Understanding how sowing rate and date effect autumn lucerne establishment in Canterbury: A dissertation submitted in partial fulfilment of the requirement for the Degree of Bachelor of Agricultural Science with Honours at Lincoln University

Abstract

During the summer - autumn of 2006/07 a lucerne establishment experiment was undertaken to determine what sowing rate and date of lucerne is necessary for economic establishment. The affect sowing rate and date had on establishment was investigated at Lees Valley and Iversen Field Lincoln University with experiments commencing on 14/12/06 and 21/2/07, respectively. The economic sowing rate is an area of contention amongst some members of the agricultural service industry, and successful establishment of a high producing pasture species in a climate such as Lees Valley will drastically improve land productivity.

Sowings were spread over four dates for each experiment in the different locations, and sowing rates of 7, 10, 13 and 16 kg coated 'kaituna' lucerne seed/ha was used. Ground preparation at Iversen Field consisted of conventional cultivation techniques while at Lees Valley plots were direct drilled into herbicide killed vegetation. A 'Duncan' triple disk drill was used at each site. Plant populations was investigated at both experiment sites, while lucerne and weed growth as well as root and shoot measurements were taken solely at Iversen Field.

It was clear that sowing dates of 28/2/07 and 21/3/07 (Sowing Dates 3 and 4) at Lees Valley had acceptable initial establishment, however there were survivability and plant strength problems. Sowing Date 3 at Lees Valley initially had 130 seedlings/m² emerge and after winter there were only 70 seedlings/m² present. Initial emergence of seedlings at Lees Valley was 187 /m² for plots sown at 16 kg/ha and 93/m² for plots sown at 7 kg/ha.

The problematic sowing dates at Iversen Field were 16/3/07 and 30/3/07 (Sowing Dates 3 and 4 ), where the soil was to wet for Sowing Date 3 which resulted in poor initial establishment. Sowing Date 4 had acceptable initial establishment, however, plots became over-run with weeds in the winter and spring with 81 % weeds in the plots on the 9/10/07. Initial emergence at Iversen Field was 284 for plots sown at 16 kg/ha and 141 for plots sown at 7 kg/ha.

Winter and early spring yields at Iversen Field by the 9/10/07 showed Sowing Date 1 yielded 2220 kg DM/ha in comparison to Sowing Date 4 which yielded 553 kg DM/ha. These differences appear to be a direct result of the root weight that seedlings had laid down. Spring root weights were 862 kg DM/ha in Sowing Date 1 compared with 153 kg DM/ha in Sowing Date 4. This experiment has shown that sowing date is more important than sowing rate when establishing lucerne stands. Also earlier autumn sown lucerne will out-yield later autumn sown lucerne in the first spring, due to more root reserves being laid down during the autumn.