In order to explore the effective measures that could make rational utilization of livestock manure and improve nitrogen utilization of maize

a three-year field experiment was conducted to evaluate the effects of combined applications of manure and chemical fertilizers on maize yield and nitrogen utilization in irrigation silting soils. The results showed that

compared to the no nitrogen fertilizer (CK)

pH of soil treated with combined manure and chemical fertilizer decreased by 0.59 to 0.86

soil bulk density decreased by 8.05% to 10.74%. Soil organic matter of combined application of organic manure and chemical fertilizer (N1M1

N2M2) was increased by 0.86 g/kg and 0.44 g/kg per year

respectively; total nitrogen concentration was increased by 0.09 g/kg and 0.06 g/kg per year

respectively; the concentration of alkali-hydrolyzable nitrogen was increased by 4.74 mg/kg and 3.68 mg/kg per year; plant-available phosphorus concentration was increased by 6.62 mg/kg and 5.35 mg/kg per year; plant-available potassium concentration was increased by 8.46 mg/kg and 6.66 mg/kg per year. Compared to that in the conventional chemical nitrogen treatment (N1)

maize yield was increased by 12.38% and 13.43% in the third year by the N1M1 and N2M2 treatment

respectively; the NUE was increased by 10.98% and 16.20%; the AEN was increased by 4.65 kg/kg and 10.50 kg/kg; the PFPN was increased by 4.65 kg/kg and 21.02 kg/kg

respectively. Therefore

soil pH value and bulk density were all decreased in lowered chemical nitrogen combined with manure as compared to the conventional chemical nitrogen

soil organic matter and nutrient concentration were all significantly increased. Combined application of organic manure and chemical fertilizer had a positive effect on maize yield and nitrogen utilization. Applying chemical nitrogen at 168 kg/hm2 + manure nitrogen at 72 kg/hm2 could maintain maize yield and alleviate environmental pollution in irrigation silting soils of Ningxia.