缓释尿素对土壤微生物群落、酶活性及辣椒产量的影响

Effects of slow-release urea on soil microbial community,enzyme activity and yield of pepper

【目的】研究不同养分释放速率的缓释尿素对辣椒土壤微生物数量、土壤酶活性及产量的影响并确定最佳施氮量.【方法】以辣椒早熟品种‘陇椒2号’为试验材料,分别施加300、350、400、450kg/hm^2的两种缓释尿素,以等量普通尿素为对照,测定土壤微生物数量、土壤酶活性及辣椒产量.【结果】与施用等量CU(普通尿素,含氮量46%)相比,施用缓释尿素SRU90(含氮量41%,氮素释放期为90d)和SRU180(含氮量41%,氮素释放期为180d)显著提高了养分释放中后期(60～90d)真菌、细菌和放线菌数量,同时施氮量对以上3种菌群的影响程度有所差异,当施氮量为350和400kg/hm^2时刺激微生物繁殖的效果明显;两种缓释尿素处理下土壤脲酶和碱性磷酸酶活性较等量CU低,对于酶的激活作用较弱,并对土壤过氧化氢酶活性无显著影响;施用SRU90与SRU180可有效提高辣椒产量,其中,SRU180在350kg/hm^2施氮量下产量最高,但当3种尿素施氮量达到或超过400kg/hm^2时,辣椒减产显著.【结论】缓释尿素促进三大类微生物中后期的生长繁殖并且有效延长了对土壤酶的作用时间,较普通尿素有利于提高辣椒产量,350kg/hm^2SRU180是较佳的施肥组合.

【Objective】To research effects of different slow-release urea on soil microbial community,enzyme activity and yield of pepper and determined the optimum amount of nitrogen for pepper.【Method】Pepper varieties‘long Jiao 2’was used to apply two kinds of slow-release urea under 300,350,400,450 kg/hm 2 nitrogen level and conventional urea as control.【Result】SRU90(nitrogen content is 41%,nitrogen release period is 90 d)and SRU180(nitrogen content is 41%,nitrogen release period is 180 d)significantly improved the quantity of fungi,bacteria,and actinomyces on middle and late(60~90 d)stage compared with equivalent application of CU.Meanwhile,the effect of nitrogen application on the above 3 species was various,and the microorganism was effectively stimulated when the nitrogen application was 350 and 400 kg/hm 2.The activity of urease and alkaline phosphatase applied with 2 kinds of slow release urea was lower than equal CU,so the activation of enzyme was weaker,and there was no significant effect on catalase activity.The yield of pepper was increased by applied with SRU90 and SRU180,and it was the highest applied with 350 kg/hm 2 SRU180,however the yield decreased significantly when the nitrogen application exceeded 400 kg/hm 2.【Conclusion】Slow-release urea promote the growth of microorganisms on middle and late stage and effectively prolonged the action time of soil enzymes.Meanwhile,slow-release urea increase the pepper yield,and SRU180 at 350 kg/hm 2 shows a better results.