保水剂施用方式对杨树苗根系特性和生长及土壤酶活性的影响

Application Methods of Super Absorbent Polymers: Effect on Root Characters and Growth of Poplar Seedlings and Soil Enzyme Activities

为探讨在减量灌溉条件下保水剂不同施用方式对杨树根系特性与生长的作用效果,通过盆栽试验研究了在常规灌溉量60%的条件下单施尿素(U)、单施保水剂(S)、保水剂-尿素混施(SUM)与保水剂-尿素凝胶(SUG)等处理对杨树苗根系特性、土壤酶活性及生长的影响。结果表明:与U处理相比,SUG处理显著提高了杨树苗根系活力、根系总吸收面积与活跃吸收面积及根系分泌物含量;同时,SUG处理明显增强了根际土壤脲酶、脱氢酶、多酚氧化酶和蔗糖酶活性。此外,该处理还显著促进了杨树苗株高与地径的生长。与SUG处理相比,S、SUM处理对杨树苗根系特性与生长的影响作用较小。在减量灌溉条件下施用保水剂的3种方式中,保水剂-尿素凝胶方式更利于改善杨树苗根系特性和增强土壤酶活性,并促进生长。

The paper aims to explore the effects of different application methods of super absorbent polymers(SAPs)on root characters and growth of Populus euramericana‘Neva’seedlings under the condition of reducing the irrigation amount.Based on a pot experiment including 5 treatments,i.e.CK(neither fertilizer nor SAP was applied),U(urea was applied alone),S(SAP was applied alone),SUM(SAP was mixed with urea)and SUG(gel was made of SAP and urea),we studied the effects of application methods of SAPs on root characters and growth of Populus euramericana‘Neva’seedlings,and enzyme activities of rhizosphere soil.The results indicated that:compared with U treatment,the SUG treatment obviously improved the root activity,the total absorption area and the active absorption area of root,and the root exudate content of Populus euramericana‘Neva’seedlings,meanwhile,SUG treatment obviously enhanced the activity of urease,dehydrogenase,polyphenol oxidase and invertase,additionally,the SUG treatment significantly promoted the growth of plant height and ground diameter.However,S and SUM treatments had less effect on the root characters and growth of Populus euramericana‘Neva’seedlings compared with SUG treatment.As a result,among the 3 application methods of SAPs,SUG treatment is beneficial to improving the root characters,enzyme activities,and promoting the growth of Populus euramericana‘Neva’seedlings under the condition of reducing the irrigation amount.