared to the
open field. 31.76% increment were detected for Sorghum grain yield under the canopy of four
tree species. It can be concluded that these tree species have the potential to increase grain
yield beneath its canopy. So retaining these tree species in the agricultural setting of the study
areasto maintaining soil fertility and provide services to the farmers.
