不同栽培年限日光温室土壤养分累积特性研究

Nutrient Accumulation in the Sunlight Greenhouse Soils with the Different Cultivating Years

测定了陕西关中地区不同栽培年限日光温室土壤养分含量,以评价其土壤养分累积特性。结果表明:测定的日光温室土壤养分及土壤电导率有随温室栽培年限增加而增加的趋势,但10年棚龄的温室各测定指标有所降低。不同测定指标的年平均增长率相比为有效磷>硝态氮>速效钾>电导率>全氮>有机质>铵态氮,其中土壤有效磷、速效钾和硝态氮含量的平均年增加幅度为31.1%、19.2%和17.4%。7年棚龄的日光温室土壤硝态氮的累积最高,累积的硝态氮主要集中在0～40cm土层,40cm以下土壤剖面的累积量呈现逐渐降低的趋势。揭棚休闲的8月份期间土壤剖面各土层硝态氮累积量明显高于7月土壤剖面各土层,说明夏季休闲期间并未发生硝态氮的淋溶,这可能与这一阶段降雨量明显少于正常年份有关。

The nutrients in the soils under solar greenhouses built in different years in Guan-zhong Plain, Shaanxi Province, were determined to evaluate the nutrient accumulation in the soils. The results showed that the accumulation of organic matter, total nitrogen, available phosphorus and available potassium in the solar greenhouse soils was significantly increased with the cultivating year of the greenhouses. However, for the greenhouse with 10-year cultivating history, these indices showed a decreasing trend. The annually increasing rates for the different nutrients were as follows： available P〉NO3^--N〉available K〉electronic conductivity〉total nitrogen〉organic matter〉NH4^＋-N. The annually increasing rates of available P, nitrate and available K were 31.1%, 19.2% and 17.4%, respectively. Nitrate accumulation in 7-cultivating year reached the highest level compared to other cultivating years. The accumulated nitrate was mainly in 0-40 cm soil depth, and decreased significantly with the depth of soil profile. The content of nitrate in soil profiles sampled in August was higher than that in July, indicating the accumulation of nitrate in the fallow period. This was perhaps related to the low precipitation during the fallow period in this year.