Effects of combined application of silicon and phosphorus fertilizers on dry matter accumulation and distribution and grain yield of spring maize in low phosphorus soils

In order to explore the benefits of combined application of silicon and phosphate on maize production, a field plot experiment was conducted from 2014 to 2015. The effects of different rates of phosphate and silicon fertilizers application on leaf area index, net photosynthetic rate and transpiration rate at jointing and silking stages, dry matter accumulation in different organs at jointing, silking, grain-filling and maturity stages, and grain yield and yield components of spring maize were investigated using maize varieties ‘ZH2’ and ‘ZH115’ in low phosphorus soils. Compared with control plot (P0Si0), net photosynthetic rate and leaf area index at jointing and silking stages increased significantly under application of phosphorus, silicon fertilizers and the combined application of both fertilizers. Also dry matter accumulation at jointing, silking, grain-filling and maturity stages, dry grain weight ratio at grain-filling and maturity stages, and grains per ear, spike length, 1000-kernel weight and gain yield increased under the above three fertilization treatments. However, dry weight ratio of leaf at filling and maturity stage, dry weight ratio of stem and sheath at grain-filling stage and bare top length decreased. Specifically for phosphorus fertilization treatment, the increases or reductions in the above mentioned parameters were more obvious than those for silicon fertilization treatment. The largest changes were found in the combined application of phosphorus and silicon fertilizers. There was a significantly synergic effect on the investigated parameters between phosphorus fertilizer and silicon fertilizer. Furthermore, grain yield of corn was positively related with dry matter accumulation at jointing stage, silking stage, grain-filling stage and maturity stage in 2014–2015. Compared with phosphorus fertilizer treatment, grain yield increased by 1 288.57 kg·hm^-2 (in 2014) and 1 313.61 kg·hm^-2 (in 2015) under combined phosphorus and silicon fertilization treatment. This indicated that there was a sustainable increase in yield due to the combined application of phosphorus and silicon fertilizers. In summary, dry matter accumulation and photosynthesis improved during the early growth stage, dry matter distribution rate in each plant part was optimized during the later growth stage, and maize yield eventually increased by the combined application of phosphorus and silicon fertilizers in low available phosphorus soils in the hilly uplands of Sichuan Basin.