Effect Of Special Compound Fertilizer And Combined With Organic Fertilizer And Green Manure On Lane Late Navel Orange

Facing the risk to fragile ecosystem of my country’s Three Gorges area,as the rapid development of Lane late navel orange,excessive application of chemical fertilizers and single fertilization mode lead to tree nutrient imbalance,unstable fruit yield and quality,and weak water and soil conservation capabilities.In this study,on the basis of two-year decrement application of citrus special compound fertilizer,field trial was adopted,with9-year-old Lane late navel orange and rootstock as fructus Aurantii.The habitual fertilization was used as the control to study the effects of continuous decrement application of citrus special compound fertilizer combined with organic fertilizer,single and mixed green manure sowing on soil nutrient supply,tree nutrient content,fruit yield and quality,and nutrient efficiency,aiming at fertilization model for improving the fruit quality and nutrient efficiency of citrus in the Three Gorges Reservoir area,and to provide scientific basis and technical support for promoting the high-quality development of the lane late navel orange industry in the Three Gorges Reservoir area.The main results obtained are as follows:1.Applying the same amount of citrus special compound fertilizer for 4consecutive years(2017-2020)can significantly increase the yield of Lane late navel orange fruit by 48.67%;single fruit weight and edible rate are significantly increased,and the solid-acid ratio and juice yield have a trend of improvement;The nutrient removal ratio of the fertilizer to the fruit increased by 44.47%;the monthly nitrogen,phosphorus and potassium content of leaves and the average annual soil available nitrogen,phosphorus and potassium content increased.The continuous reduction of 25% citrus fertilizer for the first 3 years(2017-2019)did not significantly affect the fruit yield and quality,but with the extension of the year,the fruit yield increase rate in the fourth year dropped to 8.64%,which was not significantly different from habitual fertilization;Fruit soluble solids,solid-acid ratio,and vitamin C all showed a downward trend,which significantly reduced the nitrogen content of citrus leaves.Starting from the third year(2019),the soil organic matter and available nitrogen and phosphorus nutrient content decreased significantly.2.For 4 consecutive years(2017-2020),the output of applying the same amount of citrus special compound fertilizer combined with bio-organic fertilizer continued to increase,and the output increased by 50.50% in the fourth year;the soluble solid content of the fruit and the vitamin C content have a tendency to increase;fertilizer;The nutrient removal ratio of the fertilizer to the fruit increased by 56.03%;in the early stage of fruit development(May to July),the fertilizer efficiency was slow,and the leaf N,P,and K content was lower than the equivalent amount of special fertilizer treatment,but the available soil nitrogen,phosphorus and potassium content throughout the year was not equivalent to the equivalent amount of special fertilizer.Significant difference,the content of organic matter has increased significantly.3.Under the condition of 25% decrement application of special compound fertilizer,planting vetch vetch or ryegrass and mixed sowing of green manure for 2 years(2019-2020)can significantly increase fruit yield by 3.57-26.19%;significantly increase single fruit weight,edible rate,solids,and solid acid.The nutrient removal ratio of the fertilizer to the fruit increased by 27.05%;the leaf nitrogen content decreased,and the soil available nitrogen,phosphorus,and potassium content was lower in the early period(May to July).After the green manure was pressed in July,the green manure increased significantly.Intercropping green manure improved the soil organic matter Content,soil water content and porosity reduce soil bulk density;soil invertase,urease,and phosphatase activities are significantly increased;fruit yield is significantly positively correlated with soil invertase and phosphatase,fruit soluble solids and vitamin C are all related to soil organic matter,sucrase,phosphatase,and available phosphorus are significantly positively correlated,indicating that green manure promotes the quality and yield of Lane late navel orange by improving basic fertility and enzyme activity.4.Green manure mixed sowing for 2 years(2019-2020)can significantly increase the dry matter yield of green manure and the total accumulation of N,P,and K nutrients,and promote the accumulation of leaf phosphorus and potassium.The mixed sowing treatment is at the later stage(September-November)Soil effective nutrient and enzyme activity increased more,but the difference was not significant;the yield increase rate was10.62% higher than that of unicasting,and the effect of green manure mixed sowing was better than that of green manure unicasting in increasing single fruit weight,edible rate and soluble solids.Among different mixed sowing ratios,the overall effect of 6:4 mixed sowing of vetch and ryegrass was the best.In summary,the continuous application of citrus special compound fertilizer with the same amount of nitrogen,phosphorus and potassium nutrients has a significant effect on improving the quality and efficiency of Lane late navel orange;25% decrement application of citrus special compound fertilizer,on the one hand,combined with bio-organic fertilizer can protect the soil,stabilize production and improve quality.On the other hand,the mixed planting of legumes and non-legumes green manure can be used to lose weight,improve quality,increase efficiency,and improve fertility,and is ecologically friendly.