土壤条件对陆稻根系生长的影响

STUDIES ON THE GROWTH OF UPLAND RICE ROOTS UNDER VARIOUS SOIL CONDITIONS

采用“三维坐标容器法”,研究了三种土壤条件对陆稻根系生长的影响。结果表明:1.不同土壤条件下,根系入土深度均在 60 cm左右。2.不同土壤类型中,根系体积（V）、总表面积（St）、活跃表面积（Sa）、长度（L）、干重（Wd）、密度（D）随入土深度的增加而减少,Sa/St大致在同一水平;潮砂土以上层粗根为多,生长居中:红壤土以下层细根为多,生长最好;水稻土最差。3 不同地下水位中,L、Wd、V、D随入土深度的增加而递减,且在不同垂直土层中的分布,均为水层深6cm（A处理）>水层深4cm（B处理）>水层深2cm（C处理）,但 A处理在 30～50 cm处有较大的回升,即深层（30～60cm）根细、多;A、B处理的St、Sa有升有降,但三种处理的Sa/St均随垂直深度增加而增加。4.不论何种土壤温度,V、L、D、Wd、St、Sa随着入土深度的增加、土温的升高和生育期内土壤积温的减少而明显减少;在不同垂直土层中,5月8日播种（b）、6月8日播种（c）间V无明显差异,与4月8日播种（a）有较大差别:a、b间Wd无明显差异,但与c有较大差别;Sa/St随入土深度的增加、土温的日益升高、生育期内土壤积温的减少而增强,且处理a<b<c。

Under various soils, groundwater levels and soil temperature during days of growth stages, the growth of upland rice root system were studied by three-dimensional coordinate container method. The results were as follows:1. Under various soil conditions, the depth of root system distribution was generally about 0.60 m.2. Regardless of soil types root volume, total area and active area of root surface, root length, dry weight of roots and root density decreased gradually with soil vertical depth, but active/total area of root surface fluctuated lightly. Giving overall consideration to all root parameters, the growth of upland rice root system was the best in red clay soil, the next was in sandy fluvo-aquic soil, the worst was in paddy soil.3. Under various groundwater levels, root length, root dry weight, and the distribution of every soil layer were the treatment A(6 cm water layer) > B(4 cm water layer) > C(2 cm water layer) , root volume and root density decreased gradually with root system vertical distribution depth, but the treatment of A increased strongly between 0.30 m and 0.50 m. Total area and active area of root surface of A and B increased or decreased with root system vertical distribution depth, total area of root surface, active area of root surface of C decreased with root system vertical distribution depth, and active area/total area of root surface of A, B, C increased with root system vertical distribution depth.4. Under various soil temperature, root length, root dry weight and root volume, root density, total area and active area of root surface decreased gradually with root system vertical distribution depth, the increase of soil temperature and the decrease of the accumulation of temperature during days of growth stages. The distribution of every layer/total quantity of root volume was not different between the treatmentof b(date of sowing: 8th, May) and c(date of sowing: 8th, June) , but was evident difference between b (date of sowing: 8th, May), c( date of sowing: 8th, June) and a (date of sowing: 8th, April); the distribution of every layer/total quantity of root dry weight was not different between the treatment of a and b, but was different evidently between a, b and c; the distribution of every layer/total quantity of root length was not different between a, b and c; active area/total area of root surface of a, b, c increased with root system vertical distribution depth, the increase of soil temperature, the decrease of the accumulated soil temperature during days of growth stages. The ratio of active area to total area of root surface is in order of the treatment a < b < c for the depth between 0.0 m and 0.6 m.