不同生长年限老芒麦根际土壤肥力特征

Comprehensive evaluation of rhizosphere soil fertil⁃ ity of Elymus sibiricus in different growing years

摘要:

【目的】探讨生长年限对老芒麦根际土壤肥力的影响，为老芒麦种植提供土壤养分管理和施肥参考。【方法】以种植于青海省海晏县“青牧 1 号”老芒麦根际土壤为研究对象，连续 2 年(2018 年和 2019 年)监测不同生长年限 3 个样地(样地 1：3 龄到 4 龄；样地 2：4 龄到 5 龄；样地 3：7 龄到 8 龄)老芒麦根际土壤化学特征变化规律。【结果】2019 年 3 个样地 pH 值分别较 2018 年降低了 2. 77%、2. 25% 和 2. 24%，速效钾含量分别减少了 18. 08%、48. 24% 和 41. 32%。2 年之间样地 2 和样地 3 有机质变化差异不显著，而全钾分别较 2018 年升高了 11. 36% 和 10. 78%。样地 1 和样地 2 全磷含量均降低，但样地 3 含量升高了 33. 59%。样地 3 全氮降低显著且较 2018 年减少了 30. 65%；3 个样地老芒麦根际土壤过氧化氢酶、蔗糖酶和碱性磷酸酶活性随生长年限增加均呈显著降低趋势(P＜0. 05)，而土壤脲酶活性则明显增加了 29. 70%、13. 41% 和 118. 08%。【结论】主成分分析表明，3 龄和 4 龄老芒麦根际土壤肥力较高，全氮和蔗糖酶对老芒麦根际土壤质量贡献最大。

Abstract:

【Objective】 The effects of growth years on rhizosphere soil fertility were explored，which could pro‐ vide reference for soil nutrient management and fertilization for Elymus sibiricus planting.【Method】 The rhizosphere soils of Elymus sibiricus cv. Qingmu No. 1 planted in Haiyan County，Qinghai Province in different growing years (plot 1，plot2 and plot 3 represent 3 to 4 years old，4 to 5 years old and 7 to 8 years old，respectively) were used as materials. The change trends for soil fertility were investigated in two consecutive years (2019 and 2018).【Result】 The soil pH of three plots decreased by 2. 77%，2. 25% and 2. 24% while available potassium decreased by 18. 08%， 48. 24% and 41. 32%，respectively，in comparison of those in 2019 and 2018. The contents of organic matter of plot2 and plot3 had no significant difference between 2019 and 2018. However，the total potassium increased by 11. 36% and 10. 78%，respectively. The contents of total phosphorus of plot1 and plot2 decreased while plot 3 increased by 33. 59% in 2019 compared with those in 2018. The total nitrogen content of plot 3 significantly decreased by 30. 65% in 2019 than 2018. Moreover，catalase，sucrose and alkaline phosphorus activities of three plots showed decreasing trend (P＜0. 05) while urease activity in 2019 increased by 29. 70%，13. 41% and 118. 08%，respectively，compared with those in 2018.【Conclusion】 Principal component analysis showed that rhizosphere soil fertility of Elymus sibiri- cus was higher in 3 ‐ and 4 ‐ year old plants and the total nitrogen content and sucrose activity could play important roles in rhizosphere soil quality of Elymus sibiricus.