Effects of Planting Depth on Vegetative Characteristics of Three Forage Grasses at 14 Days Post Emergence1
- C. R. Tischler and
- P. W. Voigt2
Deep planting has often been advocated as a method of improving seedling establishment of plants in semi-arid regions. However, because deep planting could theoretically reduce seedling vigor, the potential for greater moisture availability could be offset by slower growth. In the case of forage grasses, a slower rate of growth could result in slower development of the adventitious root system. The present study was undertaken to investigate effects of depth of planting on performance of seedlings of kleingrass (Panicum coloratum L.), weeping lovegrass (Eragrostis curvula Schrad. Nees), and wilman lovegrass (Eragrostis superba Peyr.). Seed were planted at 2, 4, 6, and (kleingrass only) 8 cm and grown at 21/29°C in plastic cones the growth chamber. Plants were excavated and evaluated at 14 days post emergence. Subcoleoptile internode (SI) length was used to indicate actual planting depth and to determine the relation of depth of planting to other plant characteristics. With increasing SI length, days to emergence increased while shoot weight, root weight, and number of leaves decreased for all species. Length of longest adventitious root, mean adventitious root length, total adventitious root length, and number of adventitious roots decreased with increasing SI length for kleingrass and wilman lovegrass, but the adventitious root development of weeping lovegrass was not significantly affected by SI length. Primary root length decreased with increasing SI length for all species. However, primary root depth (primary root length + SI length) increased with increasing SI length in kleingrass, decreased with increasing SI length in weeping, and did not change with increasing SI length in wilman lovegrass. These results indicate that the response of primary root depth to SI length (or depth of planting) varies from species to species. Although wilman lovegrass displayed the most vigorous growth at shallow planting depths, Kleingrass had a higher fresh weight at harvest, at a planting depth of 6 cm. Hence, performance of a species (in terms of fresh weight) at one depth of planting can be a poor indicator of performance at other planting depths. In general, increasing planting depth tends to have a negative influence on post-emergence performance of the three grass species investigated. Deep planting should be correlated with controlled water availability and plant survival to draw any concrete conclusions. Early growth may only be of temporary significance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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