不同空间配置套作大豆后期农学参数及光谱特征分析

Soybean agronomic and hyperspectral characteristics at later stage under spatial patterns of maize-soybean intercropping

以玉米-大豆套作种植模式为研究对象,通过设置不同的大豆行距调整大豆与玉米的空间位置(大豆行距设置为30cm和70cm,即距离玉米行分别为60cm和40cm),研究套作大豆后期(套作玉米收获后)农学参数变化及光谱响应特征。结果表明,由于苗期受玉米荫蔽作用,距离玉米行越近,大豆冠层透光率越低,玉米收获后大豆花期(8月10日)生物量、株高、水分含量及叶绿素在不同处理条件下差异明显。玉米收获后直至盛荚期(9月9日)和鼓粒期(10月6日),大豆迅速恢复生长,各农学参数存在差异,但不显著。通过大豆冠层反射率分析,绿峰区域(550nm左右)和近红外区域(760～1 000nm)能够很好地解析大豆叶绿素和水分变化规律。

Field experiment with typical maize and soybean relay strip intercropping systems was carried out to investigate physiological indexes and hyperspectral characteristics of soybean. Three treatments were compared ： （i） sole crop soybean （CK）; （ii） soybean row spacing 30cm, and 60cm away from maize row; （iii） soybean row spacing 70cm, and 40cm away from maize row. In soybean canopy adjacent to maize during early florescence stage, it was found that the shorter distance between soybean and maize, the more biomass, plant height, water content and chlorophyll content of soybean would be reduced. The PAR （ photosynthetically active radiation） transmittance was also reduced. Due to growth recovery after maize harvest, differences of physiological indices among three treat- ments were not significant. Spectral reflectance of green peak region （ about 55Onto） and near - infrared region （760 to 1000nm） could reflect the changes of chlorophyll and water content well in soybean canopy.