Potassium Absorption Efficiency Of Maize And Its Response Mechanism To Soil Basic Productivity

The high quality and high yield of maize is the key to ensure Chinese food security and stability.Potassium is a necessary nutrient element to maintain the normal growth and development of maize,and plays an important role in improving the lodging resistance of maize.Facing the increasingly serious problems of potassium resource poverty,the decline of potassium absorption efficiency,resource waste and environmental pollution in the process of maize production in China,this study aims to improve the potassium absorption efficiency of maize.On the one hand,by tapping the potential of maize,this study evaluated the potassium efficiency of maize inbred lines and hybrid combinations of different genotypes to clarify their physiological characteristics of potassium efficiency.The good genotypes with low potassium tolerance were improved by using their genetic characteristics,so as to provide a theoretical basis for the screening of potassium efficient inbred lines and the identification of potassium efficient hybrid combinations;On the other hand,by tapping the production potential of the soil itself,this thesis analyzed the effects of straw returning and combined application of potassium fertilizer on topsoil soil potassium level in three ecological areas of Inner Mongolia,and clarified the response mechanism of maize potassium absorption efficiency and yield to soil basic productivity,in order to achieve the sustainable high quality,high yield and high efficiency of spring maize.The main results are as follows:1.In this study,the tolerance index,yield and potassium absorption efficiency of maize were analyzed by cluster analysis,50 maize inbred lines with different genotypes were divided into 17 high potassium absorption efficiency types,16 medium potassium absorption efficiency types and 17 low potassium absorption efficiency types;48 maize hybrids and 4 control varieties were divided into 12 high potassium efficiency types,20medium potassium efficiency types and 20 low potassium efficiency types,which laid a foundation for further studying the physiological characteristics,genetic basis and potassium efficient breeding of different genotypes of maize.2.In this study,through the correlation analysis between potassium absorption efficiency of maize grain and various indexes,stem diameter,grain protein content,potassium content of leaf and stem at maturity,potassium content of grain at maturity,potassium absorption efficiency of leaf and stem at maturity were selected as the screening indexes of potassium absorption efficiency of maize grains,which provided a basis for the screening of potassium efficient maize inbred lines and the identification of potassium efficient maize hybrid combinations.3.Through the analysis of combining ability of maize yield and potassium absorption efficiency,6 dominant hybrid combinations were selected in this study,which were PHG86×NP49,Zong-31×Zheng58,B123×G303,4676A×Chang7-2,792×Chang7-2,4676A×NP49.These hybrid combinations can be used for in-depth study of high potassium and high efficiency maize varieties.4.Through the study of topsoil soil in three ecological areas from east to west in Inner Mongolia,the results showed that straw returning combined with potassium fertilizer inputted 166.54 kg/hm²-196.76 kg/hm²of K₂O into the soil,which was equivalent to the application of 3.70-4.37 times of pure potassium.Straw returning combined with potassium fertilizer could improve soil basic productivity by optimizing soil potassium level.5.The improvement of soil basic productivity could not only meet the demand for soil potassium for the normal growth and development of spring maize,but also effectively supplement the consumed available potassium content in the soil,maintain the balance of soil nutrients,provide a good environment for the growth and development of maize roots and the grain potassium absorption,and increase the maize yield by 26.11%-30.44%.Finally,the synergistic improvement of potassium absorption efficiency and yield of spring maize can be popularized and applied in Inner Mongolia.