沿江平原稻麦轮作系统维持钾素平衡和作物高产的钾肥运筹研究

在安徽沿江平原的稻麦轮作试验结果表明,施用钾肥可明显增加稻麦产量,但过多施用钾肥,产量呈现下降;除最高施钾处理外,水稻的钾肥效率也随施钾量的增加而提高,小麦则呈现相反的趋势。稻麦施钾收益差异与钾肥效率变化趋势一致;水稻和小麦地上部钾吸收量随着施钾量的增加,也呈上升趋势。水稻和小麦各处理籽粒氮、磷吸收量均高于秸秆,而秸秆钾吸收量明显高于籽粒;随着钾肥投入的增加,水稻和小麦钾吸收量也明显呈上升趋势,水稻收获后各处理钾素均出现亏缺,但随着施钾量的提高,钾素亏缺程度减轻;小麦施钾(K2O)117 kg/hm2以上时,农田钾素出现相应盈余。水稻或稻麦合计,钾肥利用率均随着施钾量增多呈明显下降趋势。从保证稻麦高产高效,维持土壤钾素肥力考虑,水稻施钾(K2O)156 kg/hm2、小麦施钾117 kg/hm2可作为类似生产条件农区的钾肥推荐用量。

Study on Potassium Strategy to Maintain Crop High Yield and Potassium Balance in Cropland Under Rice-wheat Rotation Systems

A field experiment under the rice-wheat rotation was conducted in Plain along the Yangtze River in Anhui. The results indicated that the yields of rice and wheat were enhanced with the increasing of potassium rate, whereas the yields decreased with excessive potassium fertilizer application. Except for the highest potassium rate treatment, potassium fertilizer efficiency of rice was also enhanced with the increase of potassium fertilizer, while there was an opposite trend for wheat compared with rice. Moreover, the difference of potassium fertilizer income exhibited a similar trend in potassium fertilizer efficiency under the rice-wheat rotation system. K absorption in aerial part increased with the improvement of potassium fertilizer rate. N and P absorption in grain for all the treatments under the rice-wheat rotation system was significantly higher than the straw whereas there was higher K absorption in straw compared with grain. With the improvement of potassium fertilizer, the absorption of straw and grain for rice and wheat exhibited a significantly increasing trend. In addition, potassium for all treatments in the farmland system showed a deficit after rice harvesting. However, the deficit was mitigated with the increasing of potassium rate. Moreover, potassium in the farmland exhibited a surplus pattern in the wheat growing season when the application rate of potassium was more than 117 kg/hm2. The potassium fertilizer efficiency showed an obvious decreasing trend with the increase of potassium rate. Therefore, it was preliminarily concluded that the application rate of potassium 156 kg/hm2 and 117 kg/hm2 for rice and wheat respectively was a prefer choice for fertilization strategy in order to guarantee high yield and maintain soil potassium fertility in the similar regions.