不同株行距配置对夏大豆群体结构及光截获的影响

以田间试验(2006—2007年)为基础,分析了地上部干物质、叶面积指数(LAI)、光合有效辐射(PAR)、光能利用率和植株形态指标变化特征,夏大豆‘鲁豆4号’(Glycine maxcv.Ludou 4)在同一密度(3.09×105株/hm2)下设5种株行距配置方式,即行距×株距分别为18 cm×18 cm(A)、27 cm×12 cm(B)、36 cm×9 cm(C)、45 cm×7.2 cm(D)、54 cm×6 cm(E)。结果表明,大豆在生育期间干物质变化因株行距不同而产生差异,2006和2007生长季的各处理干物质分别在播种后第70天和90天达到最高,播种后第80天和100天时,A处理比E处理分别高21.6%和34.0%;不同层次干物质积累重心随行距加大有上移趋势。各处理LAI随行距扩大、株距减少有下降趋势,其中,A和B处理LAI表现较稳定,LAI相对较高且时间较长。光能利用率随行距加大有降低趋势,A和B处理显著高于E处理(P0.05)。夏大豆在不同株行距配置下,株粒数、百粒重与产量相关系数分别为0.941*和0.926*(2006年),0.995*和0.892*(2007年),随行距变小PAR透射率降低、截获率和光能利用率上升而产量增加,A和B处理产量显著高于E处理(P0.05)。说明夏大豆在雨养农业条件下,植株相对均匀分布可改善群体结构和增强光截获,进而提高群体光能利用率和产量。

Effect of different plant-row spacing on population structure and PAR interception in summer soybean

Changes in aboveground dry matter (DM), leaf area index (LAI), photosynthetically active radiation (PAR), solar energy utilization efficiency, and configuration of plant were investigated in field experiment during the growing seasons of summer soybean (Glycine max cv. Ludou 4) in 2006 and 2007. The summer soybean experiment consists of 5 planting patterns under the same plant population density (3.09 × 10~5 plant/hm~2). Row spacing (cm) × plant spacing (cm) was 18 cm×18 cm (A), 27 cm×12 cm (B), 36 cm×9 cm (C), 45 cm×7.2 cm (D), and54 cm6 cm (E), respectively. The differences in dry matter weight under different plant-row spacing were observed. The DM of all treatments reached maximum at 70 days after sowing (DAS) and 100 DAS, however, the DM of A treatment was 21.6% and 34.0% higher than that of E treatment at 80 DAS and 100 DAS, respectively. Accumulative priority of DM at different portions of the whole plant increased with widening of row spacing. The LAI of all treatments decreased with row spacing widened, and that of A and B treatment had higher value and longer time than the others. The solar energy utilization efficiency of different treatments generally increased with row spacing increased. For different plant-row spacing of the summer soybean population, number of grain per plant and 100 grain weight were positively correlated with yield, and correlation coefficients were 0.941~* and 0.926~* (in 2006), 0.995~* and 0.892~* (in 2007), respectively. PAR transmittance rate decreased, interception rate and solar energy utilization efficiency increased with a narrowing in row spacing, and thus yield increased. The yields of A and B treatments were significantly higher than that of E treatment (P < 0.05). The summer soybean population of relatively uniform distribution improves population structure, and increases the PAR interception, solar energy utilization efficiency and yield under raided agriculture.