Effects of potassium application on the distribution，utilization efficiency of potassium in rice and soil potassium balance
为宁夏引黄灌区水稻钾肥合理施用提供参考，2013～ 2014年以“节 3号”水稻为试验材料，采用单因素随机区组设计研究不同施 K 2O量(0、30、60、90、120 kg/hm2)对水稻产量、成熟期钾素分配比例、钾肥利用效率及土壤钾素平衡的影响，以明确宁夏引黄灌区水稻生产钾肥适宜用量。结果表明:施用钾肥显著提高水稻实粒产量和秸秆产量，平均增产率分别为10.0%、16.9%和19.0%、8.3%，降低空秕粒产量15.9%、34.7%。钾肥用量和水稻籽粒产量之间有极显著的二次曲线关系，两年中最高产量施钾量分别为 129.6、122.5 kg/hm2，最佳经济产量施钾量分别为110.7、111.4 kg/hm2。成熟期水稻秸秆钾素分配比例占 80%以上，其次为实粒 13.2%～ 15.5%、14.0%～ 17.6%，空秕粒低于 3%。实粒钾素累积量两年趋势相似，K 120处理累积量最高，较对照提高 13.9%、50%。空秕粒钾素累积量随着钾肥用量的增加而降低，较对照均有显著差异。水稻地上部钾素累积量两年均以K90处理最高，较对照提高22.5%、20.2%。水稻钾肥利用效率范围为28.6%～46.0%，16.6%～46.3%，两年均为 K 90处理最高。钾肥偏生产力和农学利用率随施钾量的增加而下降。施用钾肥各处理土壤钾素均表现为匮缺，其中120 kg/hm2施钾处理土壤亏缺量最低，较对照分别降低42.7%、39.5%。生产中实施秸秆还田后对土壤的钾素补充范围分别为 160.2～203.1、173.4～ 205.7 kg/hm2，实施秸秆还田后施钾量高于 60 kg/hm2以上可以维持钾素平衡。综合考虑提高水稻产量、钾肥利用效率及维持土壤钾素平衡等因素，在目前的生产条件下，宁夏引黄灌区水稻施钾量在 110.7～ 129.6 kg/hm2范围内为宜。
This paper determined the appropriate amount of potassium fertilizer for rice production to provide a reference forreasonable application of ricepotassium(K)fertilizer in Ningxia Yellow Irrigation Area. The rice variety Jie No. 3 was usedas the test material，and a single factor random group design experiment was conducted to examine the impact of K applicationrates(0，30，60，90 and 120 kg/hm2)on grainyield，distribution proportion of potassium in maturestage，utilizationefficiency of potassium fertilizer and the balance of soil potassium. Results showedthat，compare with the no application ofK，all treatments with K application significantly increased the yield of full grain and straw inrice，the increase rates were10.0%，16.9% and19.0%，8.3%，at the sametime，the production of empty grain was reduced by 15.9% and34.7%， respectively. There is a significant quadratic curve relationship between the amount of potassium fertilizer and rice grain yield.In 2013 and2014，the maximum yield of potassium application was129.6，122.5 kg/hm2，the best economic yield of K was110.7，111.4 kg/hm2，respectively. More than 80% of potassium was distributed in straw at maturity stage ofrice，in solidgrains there was 13.2%～ 15.5% or 14.0%～ 17.6% for different years，and less than 3% distributed in empty grain. The trend of potassium accumulation in rice full grains was similar in the two years. The highest potassium accumulation occurred in K120treatment，which was 13.9% and 50% higher than that in control. The accumulation of potassium in empty grainsdecreased with the increase of potassium fertilizer，which was significantly different with the control. The accumulation of potassium in aboveground parts of rice was the highest in K90treatment for both the twoyears，which was 22.5% and 20.2% higher than that of control. The potassium fertilizer use efficiency of rice ranged from 28.6%～46.0%，16.6%～46.3%， and was the highest in K90 treatment in two years. Partial productivity and agronomic efficiency of potassium fertilizer in rice decreased with the increase of potassium application. Potassium deficiency was found in all treatments of potassium fertilizerapplication，among which 120 kg/hm2was thelowest，which was42.7%，39.5% lower than the control. The soil potassium supplementation range was 160.2～203.1，173.4～ 205.7 kg/hm2 after the straw was returned to the field in production. The potassium application amount with straw return should be higher than 60 kg/hm2 to maintain the potassium balance.Considering comprehensively the factors such as riceyield，potassium fertilizer utilization efficiency and soil potassiumbalance，it is appropriate to apply potassium at 110.7～ 129.6 kg/hm2 in Ningxia Yellow River Irrigation Area under current production conditions.