Abstract:

The study explored the regulating effect of combined application of organic manure and chemical fertilizer on summer maize root distribution and yield, and investigated the effect of maize root system on yield formation, aiming to promote root and soil interaction, enhance root and water-fertilizer coupling, and improve yield and nitrogen (N) use efficiency. ‘Zhengdan 958’ was used as the experimental material. There were four treatments: chemical fertilizer treatment (U), organic manure treatment (M), organic manure combined with chemical fertilizer (U+M), and no fertilizer treatment (CK). The difference of N use efficiency under the combined application of organic manure and chemical fertilizer was studied in field experiments. The results showed that U+M increased root dry weight and root length density, especially root length density in 40-80 cm soil layer. It also prompted deep root growth and reasonable root spatial distribution, improved the harmony of deep roots and nutrients, extended the root function period, which could not only meet the nutrient requirement in the early maize growth stage but also provide sufficient nutrient for the later period. So, the combined application of organic manure and chemical fertilizer had higher nitrogen accumulation amount, nitrogen partial productivity, and nitrogen agronomic utilization efficiency compared with other treatments, and it was beneficial to grain formation and yield increase. Chemical fertilizer treatment and organic manure treatment enhanced root growth in topsoil, which was not conducive to yield formation. In short, the combined application of organic manure and chemical fertilizer can maintain N balance and improve N use efficiency on the premise of keeping the yield level and reducing environment risks. The study can provide a theoretical basis for maize production in the Huang-Huai-Hai region.

Key words: maize, combined application of organic manure and chemical fertilizer, root system, yield, nitrogen use efficiency