低氮条件下间作大豆对宿根蔗内生固氮菌固氮酶活性、氮素积累及产量的影响

【目的】探讨低氮条件下间作大豆对宿根蔗内生固氮特性及生长的影响,为生产上合理应用甘蔗/大豆间作提供理论依据。【方法】采用裂区试验,以单、间作不同种植模式为主因素,以ROC22、B8和GT213个甘蔗品种为副因素,比较低氮条件下不同处理间甘蔗的产量、氮素积累及内生固氮菌固氮酶活性的差异。【结果】低氮条件下,与甘蔗单作处理相比,甘蔗/大豆间作处理的宿根蔗茎径、有效茎数和产量分别提高5.1%~8.7%、7.9%~31.0%和9.0%~40.5%,而不同处理间的株高没有明显差异。间作处理可显著提高宿根蔗的茎、叶内生固氮菌固氮酶活性,其中ROC22茎、叶中的固氮酶活性增幅最大,分别提高了59.35和0.98~1.89 nmol C2H4/gFW·h。除分蘖期间作处理B8叶片的全氮含量和GT21的氮素总积累量显著提高18.8%和35.2%外(P<0.05,下同),其他品种叶片的全氮含量和氮素积累量在处理间差异不显著(P>0.05);伸长期时,间作处理下蔗茎的全氮含量和氮素积累量均较单作有不同程度提高,其中ROC22和GT21的氮素总积累量分别显著提高35.0%和81.1%。【结论】低氮条件下,间作大豆可明显提高宿根蔗的内生固氮菌固氮酶活性、氮素积累及产量,其中以GT21间作大豆的增产效果最佳。

Effects of intercropping with soybean on nitrogenase activity of endophytic nitrogen-fixing bacteria,nitrogen accumulation and cane yield of stubble cane under low nitrogen condition

Objective]The effects of sugarcane-soybean intercropping on characters of endophytic nitrogen-fixation and growth in stubble cane under low nitrogen condition were studied to provide theoretical references for the applica-tion of sugarcane-soybean intercropping. Method]A split plot experiment was conducted using cropping patterns (mono-culture and intercropping ) as principal factors and sugarcane cultivars ( B8 , ROC22 and GT21 ) as secondary factors , and the nitrogenase activity of endophytic nitrogen-fixing bacteria , nitrogen accumulation and cane yield of sugarcane under low nitrogen condition were analyzed among different treatments . Result]The results showed that , compared with the monoculture treatment , stalk diameter , millable stalks and cane yield of stubble crop under low nitrogen con-dition in the intercropping treatment were increased by 5.1%-8.7%,7.9%-31.0% and 9.0%-40.5%,respectively,while the plant height showed no obvious difference between cropping patterns. Intercropping treatment significantly increased the nitrogenase activities of endogenous nitrogen-fixing bacteria in stalks and leaves ,and the increments were 59.35 nmol C2H4/gFW·h and 0.98-1.89 nmol C2H4/gFW·h in variety ROC22,respectively,which were higher than those in B8 and GT21. Except that nitrogen content in leaves of B8 and total nitrogen accumulaction in leaves of GT21 at tillering stageweresignificantlyincreasedby18.8% and 35.2%,respectively(P<0.05,the same below).Nosignificantdiffer-ences in nitrogen content and accumulation in leaves between different treatments were observed in others (P>0.05), while the nitrogen content and accumulation in stalks at elongating stage in intercropping treatment were increased and total nitrogen accumulation in stalks of ROC22 and GT21 was significantly increased by 35.0% and 81.1%, respectively.Conclusion]Sugarcane-soybean intercropping can significantly improve nitrogenase activity of endophytic nitrogen-fix-ing bacteria , nitrogen accumulation and cane yield in stubble crop under low nitrogen condition , and the positive effect on yield of intercropping is the highest in GT21 among 3 the three varieties.