Effects Of Different Cultivation Practices On Rice Root System And Rhizosphere Soil Environment

Rice is an important food crop in my country.By 2030,China’s rice production must increase by 20%from the current level to meet the development of population and society.The increase of rice yield is overly dependent on a large amount of input of water and fertilizer resources,which often leads to high yield and low water and fertilizer utilization efficiency in production.One of the main factors limiting the high yield and efficient use of nutrients in single-season rice is improper cultivation practices.Through a lot of research,domestic scholars have formed a number of important cultivation and management models.These models optimize various management methods for different rice varieties.integration and give full play to the production potential of rice.By constructing a high-yield and nutrient-efficient cultivation technology system for rice,the synergistic improvement of yield and resource utilization efficiency can be achieved.In this paper,the Yongyou 2640,Wuyunjing 24（2019）,Yangdao 6,and Jinxiangyu 1（2020）varieties were used as materials for field experiments.Irrigation and increased application of cake fertilizers are treated with 6 kinds of cultivation practices,and research is carried out from the aspects of rice population characteristics,root system,soil,microorganisms（bacteria）,etc.,in order to study the impact of different cultivation practices on rice root system and soil environment,and provide a theory for rice high-yield cultivation.basis and practical guidance.The main results are as follows:1.Yield and composition factorsThe yields of Yongyou 2640 under the treatments of densification and nitrogen reduction,precise irrigation,and increased application of cake fertilizer were 12.80 t hm-2,13.35 t hm-2,and 13.55 t hm-2·Compared with the local conventional treatment（control）,the increases were respectively were 6.3%,11.4%,and 13.4%.The yields of Wuyunjing 24 under the three treatments were 10.10 t hm-2,11.00 t hm-2 and 11.60 t hm-2,which were 2.6%,11.6%and 17.8%higher than the control,respectively.The yields of Yangdao 6 under the three treatments were 10.37 t hm-2,11.08 t hm-2,and 11.49 t hm-2,with an increase of 10.90%,18.50%,and 22.89%,respectively.The yields of Jinxiangyu 1 under the three treatments The yields were 10.82 t hm-2,11.61 t hm-2,11.93 t hm-2,and the yield increases were 6.34%,14.05%,and 17.19%,respectively.The improvement of the yield of the above three cultivation measures was mainly due to the significant increase of the total spikelet amount,especially the cultivation treatment of increasing the application of cake fertilizer.2.Agronomic and physiological traitsCompared with the control,the treatments of densification and nitrogen reduction,precise irrigation,and increased application of cake fertilizer improved the rice tillering rate,leaf area index and dry matter accumulation at main growth stages,high-efficiency leaf area index at heading stage,and nitrogen use efficiency.（agronomic use efficiency of nitrogen fertilizer,physiological use efficiency of nitrogen fertilizer,absorption and utilization efficiency of nitrogen fertilizer,partial productivity of nitrogen fertilizer,productivity of nitrogen rice）.It shows that the optimized cultivation measures can improve the agronomic and physiological characters of rice,and then improve the quality of the population,which is ultimately conducive to the formation of high yield.3.Root Morphology and Physiological CharacteristicsCompared with the control,the treatments of densification and nitrogen reduction,precise irrigation,and increased application of cake fertilizer increased the root dry weight,root diameter,root length,root oxidative power,root injury flow,and organic acids in root exudates in the main growth stages of each variety.Total amount,zeatin and zeatin riboside content in roots.It indicated that the optimized cultivation measures improved the morphological and physiological characteristics of rice roots in the underground,strongly supported the growth of the above-ground groups,and coordinated the relationship between the root and cap,thereby promoting the improvement of rice yield and efficiency,4.Rhizosphere and non-rhizosphere soil nutrients,enzymes,microorganisms（bacteria）Under each treatment,the content of nutrients（nitrogen,phosphorus,potassium）and urease activity in the rhizosphere soil in the main growth period of each variety were significantly lower than those in the non-rhizosphere soil,the pH in the rhizosphere soil was slightly lower than that in the non-rhizosphere soil,and The activity of sucrase was higher than that of non-rhizosphere soil.The bacterial community structure of each treatment did not change,but only changed the bacterial abundance and proportion of each phylum.The bacterial a diversity in the rhizosphere soil was higher than that in the non-rhizosphere soil during ear differentiation.Compared with the control,the treatments of densification and nitrogen reduction,precise irrigation,and increased application of cake fertilizer increased the soil nutrient content,pH value,nitrate nitrogen content,invertase and urease activities,and significantly decreased the ammonium nitrogen content in the soil.These results showed that the optimized cultivation measures improved soil nutrients and enzyme activities,increased bacterial community diversity,and improved soil environment,which was ultimately beneficial to the realization of high yield and high efficiency of rice.