施钾量对膜下滴灌甜菜光合性能以及对产量和品质的影响

膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量,于2014—2015年在内蒙古凉城县设K_2O 0、90、180、270和360 kg hm~(–2) 5个施肥处理进行了研究。结果表明,钾素能够提高甜菜的光合性能,如促进株高、叶面积指数、净光合速率的增加;施钾肥180、270和360kghm~(–2)显著提高了叶丛快速生长期甜菜的净光合速率,影响净光合速率的最主要因素是RuBPCase活性,其次是气孔导度,净光合速率与甜菜产量呈极显著正相关。适宜的钾肥用量有利于块根、叶柄和叶片干重的增加及产量增加,但施钾过量,块根干物质分配比例下降,含糖率下降,块根干物质分配比例与甜菜含糖率呈显著正相关。施钾量270 kg hm~(–2)时产量最高, 90 kg hm~(–2)时含糖率最高,当施钾量大于180 kg hm~(–2)时,块根中K~+、Na~+含量增加,大于270 kg hm~(–2)时,块根中α-氨基酸含量增加,施钾量180 kg hm~(–2)时产糖量最高。综合考虑施钾量对膜下滴灌甜菜产量和品质的影响,内蒙古甜菜种植优势区域的钾肥推荐施用量为180 kg hm~(–2)。

Effects of Potassium Application on Photosynthetic Performance,Yield, and Quality of Sugar Beet with Mulching-drip Irrigation

The technology of drip irrigation under mulch is widely used for sugar beet cultivation in cold and arid region of Inner Mongolia. In order to investigate proper potassium application rate and effects of potassium on photosynthetic characteristics, yield and quality on sugar beet with mulching-drip irrigation, a field experiment was conducted at Liangcheng city of Inner Mongolia in 2014-2015 with five treatments (0, 90, 180, 270, and 360 kg ha ^-1)potassium application. The results indicated that potassium could increase the photosynthetic performance of sugar beet, enhancing plant height, leaf area index and net photosynthetic rate. The treatments of 180, 270, and 360 kg ha ^-1 potassium fertilizer increased the net photosynthetic rate, which mainly affected by RuBPCase activity, followed by stomatal conductance. Proper potassium application benefited dry weigh increasing of roots, shoots and leaves, and yield increasing. But excessive application of potassium fertilizer significantly decreased the dry matter distribution to roots, and sugar content. There were the highest yield 270 kg ha ^-1 potassium application, the highest sugar content in the treatment of 90 kg ha ^-1 potassium and the largest economic benefits in the treatment of 180 kg ha ^-1potassium. When the application amount of potassium was more than 180 kg ha ^-1, the contents of K ⁺ and Na ⁺ increased in root. When the application amount of potassium was more than 270 kg ha ^-1, the content of α-amino acid in roots increased. According to the effects of potassium on sugar beet yield and quality, the recommended potassium fertilizer rate was 180 kg ha ^-1 in the main sugar beet planting area in Inner Mongolia.