Line sowing and deeper rotary tillage improve seedling establishment and wheat yield in rice–wheat rotation

Abstract

Wheat (Triticum aestivum L.) yield is primarily limited by puddled and wet soil under the rice–wheat rotation system. This study was conducted to determine whether seedling establishment of wheat could be improved through adjusting sowing and tillage methods. The effects of broadcast or line sowing and shallow or deeper rotary tillage on the wheat seed distribution and germination in different soil layers, the variations of soil water content, and wheat growth characteristics were investigated at the Yangtze River basin, China. The results showed that compared to broadcast sowing, the seed germination rate of line sowing was increased by 5%–7% due to the more vertically uniform distribution of seeds in the 0- to 15-cm soil layer; furthermore, tiller number, aboveground biomass, leaf area index, relative leaf chlorophyll content, and root number were significantly higher under line sowing. Consequently, the wheat yield obtained using line sowing significantly increased by 9%–13% compared to using broadcast sowing. Compared to shallow rotary, deeper rotary not only improved the above values but also decreased soil water content by 5%–11% in 0- to 20-cm soil layers at the seedling stage, which was beneficial to the emergence of post-rice wheat seeds. The wheat yield under deeper rotary was 5%–12% higher than under shallow rotary. Among all treatments, the best performance of seed distribution and germination, wheat growth, and yield was observed for the combination of line sowing and shallow rotary. Therefore, it can be considered a favorable practice to improve seedling establishment and wheat growth in the rice–wheat rotation system.