根系分隔方式对燕麦/豌豆间作地上生物量、土壤养分及根系性状的影响

Effects of root separation on aboveground biomass,soil nutrient contents,and root characters of intercropped oat and pea

为了解燕麦/豌豆间作系统中根系分隔对地上生物量和土壤养分的影响,本研究设燕麦单作、豌豆单作、燕麦豌豆间作不分隔、尼龙网分隔和塑料膜分隔共5个处理,分析了燕麦/豌豆间作后株高、地上生物量、土壤养分和根系性状的变化。结果表明,塑料膜分隔处理降低了燕麦株高和间作地上生物量,其土地当量比小于1,而尼龙网分隔、不分隔处理的土地当量比大于1,间作优势明显。塑料膜分隔处理的土壤有机质含量较尼龙网分隔和不分隔处理降低了14.75%~78.53%,有效磷含量降低了9.31%~29.73%,土壤全氮含量在拔节和开花期的根系分隔处理中无显著变化(P>0.05),灌浆期塑料膜分隔较尼龙网分隔和不分隔处理分别降低了22.16%和18.38%,成熟期不分隔处理较塑料膜分隔高10.83%(P<0.05)。对豌豆而言,塑料膜分隔处理的土壤有机质含量显著高于不分隔和尼龙网分隔。此外,不分隔处理的燕麦根长较尼龙网分隔、单作和塑料膜分隔分别增加了43.03%、59.02%和96.38%;根表面积分别增大了14.84%、30.20%和45.55%;根体积分别增加了17.37%、38.15%和106.15%。由此可见,燕麦/豌豆间作显著影响了作物的根系性状,使根系对土壤养分的竞争力发生了变化,从而影响了地上生物量;根系互作越紧密,燕麦和豌豆的地上生物量越高;根系无互作的塑料膜分隔导致燕麦根系生长较差,土壤养分含量较低,间作生物量较低。

The aim of this research was to explore the effects of root separation on aboveground biomass and soil nutrient contents in an oat(Avena sativa)/pea(Pisum sativum)intercropping system.Five treatments were applied in a field experiment:Oat monoculture,pea monoculture,unseparated oat/pea intercropping,oat/pea intercropping with nylon mesh separation,and oat/pea intercropping with plastic film separation.The changes in plant height,aboveground biomass,soil nutrients and root traits after oat/pea intercropping were analyzed.The results showed that the plant height and the aboveground biomass of intercropped oat/pea were reduced by the plastic film separation treatment,with a land equivalent ratio lower than 1,whereas the land equivalent ratios in the nylon mesh separation and unseparated treatment were higher than 1,and intercropping had obvious advantages.The soil organic matter content and available phosphorus content were 14.75%-78.53%lower and 9.31%-29.73%lower in the plastic film separation treatment than in the nylon mesh separation treatment and unseparated treatment,respectively.In the root separation treatments,there was no significant difference in the soil total nitrogen content between the jointing and flowering stages(P>0.05).Compared with the nylon mesh separation and upseparated treatments,the plastic film separation treatment showed 22.16%and 18.38%lower soil total nitrogen content,respectively,at the grain-filling stage.At the mature stage,the soil total nitrogen content was 10.83%higher in the non-separated treatment than in the plastic film separation treatment(P<0.05).For pea,the soil organic matter content was significantly higher in the plastic film separation treatment than in the unseparated and nylon mesh separation treatments.In addition,the length of oat roots in the unseparated treatment was 43.03%,59.02%,and 96.38%higher than that in the nylon mesh separation treatment,single cropping treatment,and plastic film separation treatment,respectively.The surface area of oat roots in the unseparated treatment was 14.84%,30.20%and 45.55%higher than that in the nylon mesh separation treatment,single cropping treatment,and plastic film separation treatment,respectively.The volume of oat roots in the unseparated treatment was 17.37%,38.15%and 106.15%higher than that in the nylon mesh separation treatment,single cropping treatment,and plastic film separation treatment,respectively.In conclusion,oat/pea intercropping significantly affected the root characteristics of both crops,and changed the competitiveness of roots for soil nutrients,thus affecting aboveground biomass.The closer the root interaction,the higher the aboveground biomass of oat and pea plants.Plastic film separation without root interaction resulted in poor root growth,lower soil nutrient contents,and the lowest aboveground biomass of both crops.