包膜尿素与普通尿素掺混施用方式对土壤脲酶及春玉米生长的影响

Effects of different application modes of coated urea and common urea mixture on soil urease and spring maize physiological property

采用大田试验,以不施氮为对照,采用释放期为60 d的包膜控释尿素(30%)与普通尿素(70%)掺混,研究了其不同施用方式(侧施、底施、分层施)对土壤脲酶及春玉米叶片净光合速率、保护酶活性的影响。结果表明:相同施氮水平下,底施处理0~40 cm土壤脲酶活性显著高于侧施和CK,尤其是在春玉米抽雄、灌浆期,但底施与分层施处理间没有显著差异。其中0~20 cm土层底施处理脲酶均值高于分层施、侧施和CK,分别为4.03%、55.94%和58.01%;20~40 cm土层底施处理脲酶均值高于分层施、侧施和CK,分别为3.77%、57.07%和67.37%。各处理植株和籽粒全氮含量变化趋势也基本一致,均表现为底施>分层施>侧施>CK。采用底施处理在抽雄与灌浆期较分层施、侧施和CK叶片净光合速率平均值分别高3.61%、11.42%和33.43%,同时底施还提高了叶片超氧化物岐化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性。与分层施、侧施、CK相比,采用包膜尿素与普通尿素掺混底施春玉米产量分别增加0.42%、5.81%、49.23%。采用包膜控释尿素与普通尿素掺混底施效果明显且减少成本,是适宜北京地区推广的施用方式。

Field experiment was conducted to study the effects of applying 30% coated controlled release urea of 60 d release duration mixed with 70% common urea by different applying methods,i. e. side-dressing,bottom application and layer by layer application,on soil urease,net photosynthetic rate and protective enzymes activity of spring maize leaves with none Nfertilizer used（ CK） as control. The results showed that under the same N-fertilizer supply,the soil urease under bottom application was significantly higher than those of side-dressing and CK,especially at tasseling and filling stage,but no significant difference of the urease at 0 - 40 cm layer between bottom and layer by layer applications was observed. Compared with layer by layer application,side-dressing and CK,the means of soil urease under bottom application was increased by 4. 03%,55. 94% and 58. 01% at 0 - 20 cm layer,and increased by 3. 77%,57. 07% and 67. 37% at 20 - 40 cm layer,respectively. The total N content in plant and grain among different treatments presented the same trend： bottom application layer by layer application side-dressing CK. At tasseling and filling stage,compared to layer by layer application,side-dressing,CK treatment,the leaf net photosynthetic rate under bottom application was increased by 3. 61%,11. 42% and 33. 43%respectively. In the meanwhile,CAT,SOD and POD activities of leaves were improved under bottom application. In addition,compared to layer by layer application,side-dressing,CK,maize yield under bottom application treatment was increased by0. 42%,5. 81% and 49. 23%,respectively. Therefore,the bottom application of the coated controlled release urea mixed with common urea with low cost and obvious effect,is suitable for promotion in Beijing area.