【摘要】 用挖坑冲洗法和改良根钻法研究了耕层(0~30cm)和1m土体内冬小麦根系生物量及其空间分布。研究结果表明,用根钻在垄上、垄间和与垄相切3个位置取样的采样方法较挖坑冲洗法优越。冬小麦根系总量一般在抽穗前后达到最大,一般为2.5~3.5t/hm2。收获期的总根量一般为2.0t/hm2左右。严重的氮素短缺、干旱和盐分胁迫条件下,灌浆期的根总量明显减少,但深层根系比例相对较大。然而,从单穗平均根量来说,并不一定减少,连续5季不施氮肥条件下的单株根量甚至可能是水肥充足处理单株根量的1.5~2.0倍。水肥适宜条件下,抽穗期以后根系在土壤剖面中的分布从上而下大致每10cm减少一半,总根量可用公式R=Σ[(12)n-1×y1](R为总根量,y1为0~10cm土层的根量,单位:t/hm2)近似表示。更多还原

【Abstract】 Root biomass of winter wheat in 0~30 cm and 0~100 cm soil layers was studied using root core and dig sampling method. It was found that the root core method was superior to the other with three sampling position was: (1) within the rows,(2) between the rows and (3) in an intermediate position, i.e. with one edge of the core touching the row. Wheat root biomass reaches the peak as 2.5~3.5 t/hm2 at the head sprouting stage, and is about 2.0 t/hm2 at mature stage. Root biomass under serious nitrogen shortage, water shortage and saline water irrigation conditions are generally smaller than that under feasible conditions. With salt, nitrogen and water stress, the ratio of root biomass in deep soil compartment is generally higher than free from these stress factors. But the average root biomass for each ear is, however, not necessary less than that under feasible condition. And it was even 1.5 to 2.0 times as much as those under feasible condition for wheat growth under serious nitrogen shortage condition. And it was found that root biomass in a 10 cm thickness soil compartment was about half of that in the adjacent upper compartment. As a result, the total root biomass of winter wheat could be expressed asR=Σ[(1-2)n-1×y1], in which R represents the total root biomass (t/hm2), and the y1 represent the root in the 0~10 cm soil compartment.更多还原