长期连作黄壤烟地养分变化及其施肥效应分析

通过贵州黄壤烟地大田土壤样品的采集、分析以及盆载试验 ,对连作烟地养分的变化及其对植株生长与养分吸收的影响进行了研究。结果表明 :在优质烟区的施肥条件下 ,烤烟长期连作后土壤有效养分出现不同程度的积累 ,其大小顺序为P >S >K >Mg >Ca。在施用氮、磷肥基础上对连作烟地增施钾肥后 ,烟叶含钾量明显上升 ,但烟叶的钙和镁含量则明显下降 ,而在施用氮、磷、钾肥基础上对烟地增施钙或镁后 ,烟叶的氮和钾含量有下降的趋势 ;对磷和硫水平较高的连作烟地继续施用较多的磷和硫 ,能明显降低烟叶中镁的含量。在P、K、S水平较高的烟地上 ,减少P、S施用量对烟叶产量未产生明显影响 ;而对连作烟地增施钾肥的同时 ,增施适量的镁肥能明显地提高烟叶的产量。

Nutrient changes of yellow soil successively planted flue-cured tobacco and its fertilization effect

The change of soil nutrients with successive planting and effect of its on growth and nutrient absorption of tobacco plants were studied by collecting and analyzing soil samples in field and pot trial. The results showed that 1) with the successive planting of flue\|cured tobacco, the available nutrients in the soil were accumulated yearly under normal fertilization, especially P, S, and K, 2) the concentration of Ca and Mg in tobacco leaves were obviously reduced under applying K fertilizer while the application rates of N and P fertilizers were constant, and that the concentration of K in leaves had the trend of reduction with applying Ca or Mg fertilizer. Applying Mg fertilizer to the soils, with higher P, S, and K, was promoted the growth of flue cured so that to increase the yields.