Physiological-biochemical responses of wheat to blending controlled-release potassium chloride and soluble potassium chloride

The crop yields and potassium use efficiency (KUE) could be enhanced by controlled-release potassium chloride (CRK), yet the effects of blending 50 % CRK and 50 % soluble potassium chloride (BBF), on crop physiologicalbiochemical characteristics were not reported. We carried out a five-year field experiment during 2014-2019 with five K fertilization treatments in a completely randomized block design using wheat (Triticum aestivum. L.) as a testing crop. The results showed that: compared with K1 (full-dose of soluble potassium chloride (KCl)) treatment, the SPAD value and photosynthetic rate of BBF1 (full-dose of BBF) treatment were increased by 7.3-12.2 % and 36.5-59.0 %, respectively, at jointing and grain-filling stages; the auxin and abscisic acid in leaves and roots of BBF1 treatment proliferated by 14.0 %, 27.2 % and 19.5 %, 25.0 %, respectively, at jointing stage; the root total volume and surface area of BBF1 treatment were sharply risen by 80.2 % and 38.8 %, respectively, at jointing stage. The yield and net profit of BBF1 treatment increased by 5.0-19.7 % and 7.2-28.7 %, respectively. With K fertilization rate reduced by 30 %, BBF2 treatment produced almost the same yield as with the 100 % rate of monotypic soluble KCl treatment. This study demonstrated that combining CRK and soluble KCl improved the root physiological characteristics and endogenous hormones of wheat and consequently increased wheat yield.