ABSTRACT

Emergence of unharvested potatoes that survived during winter becomes source for nematodes and diseases, causing serious weed problems in rotational crop fields. Herein, we describe frost killing of unharvested potatoes in potato–wheat rotation fields using snow compaction ‘yuki-fumi’ under multiple climate conditions. The effect of snow compaction in controlling volunteer potato over winter wheat was verified in 17 farm fields in Hokkaido, Japan from 2015–16 to 2017–18. A reduction in the temperature of soil under ‘yuki-fumi’ was slower than that under snow removal ‘yuki-wari’, which was used in previous studies. However, snow compaction achieved a substantial reduction in volunteer potato sprouting in most of the experimental sites. The sprouting of volunteer potatoes was reduced in snow-compaction blocks with soil temperatures below −3°C. For winter wheat sowing in potato–wheat rotation, the soil is tilled to a shallower depth than that for other crops, and thus, unharvested potato tubers are not pushed down during field preparation for wheat sowing. Consequently, even if the soil temperature drops slightly, snow compaction can regulate the sprouting of volunteer potatoes. Snow compaction did not exert any apparent influence on wheat growth and grain yield. At some sites with a deeper snowpack, development of soil frost and reduction in soil temperature did not progress with continued snow compaction owing to fallen snow. We validated the usefulness of snow compaction as a countermeasure to control volunteer potatoes in snowy regions.

摘要

冬季幸存的未收获马铃薯的出现成为线虫和疾病的根源，在轮作作物田中引起严重的杂草问题。在这里，我们描述了在多种气候条件下使用雪压实“ yuki-fumi ”在马铃薯-小麦轮作田中未收割的马铃薯的除霜作用。2015-16年至2017-18年间，日本北海道的17个农田证实了雪压实对控制志愿马铃薯的控制作用超过了冬小麦。“ yuki-fumi ”下土壤温度的降低速度比除雪“ yuki-wari ”下土壤的降低速度慢”，这在以前的研究中曾使用过。但是，在大多数实验地点，积雪压实使志愿者马铃薯的发芽率大大降低。在土壤温度低于-3°C的积雪压实块中，志愿马铃薯的发芽减少。对于以马铃薯-小麦轮作方式播种的冬小麦，土壤耕作的深度要比其他作物的耕作浅，因此，未播种的马铃薯块茎在进行小麦播种的田间准备工作期间不会被压低。因此，即使土壤温度略有下降，雪压实也可以调节志愿马铃薯的发芽。雪压实对小麦的生长和籽粒产量没有任何明显的影响。在一些积雪较深的地方，由于降雪，持续压实雪，土壤霜冻的发展和土壤温度的降低没有进展。我们验证了积雪压实作为在多雪地区控制志愿马铃薯的对策的有用性。