日本虎杖覆盖对连作的影响——日本西阿瓦陡坡土地农业系统传统耕作评价

禾本科物种(例如银草、芦苇)在日本传统的地膜覆盖农业中普遍使用,西阿瓦地区是全球重要的农业遗产系统(GIAHS)所在地。传统上,这里的农民使用银草覆盖农业土壤。但当地农民从长期的经验中了解到,日本虎杖覆盖更适合该地区茄科作物的种植。目前尚不清楚日本虎杖覆盖物为何对茄科作物的种植有益。在本项研究中,我们假设日本虎杖覆盖物可能会有效避免连续种植马铃薯的危害。因为过去每年都会种植两次本地马铃薯,因此,我们调查了日本虎杖覆盖对连续种植马铃薯以及番茄种植后对马铃薯产量的影响。在2018年进行的田间试验中,我们首先在连续马铃薯栽培的土壤和未耕种的土壤中比较了日本虎杖覆盖、银草覆盖和无草覆盖(对照)对马铃薯产量的影响,结果表明日本虎杖覆盖减少了马铃薯产量的降低程度。其次,我们比较了番茄种植后的土壤和未耕种的土壤中的虎杖覆盖和无草覆盖对马铃薯产量的影响,结果再次表明了日本虎杖覆盖减少了马铃薯生长和产量下降的程度。这些发现表明用日本虎杖覆盖有助于避免连续种植马铃薯的风险。

Effect of Japanese knotweed(Fallopia japonica)Mulching on Continuous Potato Cropping:Modern Evaluation of Traditional Japanese Knotweed-mulch Farming in Nishi-Awa Steep Slope Land Agriculture System,Japan

Poaceae species such as silver grass or reed are commonly used in traditional mulch farming in Japan,where the Nishi-Awa area is a Globally Important Agricultural Heritage Systems(GIAHS)site.Farmers here have traditionally used silver grass for mulch farming;furthermore,local farmers have learned from long-standing experience that Japanese knotweed(Fallopia japonica,Polygonaceae)is better for cultivation of solanaceous crops in this area.However,it is unclear why Japanese knotweed mulching is beneficial for cultivation of solanaceous crops.Thus,in this study,we hypothesized that Japanese knotweed mulching may be effective in avoiding hazards associated with continuous potato cropping,as native potato used to be cultivated twice a year in the past.Therefore,we investigated the effects of Japanese knotweed mulching on continuous potato cropping and after tomato cropping,which is another solanaceous crop species.Field experiments were conducted in 2018.First,we compared Japanese knotweed mulching,silver grass mulching and no grass mulching(control)in a soil under continuous potato cultivation and in an uncultivated soil.As a result,the extent of the potato yield decrease was reduced by Japanese knotweed mulching.Secondly,we compared Japanese knotweed-mulching and no grass mulching in a soil after a tomato crop and in an uncultivated soil.The extent of decrease in potato growth and yield was also reduced by Japanese knotweed mulching.These findings indicate that mulching with Japanese knotweed helped to avoid the risks associated with continuous potato cropping.