A field research experiment was conducted in
the 2020/2021 rain season at St. Joseph Secondary
School in Beitbridge to evaluate the effect of Biochar and
trichoderma on forage sorghum yield in semi-arid
regions of Southern Zimbabwe. The trial was a factorial
experiment in a Randomised Complete Block Design
(RCBD) and were replicated three times. Germination
percentage, plant height, stem girth, leaf area as well as
yield (Wet and dry mass) of forage sorghum were the
parameters measured and the data was analysed using
Genstat, (Analysis of Variance at P<0.05). The results
showed that T. harzianum significantly improved
germination percentage of forage sorghum by 3.92% at
P<0.05, that is Control recorded 86.26% and 1gm/m2
recorded 90.18% and biochar levels did not improve
germination of forage sorghum. T. harzianum did not
show any increase in growth in relation to plant height,
however, it promoted growth of stem girth from 2.096cm
to 2.412cm (on week 3) and 6.07cm to 6.69cm (on week
7) at P<0.01 and P0<05 respectively. T. harzianum
increase growth of leaf area by 34cm2
from 272.8cm2
(control) to 306.8cm2
(on week 5) at P<0.01. The
interaction between biochar and T. harzianum also
resulted in a significant growth on stem girth on the
third week which recorded the highest stem girth of
2.749cm against 2.013cm from the control treatment at
P<0.01 and at 7th week, stem girth increased by 2.22cm
at P<0.05. Biochar also resulted in increase in growth of
leaf area of forage sorghum at P<0.05 on week 5,
(Control treatment recorded 268.2cm2
, 3tha-1 produced a
leaf area of 292.2cm2
and 5ha-1
yielded 308.9cm2
) and
P<0.01 on week 7. The interaction between biochar and
T. harzianum also showed a significant increase in
growth of stem girth on the third week and seventh week
at P<0.01 and P<0.05 respectively. Biochar increased the
height of forage sorghum between biochar application
rates, that is between control (No biochar) at 20.6cm and
3tha-1
levels (24.22cm) at P<0.01 at 2 weeks, P<0.01 at
5th week (No biochar-64.4cm, 3tha-1
- 72cm and 5tha-1
-
78.7cm) and P<0.01 at week 7. There was an increase in
wet mass yield by 4.8tha-1
on 3tha-1 biochar and 9.8tha-1
on 5tha-1 biochar at P<0.01. Dry matter yield increased
by 1.1tha-1
on 3tha-1 biochar and 3.06tha-1
on 5tha-1
biochar. Farmers are therefore recommended to make
use of T. harzianum to enhance seed germination as well
as make use of available forestry waste to make biochar
such that they will improve forage sorghum yields as
well as livestock productivity.
Keywords : Biochar, Trichoderma harzianum, forage sorghum.