Shi Duopeng, Ye Zizhuang, Li Huitong, Lyu Shenqiang, Wang Linquan, Zhou Chunju
College of Natural Resources and Environment, Northwest A＆F University, Yangling 712100, Shaanxi, China.
College of Life Sciences, Northwest A＆F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2023 Feb;34(2):442-450. doi: 10.13287/j.1001-9332.202302.013.
The effects of nitrogen fertilizer and biochar on topsoil quality in the drylands of northwest China were studied in field trials for two years. A split plot design with two factors was adopted, with five nitrogen rates (0, 75, 150, 225 and 300 kg N·hm) as main plots, and two rates of biochar (0 and 7.5 t·hm) as submain plots. We collected soil samples at 0-15 cm depth after two years of winter wheat-summer maize rotation and measured physical, chemical, and biological properties. The minimum data set (MDS) was established by using principal component analysis and correlation analysis to analyze the responses of soil quality to nitrogen fertilizer and biochar addition. The results showed that the combined application of nitrogen fertilizer and biochar could improve soil physical properties, increase macroaggregate content, reduce soil bulk density, and increase soil porosity. Both fertilizer application and biochar application had a significant effect on soil microbial biomass carbon and nitrogen. The application of biochar could improve soil urease activity and the contents of soil nutrients and organic carbon. Six out of 16 indicators (urease, microbial biomass carbon, total phosphorous, total nitrogen, pH, and available potassium) relating to soil quality were used to construct MDS, and soil quality index (SQI) was calculated. The variation range of SQI was 0.14-0.87, with that of 225 and 300 kg N·hm nitrogen application combined with biochar application being significantly higher than other treatments. Soil quality could be significantly improved by application of nitrogen fertilizer and biochar. Interactive effect was observed, which was particularly stronger under high nitrogen application rate.
通过两年的田间试验，研究了氮肥和生物炭对中国西北旱地表土质量的影响。试验采用两因素裂区设计，主区设置5个施氮量水平（0、75、150、225和300 kg N·hm），副主区设置2个生物炭施用量水平（0和7.5 t·hm）。经过冬小麦-夏玉米两年轮作后，采集0-15 cm深度的土壤样品，测定土壤的物理、化学和生物学性质。利用主成分分析和相关性分析建立最小数据集（MDS），以分析土壤质量对氮肥和生物炭添加的响应。结果表明，氮肥与生物炭配施可改善土壤物理性质，增加大团聚体含量，降低土壤容重，提高土壤孔隙度。施肥和施用生物炭对土壤微生物生物量碳和氮均有显著影响。施用生物炭可提高土壤脲酶活性以及土壤养分和有机碳含量。选取与土壤质量相关的16项指标中的6项（脲酶、微生物生物量碳、全磷、全氮、pH值和速效钾）构建MDS，并计算土壤质量指数（SQI）。SQI的变化范围为0.14-0.87，其中施氮量为225和300 kg N·hm且配施生物炭处理的SQI显著高于其他处理。施用氮肥和生物炭可显著改善土壤质量。观察到交互效应，在高施氮量条件下交互效应尤为明显。
