| Citrus belongs to the genus Citrus of Rutaceae.The yield and area of Citrus in China rank first in the world,and it is the largest fruit tree in South China.However,there is still a big gap between the yield of Citrus in China and the world average level.Poor soil conditions,extensive management and unreasonable fertilization in citrus orchards are the main reasons for the low yield and poor quality of Citrus in China.Therefore,this paper intends to ascertain the nutrient abundance and deficiency of citrus orchards in Hunan Province by investigating and analyzing the nutrient status of soil and trees in citrus orchards in the main citrus producing areas of Hunan Province.Then,by sampling and analyzing several kinds of organic fertilizers commonly used in production,2-3 kinds of suitable organic fertilizers are selected according to the soil characteristics of citrus orchards in Hunan Province for field experiments to verify the effect of organic fertilizers on citrus.It provided theoretical basis for scientific fertilization of citrus orchards in Hunan Province.give the result as follows:The total nutritional status of citrus orchards in Hunan Province was as follows: soil acidification was serious in citrus orchards,soil pH of 68.8% orchards was lower than 4.8;soil organic matter content of 89.7% orchards was suitable or abundant.The contents of available nitrogen,available phosphorus,available potassium,available calcium,available magnesium and available boron in soil were low,the contents of available iron,available manganese and available copper were excessive,and the contents of nitrogen,calcium,magnesium,boron and zinc in leaves were low..According to the analysis of mineral elements in soil,leaves and fruits of citrus orchards in four sweet orange producing areas,the contents of mineral elements in soil,leaves and fruits of citrus orchards in different areas are quite different.The content of available phosphorus in soil of southern Hunan is lower than that of Western Hunan,and the content of iron,manganese and copper is higher than that of Western Hunan.The contents of K,Ca and Mg in leaves of Western Hunan were slightly lower than those of southern Hunan.The contents of mineral elements in fruits in southern Hunan were higher than those in Western Hunan.In addition,the correlation between large and medium elements in soil,leaves and fruits was analyzed.The results of organic fertilizer field experiment showed that the application of organic fertilizer could reduce the titratable acid content of fruits in varying degrees,and increase the content of soluble solids and Vc.Fertilizer-9 had better effect on sweet orange and Fertilizer-2 had better effect on Orah and Ponkan.Generally speaking,treatment 4 showed better effects on different varieties.. |
