Effects of nitrogen fertilizer management on yield, dry matter and N accumulation of maize cultivar Jinshan 10 used for both grain and feed purpose in Keerqin

Objectives Aiming at unreasonable method of applying fertilizer, such as using more N fertilizer and less organic matter, we did some research about effects of N fertilizer application on yield, dry matter and N accumulation of dual-purpose maize in Keerqin, Inner Mongolia, China. The purpose of this study was to supply the basis for reasonable application of fertilizers to high-yield cultivation of dual-purpose maize in Keerqin, Inner Mongolia.

Methods Maize cultivar of Jinshan 10 was selected as the test material in a field experiment. Four treatments were designed, namely no N fertilizer (CK), recommended N rate of 260 kg/hm² (R), 15 kg/hm² N from 15000 kg/hm² manure plus 245 kg/hm² N from fertilizer to make a combined application (C), and farmer’s current N rate of 270 kg/hm² (F). The yield, dry matter and N accumulation of dual-purpose maize were analyzed in consecutive two growing seasons in Keerqin.

Results The highest spike length, spikelet number, 100-grain weight and yield were all obtained in the C treatment, in which the biomass amount was 55.5%, 4.6% and 3.7% higher than those in the CK, R and F treatments, and the grain yield was 50.8%, 6.6% and 6.9% higher than those in the CK, R and F treatments (P < 0.01). The content of crude protein and fat in stem in the C treatment were 12.7% and 6.7%, 10.2% and 5.2% higher than those in the R and F treatments. The dry matter accumulation before and after the silking stage was significantly improved, and the dry matter accumulation rate and contribution rate to grain formation after the silking were also improved in the C treatment. The dry matter and N accumulation amount was improved through its higher limited growth amount and the maximum rate, the limited growth amount of dry matter and N uptake in the C treatment were 0.04–0.71 kg/m² and 1.13–11.34 g/m² higher than those in other treatments, the maximum rates of dry matter and N accumulation were increased by 0.0162–0.0826 kg/(m²·d) and 0.0448–0.8858 g/(m²·d).

Conclusions The manure N and fertilizer N combination is necessary for the dual-purpose maize production, as it can provide sufficient nutrient supply for the rapid growth and dry matter accumulation after the silking stage. With the manure and N fertilizer treatment, the last yield, the forage biomass and crude protein, crude fat content were all improved, which was good for the dual-purpose maize in Keerqin.