Subsoil compaction in arable farming caused by increasingly heavy machinery results in increased subsoil strength and reduced aeration and water flow. This can restrict root growth and reduce crop yield. To mitigate these effects of subsoil compaction, we included a deep-rooted catch crop of fodder radish (Raphanus sativus var. oleifera) in a rotation of spring barley (Hordeum vulgare). The objective was to determine the effect of subsoil compaction on root growth and grain yield of barley, and to investigate the creation and use of biopores for subsequent root growth. Studies were carried out in 2013–2016 in a soil compaction experiment established in 2010 on a sandy loam. The soil had for four consecutive years (2010–2013) been compacted with multi-passes in an 8 Mg wheel load treatment (M8) or had not been compacted (Control). Spring barley was grown every year and fodder radish was grown as a catch crop from harvest to winter in 2013–2016. Penetration resistance to 90 cm depth was measured in 2015 at a soil water content near field capacity. Root growth and biopore reuse were investigated using horizontal minirhizotrons installed at 30, 50 and 70 cm depth from 2013–2016. Spring barley grain yield was recorded annually. We found that M8 caused critical subsoil compaction with penetration resistance peaking at 3.5 MPa in the upper subsoil (30−40 cm depth). Subsoil compaction reduced root growth by c. 50 % at 30 cm depth and barley yields by 6–8 % compared to the Control in three years after cessation of the compaction treatment. The number of biopores that were reused were higher for fodder radish than for spring barley, 4.1 % and 3.1 %, respectively, but did not differ between compaction treatments. Our study displayed a marked, negative residual effect of soil compaction on above- and belowground crop growth. There was no tendency towards a recovery within the years studied (1–3 years after compaction). Severe subsoil compaction is a widespread problem and therefore we call for more studies on the spatio-temporal dynamics of the creation and subsequent use of biopores for root growth as these are essential for the recovery of compacted subsoils.

由于越来越重的机械设备而导致的耕作中的地下土壤压实导致地下土壤强度的提高以及通气和水流的减少。这会限制根系生长并降低作物产量。为了减轻地基压实的这些影响，我们包括饲料萝卜（的根深蒂固的闲作物萝卜变种油茶春大麦的旋转）（大麦）。目的是确定地下土壤压实对大麦根系生长和籽粒产量的影响，并调查生物孔的形成和使用，以用于随后的根系生长。研究于2013年至2016年在2010年建立的沙质壤土土壤压实实验中进行。在8 Mg车轮载荷处理（M8）中，土壤已连续四年（2010-2013）进行多道压实，或没有压实（对照）。从2013年到2016年，每年从收获到冬季，每年都会种植大麦春季萝卜和饲料萝卜。2015年在接近田间持水量的土壤含水量下测量了90厘米深度的抗渗透性。从2013–2016年开始，使用安装在30、50和70厘米深度的水平微型根管对根生长和生物孔再利用进行了调查。每年记录大麦春季单产。我们发现，M8引起了严重的地下土压实，在上部地下土（30-40 cm深度）中的渗透阻力达到3.5 MPa的峰值。下层土壤压实使根生长减少了c。在停止压实处理后的三年内，在30 cm深度处50％的大麦产量比对照组大6-8％。饲料萝卜的可重复利用的生物孔数比春季大麦的高，分别为4.1％和3.1％，但压实处理之间没有差异。我们的研究表明土壤压实对地上和地下作物生长具有明显的负面影响。在研究的年份（压实后的1-3年）内没有恢复的趋势。