Main content area

Effects of Different Fertilizer and Irrigation Water Types, and Dissolved Organic Matter on Soil C and N Mineralization in Crop Rotation Farmland

Shang, Fangze, Ren, Shumei, Yang, Peiling, Li, Changsheng, Ma, Ning
Water, air, and soil pollution 2015 v.226 no.12 pp. 396
agricultural land, ammonium sulfate, crop rotation, dissolved organic carbon, dissolved organic nitrogen, groundwater, irrigation water, microirrigation, mineralization, nitrogen, nitrogen fertilizers, soil organic carbon, soil sampling, soil types, summer, urea, wastewater irrigation, water shortages, wheat
Inorganic N fertilizer and irrigation water types on the C and N dynamics are poorly understood. This work aimed to evaluate the effect of different N fertilizer and irrigation water types on soil C and N mineralization. The farmland experiment was conducted with three types of N fertilizer (urea, ammonium sulfate, and slow-release urea) and drip irrigation with two types of water (groundwater and reclaimed water) for a summer maize-winter wheat crop rotation. Soil samples were collected from the experimental farmland for incubation experiments. The results showed that the average cumulative mineralization of soil C (incubation 20 days) and N (incubation 14 weeks) in different treatments ranged from 73.50 to 91.37 mg kg⁻¹ and 52.65 to 64.04 mg kg⁻¹, respectively. N fertilization significantly increased dissolved organic carbon (DOC), dissolved organic nitrogen (DON), soil organic carbon (SOC), and soil organic nitrogen (SON) contents in the soils, but N fertilizer and irrigation water types had no significant influence on them. Correspondingly, N fertilization significantly enhanced the mineralization of C by 14.14–21.22 % and N by 15.81–22.16 % in soils but no significant difference among different N fertilizer types. Compared with groundwater, reclaimed water irrigation enhanced the mineralization of C by 3.33 % and N by 1.01 %, but the difference was not statistically significant. The cumulative mineralization of C and N in soils after DOM removal average significantly decreased 9.83 and 14.83 %, respectively, which indicates that DOM plays an important role in soil C and N mineralization. Our results indicate that inorganic N fertilization promotes soil C and N mineralization, which may inevitably aggravate global warning. Reclaimed water irrigation had similar influence on soil C and N mineralization as groundwater irrigation; thus, we recommend irrigation with reclaimed water in water shortage areas.