Varied previous crops on improving oilseed flax productivity in semiarid Loess Plateau in China

To investigate the effects of crop rotation on oilseed flax growth and yield, three season experiments were carried out in semi-arid area of Dingxi, Gansu from 2017 to 2019. The designed 6 rotational systems were FFF (flax-flax-flax), PFF (potato-flax-flax), WPF (wheat-potato-flax), FPF (flax-potato-flax), PWF (potato-wheat-flax) and FWF (flax-wheat-flax). Flax growth and yield investigation results showed that crop rotation increased leaf area duration, dry matter accumulation, seed nitrogen accumulation, water and nitrogen used efficiency, compared with continuous cropping of flax. Flaxseed yields in rotation systems were 22.23%–44.11% greater than those of continuous cropping system. Those in wheat and potato stubbles had higher tiller number (21.43% and 29.46%), more branches (14.24% and 6.97%), effective capsules (26.35% and 28.79%), higher water use efficiency (40.26% and 33.5%), higher nitrogen partial factor productivity (33.85% and 31.46%) and dry matter (41.98% and 25.47%) than those in oilseed flax stubble. It concluded that crop rotation system was an effective measure for oilseed flax productivity in semi-arid area by improving yield components and promoting biomass.