Effects Of Different Irrigation And Fertilizer Managements On Nitrogen Transfer And Transformation In Black Soil Of Facility Vegetable Field

Based on the experiment of facilities vegetable fields in black soil region in Heilongjiang Academy of Agricultural Sciences,this thesis studied five irrigation and fertilizer treatments,namely,conventional irrigation and fertilizer,80% conventional fertilizer,80% conventional irrigation,80% biochar,80% irrigation and 80% fertilizer and biochar.At the same time,leaching buckets were buried at 90 cm of conventional irrigation and fertilizer,80% conventional fertilizer,80% conventional irrigation and 80% conventional irrigation,conventional irrigation,and fertilizer + biochar treatments respectively.Leachate was collected regularly.The effects of different irrigation and fertilizer managements on nitrogen migration and transformation in a vegetable field in the black soil region were studied.The main results are as follows:1.The soil total nitrogen contents in the five irrigation and fertilizer treatments all decreased with the increasing soil profile depth in the 0-300 cm soil profile.In the 0-100 cm soil profile,the average soil total nitrogen content of the five irrigation and fertilizer treatments decreased rapidly from 2.30 g/kg to 0.66 g/kg.The mean value of nitrate nitrogen decreased rapidly from 24.59 mg/kg to 2.29 mg/kg in the 0-70 cm soil layer with the decrease of profile level in the five irrigation and fertilizer treatments,while the removal of nitrate nitrogen in the 70-300 cm soil layer was not significantly affected by 80% conventional irrigation,80% conventional fertilizer,80% conventional irrigation and fertilizer + biochar and 80% irrigation and 80% fertilizer + biochar treatments.There was no significant change in ammonium nitrogen content in 0-300 cm soil profile under five irrigation and fertilizer treatments,and no significant effect on ammonium migration was observed under 80% conventional irrigation,80% conventional fertilizer and conventional irrigation and fertilizer + biochar treatments.2.During the four critical growth stages of eggplant,the soil profile was 0-100 cm,the soil nitrate nitrogen content of five irrigation and fertilizer treatments ranged from 1.04 mg/kg to 148.41 mg/kg and decreased with the decrease of profile level.80% irrigation and 80% fertilizer plus biochar treatment could inhibit the nitrate nitrogen migration in eggplant soil.Ammonium nitrogen content in soil of 5 irrigation and fertilizer treatments increased from seedling stage to early fruit stage and decreased from early fruit stage to pulling seedling stage;ammonium nitrogen content in soil of 60-100 cm soil layer decreased from seedling stage to early fruit stage,then increased to full fruit stage,and finally decreased to pulling seedling stage;ammonium nitrogen content in soil of 5 irrigation and fertilizer treatments was dissected in 0-100 cm soil at each critical growth stage of eggplant.There is no obvious law of change on the surface.3.During the whole growth period of eggplant,the total amount of soluble total nitrogen,nitrate nitrogen and ammonium nitrogen in the leaching solution of four irrigation and fertilizer treatments varied from 69.47 kg/ha to 92.96 kg/ha,48.37-68.47 kg/ha and 2.08-6.16 kg/ha,respectively;80% conventional fertilizer significantly reduced the total amount of nitrate nitrogen leaching in the leaching solution;80% of conventional irrigation significantly reduced the total amount of soluble total nitrogen and ammonium nitrogen leaching;both conventional irrigation and fertilizer + biochar treatments could significantly reduce the total amount of soluble nitrogen leaching.Total leaching amount of sexual total nitrogen,nitrate nitrogen,and ammonium nitrogen.The soluble total nitrogen content in the leaching solution of four irrigation and fertilizer treatments had no obvious change regularity in each period;during the growth and development of eggplant,conventional irrigation and fertilizer + biochar treatment could reduce the leaching intensity of soluble total nitrogen and nitrate nitrogen in the leaching solution;the ammonium nitrogen content in the leaching solution had no obvious change regularity during the growth of eggplant.4.During the fruiting period of eggplant,the total nitrogen uptake of eggplant fruits treated with irrigation and fertilizer ranged from 0.37 kg/ha to 16.26 kg/ha.The total nitrogen uptake of eggplant fruits treated with conventional irrigation and fertilizer plus biochar was significantly higher than that treated with conventional irrigation and fertilizer.The nitrogen uptake of eggplant fruits treated with 80% conventional irrigation,80% conventional fertilizer and 80% irrigation,80% fertilizer and biochar had no significant effect.The yield of eggplant varied from 25.91 t/ha to 30.80 t/ha in five irrigation and fertilizer treatments.The effects of 80% conventional irrigation,80% conventional fertilizer,conventional irrigation and fertilizer + biochar treatments on the yield of eggplant did not reach a significant level.The biomass of five irrigation and fertilizer treatments ranged from 49.00 t/ha to 57.35 t/ha.80% conventional irrigation and 80% irrigation,80% fertilizer and biochar treatments could significantly reduce the biomass of eggplant.80% conventional fertilizer and 80% conventional irrigation and fertilizer + biochar treatments had no significant effect on the biomass of eggplant.