Groei en ontwikkeling van sojabooncultivars by verskillende rywydtes

[摘要] English: Several studies in especially the United States of America showed that soybeansproduced higher yields when planted in narrow rows as opposed to wide rows. Thehigher yields were mostly attributed to better solar interception as a result of a higher leafarea index. A denser leaf canopy increases water use efficiency and decreases weedcompetition.Therefore the influence of cultivars and row spacing on the growth and development ofsoybeans was evaluated. The experiments were conducted at two divergent localities,namely Bergville, Kwazulu-Natal and Bloemfontein, Free State during the 2000/01 and2001/02 seasons with six cultivars (PAN660/564, Dumela, A5409, LS666, Tops andSNK500) and two row spacings (0.45 and 0.90 m). An effort was made to use or imitatecommercial cultivation practices.Several plant physiological components were measured, namely during the floweringstage: plantheight, leaf mass, number of leafs, number of branches and leaf area index;and during physiological ripe stage: number of pods, pod mass and seedmass. During theflowering stage the nutrient concentrations in the above ground plant material was alsodetermined. The water use efficiency over the growing season was also quantified.Neither the cultivars nor the row spacing had a significant influence on nutrientconcentrations in the above ground plant material. The water use efficiency, although notstatistically analyzed, was higher at the narrow than wide rows.Most of the above ground plant components that were measured had higher values at the0.45 than 0.90 m rows. The one plant component that stood out in this regard was thenumber of branches that developed per unit surface area. When soybeans is planted atthe same density in the 0.45 and 0.90 m rows the distance between adjacent plants in thenarrow rows (0.074 m) is twice of that in the wide (0.037 m) rows. The consequencethereof was that the soybeans developed significant more branches in the narrow thanwide rows.The more branches in the narrow rows resulted in a more bushy plant which broadenquicker. As a result of this together with the smaller distance between adjacent rows thesoil surface was covered faster and therefor a higher leaf area index at the narrow than thewide rows. This higher leaf area index at the narrow than wide rows is in accordancewith results reported by other researchers. They suggested the higher leaf area indexresulted in earlier and higher solar interception. Although seed yields differed not alwayssignificantly between the narrow and wide rows, the yields were consistent higher at thenarrow rows. Soybeans should be therefore rather planted in narrow (0.4 - 0.6 m) than wide (0.8 - 1.0m) rows if possible. An aspect that warrants investigation is the planting of soybeans at different densities in the narrow rows.

[发布机构] University of the Free State