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设施蔬菜种植已经成为高寒地区一种重要的土地利用方式,研究设施蔬菜土壤质量演变规律对高寒地区菜地养分管理和土壤质量提升策略以及蔬菜产业可持续发展规划具有重要意义。在西藏拉萨地区分别选取种植1年、5年和10年的设施菜地,并以农田、草地为对照,测定并比较土壤质量指标变化情况。结果表明,高寒地区设施菜地土壤EC值均高于农田和草地;但pH值低于草地,并随着种植年限的增加而显著降低。在0～15 cm土层,农田和菜地土壤有机质、C/N比值低于草地,而在15～30 cm土层,5年、10年设施土壤有机质、C/N比值显著高于1年设施种植土壤以及农田和草地。设施菜地体系增加了0～15 cm与15～30 cm土层土壤全氮的含量。与农田和草地相比,设施菜地土壤铵态氮、硝态氮、有效磷和可交换性钾出现明显累积现象,特别是5年和10年设施菜地。由此可见,在目前管理措施下,高寒地区设施菜地在连续种植5年后,土壤出现严重酸化和养分不平衡现象,应采取有效措施防止土壤质量退化。
Planting vegetables has become an important land use pattern in the alpine region. Studying on the evolution law of vegetable soil quality is of great significance to the strategies of nutrient management and soil quality improvement in vegetable fields and the sustainable development planning of vegetable industry in the alpine region. In the Lhasa area of Tibet, the vegetable plots were planted for 1 year, 5 years and 10 years respectively. The farmland and grassland were taken as control to determine and compare the changes of soil quality index. The results showed that the soil EC value of the vegetable garden in the alpine region was higher than that in the farmland and the grassland, but the pH was lower than that in the grassland, and decreased significantly with the increase of the planting time. Soil organic matter and C / N ratio of farmland and vegetable field in 0 ~ 15 cm soil layer were lower than grassland, while soil organic matter and C / N ratio of soil in 15 ~ 30 cm soil layer, 5 and 10 years were significantly higher than 1 year Facilities for planting soil and farmland and grassland. The vegetable garden system increased soil total nitrogen in 0 ~ 15 cm and 15 ~ 30 cm soil layers. Compared with farmland and grassland, the soil ammonium nitrogen, nitrate nitrogen, available phosphorus and exchangeable potassium in the vegetable field show obvious accumulation phenomenon, especially 5 years and 10 years of vegetable fields. Thus, under the current management measures, after five years of continuous vegetable cultivation in the alpine region, the soil shows serious acidification and nutrient imbalance, and effective measures should be taken to prevent soil quality degradation.