增施铵态氮对北方冬季基质栽培普通白菜根系特性及养分利用的影响

为了探究我国北方地区冬季叶菜类蔬菜基质栽培中N素的高效利用模式,以普通白菜为试材进行盆栽试验,以全量硝态氮供应(N素供应量17.33 mmol·L~(-1))为对照,设置25%、40%、60%3个增铵水平,观测普通白菜生长过程中根系的生长、活力以及N素代谢关键酶活性,测定其养分吸收、产量及品质。结果表明:增铵25%～40%能够提高普通白菜根系总长、根表面积和体积,促进根系发育,提高其对N、P素的吸收;相对全硝态氮素供应,增铵能够显著降低普通白菜硝酸盐含量,显著提高可溶性糖含量,但对单株质量无显著影响;增铵40%处理的氮肥偏生产力比增铵25%、60%处理分别提高了3.7%和3.8%,并显著提高了普通白菜地上部干物质量。综上,北方冬季设施栽培普通白菜,以硝态氮(17.33 mmol·L~(-1))为主配增施40%铵态氮的效果最好。

Effects of Increasing Application of Ammonium Nitrogen on Root System Characteristics and Nutrients Utilization of Pakchoi under Substrate Cultivation in Northern China in Winter

In order to investigate the high efficient utilization model of N in leaf vegetables substrate cultivation at northern China in winter，this paper took pakchoi as material and total NO₃^--N as the contrast； conducted pot experiment and designed 25%，40%，60% of 3 N increasing level treatments；observed the growth and activity of root system and N metabolism key enzyme activity during the growth process of pakchoi；and measured its nutrient absorption，yield and quality．The results showed that the treatment of increasing 25%-40% NH₄⁺-N could increase the root length，root surface area and root volume，promote root system development； enhance its absorbtion of N and P．Compared with total NO₃^--N treatment（CK）this treatment of increasing NH₄⁺-N ratio could significantly decrease the nitrate content，increase the content of soluble sugar，and yet had no significant effect on the single plant mass．The nitrogen partial factor productivity of increasing 40% NH₄⁺-N treatment was respectively 3.7% and 3.8% higher than that of increasing 25%，60% NH₄⁺-N treatments，and the above-ground dry matter of the pakchoi was significantly increased either．To sum up，in northern China for protected vegetable cultivation of pakchoi in winter，the suitable N application（17.33 mmol·L^-1），plus increasing 40% NH₄⁺-N can achieve the best effect．