6 May 2014

2 minute read

Stage of maturity and plant density are major factors affecting both yield and nutritive value of whole-plant maize silage, writes Dr Islam.

A study was conducted to investigate the effect of maize maturity and plant density on yield and nutritive value of maize silage.

A University of Sydney study could actually lead farmers to rethink maize harvest dates

A hybrid forage maize (Pioneer 2307) was grown at Camden with two plant densities (High, 74,000 plants/ha; and Low, 66,000 plants/ha) and harvested at three different stages of maturity (31, 38 and 45 per cent dry matter [DM]).

After harvesting at ~20 cm above ground level, maize plants were chopped immediately to a particle length of 2.5 cm and ensiled in micro-silos. Silage samples were analysed for chemical composition and nutritive value following in vitro digestibility technique.

Increasing plant maturity from 31 per cent to 45 per cent DM increased whole plant weight from 136 to 172 g DM/plant and stem weight from 54 to 83 g DM/plant, respectively. As a result increasing maturity from 31 per cent to 45 per cent DM increased DM yield from 20.9 to 26.3 t/ha (Fig 1).

Increasing maturity was associated with greater starch concentration from 25.3 to 36.5 per cent but did not affect CP, fibre function and ME concentration of maize silage (Table 1).

However, increasing density had no effect on starch but increased fibers and decreased CP from 6.3 to 5.9 per cent . As a result increasing density decreased ME from 10.4 to 9.8 MJ/kg DM (Table 2).

Increasing maturity was associated with greater starch concentration from 25.3 to 36.5 per cent but did not affect CP, fibre function and ME concentration of maize silage (Table 1).

These results have made us re-think the actual time of harvest, as drier plants increased yield and starch.