为探明甘蓝生产的最佳施氮量,以奥奇利为供试材料,设置0(N0)、126(N1)、180(N2)和 234 kg/hm2(N3)4 个纯氮施用量,研究不同施氮量对其产量、土壤养分、植株养分含量及养分利用的影响.结果表明:与不施氮处理相比,N2 单株鲜重显著增加,增幅为 63.8%;N1、N2 和N33 个施氮处理的甘蓝产量显著高于不施氮处理,增幅为17.2%-25.3%;土壤全氮、全磷、全钾随氮肥用量的增加整体表现出先增加后减少的趋势,土壤碱解氮随施氮量的增加而增加;不同施氮处理下甘蓝氮素利用效率有所不同,甘蓝氮肥农学效率和氮肥偏生产力均以N3最低.适当增施氮肥可增加土壤全氮、全磷和全钾含量,能增加甘蓝单株鲜重及产量;综合考虑产量及其氮素利用效率,黔中地区甘蓝施氮量以126 kg/hm2 为宜.
A field experiment was carried out to explore the nitrogen uptake and utilization of cabbage(Brassica oleracea L.'Aoliqi')under different nitrogen application rates and determine the optimal nitrogen fertilizer level for cabbage production.Four nitrogen treatments of 0(N0),126(N1),180(N2),and 234 kg/hm2(N3)were designed.The effects of different nitrogen application rates on the content of nutrients in soil and plants and the yield and nutrient utilization of cabbage were investigated.The results showed that the fresh weight per plant in N2 treatment was 63.8% higher than that in N0 treatment.The yields of cabbage in N1,N2,and N3 treatments were 17.2%-25.3% higher than that in N0 treatment.The content of total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus,and available potassium in soil and that of total nitrogen,total phosphorus,and total potassium in plants increased with the increase in nitrogen dosage.The nitrogen use efficiency of cabbage varied in different nitrogen treatments.Specifically,the agronomic efficiency and partial productivity of nitrogen fertilizer by cabbage were the lowest in N3 treatment.In conclusion,the available nitrogen,available phosphorus,and available potassium in soil increased with the increase in nitrogen fertilizer level,and appropriate nitrogen application increased the total phosphorus and total potassium in soil and the fresh weight per plant and yield of cabbage.Considering the yield and nitrogen use efficiency,we suggested 126 kg/hm2 as the optimal nitrogen fertilizer level.