不同密度处理下玉米根系干重空间分布动态的研究

Study on Dynamic Variation of Root Dry Weight Space Distribution on Different Densities of Maize

采用根钻挖掘法对不同密度处理下玉米根系干重在土壤中的空间分布特征进行了研究。结果表明:不同密度处理下,各取样点0～100cm土层内根系干重在整个生育期内均呈单峰曲线变化,峰值出现在灌浆期前后。在1/2行距处随着密度的增加,根系干重呈增加趋势变化;在1/2株距处,中密和高密处理差异较小,但显著大于低密。在1/4行距处,根系干重则随着密度的增加而逐渐减少。根系达到干重最大值后的下降过程均以高密处理的下降速度最快。不同取样点根系干重在土壤中的垂直分布情况为在大喇叭口期以前,根系干重最大值出现在10～20cm的土层内,而后随着土层深度的增加根系干重迅速下降;大喇叭口期以后根系干重在土壤中的垂直分布呈负指数曲线趋势变化。密度对不同取样点根系干重影响主要表现在0～40cm土层内1/2行距处拔节期各密度处理间无明显差异;小喇叭口期到灌浆期表现为高密>中密>低密;成熟期表现为中密>高密>低密。1/4行距处大喇叭口期以前各密度处理之间的差异不明显;从吐丝期到成熟期,中密和低密处理各土层的根重差异不明显,但均较高密处理的大。1/2株距处在大口期以前中密处理和高密处理各土层的根重无明显差异,但均较低密处理高,吐丝期以后各土层的根重则以中密处理最大,高密次之,低密最小。

With the roots drill excavate experiments, studies on distribution and dry material accumulation on different densities of maize with the root drill. The result showed that at maize growth and development period, changes current was a single apex of roots dry weight from different densities. The Maximal value appeared in the grain filling period. Comparison the maximal of different densities at 1/2 individual plant space, with the density increasing by root dry weight increased, at 1/2 row space, difference is less on height density and middle density, but above low density, at 1/4 row space, with the density increasing by root dry weight reduced. In the horizontally distribution, root dry weight decreased gradually from the root center to outer space. Root dry weight perpendicularity distributing in soil, in pre-tassel before, dry measure maximum value appeared within 10 - 20 em＇s soil layers. At pre-tassel ling after. Root dry weight distributes memorial negative exponent curve law changed in perpendicularity in soil.