Modelling variety dependant least limiting water range: assessing the limits to root elongation in field soil.

压实被列为影响许多英国土壤的主要问题之一，并可能限制作物产量。压实会影响构成田间土壤的土壤颗粒和孔隙的整体网络，减少孔隙空间，影响土壤的持水能力和水力特性。土壤的质地和含水量也会影响土壤的硬度。如果土壤太硬，根系无法穿透，缺乏氧气或处于缺水条件下，根系伸长就会受到限制。一般植物/根对这些可变特性的响应可以用图形表示为最小限制水分范围（LLWR，见图：特定土壤中不显著限制植物生长的水分范围，使用土壤强度（SS）、萎蔫点（WP）和缺氧（OD）等标准生长限制因子计算。）这种计算考虑了土壤强度、缺氧和水分亏缺的平均极限。然而，不同作物品种的根系伸长对水分亏缺和土壤强度的响应差异较大。这些差异的基础是根系性状的差异，以及这些性状与孔隙结构、水分有效性和土壤强度的关系（例如，在压实土壤中，边缘细胞有助于伸长）。因此，植物性状的有效性与土壤结构之间存在着内在的联系。本项目的目的是建立一个基于LLWR可视化方法的模型，该模型允许根据生根性状考虑根与土壤相互作用对单个品种的影响。该模型将有助于评估品种对土壤耕作的反应差异是否与特定品种的限制水分范围的潜在差异及其对复杂土壤的反应有关。

Compaction is listed as one of the major issues affecting many UK soils and can limit crop yields. Compaction affects the integral network of soil particles and pores that comprise field soil, reducing the pore space and affecting the water holding capacity and the hydraulic properties of soil. The soil texture and moisture content can also influence the hardness of the soil. Root elongation is restricted if the soil is too hard for the roots to penetrate, lacks oxygen or is under water deficit conditions. The response of an average plant / root to these variable properties can be captured graphically as the least limiting water range (LLWR, See Figure: the range of water in a specific soil that does not significantly limit plant growth, calculated using standard growth limiting factors of soil strength (SS), wilting point (WP) and oxygen deficiency (OD). )This calculation takes into account average limits of soil strength, oxygen deficiency and water deficit. However crop varieties differ particularly in their root elongation responses to differences in water deficit and soil strength. These differences are underpinned by variances in root traits and how these relate to the pore structure, water availability and soil strength (e.g. Border cells assist in elongation in compacted soil). There is therefore an integral link between plant trait effectiveness in assisting in plant performance and the soil structure. The aim of this project is to develop a model based on the LLWR visual approach that allows the effect of root: soil interactions on individual varieties to be taken into account based on the rooting traits. The model will assist in assessing whether differences in variety responses to soil tillage are linked to underlying variances in the limiting water ranges for the specific varieties and their response to complex soils.