No abstract

Tillage management is a direct factor in affecting soil quality, which is a key factor in sustainable agriculture. However soil quality evaluation needs significant manpower, material resources and time. To explore the sensitive indicators of soil quality affected by tillage management, eight soil physical and chemical properties under three tillage managements, including plow tillage, subsoiling tillage and rotary tillage, were determined under a long-term experiment in North China Plain. The results showed that subsoiling tillage management had the highest soil organic carbon and total nitrogen in the 0–20 cm layer and the lowest soil bulk density in the 30–40 cm layer. Rotary tillage management had the highest soil water content in the 0–40 cm layer. Meanwhile, compared to 2002, the soil organic carbon, total nitrogen and soil bulk density had varied greatly in 2012, but there was no significant difference between 2012 and 2018. However, other property concentrations tended to increase in 2002, 2012 and 2018. In addition, there was a significant linear relationship between soil quality index and grain yield. Subsoiling tillage management had the highest soil quality index and gain yield both in 2012 and 2018. The soil quality can be evaluated through the sensitive indicator of soil organic carbon, total nitrogen, soil bulk density, total phosphorus and soil water content, which provides a scientific basis for selecting reasonable tillage management and evaluating soil quality in this agricultural production area or other similar areas.

Long-term single tillage causes serious deterioration of land quality and reduction of crop yield. Tillage rotation can alleviate the problems caused by long-term single tillage. However, the effects of different tillage rotations are still very limited. A tillage rotation experiment was conducted in the North China Plain to evaluate the impacts of tillage rotation on soil organic carbon (SOC), soil total nitrogen (STN) and crop yield. There were eight treatments with two main factors: tillage practice (four types: rotary tillage (R, 2002–2017), subsoiling tillage (S, 2002–2017), rotary to subsoiling tillage (RS, 2015–2017) and subsoiling to rotary tillage (SR, 2015–2017)) and straw management (two types: straw return (F) and straw removal (0)). RSF treatment yielded the highest SOC, at 12.53 g/kg.<br /> RSF significantly increased SOC by 41.4% compared to RF, while SRF significantly reduced SOC by 11.1% compared to SF. In addition, RSF significantly increased STN content by 21.7% compared with that under RF. Compared with SF, SRF promoted the uniform distribution of soil nitrogen in the 0–20 cm soil layer. Among the treatments, the RSF treatment yielded the highest SOC stock (SOC_S) and STN stock (STN_S), which were 67.68 t/ha and 6.63 t/ha, respectively. Compared with RF treatment, RSF treatment greatly increased SOC_S, by 31.7%. Both tillage rotation treatments increased STN_S by 13.3% under RSF compared to RF, and by 2.3% under SRF compared to SF. In 2016, the annual yield was highest under RSF treatment at 19.80 t/ha. In 2017, the annual yield was highest under SF treatment at 21.37 t/ha, and next highest under RSF at 20.94 t/ha. In summary, long-term rotary tillage followed by subsoiling tillage combined with straw return (RSF) can significantly increase SOC, STN and crop yield. The rotation of rotary tillage to subsoiling tillage combined with the straw return is an effective measure for improving soil quality and increasing crop yields in the North China Plain.