Effects Of Nitrogen Fertilizer Dosage And Supplemental Irrigation On Sugar Beet Growth And Yield

Aiming at the problems of low precipitation in the early stage of Sugarbeet cultivation in Northeast China and the decrease of Sugarbeet Yield and quality caused by improper application of nitrogen fertilizer,nitrogen application and quantitative irrigation experiments were carried out in the experimental base of Heilongjiang Bayi Agricultural University in 2019 and 2020 to provide theoretical basis for scientific water and fertilizer management of Sugarbeet.In 2019,N0(0 kg/hm~2),N1(60 kg/hm~2),N2(90 kg/hm~2)and N3(120 kg/hm~2)were set in plot experiment.In 2019,T1(blank control),T2(N=120 kg/hm~2,rain fed),T3(N=120 kg/hm~2,supplementary irrigation)were set in regional experiment;in 2020,T1(blank control),T2(N=90 kg/hm~2,rain fed),T3(N=90 kg/hm~2,supplementary irrigation)were set in regional.The dry matter quality,plant nutrient accumulation,soil nutrient and soil enzyme activity of Sugarbeet at different growth stages were determined.The results showed as follows:1.Compared with N0,N1 and N3,N2 dry matter accumulation increased by 2.82%,0.58%and 2.63%,yield increased by 10.94%,2.01%and 5.82%,sugar yield increased by 8.53%and N2 increased by 0.20%.2.Compared with N0,N1 and N3,total nitrogen accumulation of N2 increased by 53.96%,60.51%and 24.78%,total phosphorus accumulation increased by 46.94%,2.95%and 5.67%,total potassium accumulation increased by 71.46%,29.51%and 28.65%,respectively.3.Compared with N0,the contents of alkali hydrolyzable nitrogen and available P in N2 soil0～20cm increased by 20.89%and 14.68%,respectively.Compared with N0,N1 and N3,the phosphatase activity in 0-20 cm soil under N2 treatment increased by 31.14%,15.94%and19.40%,respectively,and the catalase activity in 20-40 cm soil increased by 2.25%,1.11%and7.05%,respectively;Compared with N0,N1 and N3,the urease activity of N2 increased by13.79%,8.19%and 8.19%,respectively;20～40 cm increased by 10.34%,4.91%and 10.34%respectively.4.Compared with water setting,the total dry matter accumulation and yield increased by4.50%and 56.07%in 2019 and 18.81%and 12.42%in 2020,respectively;Compared with T2,the absorption of nitrogen,phosphorus and potassium in T3 increased by 5.26%,28.13%and16.18%in 2019,and increased by 17.05%,23.05%and 17.46%in 2020.5.In 2019,the contents of available N and P in 0～20cm soil of T3 treatment increased by7.24%and 0.58%respectively compared with T2 treatment,and increased by 7.24%and 1.62%in 2020,indicating that supplementary irrigation is beneficial to the increase of available N and P in 0～20cm soil.6.In 2019,the activities of phosphatase,catalase and urease in 0～20cm soil layer of T3treatment were increased by 3.08%,0.78%and 8.47%compared with T2 treatment,respectively;In 2020,it will increase by 25%and 11.33%respectively.