基于主成分分析的不同轮作施肥模式下赤红壤肥力质量变化

Lateritic Red Soil Fertility Changes under Different Crop Rotation and Fertilization Modes Based on Principal Component Analysis

本研究以南方典型赤红壤区连续5年轮作施肥定位试验点的菜田土壤为材料,定量评价推荐施肥和习惯施肥不同轮作方式下菜田土壤肥力质量的变化。通过主成分分析法对每个轮作周期内的土壤有机质、碱解氮、速效磷、速效钾含量多元肥力指标进行线性变换后计算土壤肥力指标的综合得分,采用欧氏距离作为不同处理肥力之间的差异大小,并对各轮作施肥处理土壤肥力质量进行系统聚类。结果表明,5年不同轮作施肥处理土壤肥力的差异主要表现在碱解氮和速效磷含量上。相同轮作施肥处理的土壤肥力在第一主成分和第二主成分轴上分布相近,同一施肥处理下随轮作年限的延长土壤肥力呈现稳定变化趋势。5年轮作施肥各处理土壤肥力质量综合得分较高的为推荐施肥方式下的菜-菜-稻轮作。因此长期轮作下采用推荐施肥方式有利于赤红壤的培肥作用,菜-菜-稻轮作的土壤肥力质量优于其他轮作施肥处理。

A five-year crop rotation and fertilization fixed experiment was conducted in a typical lateritic red soil region of southern China.Quantitative evaluation was carried out to analyze the effects of recommended fertilization and conventional fertilization under different crop rotation modes on soil fertility in the vegetable fields.The principal component analysis was used to calculate the score of soil fertility indexes after linear transformation of the raw data of soil organic matter,alkali-hydro nitrogen,available phosphorus and available potassium in each crop rotation cycle.The euclidean distance was used to cluster the soil fertility of each crop rotation and fertilization treatment.The results showed that the difference of soil fertility under different crop rotation and fertilization treatments in the five years was mainly manifested in the content of alkali-hydro nitrogen and available phosphorus.The distribution of soil fertility in the first and second principal component axises was similar in the same crop rotation and fertilization treatment group.Under the same fertilization treatment,the soil fertility showed a stable change trend with the extension of crop rotation years.The highest comprehensive score of soil fertility was obtained under the treatment of vegetable-vegetable-rice rotation with recommended fertilization.It could be concluded that the recommended fertilization under long-term crop rotation was beneficial to the fertility improvement of lateritic red soil,and the effect of the vegetable-vegetable-rice rotation was better than that of the other crop rotation and fertilization treatments.