The implementation of unsuitable tillage practices has the potential to disrupt the structure integrity of the ploughed layer, as well as to influence the physical parameters of the soil. The application of a reasonable tillage method has been demonstrated to result in an improvement in the physical quality of the soil. Three autumn tillage practices have been implemented at the Dongyang Experimental Station of Shanxi Agricultural University since 2016: no-tillage with straw mulch (NTS), autumn rotary tillage with straw incorporation (RTS), and autumn plough tillage with straw incorporation (PTS). The impact of autumn tillage practices on soil physical quality in the 0–30 cm profile of spring corn fields was evaluated following the corn harvest in 2018 and 2019. The results showed that compared to the NTS treatment, the application of RTS was found to have decreased significantly by 9.6%–24.2% in soil bulk density, while it increased significantly by 12.8%–34.0% in total porosity and by 43.5%–146.4% in macroporosity at a depth of 5–10 cm. In comparison to the NTS treatment, the adoption of PTS was found to decrease significantly by 10.7%–30.5% soil bulk density, while it increased significantly by 9.9%–42.7% the total porosity and 23.1%–202.8% the macroporosity at a depth of 0–10 cm. Furthermore, the soil microporosity significantly increase of 7.5%–11.1% under the RTS treatment at the 0–5 cm soil depth and 7.7%–11.2% under the PTS treatment at the 10–20 cm soil depth. Soil physical quality index (SQI) significantly increase under the RTS and PTS treatments, with a 41.26% and 57.57% improvement, respectively, in comparison to the NTS treatment. In summary, the adoption of autumn tillage with straw return (RTS and PTS) demonstrated a reduction in soil bulk density, an increase in soil porosity, macroporosity, and a promotion of capillary porosity, and promoted the improvement of soil physical quality on the Eastern Loess Plateau when compared to no-tillage with straw mulch (NTS).

Cabbage cultivation has been observed to significantly hinder the growth of subsequent crops in the cold, arid regions of Shanxi Province. To investigate the allelopathic effects of cabbage (Brassica oleracea L. var. Capitata L.) on seed germination and seedling growth of three crops commonly cultivated in such areas, we studied the effects of water extracts from air-dried cabbage leaves on cocozelle, kidney bean, and corn. Experiments were conducted using both petri dish filter paper and pot culture methods to simulate natural conditions. The results indicated that cabbage leaf water extracts at concentrations of 0.01-0.04 g·mL^-1 significantly inhibited seed germination. At higher concentrations (0.06-0.08 g·mL^-1), the extract markedly suppressed seedling growth in all three crops (p < 0.05), with the degree of inhibition increasing alongside concentration. Radicle elongation in cocozelle and corn was more strongly inhibited than germ elongation at the same extract concentration, In contrast, kidney bean showed greater inhibition of germ elongation than radicle elongation at 0.04 g·mL^-1. Malondialdehyde (MDA) content was elevated in kidney bean and corn seedlings treated with cabbage extract, indicating oxidative stress. At extract concentrations of 0.06-0.08 g·mL^-1, antioxidant enzyme activities, such as antioxidase superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were enhanced in all three crops. The comprehensive allelopathic inhibition followed the order: cocozelle > corn > kidney bean. The differences appear to be related to the changes in MDA content and antioxidant enzyme activity. Based on these findings, rotating cabbage and kidney bean may help reduce negative allelopathic effects. It is also recommended to remove the entire aboveground portion of cabbage during harvest to reduce allelochemical residues in the soil and minimize their inhibitory impact on subsequent crops.

Reducing nitrogen (N) fertilizer input while sustaining maize yield and alleviating nitrogen leaching is a significant challenge due to economic and practical feasibility, as well as the environmental friendliness of this process. However, it remains unclear whether reducing nitrogen by using a blend of slow/controlled-release nitrogen fertilizer (SCRNF) with urea at an equal nitrogen rate can achieve the desired yield and mitigate nitrogen leaching. A field experiment consisting of four treatments (240 kg·N·hm⁻², 100% urea, CK; 240 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF, N100%; 192 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF under 20% N reduction, NR20%; 144 kg·N·hm⁻², 50% N from urea and 50% N from SCRNF under 40% N reduction, NR40%) was conducted in Shanxi from 2019 to 2021. In this study, we explored the effects of a mixture of SCRNF and urea on grain yield, yield components, main agronomic traits, nitrogen partial factor productivity, and content of nitrate/ammonium nitrogen in soil in maize under decreasing amounts of nitrogen fertilization. The results showed that the mixture of SCRNF and urea can improve spring maize yield under reduced nitrogen input, with its yield and yield component factors generally performing better than those of the control. The yield of the NR20% treatment was highest in 2020 and 2021, increasing by 8.8% and 11.7% over CK, respectively; the NR20% and NR40% treatments had no significant impact on the main agronomic traits of spring maize, such as plant height, leaf area, shoot biomass, and SPAD value of the ear leaf, compared with CK; the NR20% and NR40% treatments significantly (p < 0.05) enhanced nitrogen partial factor productivity but reduced nitrate and ammonium nitrogen in 0~200 cm soil over the three years compared with CK. Therefore, reducing nitrogen input by 20% with 50% N from urea and 50% N from biodegradable film-coated urea was an appropriate nitrogen fertilizer management measure for mitigating environmental risks without compromising maize yield in North China.