Abstract A two-year consecutive field experiment was conducted in purple soil in southwest China, to clarify the effects of biochar (0, 10, 20 and 40 t ha −1 , namely, B0, B10, B20 and B40) combined with nitrogen reduction (100%, 80% and 60% of conventional nitrogen application rate, namely, N100, N80 and N60) on soil fertility. The performance of thirty-four indices related to soil chemical, physical and biological properties was evaluated by gray correlation analysis, principal component analysis and cluster analysis to determine the most appropriate mode for soil fertilization, and to identify the main soil environmental factors affecting rapeseed yield under the biochar combined with nitrogen reduction. The results indicated that available phosphorus, geometric mean diameter of water stability, fungi number, and the utilization of sugars, amino acids, polymers and carboxylic acids by microorganisms could be used as the main soil factors affecting rapeseed yield. The highest score of soil quality was observed in N100B10 treatment, followed by N80B10 and N100B20 treatments, which were almost in line with the results of rapeseed yields. Cluster analysis classified 12 treatments into 5 main groups on the basis of the measured parameters, which was mostly consistent with the result of soil quality scores. Considering both economic and environmental benefits, 10 t ha −1 biochar combined with 144 kg ha −1 nitrogen was the best combination to restore crop productivity and soil quality, and to achieve nitrogen decreasing and benefit increasing. This study provided scientific basis for the rational fertilization and scientific management of biochar combined with nitrogen fertilizer in purple soil area of southwest China.
A POVs-based Cu(i)–MOF was synthesized and utilized as a heterogeneous catalyst for the cyclization of CO2with propargylic alcohols to obtain value-added α-alkylidene cyclic carbonates, exhibiting high catalytic activity and sustainability.
Reduction of soil fertility and production efficiency resulting from excessive application of chemical fertilizers is universal in rapeseed-growing fields. The main objective of our study was to assess the effects of biochar combined with nitrogen fertilizer reduction on soil aggregate stability and rapeseed yield and to identify the relationship between yield and soil aggregate stability. A two-factor field experiment (2017-2019) was conducted with biochar (0 (C
Biochar has the potential to effectively improve yield and nitrogen use efficiency (NUE) of upland crops in different soil types. However, it is unclear for rapeseed in purple soil under N reduction. A 2 years field experiment was conducted in southwest China, to evaluate the combined effects of nitrogen (180, 144 and 108 kg ha−1, named N100, N80 and N60, respectively) and biochar (0, 10, 20 and 40 t ha−1, named B0, B10, B20 and B40, respectively) on rapeseed growth, NUE and yield. Compared with B0, B10 significantly improved growth, NUE and yield, while nitrogen reduction had an opposite effect. The better management practices were N80B10 and N100B10, which increased NUE by 10.0% and 10.2%, and grain yield by 16.1% and 21.8%, respectively, compared with N100B0. Path analysis revealed that effective pods and root surface area, root volume had significant and direct path coefficients with variances in seed yield and NUE, respectively. Besides, positive residual effectiveness of biochar was preserved for at least 2 years. This study indicated that B10 could replace 20% nitrogen to promote rapeseed root development and yield formation, thus achieving both high yield and high NUE for at least 2 years in upland purple soil.
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