In a dry autumn, is it better to sow pasture seed early and wait for rain or wait for rain, then sow seed?

 

If you can do it, early sowing has several benefits: contractors aren’t so busy; seed is set to grow when rain comes; new pasture is ready for its first grazing sooner; winter growth is better, and this sets up better persistence.

 

The main question with early sowing has been how well seed keeps in the soil, so we tested this.

In a replicated trial near Cambridge, Trojan perennial ryegrass with NEA2 endophyte was sown 20 February, 20 March and 27 April. The first sowing was in very dry conditions, and seed sat in the soil with no sign of germination until 45 mm of rainfall on 4 April (43 days later).

 

Dark peat soil was chosen as this is known to become very warm. At the seed sowing depth of 2 cm, the soil temperature at 10am on 20 February was 49.1°C. On 20 March it was 41.7°C; on 27 April, 27.0°C.

Two key results stood out. First, seed sowed early established quicker and grew more.

 

February and March sowings grew 2 t DM/ha more than the April sowing (5.8 t versus 3.8 t), measured over 5 grazings from May to October.

 

This is because the early sown seed was read to go and germinated with the rain, i.e. much earlier than the late sown seed.

 

At the Forage Value Index figure of $0.31c/kg DM, that’s $620/ha operating profit in a dairy system. Second, endophyte levels were not affected by early sowing; these were the same for all sowing dates.

 

Conclusion? Sowing early (from 20 Feb) in dry conditions with treated seed is easier for contractors, means faster establishment, more yield, and sets up better pasture persistence. Trojan NEA2 seed can keep well in the soil for six weeks without significant rain.

 

Endophyte levels tested for Trojan NEA2 & rainfall for 3 sowing dates at Cambridge in 2014

 

Notes: Seed endophyte levels of Trojan NEA2 sown was 88%. Results reported were tested on 17 December 2014 using 8 replicates of 50 tillers/plot.  Note: field immuno-blotting technique typically underestimates endophyte levels.   LSD (5%) statistical difference is given on top of bars. There were no differences between sowing dates.