On the shoulders - 2015 season overview

Published 20 November 15

Following a good growing season in 2014, grass production in 2015 was underpinned by exceptional growth at the shoulders of the season. As we now collate the last of the grass figures for this year, AHDB Dairy’s Dr Debbie McConnell takes a look at how growth and quality has fared across the thirteen Forage for Knowledge (FFK) farms throughout 2015.

Grass growth

The 2015 growing season has seen a second consecutive good year of growth across GB, however it has not been without its challenges with wintery conditions extending well into March and many northern regions experiencing a cooler, wetter summer than normal. Despite these challenges, good growth in April, and above average temperatures in September, led to an extra 0.5 t DM/ha being produced in the shoulder months, helping maintain a season average of 12.2 t DM/ha across the FFK farms.

Following a slow start in March, above average air temperatures and very low rainfall levels in April (64% of expected) led to a rapid rise in growth rates with 30% more grass produced in April (1617kg DM/ha) compared to the 2010 – 2014 average (Figure 1). 

Season overview 1

Figure 1: Monthly grass growth totals in 2015 compared to the 2010-2014 average throughout the growing season.

With good conditions extending into May and growth rates averaging 68kg DM/ha/day, summer drought-like conditions came earlier than expected in June. Low rainfall reducing growth rates (Figure 2), especially in the southern part of GB and, as a result, monthly growth was 10% below average, yielding (1914kg DM/ha) across the FFK farms.

A cooler, wetter summer followed for many northern parts of GB (Figure 2), making grazing and field operations difficult on areas of poorer draining soils. Despite this solar radiation, temperature and consequently grass growth remained on par with averages for this time of year.

Season overview 2

Season overview 3

Figure 2: Rainfall totals for June and July 2015 as a percentage of the long-term average (1981- 2010)

September and October saw the return of the Indian Summer in GB which brought with it good grass growing conditions. This led to an extra 280kg DM/ha being produced during these two months. Coupled with relatively dry conditions, many farmers have made the most of these good conditions and have managed to extend the grazing season by two to three weeks. Good growth has continued well into November with growth rates averaging between 20 to 30kg DM/ha/day in the last few weeks.

 

Grass Quality

Testament to the management on the FFK farms, grass quality has again remained good over the course of the season with dry matter, crude protein and metabolisable energy (ME) averaging 18.3%, 23.8% and 12.0 MJ/kg DM, respectively (Figure 3).

Season overview 4

Figure 3: 2015 grass quality results from the 13 FFK farms.

As expected, there is a steady seasonal decline in grass dry matter content, however ME levels were almost unchanged throughout the season, still averaging 12.2 MJ/kg DM on 20 October. High crude protein levels in the latter part of the season most likely reflect the good soil temperatures we have seen throughout September and October which has meant soil nitrogen mineralisation rates remain high.

Forage for Knowledge grass growth monitoring will be starting again in February 2015. We would like to thank all the FFK farmers for their contributions to the newsletter over the last 11 months and wish all our contributors and readers a Merry Christmas and a Peaceful New Year.