| The key technologies of floating seedling in Chongqing mountainous tobacco area were scattered,incomplete,unsystematic and difficult to implement.From 2019 to 2021,taking Fengjie tobacco-growing area in Chongqing as the experimental object,the key technology system,precise operation process and innovative supervision mode were studied.The effects of different sowing dates,different sowing methods,pest control and water and fertilizer regulation on the improvement of seedling quality were studied.The effects of seedling sowing,temperature and humidity control of seedling bed,and seedling management process optimization on the cost reduction and quality improvement of seedling were explored.The early warning and monitoring mode of the Internet of Things on the improvement of seedling management efficiency was studied.The main conclusions are as follows:1.Study on key technologies for improving the quality of floating seedlingStudy on sowing time.Chongqing mountain tobacco area is very vulnerable to low temperature and cold damage.Premature sowing time will lead to low seedling emergence rate,long seedling age and weak seedlings.The suitable sowing time for low altitude tobacco area(about 800 m above sea level)is about March 5,the suitable sowing time for medium and high altitude tobacco area(1100-1300m)is about March 10,and the suitable sowing time for high altitude tobacco area(> 1300m)is about March 15.During this period,the sowing time is,Tobacco seedlings can reach the standard of strong seedlings in 12 days and 50-55 days,which is conducive to cultivating high-quality tobacco seedlings.Study on sowing method.The precision sowing technology of single hole and single seed had a significant effect on ensuring the consistency of sowing depth and improving the seedling rate.Compared with single hole and double seed sowing,the difference in seedling emergence rate was not obvious,and the seeding emergence uniformity was improved to 98.2% and 5.9%,which reduced the operation of inter-seedling and seedling supplement,and reduced the risk of disease infection and transmission.Study on pest control technology.Considering the occurrence and control of diseases and insect pests in mountainous tobacco areas of Chongqing comprehensively and systematically from the triangle relationship of diseases,a simplified technology system of seedling diseases and insect pests was constructed.The control effect of diseases and insect pests was significantly better than that of conventional pest control technology.The disease plant rate was reduced by 6.54%,no virus disease occurred,and the seedling rate was increased by 3.2%.Compared with the control group,the plant height,stem circumference and maximum leaf length were increased by 1.08 cm,0.34 cm and 0.87 cm,respectively,which had great promotion value.Study on water and fertilizer regulation technology.The water depth test of different nutrient pools proved that the water depth of 7-10 cm was not only conducive to the warming of water body,but also convenient for the operation and management of greenhouse seedling.The standard of nitrogen application rate of well cellar seedlings was 9 mg/plant-11 mg/plant,and the increase of phosphorus and potassium fertilizer in the later stage could promote the increase of total length,surface area,shadow area and root tip number of roots,and improve the quality of tobacco seedlings.The treatment combination of 9 mg nitrogen in the early stage and 15-18 mg phosphorus and potassium fertilizer in the later stage was the best.2.Research on the flow pattern of floating seedling operation and managementResearch on sowing process.Using the ’6216’ precision seeding process could improve the seeding quality of seedlings,and the seeding efficiency could reach 350trays/(person/day).Compared with the random combination seeding,the seeding efficiency increased by 78 trays/(person/day),and the labor saving rate reached 27.97%.Combined with the promotion of single hole and single seed seeding technology,the seeding labor cost could be reduced by CNY 3-4 per 667 m2.Research on temperature and humidity control of seedling bed.According to the management idea of ’early rising,central control,late protection’,the highest temperature during the day from sowing to reporting seedling stage should be controlled within 28 °C,and the highest temperature during the day from reporting seedling stage to full seedling stage should be controlled within 28 °C to ensure the emergence of seedlings.Under the premise of ensuring the ventilation of seedling shed(the relative humidity of seedling shed < 85%),the highest temperature from small cross stage to cross stage should not exceed 30 °C,and the highest temperature after cross stage should not exceed 35 °C,which would not cause damage to tobacco seedlings.The water temperature could be increased by 1.8-2.2 °C,which was beneficial to the growth and development of tobacco seedlings,could shorten the seedling period by 7 days,promote the growth of fibrous roots,increase the root-shoot ratio,and increase the strong seedling rate by 4.8%.The preparation of seedling cultivation was reduced and the cost of seedling was reduced to4.2 yuan per 667 m2.Study on seedling management.Compared with one-time seedling feeding,the implementation of segmented precision tray seedling transplanting could reduce the loss of 66 seedlings per 667 m2;compared with the basket transport,the tray transport reduced the root damage of tobacco seedlings by 38%,the survival rate of transplanting increased by 1.2%,and the incidence of virus disease decreased by 11.2%.The above precision seedling management reduced the cost of seedling up to 4.6 yuan per 667 m2.3.Innovative research on digital supervision mode of floating seedling raisingAn intelligent monitoring system of flue-cured tobacco seedling based on Internet of Things was constructed,which integrated sensing equipment,intelligent control system,module early warning and response.The system was obviously superior to the conventional supervision mode in improving the emergence rate and strong seedling rate,reducing the rate of diseased plants and virus carrying rate.The strong seedling rate was increased by 6.2%,and the labor cost of seedling management was reduced by 3 yuan per667 m2,and the cost was reduced by 93.8%.The functions of remote warning of seedling temperature and humidity,visual growth,automatic drainage,automatic replenishment and fertilization,and abnormal management were preliminarily realized.It was an effective technical means for innovative seedling supervision of flue-cured tobacco.Based on the research of key technology,process optimization and innovation supervision,the overall seedling raising cost can be reduced by 16.7 yuan / mu.The application of this supporting technology and management mode can increase the tobacco leaf income by 108.7 yuan / mu. |
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