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管理措施常常影响土壤物理性状,进而降低根系生长。在大田,测定土壤物理性状对根系生长的影响困难很大,因为这些因素不易分离开来。本研究的目的在于确定控制条件下,单一物理因素对玉米(Zea mays L)幼苗生长的影响。笔者在生长室进行试验,将玉米播种在Groseclose 粉壤土(粘质、混合型中温典型薄层湿老成土)的 A 层土壤物质中,分四种容重(1.10、1.22、1.35和1.47吨/米~3,)四种偏低的土壤水分水平(0.24、0.21、0.18和0.15米~3/米~3)、四种偏高的土壤水分水平(0.24、0.27、0.30和0.33米~3/米~3)和三种温度处理(25、21和17℃)。在 Groseclose的粉壤土中,玉米根系伸长的最佳条件是体积含水量0.24-0.27米~3/米~3,容量<1.22吨/米~3、温度25℃左右。高容量、缺氧,低温和缺水均在某种程度上影响到根系生长。低温影响最大。在21℃条件下,6日后玉米根长仅有25℃的20%左右,而17℃下的根长约为25℃的5%。根长随着容量的增加而减少。4天后,较高的土壤水分含量有助于根系生长。除了最低水平(相当于-1090千帕的基质势)外,低的土壤水分含量并不降低根系长度。
Management practices often affect soil physical properties, which in turn reduce root growth. In the field, it is difficult to determine the effect of soil physical properties on root growth because these factors are not easily separated. The purpose of this study was to determine the effect of a single physical factor on the growth of Zea mays L seedlings under controlled conditions. Experiments were conducted in the growth chamber to sow maize in layer A soil material of a Groseclose silty soil (clayey, mixed mid-temperature typical thin layer of wet, aged) in four volumes (1.10, 1.22, 1.35 and 1.47 ton / m ~ 4%), four kinds of low soil moisture (0.24,0.21,0.18 and 0.15-3 m / 3), four kinds of high soil moisture (0.24,0.27,0.30 and 0.33 m ~ 3 / m ~ ~ 3) and three temperature treatments (25, 21 and 17 ° C). The optimum conditions of corn root elongation in the soil of Groseclose were volumetric water content 0.24-0.27 m 3 / m 3, capacity <1.22 t / m 3, and temperature about 25 ℃. High capacity, hypoxia, hypothermia and water deficit all affect root growth to some extent. Low temperature has the greatest impact. At 21 ℃, the root length of corn after 6 days was only about 20% of 25 ℃, while the root length at 17 ℃ was about 5% of 25 ℃. Root length decreases as capacity increases. After 4 days, higher soil moisture content helps root growth. In addition to the lowest level (equivalent to a substrate potential of -1090 kPa), low soil moisture does not reduce root length.