粮草轮作中前茬作物土壤浸提液对后茬作物的化感效应

Effects of soil extracts from the preceding plant on allelopathy of the subsequent plant seedlings in grain-forage rotation

摘要:

【目的】为筛选区域适应性粮草轮作模式，实现农业产业结构调整。【方法】设计玉米-豌豆 （C-Pe），青贮玉米-燕麦（Sm-O），马铃薯-玉米（Po-C），豌豆-高粱（Pe-B），燕麦-青贮玉米 （O-Sm）和 2 龄苜蓿（2A）6 个不同粮草轮作模式，进行田间小区试验，前茬作物（牧草）收获后采集根区 0~20、20~40 cm 土层土壤样品，制备土壤浸提液，测定粮草轮作中前茬土壤浸提液对后茬作物幼根生长特性及根系化感效应的影响。【结果】（1）与其他模式相比，C-Pe、Sm-O 模式对后茬作物根长、 根系活力的促进作用最显著，分别比 CK 增加 83. 0%、226. 3%。（2） Sm-O 模式对后茬作物株根干重的促进作用最显著，较对照增加 71. 9%、106. 1%。（3）所有浸提液对后茬作物根系化感效应指数均大于 0，说明 6 种粮草轮作模式前后茬均有正向的化感效应，其中，O-Sm 模式促进作用最大，综合化感效应指数 SE 在 0. 3~0. 6 之间；2A 模式促进作用最小，SE 在 0. 050~0. 20 之间。【结论】轮作模式对根系的促进作用表现为 O-Sm＞Sm-O＞C-Pe＞Po-C＞Pe-B＞2A，且 0~20 cm 土层促进作用高于 20~40 cm 土层。

Abstract:

【Objective】 In order to screen the regional adaptive grain -forage rotation patterns and realize the ad- justment of agricultural industrial structure，【Method】 six different grain-forage rotation patterns，including maize-pea （C-Pe），silage maize-oat （Sm-O），potato-corn （Po-C），pea-sorghum （Pe-B），oat-silage maize （OSm） and 2-year-old alfalfa （2A） were designed and field plot experiments were conducted. Soil samples of preced- ing crop （forage） in the root zone were collected from 0~20 cm and 20~40 cm depth after harvesting，and soil ex- tracts solutions were prepared to investigate the effects of soil leaching solutions from the preceding plant on the growth characteristics and the allelopathy effects of the early roots from the subsequent plant in the grain-forage rota- tion.【Result】 The results showed that：1） compared with other patterns，the C-Pe and Sm-O patterns had themost significant effects on root length and root activity of subsequent plant，increasing 83. 0% and 226. 3%，respec- tively，compared with CK. 2） The Sm-O pattern had the most significant effects on root dry weight and root activity of the subsequent plant，increasing 71. 9% and 106. 1%，respectively，compared with CK. 3） The indices of the allelo- pathic effects of all the extracts on the roots of the post-crop plants were greater than 0，indicating that the six cereal grass rotation patterns had positive allelopathic effects on both the pre- and post-crop. The O-Sm pattern had the greatest allelopathy effect with the allelopathy effect index （SE） among 0. 3~0. 6. The 2A pattern had the lowest al- lelopathy effect with the SE among 0. 05~0. 2.【Conclusion】 The order of promoting effects of crop rotation patterns on root system was O-Sm＞Sm-O＞C-Pe＞Po-C＞Pe-B＞2A，and the promoting effect of 0-20 cm soil layer was higher than that of 20~40 cm soil layer.