This document provides examples of how to calculate the seed rate per hectare for different crops. It lists the key factors needed for calculation such as spacing, germination percentage, purity percentage, 1000 grain weight, and plant population per hectare. It then shows step-by-step calculations for seed rates of various crops like mung bean, pigeon pea, groundnut, green gram, jute, maize, upland rice, and rice. The calculations follow a consistent formula and take into account additional needs like seeds for gap filling.

2. How do I calculate seed
per hectare?

3. • Quantity of seed sown per unit area.
• The seed rate depends on spacing or plant
population, test weight, germination
percentage.
• Seed rate (kg/ha)=
𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑 𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑 𝒑𝒑𝒑𝒑𝒑𝒑 𝒉𝒉𝒉𝒉 × 𝑵𝑵𝑵𝑵. 𝒐𝒐𝒐𝒐 𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔 𝒑𝒑𝒑𝒑𝒑𝒑 𝒉𝒉𝒉𝒉𝒉𝒉𝒉𝒉× 𝑻𝑻𝑻𝑻𝑻𝑻𝑻𝑻 𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘(𝒈𝒈
)× 𝟏𝟏𝟏𝟏𝟏𝟏 × 𝟏𝟏𝟏𝟏𝟏𝟏
𝒈𝒈𝒈𝒈𝒈𝒈 𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒈𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑 × 𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑 𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑 × 𝟏𝟏𝟏𝟏𝟏𝟏𝟏𝟏 × 𝟏𝟏𝟏𝟏𝟏𝟏𝟏𝟏

4. 1. Calculate the seed rate of mung bean for sowing 1 hectare of
crop from the following:
spacing=30cm×10cm
germination %=92%
purity %=85%
1000 grain weight =36g
Solution:
Plant population=
10000𝑚𝑚𝑚
0.3𝑚𝑚×0.1𝑚𝑚
=333333.33
Seed rate =
333333.33×36×100×100
92×85×1000×1000
=15.34 kg/ha (Ans).

5. 2. Calculate the seed rate of pigeon pea for sowing 1 hectare of
crop from the following:
spacing=60cm×25cm
germination %=87%
purity %=86%
1000 grain weight =70g
Solution:
Plant population=
10000𝑚𝑚𝑚
0.6𝑚𝑚×0.25𝑚𝑚
=66666.67
Seed rate =
66666.67×70×100×100
87×86×1000×1000
=6.23 kg/ha (Ans).

6. 3. Calculate the seed rate of ground nut for sowing 1 hectare of
crop from the following:
spacing=50cm×20cm
germination %=92%
purity %=95%
1000 grain weight =200g
shelling%=60%
Solution:
Plant population=
10000𝑚𝑚𝑚
0.5𝑚𝑚×0.2𝑚𝑚
=100000
Seed rate of kernels=
100000×200×100×100
92×95×1000×1000
=22.88≈23 kg/ha
Quantity of unshelled pods needed for sowing in kg/ha =
100/60×23=38.33 kg/ha (Ans).

7. 4. Calculate the seed rate of green gram for sowing 1 hectare of
crop from the following:
spacing=45cm×10cm
germination %=80%
1000 grain weight =48g
Solution:
Plant population=
10000𝑚𝑚𝑚
0.45𝑚𝑚×0.1𝑚𝑚
=222222.22
Seed rate=
222222.22×48×100
80×1000×1000
=13.33 kg (Ans).

8. 5. Calculate the seed rate of Jute for sowing 1 hectare of crop
from the following:
spacing=25cm×10cm
germination %=90%
purity percentage= 85%
test weight =6.5g
Solution:
Plant population=
10000𝑚𝑚𝑚
0.25𝑚𝑚×0.1𝑚𝑚
=400000
Seed rate=
400000×6.5×100×100
90×85×1000×1000
=3.39 kg (Ans).

9. 6. Calculate the quantity of maize seed for sowing 1 hectare of
crop from the following:
spacing=75cm×20cm
germination %=90%
purity percentage= 90%
test weight =250g
seed required for gap filling=5% of total weight of seeds.
Solution:
Plant population=
10000𝑚𝑚𝑚
0.75𝑚𝑚×0.2𝑚𝑚
=66666.67
Seed rate=
66666.67×250×100×100
90×90×1000×1000
=20.576 kg
Amount of seed required for Gap filling=
5
100
×20.576= 1.028 kg
Total seed required for 1 hectare area= 20.576+1.028=21.604≈
22kg/ha (Ans).

10. 7. Calculate the seed requirement for upland rice for sowing 1
hectare of crop from the following:
spacing=20cm×30cm
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/m².
Solution:
Plant population=
10000𝑚𝑚𝑚
0.2𝑚𝑚×0.3𝑚𝑚
=166666.67
Replacing bird damaged seeds, 1m² area= 10 seeds
10000m² area= 100000seeds
Total no. of plant population= 166666.67
+100000=266666.67
Seed rate=
266666.67×25×100×100
95×90×1000×1000
= 7.79≈8 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=20cm×20cm
No. of seedlings per hill=3
germination %=95%
purity percentage= 90%
test weight =25g
seedlings required for gap filling=12/5 m² area
Solution:
Plant population=
10000𝑚𝑚𝑚
0.2𝑚𝑚×0.2𝑚𝑚
=250000×3= 750000
Seedlings required for gap filling.
For 5m² seedlings required= 12
For 10000m²= 12/5×10000=24000 seedlings.
Total plant population= 750000+24000=774000
Seed rate=
774000×25×100×100
95×90×1000×1000
=22.63 kg/ha (Ans).