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要模拟作物吸收水分以研究水分利用和产量的关系,需要关于特定土壤在不同管理措施条件下根系持续发育方面的定量资料。本文报道了在壤砂土和砂壤土两种土壤上,施用氮肥和一次早期轻微灌溉对小麦根系发育的影响。根长指数RLI(即根际剖面根长km/m~2)和根系下扎深度(m)因管理措施而变化,但皆符合Logistic生长关系y=a/(1+b exp ct),式中t为时间(天)。各个时期根际土壤不同土层的根长比例与土壤及处理有关,且可用时间、深度及其乘积的指数函数来描述。根系在砂壤土中的发育比在壤砂土中更为集中、迅速。处理对根系的影响也随土壤而变,早期灌溉和施氮对促进根系生长的效应在砂壤土上很接近;在壤砂土上早期灌溉的效应远远大于施氮的效应。两种土壤上早灌与施氮的互作效应略低于其累加效应。而氮肥与灌溉相结合对水分利用的激发效应大于其累加效应。不同处理下的土壤水分消耗梯度恰好与拟合的根长度梯度相一致。
To simulate crop water uptake to study the relationship between water use and yield requires quantitative data on the sustainable root development of specific soils under different management practices. This paper reports the effects of nitrogen fertilizer and one early light irrigation on the root development of wheat on both sandy loam soil and sandy loam soil. Root length index (RLI) (root length km / m ~ 2) and root depth (m) varied according to management measures but all accorded with Logistic growth relationship y = a / (1 + b exp ct) Middle t is time (days). The root length ratio of different soil layers in rhizosphere soil at different periods is related to soil and treatment, and can be described by exponential function of time, depth and its product. The development of root system in sandy loam was more concentrated and rapid than that in loamy soil. The effect of treatment on the root system also changed with the soil. The effects of early irrigation and nitrogen application on root growth were similar on sandy loam soil. The effect of early irrigation on sandy soil was much greater than that of nitrogen application. The interaction effect of early irrigation and nitrogen application on the two soils was slightly lower than their cumulative effect. The combination of nitrogen fertilizer and irrigation on the water use of the stimulating effect is greater than its cumulative effect. The soil water consumption gradient under different treatments coincided with the fitted root length gradient.