From dry to damp: getting your pastures ready
New Zealand farmers know that pastoral fortunes can shift rapidly once summer’s extreme dryness gives way to cooler, wetter autumn conditions.
Benefits include faster pasture establishment, higher DM yield and potentially better pasture persistence, and it’s easier to get a contractor. It all helps get a head start on feed recovery after drought, says the company’s agronomist Will Henson.
“Last year many farmers did not sow while it was dry. When the rain came in April, it kept raining on and off for three weeks; contractors were working 24 hours a day but couldn’t keep up.”
Questions arise about early sowing, the company says, e.g. how well do seed and endophyte survive in hot, dry soil? And is there possibility of poor establishment?
In a replicated trial near Cambridge last autumn, Trojan perennial ryegrass with NEA2 endophyte was sown on three dates: February 20, March 20 and April 27. All seed was treated to protect it from insects and disease.
The first sowing was in dry conditions, and seed sat in the soil with no sign of germination until 45mm of rainfall on April 4, 43 days later.
“We deliberately chose dark peat soil for this trial, because it is known to reach high temperatures in late summer and early autumn,” Henson says.
At the seed sowing depth, the soil temperature at 10am on February 20 was 49.1°C. On March 20 it was 41.7°C and on April 27 it was 27.0°C.
Seed sowed early established quicker and grew more, Agriseeds says. The February and March sowings grew 2t DM/ha more than the April sowing (5.8t versus 3.8t), measured over five grazings from May to October.
