Objective  Effects of methods in tilling the field in the regions of cold climate in China on rice quality and yield as well as soil organic matters were investigated for improved cultivation.

  Method  Four different methods of tillage after rice harvest in preparation for the following planting season including (A) turning ground soil over in autumn, (B) tilling ground in autumn and breaking soil clusters in following spring, (C) plowing ground and pulping spent straws into soil in autumn, (D) returning and pulping stubbles to ground in autumn were employed for the testing. Effects of these varied method on the quality and yield of rice grown on the lots and the organic matters in the soil (i.e., total carbon in humus, total carbon of humic substances, and carbons of humic acid, fulvic acid, and humins) were monitored for a single factor randomized block experiment.

  Results   Of the tried tillage methods, (D) delivered the highest contents of humus-related carbons in soil on an increasing trend with time, as the indicators were higher in 2020 than in 2019. The rice yield under (C) was significantly higher by 1.45 % over (B), 2.23 % over (A) and 1.50 % over (D). There was no significant difference due to the varied tillage on the processed grain quality, such as appearance and amylose content. However, (D) seemed to be better than (C) in that regard.

  Conclusions  Tilling by plowing ground and pulping spent straws into soil in autumn (C) benefit the rice production in the following season, which was, therefore, recommended for practicing in the cold regions, such as the northeastern part of China. In addition, since (D) brought about the greatest improvement on the content of organic matters in the field soil, an autumn turning and pulping ground soil with stubbles was deemed to bring about a far-reaching effect for sustainable ecology.