Effects Of Combined Application Of Organic And Inorganic Fertilizers On Salt Control And Fertile Soil In Coastal Saline Soil And On The Yield And Quality Of Chinese Cabbage

In recent years,combined application of organic and inorganic fertilizers has played an important role in soil improvement,salt reduction,fertilization and yield increase.Coastal saline soil has low organic matter content,high salt content,compaction and poor ventilation,which affects crop emergence,reduces crop nutrient absorption and water use efficiency,and endangers crop growth.In the process of agricultural production,the application of excessive chemical fertilizers not only causes low fertilizer use efficiency,but also aggravates the harm of salt and alkali,which further causes crop yield reduction and quality reduction.The application of organic fertilizer instead of part of chemical fertilizer is beneficial to improve the physical and chemical properties of soil,alleviate the continuous deterioration of saline soil,improve the content of soil organic matter and soil nutrients,promote the high yield of crops and improve the quality of crops.In this experiment,the coastal saline soil in Dongying City was used as the test material,and the ratio test of commercial organic fertilizer and chemical fertilizer with nutrient content of 17-10-15 was carried out on Chinese cabbage in arch shed,with a total of 7 treatments.Respectively,no organic fertilizer and chemical fertilizer 1.92 t·hm^-2as control,organic fertilizer 60 t·hm^-2and chemical fertilizer 1.92 t·hm^-2,organic fertilizer 60 t·hm^-2and chemical fertilizer 1.53 t·hm^-2,organic fertilizer 120 t·hm^-2and chemical fertilizer 0.95 t·hm^-2,organic fertilizer 180 t·hm^-2and chemical fertilizer 0.63t·hm^-2,organic fertilizer 240 t·hm^-2and chemical fertilizer 0.39 t·hm^-2,organic fertilizer 300t·hm^-2and no chemical fertilizer.The effects of different treatments on soil p H value,electrical conductivity,water-soluble total salt,organic matter,total nitrogen,alkali-hydrolyzable nitrogen,available nitrogen,phosphorus and potassium content,heavy metal content and soil fractal dimension were studied,as well as the effects of different fertilization treatments on the yield and quality of Chinese cabbage,in order to screen out the ratio of organic and inorganic fertilizers with better effect of salt control and fertile soil,and provide technical support for agricultural production in coastal saline soil.The results show that:（1）The combined application of organic and inorganic fertilizers can significantly reduce the salt content and p H value of coastal saline soil.Under the conditions of this experiment,the combined application of organic and inorganic fertilizers can effectively reduce the soil p H value.In the 0～20 cm soil layer,the soil p H value and soil conductivity of the soil water soluble total salt of the treatment OF4（chemical fertilizer nitrogen substitution rate of 40%）in the two-crop cabbage experiment were significantly lower than that of the treatment F of single chemical fertilizer and the treatment O of single organic fertilizer.The salt control effect of OF4 treatment was better,which was 59.6%lower than that of treatment F and32.7%lower than that of treatment O,so that the soil conductivity was kept within the range suitable for vegetable growth and the soil p H was reduced.When the application of organic fertilizer was more than 120 t·hm^-2,the soil p H value and soil conductivity tended to increase.Excessive application of organic fertilizer would increase soil p H value and soil conductivity,thereby increasing soil salinity.（2）In the 0～20cm soil layer,compared with the treatment F without fertilization,the combined application of organic and inorganic fertilizers increased the soil nutrient content to varying degrees.The soil organic matter content increased by 24.7%～310%,the soil total nitrogen content increased by 23%～201.3%,the soil alkali-hydrolyzable nitrogen content increased by 17.7%～194%,the soil available phosphorus content increased by126.3%～991.3%,and the soil available potassium content increased by 16.2%～186.6%.The combined application of organic and inorganic fertilizers has played a good fertile soil effect.At the same time,the application of organic fertilizer can increase the fractal dimension of soil particles and enhance the ability of soil to retain fertilizer,and the content of heavy metals in soil is within the national standard.（3）The application of organic fertilizer in coastal saline-alkali land can significantly improve the yield and quality of Chinese cabbage.The results showed that the yield of OF4 was50.09%higher than that of F and 17%higher than that of OF.In the second crop of Chinese cabbage,the yield of OF4 was 330.1%higher than that of F,and 296.3%higher than that of OF.The Vc content of Chinese cabbage leaves treated with organic fertilizer was significantly higher than that of treatment F by 7%～67%,while the catalase content increased slightly,the nitrate content decreased significantly by 18.2%～42.9%,and the malondialdehyde content decreased significantly by 9.79%～22.93%.Considering the overall effect,the treatment OF4,that is,organic fertilizer 120 t·hm^-2and topdressing fertilizer 0.95 t·hm^-2,fertilizer nitrogen replacement rate 40%,the effect of controlling salt fertile soil is the best,the yield is the highest,and the crop quality can be guaranteed while increasing the yield.