Changes Of Trace Elements In The Soil Of Tomato Continuous Cropping Facilities And Their Effects On Tomato Yield And Quality

Most of the facility vegetable fertilization methods in China are combined with nitrogen,phosphorus and potassium fertilizers.The quality and yield of facility tomatoes were very high when they were first planted;however,with the increase of tomato planting years and the accumulation of N,P,and K in the soil,the yield and quality of tomatoes continued to decline;especially the facility tomato diseases that were planted for more than ten years Aggravated with the length of the planting period,showing a series of physiological symptoms of deficiency,such as chlorosis of the leaves,short plants,curling leaves,affecting plant growth and development,these symptoms are related to the absorption of medium and trace elements,long-term fertilization and tomato Under the condition of continuous cropping,how to change the trace elements in the soil of the facility,the current research has not yet reached a unified conclusion,and all need to be studied in depth.This study uses the soil of different fertilization treatment facilities for long-term fertilization and tomato continuous cropping（8 years）of Shenyang Agricultural University as the research object.The effective content changes,nutrient balance changes of calcium,magnesium and trace elements iron,manganese,copper and zinc in the research facility soil,and The growth status and absorption of medium and small amounts of tomato can analyze the effects of different nutrient accumulation conditions on the bioavailability of trace elements in soil,and provide a theoretical basis for nutrient management and sustainable development of facility agricultural production.The main findings are as follows:1.For eight consecutive years of positioning fertilized soil,with the increase in the amount of fertilization,the soil p H decreased from 6.96 to 6.38,a large amount of nitrogen,phosphorus and potassium nutrients accumulated,the effective nitrogen,phosphorus and potassium content range was 298.40 mg · kg^-1-562.51 mg · kg^-1,122.25 mg · kg^-1-381.20 mg · kg^-1,305.65 mg · kg^-1-852.33 mg · kg^-1.2.Compared with the control without fertilization,under the condition of continuous fertilization and tomato continuous cropping for 8 consecutive years,as the accumulation of N,P and K in the soil increased,the content of water-soluble calcium and magnesium in the soil was 2.05-4.21 times of that without fertilization.The exchangeable calcium and magnesium content decreased by 11.1% 44.3% and 10.9% 37.2%;the water-soluble and exchangeable ions Ca²⁺ / K + and Mg²⁺ / K + showed a downward trend,and the ratio of available calcium and magnesium to available potassium in the soil decreased.3.The management of fertilization for many years has a significant impact on the content of available iron,manganese,copper,and zinc in the arable layer.Under the conditions of fertilization,the effective content of each element is surplus,and the content of available ironand copper rises slightly with the increase of the amount of fertilizer.The effective state content of manganese and zinc did not change significantly with the increase in the amount of fertilization.In the control treatment without fertilization,the effective iron and copper content were near the lack of marginal values,manganese was in a deficit state,and zinc was temporarily in a rich state.The accumulation of soil nutrients changed the original balance of soil nitrogen,phosphorus,potassium and medium and trace elements calcium,magnesium,iron,manganese,copper,and zinc in the soil.The accumulation of available nitrogen,available phosphorus,and available potassium was 562.51,381.20,852.33 Compared with the accumulation of 298.40,122.25,and 305.65 mg·kg^-1,the effective nutrient ratio of calcium increased by 8.6%,and the effective nutrient ratio of magnesium,iron,manganese,copper,and zinc decreased by 31.2%,31.2%,44.5%,31.6% and 34.4%,the proportion changes significantly.4.Determine the distribution ratio of calcium,magnesium,iron,manganese,copper and zinc in various parts of tomato plants.The distribution of calcium,magnesium,and zinc elements in all treatments is higher than that in the lower part of the ground,and the distribution of iron,manganese,and copper elements is higher in the lower part than in the upper part.Compared with no fertilization,fertilization increased the accumulation of calcium,magnesium,iron,manganese,copper,and zinc in the ground,but as the amount of fertilization increased,the upward transport of calcium,magnesium,iron,and copper was received,while manganese It is inhibited under the conditions of nutrient accumulation when the contents of available nitrogen,available phosphorus,and available potassium are 363.46,160.26,and 338.92 mg · kg^-1.On the contrary,when zinc is removed,the contents of available nitrogen,available phosphorus,and available potassium are 363.46,160.26,338.92 The nutrient accumulation at mg · kg^-1is inhibited.5.Through the study on the quality and yield of tomatoes under different nutrient accumulations in tomato test sites after 8 years of continuous application,it was found that when the available nitrogen,available phosphorus,and available potassium contents in the soil were 363.46,160.26,338.92 mg · kg^-1,The fruit yield is the highest,and the available available nitrogen,available phosphorus,and available potassium content in the soil is 298.40,122.25,305.65 mg · kg^-1,the quality of the tomato fruit is better,and there is no significant difference between the yield and the maximum yield There is no significant difference between single fruit weights,so for better economic benefits,we can choose the amount of fertilizer N,P₂O₅,K₂ O 21.5,7.1,30.7 kg.mu^-1.