Bengough AG
Soil-Plant Dynamics Unit, Scottish Crop Research Institute, Dundee, DD2 5DA, U.K.
J Theor Biol. 1997 Jun 7;186(3):327-38. doi: 10.1006/jtbi.1996.0367.
A combined root growth and water extraction model is described that simulates the affects of mechanical impedance on root elongation in soil. The model simulates the vertical redistribution of water in the soil profile, water uptake by plant roots, and the effects of decreasing water content on increasing soil strength and decreasing the root elongation rate. The modelling approach is quite general and can be applied to any soil for which a relation can be defined between root elongation and penetrometer resistance. By definition this excludes soils that contain a large proportion of continuous channels through which roots can grow unimpeded. Root elongation rate is calculated as a function of the penetrometer resistance which is determined by the soil water content. Use of the model is illustrated using input data for a sandy loam soil. The results confirm reports in the literature that the depth of water extraction can exceed the rooting depth. The increase in mechanical impedance to root growth due to this water extraction restricted the maximum rooting depth attained, and this limited the depth of soil from which a crop could extract water and nutrients. This study highlighted the lack of published data sets for single crop/soil combinations containing both the strength/root growth information and the hydraulic conductivity characteristics necessary for this type of model. Copyright 1997 Academic Press Limited
本文描述了一个根系生长与水分提取相结合的模型，该模型模拟了机械阻抗对土壤中根系伸长的影响。该模型模拟了土壤剖面中水分的垂直再分布、植物根系对水分的吸收，以及含水量降低对土壤强度增加和根系伸长率降低的影响。该建模方法具有相当的通用性，可应用于任何能定义根系伸长与贯入阻力之间关系的土壤。根据定义，这排除了含有大量连续通道、根系可不受阻碍生长的土壤。根系伸长率是根据由土壤含水量决定的贯入阻力来计算的。利用砂壤土的输入数据说明了该模型的应用。结果证实了文献中的报道，即水分提取深度可能超过生根深度。由于这种水分提取导致根系生长的机械阻抗增加，限制了所能达到的最大生根深度，进而限制了作物能够提取水分和养分的土壤深度。本研究突出表明，缺乏针对单一作物/土壤组合的已发表数据集，这些数据集应包含此类模型所需的强度/根系生长信息以及水力传导特性。版权所有1997学术出版社有限公司
