Effects Of Different Types Of Oxygenators On Germination And Seedling Growth In Water Direct Seeded Rice System

Rice is the main grain crop in China,and direct seeding of rice is gradually becoming the main cultivation method for rice around the world.Among them,water direct seeding is the most widely used method.However,water direct seeding rice is prone to low oxygen stress caused by flooding,leading to problems such as difficult germination,low seedling rate,and slow seedling growth.This study selected six commonly used chemical oxygenators on the market（Shanghaiyu Li’an Granular Oxygen,Zhongmu Jiurun Strong Granular Oxygen,Dongzhu Nongmu Granular Oxygen,Zhongtian Jiade Calcium Peroxide,Youshuangfeng Granular Oxygen,A30KY Long acting Oxygen Enriching Particles）,and screened three oxygenators with better oxygen release effects by comparing their oxygen release time and amount.Further research was conducted on the effects of three selected oxygen enhancers on the germination and seedling growth of water direct seeding rice,as well as their yield increasing effects.The main results are as follows:1.Based on the oxygen release capacity index and referring to the oxygen release time,three oxygen enhancing agents with good oxygen release effects were selected,namely A30KY Long acting Oxygen Enhancing Particles,Zhongtian Jiade Calcium Peroxide,and Zhongmu Jiurun Long acting Particle Oxygen.2.Oxygen enhancers can significantly improve the germination rate,seedling emergence rate,and seedling rate of water direct seeding rice.Among them,A30KY oxygen enhancer has the best oxygen enhancing effect on water direct seeding rice.The germination rate,seedling emergence rate,and seedling rate of water direct seeding rice treated with 1.0 g_·m^-2of A30KY are 46.6%,43.7%,and 10.3%higher than those without oxygen enhancers,respectively.3.Three selected oxygenators can significantly increase the seedling height,leaf length,stem width,root length,root volume,and single seedling dry weight of water direct seeding rice during the three leaf and one heart stage.The amplitude of improvement compared to the control group was 10.7%-22.9%,22.7%-40%,16.7%-33%,20.3%-44.6%,27.6%-61.4%,19.1%-59.6%,157.6%-340%,with the best overall effect being the 1.0g_·m^-2treatment of A30KY long-acting oxygen enhancing particles.4.Three selected oxygen enhancers can significantly improve the root activity,root to shoot ratio,tiller number per unit area,effective panicle and yield of water direct seeding rice during the three leaf one heart stage,with increases of 7.1%-47.6%,24.2%-79.5%,101.1%-208.4%,28.3%-68.9%,33.3%-89.3%compared to the control,respectively.They also promote the synthesis of chlorophyll,but restrict the formation of root aerenchyma.The best comprehensive effect is the 1.5 g_·m^-2treatment of A30KY long-acting oxygen enhancing particles.In summary,using oxygenators to enhance the germination rate and emergence rate of water direct seeding rice seeds can significantly increase,which is beneficial for the growth of water direct seeding rice seedlings.Oxygenation can enhance the root vitality of water direct seeding rice seedlings,promote chlorophyll synthesis,nutrient absorption,and dry matter accumulation,and increase the accumulation of organic matter per unit area.The three treatments with the best comprehensive effects of different oxygenation treatments on direct seeding rice are A30KY-1.0 g_·m^-2treatment of long-term oxygenation particles,followed by A30KY-1.5 g_·m^-2treatment of long-term oxygenation particles,and2.0 g_·m^-2treatment of Zhongtian Jiade-calcium peroxide.Among them,the main oxygenation component of A30KY-long-term oxygenation particles is sodium percarbonate,and the main oxygenation component of Zhongtian Jiade-calcium peroxide is calcium peroxide.