Single basal application of controlled release nitrogen fertilizer improve yield and nitrogen use efficiency of foxtail millet

Objectives In order to provide technical support of the simplified cultivation for foxtail millet, the effect of single basal application of controlled release nitrogen fertilizer on the growth, yield of foxtail millet and fertilizer use efficiency were explored, and highly efficient one-off fertilization technique was also established.

Methods A field experiment was consecutively carried out for two years in Tai’an City, Shandong Province, in 2015 and 2016. The millet cultivar of ‘Jigu16’ was used as tested materials. The tested two controlled-release fertilizers were sulfur-coated (SN) and resin-coated (RN) urea. The nitrogen release periods of the two controlled released urea were three months and they were mixed with urea in a ratio of 2∶1. Six treatments were designed for the experiment, no fertilizer (CK), urea basal and topdressing (NPK), SN single basal application (SN1), RN single basal application (RN1), SN basal application and urea topdressing (SN2), and RN basal application and urea topdressing (RN2). The yield, nutrient uptake and agronomic traits of foxtail millet were measured after harvest.

Results The yield in SN1 was the highest among all treatments, which reached 4190.2 and 4458.3 kg/hm² in 2015 and 2016, respectively. Compared with NPK, the yield and the nitrogen use efficiency of SN1 increased by 20.1%−53.5% and 40.6%−56.3%, respectively. For the same type of controlled-release nitrogen fertilizer, the foxtail millet yield and nitrogen use efficiency of the SN1 and RN1 were significantly higher than those of SN2 and RN2, and the yield increased by 5.8%−7.3%, and the nitrogen accumulation increased by 1.6%−7.9%, the nitrogen apparent use efficiency increased by 3.7%−19.9%, the nitrogen physiological efficiency increased by 5.1%−10.1%, and the nitrogen agronomic efficiency increased by 21.4%−33.4%. At the maturity stage, different treatments showed significant difference in total N, P and K contents in straw and grain. The total N, P and K contents of straw and grain obtained in SN1 and RN1 were significantly higher than those in SN2 and RN2.

Conclusions  Considering the decreased cost in labor of fertilization, once basal application of all the controlled-release fertilizers is recommended for the high yield and high efficient millet production.