Use of 13C Isotope Discrimination Analysis to Quantify Distribution of Barnyardgrass and Rice Roots in a Four-Year Study of Weed-Suppressive Rice
Use of 13C Isotope Discrimination Analysis to Quantify Distribution of Barnyardgrass and Rice Roots in a Four-Year Study of Weed-Suppressive Rice
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DOI：
10.1614/ws-d-10-00145.1
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发表时间：
2012-01-01
期刊：
影响因子：
2.5
通讯作者：
Moldenhauer, Karen A. K.
中科院分区：
文献类型：
--
作者：
Gealy, David R.;Moldenhauer, Karen A. K.
在一项为期4年的田间研究中，“抑制杂草”的水稻品种提供了30%以上的稗草控制和持续44%的产量损失（相对于无杂草）相比，“非抑制性”的热带粳稻品种。C-13分析表明，水稻根质量占主导地位的垂直和横向内的土壤剖面与稗草侵扰的地块。在所有品种中，水稻根系占总根量的75%~ 90%，且最集中于行内土壤表层5cm处。稗草的根系分布最广的是行间5 cm处的根，占总根量的30%。总体而言，稗草根质量是约两倍高，抑制水稻相比，在非抑制水稻。杂草抑制籼稻/热带粳稻杂交一般是中间的其他两个水稻组。在0 ~ 5cm土层，稗草根量与水稻株高（r = -0.424）、产量（r = -0.306）和杂草防除等级（r = -0.524）呈显著负相关。杂草区的防除等级与水稻相对于无杂草区的高度减少百分比（r = -0.415）和产量损失百分比（r = -0.747）呈负相关，与稗草根质量占总根质量的百分比（r = -0.612）呈负相关。在杂草压力下，防除等级与水稻产量呈正相关（r = 0.429），但仅与水稻行内根量相关（r = -0.322）。显然，水稻根质量可能不是品种间稗草控制差异的主要原因。
In a 4-yr field study, "weed suppressive" rice cultivars provided 30% greater control of barnyardgrass and sustained 44% less yield loss (relative to weed-free) compared to "nonsuppressive" tropical japonica rice cultivars. C-13 analysis revealed that rice root mass predominated vertically and laterally within the soil profile of plots infested with barnyardgrass. Among all cultivars, rice roots accounted for 75 to 90% of the total root mass in samples, and this was most concentrated in the surface 5 cm of soil in the row. Barnyardgrass roots were most prevalent in the surface 5 cm between rows where they accounted for 30% of total root mass. Overall, barnyardgrass root mass was about twice as high in nonsuppressive rice compared to suppressive rice. Weed suppression by indica/tropical japonica rice crosses generally was intermediate between that of the other two rice groups. At the 0- to 5-cm depth, between-rows, barnyardgrass root mass was correlated negatively with rice height (r = -0.424), yield (r = -0.306), and weed control ratings (r = -0.524) in weedy plots. Control ratings in weedy plots also were negatively correlated with rice percent height reduction (r = -0.415) and % yield loss (r = -0.747) relative to weed-free plots, and with barnyardgrass root mass as a percent of total root mass (r = -0.612). Control ratings were positively correlated with rice yield under weed pressure (r = 0.429) but were correlated with rice root mass in-rows only (r = -0.322). Clearly, rice root mass could not have been the major cause of the differences in barnyardgrass control between cultivars.