北京西瓜主产区养分管理与连作障碍因子分析

Analysis of nutrient management and continuous cropping obstacle factors for the main watermelon production areas in Beijing

实地调查了北京3个西瓜主产区中22个村51个日光温室和春秋棚的养分管理情况,分析了土壤有机质含量、养分含量、pH、电导率(EC)、微生物和酚酸类物质含量指标,采用主成分分析法探究了西瓜连作障碍成因。结果表明,生产中化肥严重超量,有机肥以畜禽粪肥为主,肥料运筹随意。西瓜主产区土壤多为中高肥力等级,养分富集明显,土壤出现了明显的酸化、盐类物质积聚、微生物群落紊乱、酚酸类物质累积的问题。西瓜连作障碍受土壤因子影响大小顺序为放线菌、真菌>有效磷、化感物质>pH、EC>细菌、速效钾。因此,西瓜连作障碍是土壤微生物失衡、磷钾富集、酚酸类物质累积、土壤酸化和土壤次生盐渍化综合作用的结果。

In this paper,the nutrient management of 51 greenhouses,spring and autumn sheds in 22 villages in the 3 main watermelon producing areas in Beijing was investigated.Soil organic matter content,nutrient content,pH,electricity conductivity(EC),microorganisms and the contents of phenolic acid substances were analyzed to determine the impact of watermelon continuous cropping obstacle factors by principle component analysis.The results showed that chemical fertilizer amount seriously excessive,organic fertilizer mainly based on livestock manure and random addition of fertilizer applications,was very common during production.Most of the soil fertility in the main watermelon producing areas belonged to the classes of medium to high fertility,with significant nutrients enrichment and obvious acidification,salts accumulation,microbial community disorder and phenolic acid accumulation.The order of watermelon continuous cropping obstacle factors affected by soil factors were actinomycetes,fungi>available phosphorus,phenolic acid>pH,EC>bacteria,available potassium.Therefore,the main obstacle for watermelon continuous cropping was the result of combined causes of soil microbial imbalance,phosphorus and potassium enrichment,total phenolic acid substances accumulation,soil acidification and secondary soil salinization.