A field positioning experiment was conducted in spring maize continuous cropping area of Shanxi Province for four consecutive years

which included six fertilization treatments:No application of nitrogen fertilizer (CK)

one-time basal application of urea (CU1)

topdressing of urea (CU2)

resin coated urea (PCU)

sulfur coated urea (SCU) and multi-enzyme gold sustained-release urea (MEU). It was set up to study the effects of slow controlled release nitrogen fertilizers on spring maize yield

consumption of nitrogen fertilizer and nitrogen balance to provide reference for scientific management technology of spring maize nitrogen nutrition. The results showed that:(1) Slow controlled release nitrogen fertilizer treatment could significantly increase spring maize yield and promote nitrogen uptake. Compared with CU1

SCU

MEU

PCU and CU2 increased the yield of spring maize by 17.51%

9.88%

9.62% and 9.48%

respectively

while the agricultural utilization efficiency of nitrogen fertilizer was increased by 7.5

4.2

4.1 and 4.1 kg/kg

respectively. (2) There were significant differences in the uptake of fertilizer nitrogen by crops and the residual amount of fertilizer nitrogen in 0-100 cm soil layer with different fertilizers. Apparent use efficiency of nitrogen of SCU

MEU

PCU

CU2 and CU1 were 36.1%

32.5%

26.5%

26.7% and 19.5%

respectively. Residual fertilizer nitrogen in 0-100 cm soil layer accounted for 28.5%

31.6%

35.7%

35.5% and 39.1% of the nitrogen application

respectively. Additionally

compared with one-off urea application

slow controlled release nitrogen fertilizer could significantly reduce the loss of fertilizer nitrogen

by 22.65%

18.81%

8.99% and 8.47% for SCU

MEU

PCU and CU2 respectively. (3) Comprehensive analysis of nitrogen balance in different treatments showed that the SCU had the highest nitrogen uptake

261.5 kg/hm2

followed by MEU

253.5 kg/hm2. The residues amount in 0-100 cm soil layer in SCU was the lowest among the slow controlled release nitrogen fertilizer treatments

124.1 kg/hm2

and 131.04 kg/hm2 for MEU and 140.09 kg/hm2 for PCU. The apparent loss of nitrogen in SCU was the lowest

106.3 kg/hm2

and 111.6 kg/hm2 for MEU and 125.1 kg/hm2 for PCU. In the soil of main spring maize producing areas in Shanxi Province

slow controlled release nitrogen fertilizer could significantly promote the absorption of nitrogen and reduce nitrogen loss. Sulfur coated urea and multi-enzyme gold sustained-release urea have relatively good effects.