Effect of optimal irrigation, different fertilization, and reduced tillage on soil organic carbon storage and crop yields in the North China Plain

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Abstract

The objective was to evaluate the effect of different agricultural managements on soil organic C (SOC) storage and crop yields in the North China Plain (NCP). The study was conducted at five experimental stations. Different agricultural managements were designed, including optimal (OPT) and conventional (CON) irrigation and fertilization treatments, different amounts of fertilization application and residue-return treatments, and different tillage practices. Compared to the CON treatment, SOC storage in the 1 m soil profile under the OPT treatment increased by 2 t ha–1, 8 t ha–1, and 4 t ha–1 at Quzhou, Wuqiao, and Dongbeiwang sites, respectively. The annual increasing rate of SOC storages in the topsoil (0–30 cm) under the OPT treatments at Wuqiao (0.88 t ha–1 y–1), Quzhou (0.93 t ha–1 y–1), and Dongbeiwang (1.86 t ha–1 y–1) were higher than those in the CON treatments at Wuqiao (0.15 t ha–1 y–1), Quzhou (0.54 t ha–1 y–1), and Dongbeiwang (0.28 t ha–1 y–1), but the difference of grain yields between the two treatments was not significant. The SOC storage in 1 m soil profile in the no-tillage treatment with standing residue return (NT1) at Luancheng increased by 5 t ha–1 and 7 t ha–1 compared with rotary-tillage (RT) and conventional-tillage (CT) treatments, respectively, but the crop yield under no-tillage treatment was the lowest. While at Quzhou site, it increased by 3 t ha–1 in the top 40 cm soil under the NT treatment compared to the CT treatment. The annual increasing rate of SOC storage in the top 30 cm under NT treatment was also the highest (1.08 t ha–1 y–1 at Luancheng, 1.86 t ha–1 y–1 at Quzhou), compared to the other tillage treatments. At Henghsui site, the combination of the highest fertilization application and highest residue-return treatments got the highest SOC storage and the highest crop yields. We concluded that the agricultural management practices, such as optimal irrigation and fertilization treatment, the higher fertilization, residue return and RT, has significant impact on the SOC storage and agricultural sustainability in the NCP.

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