Impuesto a los Consumos Especiales (ICE)

At Ashley Dene, yield was greatest (P<0.001) in the establishment season (sowing to June 30th) when lucerne was sown from October to December, yielding 2.5 t DM/ha compared with 0.5 t DM/ha when sown in February (Table 4.4). In the second season, sowing date in the previous establishment season affected yield (P<0.05), with DM production again greatest from the October to December sown lucerne yielding 7 t DM/ha, compared with the later sowing dates yielding 6 t DM/ha, or ~15% less.

October and November sowing of lucerne had the greatest (P<0.001) yield in the establishment season at Iversen 12 producing 12 t DM/ha compared with 2 t DM/ha when sowing was delayed until February (Table 4.4). There was a sowing date effect (P<0.001) in the following regrowth season for these crops, with the October and December sown lucerne yielding 20.4 t DM/ha, compared with 15.8 t DM/ha for the January and February sown lucerne, or ~20% less.

Table 4.4 Total annual (1 July to 30 June) dry matter yields (t/ha) of lucerne sown on 10 dates from October 2010 to July 2012 at Ashley Dene and Iversen 12, Lincoln University, Canterbury, New Zealand.

Ashley Dene Iversen 12 Sowing date Establishment Year 2 Establishment Year 2 October 2010 2.4a 6.7ab 12.0a 21.5a November 2.4a 7.6a 8.0b 19.1b December 2.2a 6.4ab 8.5b 19.4ab January 2011 1.6b 5.8b 3.7c 16.6c February 0.6c 5.7b 2.6d 14.9c P <0.001 <0.05 <0.001 <0.001 SEM 0.17 0.60 0.50 1.01 October 2011 3.1a 12.1a November 2.5a 12.8a December 2.7a 8.4b January 2012 1.5b 5.8c February 0.4c 1.1d P <0.001 <0.001 SEM 0.29 0.50

Note: Sowing date treatments were given in Table 3.3. Means within a column with different letters are significantly different (l.s.d α=0.05).

Annual shoot yield decreased at both sites when sowing was delayed from October to February, in both the establishment year and the subsequent season (Figure 4.5). Annual shoot yield decreased by 5 kg DM/ha and 60 kg DM/ha per day at Ashley Dene

Sowing date

Oct Nov Dec Jan Feb

Y iel d (t D M /ha) 0 5 10 15 20 25 Year 1

Oct Nov Dec Jan Feb

Year 2

Figure 4.5 Total annual shoot yield of lucerne sown from October to February at

Ashley Dene () and Iversen 12 () in year one (black; sowing to June 2011 and red; sowing to June 2012) and year two (June 2011 to June 2012 at Lincoln University, Canterbury, New Zealand.

Note: Regressions; Ashley Dene; Year one y = -5x<8 December, -16x> 8 December, R2 _{= 0.97. Year 2 y}

= -15x, R2 _{= 0.61. Iversen 12;Year one -60x<13 December, -114x> 13 December, R}2 _{= 0.96. Year 2 y =}

-49x, R2 _{= 0.93.}

4.3.2.2 Seasonal DM yields for Ashley Dene

Seasonal DM accumulation in the establishment and subsequent growth season from sowing dates 1 to 5 at Ashley Dene are displayed in Figure 4.6. The greater (P<0.001) yield from earlier sowing in the establishment season came from the number of subsequent regrowth periods following the seedling phase. October and November sown crops had three regrowth periods, compared with only one for the February sown crop. During the establishment season, final yields attained for individual regrowth phases were consistently around 1 t DM/ha, regardless of the time of year.

In the second season five regrowth phases were achieved which differed (P<0.05) in DM yield. The spring cycles had the highest yields of 2.1 t DM/ha and 1.7 t DM/ha for the first and second cycle, respectively. The third cycle from December to February yielded 0.7 t DM/ha and 1.5 t DM/ha was grown in the fourth regrowth phase, however it was evident yields plateaued in early April. The final growth phase resulted in 0.5 t DM/ha with the onset of ground frosts in early May and snow in June.

4.3.2.3 Seasonal DM yields for Iversen 12

The pattern of seasonal DM accumulation for the establishment and following season for Iversen 12 sowing dates 1 to 5 is displayed in Figure 4.7. Similarly to Ashley Dene, the greater (P<0.001) yields attained from sowing earlier in the establishment year were attributed to the total number of growth cycles achieved within the season. The October and November sown lucerne resulted in four cycles of different yields (P<0.05), the seedling phase yielded 3.2 t DM/ha, which was reduced to 1.5 t DM/ha by the fourth regrowth cycle. The February sown lucerne resulted in one meaningful growth cycle, of 3.0 t DM/ha.

In the second season, 7 regrowth phases were managed with yields from 4.5 t DM/ha for the first two spring regrowth periods down to 0.5 t DM/ha for the last. The greater (P<0.001) annual yield for sowing dates October to December compared with that of sowing dates January and February was attributed to greater (P<0.05) final DM yields in regrowth cycles 1, 4,5 and 6 of year 2 of about 25%.

4.3.2.4 Seasonal dry matter accumulation rate

The seasonal pattern of DM accumulation rate is shown in Figure 4.8 for sowing dates 1 to 5 in the establishment and subsequent growth season for both Ashley Dene and Iversen 12. Consistent growth rates of less than 2.5 kg DM/°Cd during the establishment season at Ashley Dene reflect the low final DM yields of about 1 t DM/ha for individual regrowth periods. In comparison, at Iversen 12 growth rates showed a seasonal pattern with 7.5 kg DM/°Cd in summer decreasing to 3.0 kg DM/°Cd by late autumn.

In the second season, lucerne at both sites displayed a linear increase in growth rates from winter reaching a maximum rate in the second regrowth cycle in November of 4 and 9.5 kg DM/°Cd at Ashley Dene and Iversen 12, respectively. At Ashley Dene growth rates decreased to 0.8 kg DM/°Cd in mid-summer, before increasing to 2.9 kg DM/°Cd. In comparison, at Iversen 12, following the peak in growth rates, there was a steady decrease of 40% in growth rates down to 5.7 kg DM/°Cd in April. The onset of frosts in early May resulted in growth rates of 1 kg DM/°Cd at both sites.

Figure 4.8 Lineargrowth rates of lucerne sown on five dates; SD1 (), SD2 (), SD3 (), SD4 (▽) and SD5 (◇) at Ashley Dene and Iversen 12, Lincoln University, Canterbury, New Zealand.

Note: Thermal time accumulated using air temperature (Tb = 1 °C) as per Teixeira et al. (2011). Error

bars represent l.s.d (P = 0.05). Individual values for each regrowth period displayed in Appendix 8 and Appendix 9.

Dene displayed a similar pattern, albeit at a lower level. However, lucerne grown at Ashley Dene experienced its lowest growth rate of 0.8 kg DM/°Cd when mean temperature was at its highest of 16 °C. There was also a decrease in growth rate when temperatures were increasing at Iversen 12 during summer regrowth cycles 3 and 4. This result suggests temperature was not the only factor affecting DM production rate.

Figure 4.9 Linear growth rate of two year old lucerne crops in relation to increasing

(—) and decreasing (---) mean air temperature over the regrowth cycle at Ashley Dene () and Iversen 12 (), Lincoln University, Canterbury, New Zealand.

Note: Thermal time accumulated using air temperature (Tb = 1 °C) as per Teixeira et al. (2011). Error

bars represent l.s.d (P = 0.05). Arrows indicate direction of temperature change. Individual values for each regrowth period displayed in Appendix 8 and Appendix 9.