西安市郊区日光温室大棚番茄施肥现状及土壤养分累积特性

调查了西安市郊区100余个日光温室栽培番茄的施肥现状,并采集了60个日光温室土壤剖面样品,测定了土壤养分及盐分含量。结果表明,当地番茄的氮磷钾化肥的平均施用量分别为N 600 kg hm-2,623 kg P2O5hm-2和497 kgK2O hm-2。过量施肥特别是过量施用磷肥比较普遍。日光温室土壤0~20 cm和20~40 cm土层有机质、有效磷、速效钾含量均明显高于露地。不同地点日光温室土壤0~100 cm土层硝态氮含量及土壤电导率存在差别,但其含量均高于露地土壤,其中日光温室土壤0~100 cm土层硝态氮含量较露地的增加幅度在127%~433%之间。由于研究地区土壤多发育在河流冲积物上,地下水位埋藏浅,土壤质地相对较粗,因此,不合理施肥引起的土壤养分累积及损失,以及由此带来的环境问题值得关注。

Fertilizers Application and Nutrient Accumulations in Tomato-grown Soils under Greenhouse condition in the Suburban of Xian City

This study surveyed the application of fertilizers in more than 100 tomato-grown greenhouses,and the contents of nutrients and accumulation of salts in 60 soil depth profiles in the suburban of Xian city,Shaanxi,were also determined.The results showed that the average amounts of nitrogen,phosphorus,and potassium fertilizers were N 600 kg hm~(-2),P_2O_5 623 kg hm~(-2) and K_2O 497 kg hm~(-2),respectively.Over-application of fertilizers,especially phosphorus fertilizer,was very serious in the production of tomato cultivation.The levels of organic matter,available phosphorus and potassium in 0~20,and 20~40 cm soil layers were significantly increased in comparison with the soils cultivated under open-field vegetable crops;and the contents of NO_3-N and the EC in 0~100 cm soil profiles were also significantly increased;and the increase rates of NO_3-N in 0~100 cm soil profiles were in the range of 127%~433%.The soil in this region was mainly developed from the sediment of Weihe River,and was with the coarse texture and shallow groundwater table.Therefore,more attention should be paid to the potentially environmental issues induced by the over-accumulation and loss of nutrients from the soil profiles own to the inadequate application of fertilizers.