Mechanical and Hydric Stress Effects on Maize Root System Development at Different Soil Compaction Levels
Mechanical and Hydric Stress Effects on Maize Root System Development at Different Soil Compaction Levels
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DOI：
10.3389/fpls.2019.01358
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发表时间：
2019-10-29
影响因子：
5.6
通讯作者：
Leitner, Daniel
中科院分区：
文献类型：
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作者：
de Moraes, Moacir Tuzzin;Debiasi, Henrique;Leitner, Daniel
土壤机械阻力、通气性和水分利用率直接影响植物根系的生长。这项工作的目的是通过模拟根部生长，同时考虑 Oxisol 中这些应力的动态，来确定机械和液压应力对玉米根部伸长的影响。玉米作物在四种压实水平下种植（土壤凿刻、免耕系统、拖拉机运输的区域和收割机运输的区域），我们提出了一个新模型，可以区分机械压力和水压力。确定了深度达 50 厘米的四个压实级别的根长密度剖面、土壤容重和土壤保水曲线。此外，还对玉米的籽粒产量和芽生物量进行了量化。新模型首次利用玉米作物的现场数据描述了玉米生长过程中的机械和水分胁迫。一维和二维根长密度的模拟显示与现场条件下测量的值足够一致。模拟可以确定土壤物理条件与玉米根系生长之间的相互作用。与免耕系统相比，由于收割机运输和土壤凿凿造成的压实，谷物产量下降。作物周期中机械和水分胁迫的发生导致根部生长减少，对于农业交通地区，主要应力是机械应力，而对于土壤凿凿地区，主要应力是水应力。将机械和水压力纳入根系生长模型有助于预测未来情景，将土壤生物物理模型与天气、土壤和作物反应相结合将有助于改善农业管理。
Soil mechanical resistance, aeration, and water availability directly affect plant root growth. The objective of this work was to identify the contribution of mechanical and hydric stresses on maize root elongation, by modeling root growth while taking the dynamics of these stresses in an Oxisol into consideration. The maize crop was cultivated under four compaction levels (soil chiseling, no-tillage system, areas trafficked by a tractor, and trafficked by a harvester), and we present a new model, which allows to distinguish between mechanical and hydric stresses. Root length density profiles, soil bulk density, and soil water retention curves were determined for four compaction levels up to 50 cm in depth. Furthermore, grain yield and shoot biomass of maize were quantified. The new model described the mechanical and hydric stresses during maize growth with field data for the first time in maize crop. Simulations of root length density in 1D and 2D showed adequate agreement with the values measured under field conditions. Simulation makes it possible to identify the interaction between the soil physical conditions and maize root growth. Compared to the no-tillage system, grain yield was reduced due to compaction caused by harvester traffic and by soil chiseling. The root growth was reduced by the occurrence of mechanical and hydric stresses during the crop cycle, the principal stresses were mechanical in origin for areas with agricultural traffic, and water based in areas with soil chiseling. Including mechanical and hydric stresses in root growth models can help to predict future scenarios, and coupling soil biophysical models with weather, soil, and crop responses will help to improve agricultural management.