Modeling biopore effects on root growth and biomass production on soils with pronounced sub-soil clay accumulation
Modeling biopore effects on root growth and biomass production on soils with pronounced sub-soil clay accumulation
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DOI：
10.1016/j.ecolmodel.2013.02.016
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发表时间：
2013-05-10
影响因子：
3.1
通讯作者：
Krauss, Gunther
中科院分区：
文献类型：
--
作者：
Gaiser, Thomas;Perkons, Ute;Krauss, Gunther
具有底土粘粒积累的土壤占全球陆地表面的20%以上。这些土壤的特点是土壤质地的垂直差异和表层土以下体积密度的增加，这反过来又影响到根系渗入底土。生物孔隙是根系的优先通道，有助于克服高密度土层等物理障碍。将这些关系纳入田间种植系统模型的工作正在进行。本文提出了一种新的方法来模拟生物孔隙对根系发育的影响在土壤粘粒积累在小区尺度。在这种方法中，生物孔隙对根伸长速率的影响取决于容重和生物孔隙-根生长阈值（MPRT），生物孔隙-根生长阈值是土壤强度对根穿透的阻力被生物孔隙的密度完全抵消的生物孔隙体积。该方法被集成到模型框架SIMPLACE（先进作物和生态系统管理的科学影响评估和建模平台）的模型解决方案。采用逆模型方法，根据多因子田间试验的观测结果，对春小麦的MPRT进行了参数化。观察到的生物孔密度（直径>2 mm）在300和660孔m（-2）之间（相当于0.38-0.83%的体积比例），这取决于前茬作物。观测到的土壤容重在1.31和1.62克厘米-3之间。对于春小麦，不同土层根系密度模拟值与实测值的最佳拟合值为0.023 m（3）m（-3）（相当于土壤体积的2.3%）。平均模拟总地上生物量对MPRT敏感，当MPRT在0.023和0.032 m（3）m（-3）之间时，模拟结果与观测值的一致性最好。在同一地点的参数化模型的情景模拟表明，生物孔隙的生物量生产的短周期春小麦时，长时间的干旱发生的重要性。模拟允许一个粗略的量化的生物孔的影响相对于根伸长速率和生物量生产在地块规模的潜力扩展到田间规模。(c)2013爱思唯尔有限公司版权所有。
Soils with subsoil clay accumulation account for more than 20% of the global land surface. These soils are characterized by vertical differences with respect to soil texture and increasing bulk density below the topsoil, which in turn affects root penetration into the subsoil. Biopores are preferential pathways for roots and assist in overcoming physical barriers like high density soil layers. An integration of these relationships into cropping systems models at the field scale is on-going. This paper presents a new approach to model the effect of biopores on root development in soils with clay accumulation at the plot scale. In this approach, the effect of biopores on root elongation rate depends on bulk density and on a biopore-root growth threshold (MPRT), which is the biopore volume at which the resistance of soil strength to root penetration is completely offset by the density of the biopores. The approach was integrated into a model solution of the model framework SIMPLACE (Scientific Impact assessment and Modeling PLatform for Advanced Crop and Ecosystem management). MPRT was parameterized for spring wheat using the inverse modeling approach based on root observations from a multi-factorial field experiment on a Haplic Luvisol. The observed biopore densities (>2 mm diameter) were between 300 and 660 pores m(-2) (equivalent to a volumetric proportion of 0.38-0.83%) depending on the preceding crop. Observed soil bulk densities ranged between 1.31 and 1.62 g cm(-3). For spring wheat, the best fit between simulated and observed root densities in different layers was obtained with a MPRT of 0.023 m(3) m(-3) (equivalent to 2.3% of soil volume). The mean simulated total above ground biomass was sensitive to MPRT and had the best agreement with observed values when a MPRT between 0.023 and 0.032 m(3) m(-3) was used in the simulations. Scenario simulations with the parameterized model at the same site demonstrate the importance of biopores for biomass production of short-cycle spring wheat when prolonged dry spells occur. The simulations allow a rough quantification of the biopore effects with respect to root elongation rate and biomass production at the plot scale with the potential to be extended to the field scale. (c) 2013 Elsevier B.V. All rights reserved.