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采用分室根箱试验,研究了旱作(油菜)及水作(水稻)条件下红壤性水稻土根区与非根区土壤不同形态钾素变化特征。结果表明,无论旱作还是水作,根区与非根区土壤水溶性钾和交换性钾含量均有不同程度的降低,且根区降低幅度最大,与非根区相比差异达显著水平。根区对作物吸钾量的贡献最大,旱作和水作分别占39.6%和37.4%。非根区水溶性钾和交换性钾含量(y)与距根区距离(x)线性拟合达显著相关,距根区越近,含量越小。种植作物前后土壤各形态钾素含量变化状况表明,旱作时油菜吸收的钾主要来源于水溶性钾,其次是交换性钾;水作时水稻吸收的钾主要来源于交换性钾,其次是水溶性钾,水作促进了交换性钾的释放。当根区水溶性钾含量降低时,非根区钾逐渐向根区迁移,距根区距离越近迁移量越大,水作可促进非根区钾向根区的迁移。旱作时,由于非根区水溶性钾向根区转移速度较慢,根区土壤非交换性钾向水溶性钾转化,被作物吸收利用;而水作前后根区土壤非交换性钾含量变化不明显。
The effects of different forms of K in soils on root growth and non-root growth of paddy soils were studied under dry (canola) and water (paddy) conditions by using chamber root box experiment. The results showed that the contents of water-soluble potassium and exchangeable potassium in root-zone and non-root-zone soil all decreased to different extents, and the root zone decreased the most, and the difference was significant compared with non-root zone. The root zone contributed the most to crop potassium uptake, with dry land and water land accounting for 39.6% and 37.4% respectively. The non-root zone water soluble potassium and exchangeable potassium content (y) and the distance from the root zone (x) linearly correlated up to significant, the closer to the root zone, the smaller the content. The results showed that the potassium uptake by rape mainly came from water-soluble potassium, followed by exchangeable potassium before and after crop cultivation. Potassium absorbed by rice during water-harvesting mainly came from exchangeable potassium followed by water-soluble Potassium, water promote the exchange of potassium release. When the content of water-soluble potassium in the root zone decreased, the non-root zone potassium gradually migrated to the root zone, and the closer the distance to the root zone, the greater the migration. As a result, water could promote the migration of non-root zone potassium to the root zone. In the dry farming, the non-exchangeable potassium was transformed into soluble potassium in the root zone and absorbed by the crop due to the slower transfer of water-soluble potassium to the root zone in the non-root zone. However, the content of non-exchangeable potassium in the root zone increased Not obvious.