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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。
Through the collection, analysis and pot experiment of the soil samples from yellow soil in Guizhou yellow soil, the changes of nutrients and their effects on plant growth and nutrient uptake were studied. The results showed that under the conditions of fertilization in high quality tobacco fields, the available nutrients accumulated in different degrees after long-term continuous cropping of flue-cured tobacco with the order of P> S> K> Mg> Ca. In the application of nitrogen and phosphate fertilizer on the continuous cropping of potash fertilizer, the potassium content of tobacco leaves increased significantly, but the content of calcium and magnesium in tobacco leaves decreased significantly, while the application of nitrogen, phosphorus and potassium fertilizer on the basis of tobacco Or magnesium, the content of nitrogen and potassium in tobacco leaves tended to decrease. For phosphorus and sulfur, continuous use of more phosphorus and sulfur in continuous cropping with high level of phosphorus and sulfur could obviously reduce the content of magnesium in tobacco leaves. The decrease of P and S application had no significant effect on the yield of tobacco in the fields with higher P, K and S levels. However, with the application of K fertilizer at the same cropping stage, increasing the amount of Mg fertilizer could obviously increase the yield of tobacco leaves Yield.