Effects Of Citrate-soluble Calcium And Magnesium Fertilizer On Yield And Quality Of Processing Tomato In Calcareous Soil

[Objective]Calcareous soil can generally meet the needs of crops for calcium and magnesium.However,due to the large demand for calcium and magnesium in processing tomatoes,calcium and magnesium deficiency often occurs in the process of planting tomatoes in North China,which affects the yield and quality of processing tomatoes.Therefore,for processing tomato,even planting on calcareous soil needs to pay attention to the supplement of calcium and magnesium.Citric acid soluble calcium magnesium fertilizer is processing by a series of technical means with the discharged magnesium slag as the main raw material,and contains both citric acid soluble and water-soluble calcium and magnesium.This kind of fertilizer reuses the waste and reduces the environmental pollution caused by the discharge of magnesium slag.It is widely used in acidic soil in the south,while there is less research on Processing Tomato in calcareous soil in the north.This study discussed the relationship between the application amount of citric acid soluble calcium and magnesium fertilizer in calcareous soil and the yield and quality of processing tomato,selected the appropriate amount of calcium and magnesium fertilizer,and improved the yield and quality of processing tomato,so as to provide reference for the application of citric acid soluble calcium and magnesium fertilizer in calcareous soil and the production practice of processing tomato.[Methods]This experiment was conducted from 2020 to 2021.Field plot experiment was adopted:1.Different types of calcium and magnesium fertilizer experiment:a total of 4 treatments were set up:control,600 kg·hm^-2citric acid soluble calcium and magnesium fertilizer,450 kg·hm^-2amino acid calcium,600kg·hm^-2magnesium sulfate.2.Experiment on the application amount of medlar soluble calcium and magnesium fertilizer:the experiment is divided into two years.In 2020,five application amounts of calcium and magnesium fertilizer are set,which are 0,300,450,600 and 900 kg·hm^-2;In 2021,four calcium and magnesium fertilizer application rates are set,which are 0,450,900 and 1800 kg·hm^-2.[Main results]（1）In the process of planting processing tomato in calcareous soil,the application of different types of calcium and magnesium fertilizer can significantly promote the growth of processing tomato,reduce the occurrence of umbilical rot,improve yield,increase economic benefits and improve quality.The yield increased by 9.77%～29.83%compared with the control treatment.（2）The application of different amounts of citric acid soluble calcium and magnesium fertilizer can promote the plant height,stem diameter,aboveground and underground growth of processing tomato,increase the SPAD value of leaves,promote photosynthesis and significantly improve the net photosynthetic rate（Pn）,which is 27.82%～55.95%higher than that of the control treatment.When the application rate was 900 kg hm^-2,the leaf stomatal conductance（Gs）and transpiration rate（Tr）were the highest,and the intercellular CO₂concentration was the lowest.（3）The different dosage of Lycium soluble calcium magnesium fertilizer significantly affected the nutrient absorption and yield of processing tomato.With the increase of calcium and magnesium fertilizer application,the absorption content of nitrogen,phosphorus and potassium also increased,and the yield increase effect was better.In 2020,the absorption amount of each element was the highest when the application amount was 900 kg·hm^-2,and the highest when the application amount was 1800 kg·hm^-2in2021.Compared with no calcium and magnesium fertilizer,it increased by 29.83%and 13.20%respectively.（4）Compared with the control,different dosage of medlar soluble calcium magnesium fertilizer can increase the fruit weight,fruit size,color index,pulp thickness and ventricular number,and reach a significant level,while the nitrate content is significantly reduced.The sugar acid ratio,pulp thickness and VC content of C900 treatment in 2020 and C1800 treatment in 2021 are the highest,which are 41.44%,33.90%and 185.96%higher than CK respectively in 2020;In 2021,it is 55.01%,29.51%and 18.86%higher than CK respectively.Through comprehensive evaluation,the score of 1800 kg·hm^-2was the highest.[Conclusion]The application of citric acid soluble calcium magnesium fertilizer in calcareous soil can significantly promote the growth of processing tomato plants,increase nutrient absorption and reduce the incidence of umbilical rot,so as to improve the yield,economic benefits and quality of fruits.In this experiment,the highest yield and economic benefits were obtained when the application rate was 1800kg·hm^-2,and the quality index score was the highest through comprehensive evaluation.Therefore,the application amount of 1800 kg·hm^-2in this experiment was the best for improving quality and increasing yield.