大麦间作豌豆的种间竞争力及产量对施氮量的响应

通过优化种间关系对提高禾豆间作产量具有理论和实践指导意义,因此,本研究采用盆栽试验,设单作大麦(B)、单作豌豆(P)和大麦间作豌豆(P/B)三种种植模式,在不施氮(N0)、施纯N 200 mg/kg·土(N1)和400 mg/kg·土(N2)三个施肥水平,探讨了大麦间作豌豆的种间关系及其产量表现,以期为豆科//禾本科间作系统氮素高效管理提供理论依据。结果表明:施氮间作的土地当量比均大于不施氮间作处理,且均大于1,说明施氮有利于提高间作优势;与相应单作相比,N0、N1和N2施氮水平下的间作大麦的产量分别提高了28.1%、61.4%和48.5%,间作豌豆的产量分别提高了15.7%、24.2%和17.7%,间作优势明显。施氮提高了大麦相对于豌豆的竞争力,N1、N2水平下的间作大麦竞争力较N0水平下的竞争力分别增大了49.8%和95.2%。大麦间作豌豆的籽粒产量与大麦相对于豌豆的平均竞争力呈二次曲线相关关系,该竞争力在0.4时利于间作籽粒高产;适度控制共生期大麦的竞争力可提高间作产量,大麦盛花期是最有效的调控时期,N1水平的施氮量是优化间作大麦和豌豆竞争力、获取高产的适宜施氮水平。

Responses of interspecific competition and crop yield to nitrogen applications in a barley-field pea intercropping system

The optimization of the interspecific relationship presents a theoretical and practical significance in improving the yields of cereal/legume intercropping systems. A study with three nitrogen (N) levels: without nitrogen (N0), 200 mg urea-N/kg soil (N1) and 400 mg urea-N/kg soil (N2) was carried out to investigate the interspecific relationship and yield performance of a barley-field pea intercropping system for providing a theoretical basis for the efficient N management in cereal/legume intercropping systems. The results showed that intercropping combined with N applications can increase the land equivalent ratio (LER>1) and the mixed grain yields. Compared with the corresponding monocultures, the yield of intercropped barley was significantly increased by 28.1%, 61.4% and 48.5% in N0, N1 and N2, respectively; similarly, the yield of intercropped pea was also increased by 15.7%, 24.2% and 17.7%, respectively. N applications can greatly increase the competitiveness of barley relative to pea. Our data showed that the intercropped barley showed 49.8% and 95.2% higher competitiveness in N1 and N2 than in N0. The yields of the intercropping systems presented a quadratic relationship with the barley competitiveness to pea. There was a good improvement in grain yield when the competitiveness was at 0.4. Our data suggested that a moderate controlling of barley competitiveness can increase grain yield during the barley-field pea co-growing period and that the barley flowering stage is critical for regulating the barley competitiveness. Overall, N1 was found the most suitable N level for optimizing the competitiveness and obtaining high yields of the studied barley-field pea intercropping system.