The effect of increasing plant population on maize silage yield and quality

Abstract

For the past decade maize silage has been planted at 100000 plants/ha in New Zealand. Modern maize silage hybrids have enhanced stress tolerance making them more adaptable to higher plant populations. This study examined the effect of a range of established plant populations (85000, 100000, 115000, 130000 and 145000 plants/ha) on the yield and quality of 12 Pioneer® brand maize silage hybrids grown at 13 locations over two seasons. As plant population increased maize silage dry matter (DM) yield increased significantly (P<0.01) from 18.66 to 20.52 t DM/ha (Year 1) and from 22.10 to 23.69 t DM/ha (Year 2). Location x hybrid interaction was significant (P<0.01) for total DM yield and DM percentage. Hybrid x population and location x population x hybrid interactions were not significant. There was a significant effect of population and location x population on crude protein (Year 2) with the highest population plots having slightly lower crude protein percentages. The effects of population, location x population on all other nutritional quality parameters were not significant. Even when the cost of additional seed and seed insecticide treatment is considered, lifting established populations to 115000 to 130000 plants/ha is profitable for dairy farmers growing and feeding maize silage. Keywords: maize silage, plant population, supplementary feed