Effects of Nitrogen Reduction on Intercropping Advantage of Maize and Aconitum vilmorinianum

PurposeTo explore the effects of nitrogen reduction on the intercropping advantage of maize and Aconitum vilmorinianum in Alpine mountainous areas.

MethodsUsing the field experiment method, taking the maize intercropping A. vilmorinianum (2∶4) as the planting mode, four nitrogen application levels were set: conventional nitrogen application (IN, 144.0 kg/hm²), nitrogen reduction by 20% (IN20, 115.2 kg/hm²), nitrogen reduction by 40% (IN40, 86.4 kg/hm²), nitrogen reduction by 60% (IN60, 57.6 kg/hm²), and maize monoculture (MS) and A. vilmorinianum monoculture (AS) were also set.

ResultsCompared with monoculture, the intercropping advantage of maize and A. vilmorinianum was obviously improved; the land equivalent ratio (LER) was greater than one, and the maximum value was counted in IN and IN20. Compound yield of IN20 was significantly increased (P<0.05), 21.6% and 30.8% higher than IN40 and IN60, respectively, but there was no significant difference with IN (P>0.05); the net yield effect of IN20 was 2 837.57 kg/hm², which was significantly higher than IN60 (P<0.05), but there was no significant difference with IN (P>0.05). The effect of intercropping on maize growth was greater than that of A. vilmorinianum. Compared with IN, the maize plant height of IN20 and IN40 were increased significantly (P<0.05). There was no significant difference in maize stem diameter and A. vilmorinianum growth indexes among intercropping treatments (P>0.05). Different treatments had effects on the quality of A. vilmorinianum. Among them, the extract content of A. vilmorinianum in IN40 was the highest, which was significantly different from other treatments (P<0.05), and it was 13.4%, 10.6% and 5.6% higher than IN, IN20 and IN60, respectively. There was no significant difference of total alkaloids content among treatments (P>0.05).

ConclusionUnder the planting mode of reducing nitrogen by 20%, the intercropping advantage of maize and A. vilmorinianum is more obvious, and it has little impact on the quality of A. vilmorinianum, which achieves the purpose of increasing crop yield and reducing the amount of chemical fertilizer.