不同施氮水平下高丹草生产性能及土壤无机氮的残留

Effect of Different Nitrogen Levels on Sorghum bicolor × Sorghum sudanese Performance and Nitrogen Residues in Soil

为探明不同施氮水平对高丹草生产性能以及土壤无机氮残留的影响,试验以高丹草为材料,设置了N0（0 kg/hm2,对照）、N90（90 kg/hm2）、N180（180 kg/hm2）、N270（270 kg/hm2）、N360（360 kg/hm2）5个施氮量处理,采取随机区组设计。结果表明：①施氮肥可以显著提高苏丹草鲜草产量,其中施氮360 kg/hm2处理的产量达151 878kg/hm2。②随着施氮量的增加干物质生产效率、粗蛋白质生产效率均降低,其中施氮180 kg/hm2处理的高丹草氮肥利用率最高,施氮360 kg/hm2处理比施氮270 kg/hm2处理的氮肥利用率低10%;③土壤无机态氮主要集中在土壤表层（0-60 cm）,随着施氮量的增加,土壤氮素残留增加,但主要表现在第1次刈割后,土壤氮素残留在第2次刈割后明显下降。

Sorghum hybrid was used to investigate the effect of different nitrogen levels on performance and nitrogen residues in soil.Based on the randomized block design,five nitrogen levels of N0（0 kg/hm2）,N90（90 kg/hm2）,N180（180 kg/hm2）,N270（270 kg/hm2） and N360（360 kg/hm2） were designed.The results showed that ①nitrogen fertilizer could increase the fresh yield,and in N360 treatment the yield of 151 878 kg/hm2 was harvested;②With the increase of fertilizing nitrogen,the production efficiency of dry matter and crude protein was decreased.The highest nitrogen utilization efficiency of Sorghum hybrid was shown in N270 treatment,which was 39.34% higher than that in N360 treatment;③Soil nitrogen was mainly located in soil profile（0-60 cm）.With the increase of fertilizing nitrogen,nitrogen residues were increased,especially in the first harvest.The nitrogen residues greatly decreased in the second harvest.