| Human zinc deficiency is a common nutritional problem worldwide,the main reason is the low content of zinc in grain,which is far below than the value of biofortification.Most scholars believe that biofortification strategy-fertilization can effectively increase zinc(Zn)content of grain in a short period of time.The accumulation process of Zn first goes through the physiological processes of root absorption,xylem and phloem transport and unloading in the grain,and finally accumulates in the grain.At present,there are few reports on how the mixture of controlled release nitrogen fertilizer and urea affects its physiological process.Previous experiments have been done on the interaction of N and Zn.With the continuous advancement of industrialization and intensification,one-time fertilization has become an inevitable trend.Therefore,the purpose of experiment was to study the interaction mechanism between controlled release nitrogen fertilizer and zinc.Based on field experiments,this paper studied the effects of different ratios of controlled release nitrogen fertilizer and urea under the condition of Zn and N supply on physiological processes such as absorption,distribution and accumulation in grains of maize varieties with different nitrogen efficiency,and the main results were as follows:1.The one-time application of controlled release nitrogen fertilizer and urea could significantly increase maize yield,but the response of maize varieties with different nitrogen efficiency to the mixing ratio was different.From 2019 to 2020,Cultivars Yuhe 988(YH988)and Zhengdan 958(ZD958)achieved the highest yield at N180C1(CRU-N∶Urea-N=1∶2)and N180C2(CRU-N∶Urea-N=2∶1)treatments,which were 12.7-13.2 t·hm-2 and 14.1-15.0 t·hm-2,respectively.Grain number per panicle and 100-grain weight were increased at N180C1 treatment for YH988,and grain yield was increased by 3.8%-17.7% compared with other treatments.The grain number per spike and 100-grain weight were increased at N180C2 treatment for ZD958,and the yield was increased by 10.1%-22.4%.Meanwhile,the PIABS,leaf area index,leaf functional period and plant photosynthesis were improved at treatment N180C1 and N180C2 for cultivars YH988 and ZD958 in 2019-2010.2.The concentration and accumulation of N and Zn in corn grains were significantly increased by one-time application of controlled release N fertilizer and urea,and the results were different among cultivars with different N efficiency.From 2019 to 2020,YH988 and ZD958 achieved the maximum N and Zn accumulation at N180C1 and N180C2 treatments,respectively.At the same time,under this fertilization level,the agronomic efficiency,recovery efficiency and partial productivity of N were also relatively high.The maximum Zn uptake of YH988 and ZD958 at N180C1 and N180C2 treatments was 145 and 142 g·hm-2(2020),respectively,and the maximum Zn transfer to grains during grain filling was 28 and 33 g·hm-2(2020).At the grain filling stage of maize,the amount of Zn transferred from vegetal organs to grains was significantly correlated with the amount of nitrogen transferred from vegetal organs to grains(R2=0.2634***),and the concentration of N and Zn in grains was also significantly correlated(R2=0.3214***).In addition,64% to 93% of the Zn accumulation in maize grains was due to the Zn uptake from roots after anthesis.In conclusion,in the aquic soil maize production area of Huang-Huai-Hai region,for different maize varieties with different nitrogen efficiency,one-time application of controlled release nitrogen fertilizer and urea in a reasonable ratio can maintain high yield,but also satisfy the Zn nutrition of the plant and promote the transfer of Zn from vegetative organs to grains.Low nitrogen efficiency cultivar YH988 and high nitrogen efficiency cultivar ZD958 could achieve the highest yield,photosynthetic performance,concentration and accumulation of N and Zn at N180C1 and N180C2 treatments,respectively.These results provided a scientific basis for intensive fertilization system in maize season in Huang-Huai-Hai region. |
PDF Full Text Request