The Effect Of Different Cultivation Modes On The Growth And Development Of Lotus Root And The Study On The Control Effectiveness Of Lotus Rot Disease

Lotus root is one of the varieties of significant aquatic vegetables in China,its cultivation scale and economic benefits are among the forefront of aquatic crops.In the current,the cultivation of lotus root still had practical problems that endanger the high quality and yield of lotus roots,such as excessive fertilization,partial application of nitrogen fertilizer,lack of standard planting,and unscientific disease control.However,in the process of lotus root cultivation,there are still had practical problems such as excessive fertilization,partial application of nitrogen fertilizer,lack of standard planting specifications,and unscientific disease prevention and control.The facility cultivation of lotus root can achieve precise fertilization,improve the utilization rate of land resources,create a good growth environment for lotus root,and isolate the spread of certain diseases.Therefore,this thesis screening the optimal fertilization amount of facility lotus roots cultivation and the optimal ratio of organic fertilizer to partially replace chemical fertilizers,then we explored the best planting specifications of lotus roots and the biological control effectiveness of lotus root rot disease.This study provides a theoretical basis for reducing chemical fertilizer and increasing efficiency and efficient cultivation and management of lotus roots in northern of China.The results are as follows:1.The application of fertilizer rate of 120 kg·667m^-2 was better than other treatments,and the yield reached the highest,which was 1375.17 kg·667m^-2lotus roots.Compared with the application of 60,80,100,140 kg·667m^-2 lotus root special slow-release fertilizer,its yield increased by 79.0%,66.0%,32.5%,7.28%.2.The organic fertilizer instead of 30%and 10%controlled-release fertilizer nitrogen content are better than application of 120 kg·667m^-2 controlled-release fertilizer,they had significantly improved growth and yield quality.Among them,the yield of lotus root in L2 treatment is the highest,reaching 2734.7 kg·667m^-2,which is51.9%higher than that of CK treatment.With the increase in the proportion of alternative controlled-release fertilizers,the content of organic matter in the soil has increased compared with the initial value,and the physical and chemical properties of the soil have been improved to a certain extent after the application of organic fertilizers.3.Within the planting specification of 0.22～0.88 m²,as the planting area of a single lotus root increases,the growth of the lotus root also increases,and the number of leaves increases significantly.Among them,the growth of the lotus root,the length of the main lotus root and the nutritional quality of the lotus root treated with 0.77 m² and0.88 m² were significantly improved compared with other treatments.The total yield of lotus root with a single planting area of 0.88 m² was the highest,reaching 1540.77kg·667m^-2lotus roots.The 0.22～0.77 m² treatment increased production by 140.6%,230.0%,120%,86.3%,45.3%,and 20.3%.Therefore,the compositive performance of0.88 m² treatment is better to recommended as the specification for high-quality lotus root planting in the facility cultivation.4.The control experiments of lotus rot disease showed that the inhibition rates of Trichoderma harzianum and Bacillus subtilis on pathogenic bacteria were 61.3%and51.3%.Field experiments have found that the combination of Trichoderma harzianum and Bacillus subtilis has a significantly better control effect on lotus rot disease than any single biocontrol bacteria.The incidence of T1（adding Trichoderma harzianum）is20.0%,and T2（adding Bacillus subtilis）is 33.3%,and T3（compound liquid with Trichoderma harzianum and Bacillus subtilis）only had 10.0%.The disease index was16.7%,25.0%,and 11.7%.