Effects of partial substitution of chemical fertilizer by organic fertilizer on soil fertility in citrus orchard and fruit quality and yield of <italic>Citrus reticulata</italic> ‘Jinqiushatangju’

<bold>Objective</bold> Organic fertilizer application is one of the important measures to improve the quality and yield of <italic>Citrus reticulata</italic>‘Jinqiushatangju’.This study aims to explore the effect of different organic fertilizer application ratio on the soil fertility of orange groves，the yield and quality of <italic>Citrus reticulata</italic> ‘Jinqiushatangju’s. <bold>Method</bold> The experiment was set up with five fertilization treatments：T₁-conventional fertilization，T₂-organic and inorganic dosing（M replacing 15% of fertilizer nitrogen），T₃-organic and inorganic dosing（M replacing 30% of fertilizer nitrogen），T₄-organic and inorganic dosing（M replacing 45% of fertilizer nitrogen），T₅-organic and inorganic dosing（M replacing 60% of fertilizer nitrogen），and T₅-organic and inorganic dosing（M replacing 60% of chemical fertilizer nitrogen）.The effects of different proportions of organic fertilizers replacing chemical fertilizers on the yield，quality，soil fertility and economic benefits of <italic>Citrus reticulata</italic> ‘Jinqiushatangju’were investigated，the correlation between yield，quality and soil fertility was analyzed by Pearson correlation analysis，the effects of different fertilization treatments were comprehensively evaluated by using the method of the subordinate degree of function value. <bold>Result</bold> The results showed that the application of organic fertilizer had obvious promotion effect on the yield and quality of <italic>Citrus reticulata</italic>‘Jinqiushatangju’.Compared with the conventional fertilization，the T₄ treatment（M replacing 45% of chemical fertilizer nitrogen） had the best effect，and the yield of 45% organic fertilizer replacing chemical fertilizer treatment could be increased by 16.2% compared with that of the conventional fertilization treatment.The content of soluble solids，soluble sugar，and Vitamin C could be increased by 14%，25.3%，and 18.3%，respectively.Meanwhile，as the proportion of organic fertilizer application increased，the soil pH，organic matter，quick-acting potassium，effective phosphorus，total nitrogen，and cation exchange showed an overall increasing trend.Among them，the T₄ treatment had the best effect.In terms of input-output ratio，the net income of T₄ treatment was 25% higher than that of conventional fertilization treatment，and the input-output ratio was also the highest.The Pearson correlation analysis showed that there was a certain correlation between the yield of <italic>Citrus reticulata</italic>‘Jinqiushatangju’and quality and soil fertility.With the help of the affiliation function，the value for its comprehensive evaluation showed that the evaluation coefficient of T₄ treatment was the highest，followed by T₅ treatment，and the evaluation coefficients of the rest of the fertilization treatments were T₃&gt;T₂&gt;T₁. <bold>Conclusion</bold> Replacing part of the chemical fertilizer with organic fertilizer is an effective way to improve the yield and quality of golden autumn tangerine as well as fertilize the soil.Considering the yield and quality of golden autumn tangerine，as well as the factors of soil fertility and economic benefits.Ranging from high to low，the comprehensive effect of each fertilizer treatment is T₄，T₅，T₃，T₂ and T₁.