Swapping old pasture for new

Fifth-generation Taranaki farmer Graeme Harkness has embarked on a programme to replace the old pastures on his 160ha family property near Tariki.

“The youngest pastures were 35 years old and, according to my father, some were as old as 70 years,” he said.

“My goal is to transform the farm over 10 years so I can farm with new pastures and flatter paddocks.”

Before beginning the programme in 2006, Harkness did his homework.

He read up the seed brochures on varieties, talked to farming friend James King of southern Manawatu, booked in with the local Hutton Contracting and consulted his seed supplier, Kevin Moratti of H and T Agronomics, comon the best plan of action for his property.

Running 340 Friesian and Friesian-cross cows on 120 effective ha, he decided to renew 10 percent of his farm annually by growing summer turnips and then replanting into perennial tetraploid ryegrass and white clovers. The first paddocks replaced were easy to choose, because they were the roughest, poorest and closest to the dairy.

Before sowing the turnips, the paddocks were sprayed off in early November 2006, rotary hoed 10 days later, rolled and seed-drilled to ensure the soil was contoured effectively. The turnips were ready for eating in late January
and lasted until mid-March. Then the paddocks were power-harrowed, rolled and then roller seed-drilled with the new pasture varieties. The first grazing on the renewed pasture was around 20 May, 2007, and the cows were dried off in early June.

To ensure there was enough feed to last through the first season, Harkness locked up for silage early in mid-October and took care to ensure the nitrogen, phosphate and potassium (NPK) levels were at their optimum around the farm.

“In spring 2007, the process was repeated with another 12ha planted in turnips for summer feed,” he said.

“Given the very dry summer, having the turnips on hand was a real godsend. With our rainfall about 50 percent less than average, the turnips still performed well though their yield was about 20 percent down on 2006.

“Most encouraging was the performance of the 12ha of new pasture sown the previous year. This kept growing well despite the dry conditions and far outperformed the old pastures, which turned yellow. I was very pleased to be able to return cows to the new pastures on a 13-14 day rotation instead of the 20-day cycle I usually operate on for the other paddocks. My aim was to keep the residual pretty low, at around 1400kg of dry matter (DM)/ha.”

“The herd’s overall production dropped by just 5000kg of milksolids (MS) over the dry period, to 105,000kg for the 2007/08 season, so I think the new grass and turnips really saved me. The lowest production level we got down to was 1.3kg MS/day/cow, which I was pretty happy with.”

In spring 2007, the turnips were sown in three different paddocks to reduce the walking required by the cows and this allowed the new pasture to be resown in stages beginning in early February this year.

Looking ahead to this spring, Harkness plans to crop another 10 percent of his farm in turnips and expects his summer management to be straightforward even if there is a dry period because he’ll have 24ha of new pastures to rely on for feed. In November, 16ha of turnips will be sown as an additional 40ha has just been purchased to increase the farming operation.

After two years of the pasture renewal programme, Harkness has not yet increased his cow numbers. However, once he completes renewal on 40 percent of the farm, he aims to increase cow numbers by 40/year to a total of about 450.

On his hilly paddocks, furthest from the dairy, Harkness will undertake some grass-to-grass renewal in future to reduce potential run-off and loss of topsoil.

“At this stage, my plan is to spray, rotary hoe 10 days later and then resow with tetraploid perennial ryegrass and clovers,” he said.

Red clover

“I will also include some red clover in the mix so the pasture will have more durability in any future dry seasons.

“I’m very encouraged by the volumes and quality of grass the new pastures have produced and I’m committed to completing the pasture renewal programme over the whole farm. I can see already the benefits will be significant and taking a planned approach allows me to manage the extra feed I have available.”

Published courtesy of Dairy Exporter - August 2008