水稻根系空间分布特性的数学模拟及应用

摘要

为了明确水稻根系在土壤中的空间分布特性,通过根箱试验,获取水稻根系坐标数据,采用方程Y=a(1-bX)(Y为根系累积长度,X为横向分布距离或纵向分布深度)建立根系纵向和根系横向分布模型,并利用模型分析田间水分管理对水稻根系生长及分布的影响.结果表明,水稻分蘖期和成熟期,约88％的根系分布在10cm深度土层内,60％ ～ 70％根系分布在10 cm的横向范围内,其纵向和横向累积长度的变化均可用方程Y=a(1-bX)模拟.水分管理影响水稻根系生长数量和纵向分布,但不影响根系横向分布.间隙灌溉水稻根系分别比湿润灌溉和水层灌溉水稻根系分布深0.6和3.5 cm,根系长度分别比湿润灌溉、水层灌溉水稻多19.8％与26.4％,根系数量分别比湿润灌溉、水层灌溉水稻多28.3％及21.0％.平均角度的变化具有同样的趋势.%To clarify the root spatial distribution characteristics of rice,root box experiments were conducted to collect root distribution data.The equation Y =a (1-bX),where Y is the total root length,and X is the distance of root horizontal distribution or the depth of root vertical distribution,was used to establish root distribution model.Moreover,influences of water management on root growth and distribution were analyzed using the model.The results showed that about 88％ of roots were distributed in the top 10 cm soil layer,and 60％-70％ of the roots were distributed in horizontal range of 10 cm from the plant at tillering and ripening stages.The change in total root length with the distance of root horizontal distribution or the depth of root vertical distribution could be simulated by the equation Y =a (1-bX).Water management had impact on rice root vertical distribution and root number without affecting the root horizontal distribution.The rice roots were 0.6 and 3.5 cm deeper,19.8％ and 26.4％ longer,and 28.3％ and 21.0％ greater in number under intermittently flooded irrigation compared with wet irrigation and continuously flooded irrigation,respectively.The variation of average angle of roots showed similar tendency.