3. β’ Quantity of seed sown per unit area.
β’ The seed rate depends on spacing or plant
population, test weight, germination
percentage.
β’ Seed rate (kg/ha)=
ππππππππππ ππππππππππππππππππππ ππππππ ππππ Γ π΅π΅π΅π΅. ππππ ππππππππππ ππππππ ππππππππΓ π»π»π»π»π»π»π»π» ππππππππππππ(ππ
)Γ ππππππ Γ ππππππ
ππππππ ππππππππππππππππππππππππππππππππππππ Γ ππππππππππππ ππππππππππππππππππππ Γ ππππππππ Γ ππππππππ
4. 1. Calculate the seed rate of mung bean for sowing 1 hectare of
crop from the following:
spacing=30cmΓ10cm
germination %=92%
purity %=85%
1000 grain weight =36g
Solution:
Plant population=
10000πππ
0.3ππΓ0.1ππ
=333333.33
Seed rate =
333333.33Γ36Γ100Γ100
92Γ85Γ1000Γ1000
=15.34 kg/ha (Ans).
5. 2. Calculate the seed rate of pigeon pea for sowing 1 hectare of
crop from the following:
spacing=60cmΓ25cm
germination %=87%
purity %=86%
1000 grain weight =70g
Solution:
Plant population=
10000πππ
0.6ππΓ0.25ππ
=66666.67
Seed rate =
66666.67Γ70Γ100Γ100
87Γ86Γ1000Γ1000
=6.23 kg/ha (Ans).
6. 3. Calculate the seed rate of ground nut for sowing 1 hectare of
crop from the following:
spacing=50cmΓ20cm
germination %=92%
purity %=95%
1000 grain weight =200g
shelling%=60%
Solution:
Plant population=
10000πππ
0.5ππΓ0.2ππ
=100000
Seed rate of kernels=
100000Γ200Γ100Γ100
92Γ95Γ1000Γ1000
=22.88β23 kg/ha
Quantity of unshelled pods needed for sowing in kg/ha =
100/60Γ23=38.33 kg/ha (Ans).
7. 4. Calculate the seed rate of green gram for sowing 1 hectare of
crop from the following:
spacing=45cmΓ10cm
germination %=80%
1000 grain weight =48g
Solution:
Plant population=
10000πππ
0.45ππΓ0.1ππ
=222222.22
Seed rate=
222222.22Γ48Γ100
80Γ1000Γ1000
=13.33 kg (Ans).
8. 5. Calculate the seed rate of Jute for sowing 1 hectare of crop
from the following:
spacing=25cmΓ10cm
germination %=90%
purity percentage= 85%
test weight =6.5g
Solution:
Plant population=
10000πππ
0.25ππΓ0.1ππ
=400000
Seed rate=
400000Γ6.5Γ100Γ100
90Γ85Γ1000Γ1000
=3.39 kg (Ans).
9. 6. Calculate the quantity of maize seed for sowing 1 hectare of
crop from the following:
spacing=75cmΓ20cm
germination %=90%
purity percentage= 90%
test weight =250g
seed required for gap filling=5% of total weight of seeds.
Solution:
Plant population=
10000πππ
0.75ππΓ0.2ππ
=66666.67
Seed rate=
66666.67Γ250Γ100Γ100
90Γ90Γ1000Γ1000
=20.576 kg
Amount of seed required for Gap filling=
5
100
Γ20.576= 1.028 kg
Total seed required for 1 hectare area= 20.576+1.028=21.604β
22kg/ha (Ans).
10. 7. Calculate the seed requirement for upland rice for sowing 1
hectare of crop from the following:
spacing=20cmΓ30cm
germination %=95%
purity percentage= 90%
test weight =25g
No. of damaged seeds by birds, which are to be replaced 10seeds
per square meter i.e., 10/mΒ².
Solution:
Plant population=
10000πππ
0.2ππΓ0.3ππ
=166666.67
Replacing bird damaged seeds, 1mΒ² area= 10 seeds
10000mΒ² area= 100000seeds
Total no. of plant population= 166666.67
+100000=266666.67
Seed rate=
266666.67Γ25Γ100Γ100
95Γ90Γ1000Γ1000
= 7.79β8 kg/ha (Ans).
11. 8. Calculate the seed requirement for rice in kg/ha for sowing
1 hectare of crop from the following:
spacing of hill=20cmΓ20cm
No. of seedlings per hill=3
germination %=95%
purity percentage= 90%
test weight =25g
seedlings required for gap filling=12/5 mΒ² area
Solution:
Plant population=
10000πππ
0.2ππΓ0.2ππ
=250000Γ3= 750000
Seedlings required for gap filling.
For 5mΒ² seedlings required= 12
For 10000mΒ²= 12/5Γ10000=24000 seedlings.
Total plant population= 750000+24000=774000
Seed rate=
774000Γ25Γ100Γ100
95Γ90Γ1000Γ1000
=22.63 kg/ha (Ans).