钾肥用量对优质粳稻钾素积累利用及稻米品质的影响

 以武香粳14号和武育粳3号为材料，研究了钾肥用量对优质粳稻群体钾素积累利用和稻米品质的影响。结果表明，钾肥一次性基施，水稻群体吸钾量在K2O用量为12.8 kg/667m2时最大，过量施钾却降低了群体吸钾量，稻谷吸钾量随钾肥用量的增加而增大，增幅则逐渐降低；优质粳稻群体最大吸钾数量和比例出现在拔节至抽穗阶段，但不施钾肥和过量施钾，造成拔节前吸钾比例较大，从而抑制有效穗数；钾肥一次性基施，以N∶K2O为1∶0.8对优质粳稻产量构成和品质性状影响最佳，有较高的成穗率和结实率，显著降低稻米垩白度和直链淀粉含量，同时钾素生理效率、农艺效率较大；钾肥的穗肥追施比一次性基施，能够明显增加拔节至抽穗的吸钾数量和比例，提高实粒数、结实率和产量，降低稻米垩白度和直链淀粉含量，提高胶稠度，改善稻米品质，并显著提高钾素利用效率。

Effects of Potassium Fertilizer Application Rates on Plant Potassium Accumulation and Grain Quality of Japonica Rice

A three-year experiment was conducted in order to examine the effects of potassium (K) application rates on plant K accumulation, K use efficiency and grain quality of japonica rice (Wuxiangjing14 and Wuyujing3) from 2000 to 2002 in Dongtai, Jiangsu, China. When K fertilizer was applied as basal dressing, K uptake of rice population amounted to maximum at the K2O application rate of 12.8 kg/667m2 and excessive-fertilization decreased population K uptake, grains K absorption always increased with the increase of K fertilizer application rate, only the increment extent decreased gradually. Potassium uptake by rice population peaked in the growth season from the elongation stage to the heading stage. Non-fertilization and excessive-fertilization enhanced the proportion of plant K uptake before the elongation stage, but reduced effective panicles. With one-time application of K fertilizer as basal dressing, the highest grain yield and quality occurred at the level of 1∶0.8 of N∶K2O ratio, which significantly increased the percentage of earbearing tiller and setting percentage and K physiological and agronomy efficiencies. Also, low chalkiness degree and amylose content were found at this level. Compared to one-time application of K fertilizer as basal dressing, fertilization as panicle fertilizer caused increases in plant K uptake and proportion from elongation stage to heading stage, the number of filled grain, the setting percentage and gel consistency. Moreover, K fertilization as panicle fertilizer significantly decreased chalkiness degree and amylose content, resulting in considerable high grain yield and quality.