Effects of alginic acid-enhanced urea on nitrogen absorption,utilization,and loss of summer maize
Given the present situation of high nitrogen fertilizer application,low utilization rate,and increasing environmental problems on maize,active alginic acid was selected as a synergist to modify and enhance urea and carried out the regulation of alginate acid-enhanced urea on yield formation,nitrogen absorption,utilization and loss of summer maize,in order to provide a theoretical basis for realizing nitrogen fertilizer reduction,improving nitrogen use efficiency and reducing environmental load.Summer maize was used as the test crop,and 15N isotope tracing technology was combined with field trials in this experiment.Seven treatments were set up:no urea application(CK),urea(U),0.5%alginic acid-enhanced urea(AU1),2.5%alginic acid-enhanced urea(AU2),5.0%alginic acid-enhanced urea(AU3),20%reduction of standard urea(U-N),2.5%alginic acid-enhanced urea reduction 20%(AU2-N).One-time fertilization was adopted,and ammonia volatilization and nitrous oxide emissions were measured after fertilization.The results show that the carbohydrate C—OH stretching vibration of alginic acid-enhanced urea was observed at about 1 038 cm-1,and the intensity of NH2 vibration peak increased in 3 426-3 325 cm-1 range and at 1 584 cm-1,and C—N vibration peak at 1 450 cm-1 and 1 143 cm-1.In constant treatment,applying alginic acid-enhanced urea could increase maize yield by an average of 5.04%,nitrogen accumulation increased by an average of 13.55 kg·hm-2,and nitrogen use efficiency increased by an average of 4.63 percentage points.In reduction treatments,the yield of the U-N treatment was not significantly reduced,but the yield of the AU2-N treatment was 2.30%higher than that of the AU2 treatment,and the nitrogen use efficiency increased by 7.16 percentage points.Nitrogen residues in 0-60 cm soil increased by 2.94 and 8.21 kg·hm-2 in AU1 and AU2 treatments,respectively,compared with the U treatment.Alginic acid-enhanced urea could reduce the loss of nitrous oxide emission and leaching,and an average of 6.16 percentage points reduction rate of nitrogen fertilizer loss from constant alginic acid-enhanced urea compared with U treatment and 9.95 percentage points for the AU2-N treatment compared with the U-N treatment.Under the experimental conditions,considering maize yield,nitrogen absorption and utilization,residue,and loss,2.5%alginic acid-enhanced urea application with 20%reduction can achieve better results.
alginic acid-enhanced ureasummer maizenitrogen use efficiencynitrogen residuesnitrogen loss
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