Use of the seed rate formula below in conjunction with a target established plant population (see table below) allows greater control over the final number of plants established per square metre. Use of the formula also factors in variations in Thousand Grain Weight (TGW) as well as germination and establishment. All these factors vary greatly and make a significant difference to the final seed rate. Over-thick crops may lodge, give lower test weights and have higher disease pressure; thin crops will not have maximum yield potential and are not as competitive with weeds.
The table below provides an estimate of the expected plant establishment percentage for different drilling dates of cereals which should be included in the above calculation to determine seed rate. It's important to note that this is only rough guide that is used by the industry.
Month | Plant Establishment% | |
---|---|---|
April | Early | 95 |
Late | 90 | |
May | Early | 90 |
Late | 85 | |
June | Late | 80 |
Early | 75 | |
July | Early | 70 |
Late | 70 | |
August | Early | 80 |
Late | 85 | |
Setpember | Early | 90 |
Late | 90 |
The table below provides the recommended established plant numbers for different drilling dates of wheat. Please note the important comment below the table relating to when you may need to vary the target plant number. The table also gives some example seed rates at TGWs of 45, 50 and 55, assuming in all cases a germination of 95% and an establishment of 90%.
Drilling Month | Target Plant Population (plants/M2) | TGW (g) Seed rate in kg/ha | ||
45 | 50 | 55 | ||
April | 100-125 | 53-66 | 59-73 | 64-80 |
May | 125-175 | 66-92 | 73-102 | 80-113 |
June | 175-200 | 92-105 | 102-117 | 113-129 |
July | 200 | 105 | 117 | 129 |
August | 200-250 | 105-132 | 117-146 | 129-161 |
Setember | 250-300 | 132-158 | 146-175 | 161-193 |
*Manawatu winter wheat growers - use 20 plants/m2 less than the lowest figure above for April, May and June.
Due to the Excellent tillering capacity of EMPERO and RISTRETTO, seed rates need to be reduced as per the table below.
Drilling Date | Target Plant Population |
1-15 April | 100-120 |
16-30 April | 120-140 |
1-15 May | 150 |
16-31 May | 150 |
1-30 June | 150-200 |
AMILO tillers extremely well from an autumn sowing but will inherently produce fewer tiller from a winter drilling.
Drilling Date | Target Plant Population (plants/m2) |
April - 15 May | 125 |
16-31 May | 150 |
1 June to 15 July | 150-200 |
Drilling Month | Target Plant Population (plants/m2) |
Early - Mid April | 150 |
Mid April & May | 175 - 200 |
June | 200 - 225 |
Early spring | 225 - 250 |
Late spring | 250 - 300 |