基于长期定位监测下的近35年广西耕地质量演变趋势研究

Evolution Trend of Cultivated Land Quality Change in Guangxi in the Last 35 Years Based on Long-term Location Monitoring

耕地质量是科学施肥的重要依据。本文基于广西35个耕地质量长期定位监测点1984年~2018年监测数据,建立评价方法,研究了广西近35年来耕地质量演变趋势,有针对性地提出施肥和土壤培肥建议,以期为促进土壤科学研究、合理地进行区域农田培肥管理提供支持。结果显示,在当地常规施肥及管理耕作条件下,广西全区耕地土壤全氮、有效磷、速效钾含量总体呈上升趋势,监测后期比监测初期分别提高了16%、176%、63%,而土壤有机质含量和pH保持相对稳定。不同土地利用方式农田土壤全氮、有机质、pH变化趋势不同;旱地土壤有机质、pH呈下降态势,全氮保持平稳,而水田土壤有机质、pH平稳,全氮含量显著升高。主成分分析结果表明,35年间土壤综合肥力整体呈上升趋势,影响土壤综合肥力上升的主要因素是全氮、速效钾、有机质含量。为此,提出的该区土壤培肥的主要措施是在平衡施用氮磷钾肥的基础上增施有机肥和推广秸秆还田技术。

Cultivated land quality is an important basis for scientific fertilization.Based on 35 long-term monitoring sites of cultivated land quality from 1984 to 2018 in Guangxi, the evolution trend of cultivated land quality in the last 35 years were analyzed, and then fertilization suggestions were put forward,so as to provide support for promoting soil scientific research and carrying out regional farmland fertilization management rationally.The results showed that the contents of total nitrogen(TN), available phosphorus(AP) and available potassium(AK) in the cultivated land in Guangxi under the normal fertilization model were increased by 16%, 176% and 63% in the late monitoring period compared with the early monitoring period, respectively. The content of soil organic matter(SOM) and pH remained relatively stable. The variation trends of soil TN, SOM and pH were different under different land use patterns. SOM and pH were decreased,and TN remained stable in the dry land, while SOM and pH were stable, and TN was increased significantly in the paddy field. Principal component analysis showed that TN, AK and SOM were the key factors affecting the comprehensive soil fertility. In the past 35 years, soil comprehensive fertility was continuously improved. Increasing organic fertilizer and popularizing straw returning technologyshould be applied combined with balancedapplication of N, P and K fertilizers in the area.