Effects of different potassium application rates on yield, quality and physiological characteristics of dryland winter wheat

A field trial was carried out in arid experimental area of Mengjin county, Henan province to examine the effects of different potassium fertilizer rates on yield, quality and physiological characteristics of winter wheat. The results showed that applying proper rate of potassium fertilizer could increase wheat grain yield, seed quality and photosynthetic properties. In the range of K2O 0–225 kg/ha, the effective tillers, seed numbers per ear and 1000-grain weight of wheat all increased with potassium fertilizer rate. Compared with K0, application of potassium fertilizer could improve wheat seed lysine concentration and milling ratio by 10.8%–13.5% and 2.7%–11.8%, respectively, increase wheat flour Sedimentation value, Development and Stability time by 4.3%–13.3%, 23.5%–41.2% and 26%–34%, respectively, and decrease wheat flour softening degree by 28.6–31.6%. The treatment with K2O 150 kg/ha could increase the nitrate reductase activity, but the reductase activity decreased when the potassium fertilizer rate exceeded this level. Additionally, in the range of K2O 0–300 kg/ha, increase of potassium fertilizer resulted in the rise of GPT enzyme activity, chlorophyll content and PSII quantum efficiency in wheat leaves, but the value of these indexes decreased with plant growth. Potassium accumulation in wheat plant increased with potassium fertilizer rates, but potassium fertilizer recovery rate decreased. The highest potassium fertilizer recovery rate (43.3%) was obtained when 75kg/ha potassium fertilizer (K2O) was applied.