黄土高原旱地土壤质量评价指标研究

Content of soil mineral nitrogen as influenced by sample extraction and preservation

  • 摘要: 基于设置在陇中黄土高原半干旱区的长期定位试验, 运用综合评价模型, 定量评价了小麦→豌豆双序列轮作系统6种不同耕作方式对土壤质量的影响。结果表明, 采用加权综合法和加乘法则对土壤质量进行综合评价, 能够较好地反映土壤质量的实际情况, 敏感地反映耕作方式对土壤质量的影响。运用逐步判别分析法对6种不同耕作方式传统耕作(T)、免耕作(NT)、传统耕作秸秆还田(TS)、免耕秸秆覆盖(NTS)、传统耕作地膜覆盖(TP)、免耕地膜覆盖(NTP)下29项土壤属性指标进行筛选, 建立了包括团粒结构、全氮、速效氮、有机质、蔗糖酶活性、作物产量、种植纯收益和产投比8项因子的简化评价指标体系。原始评价指标体系下2种轮作序列土壤质量指数排序均为NTS>TS>NTP>NT>TP>T; 简化评价指标体系下豌豆→小麦轮作序列土壤质量指数排序为NTS>TS>NTP>NT>T>TP, 而小麦→豌豆轮作序列土壤质量指数排序为NTS>TS>NT> NTP>T>TP。进一步相关分析和方差分析表明, 应用逐步判别分析法建立的简化指标体系具有较高的代表性, 可适用于黄土高原半干旱区土壤质量评价。

     

    Abstract: Based on long-term field experiments at Dingxi in the western Loess Plateau, the effects of different agricultural measures on soil quality were studied using an integrated assessment model. A total of 6 agricultural measures with 2 tillage systems and 3 ground-cover forms were used. The agricultural measured included conventional tillage (T), no-tillage (NT), conventional tillage with straw incorporation (TS), no-tillage with straw mulching (NTS), conventional tillage with plastic-film mulch (TP) and no-tillage with plastic-film mulch (NTP). The experiment was conducted in two rotation sequences. Sequence 1 started with pea followed by spring wheat (P→W) whereas sequence 2 started with spring wheat followed by field pea (W→P). The results showed that soil quality evaluation with integrated-weighted and addition-multiplication methods reasonably reflected actual soil conditions, and the effect of tillage variations on soil quality. The 8 most sensitive indicators were selected from a total of 29 assessment indictors vial discriminative analysis. The selected indicators were used to evaluate soil physical quality, fertility, health and land productivity in the semi-arid areas of the Loess Plateau. These 8 indicators included soil aggregates, organic matter, total nitrogen, available nitrogen, invertase activity, grain yield, net income and output/input ratio. Based on the 29 indicators, the order of soil quality index (SQI) ranked from high to low was NTS, TS, NTP, NT, TP and T in both rotation sequences. Again based on the 8 indicators, the orders of SQI ranked from high to low were NTS, TS, NTP, NT, T and TP in the P→W rotation sequence, and NTS, TS, NT, NTP, T and TP in the W→P rotation sequence. The results of the 2 assessment systems were similar and highly correlated. This indicated that the 8 indicators were sufficiently representative of the soil conditions in the western Loess Plateau.

     

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