Study On The Technology Of Reducing Chemical Fertilizers For Lane Late Navel Orange And Satsuma Mandarin In Hubei Province

Yichang,Hubei province is a citrus-advantaged industrial zone delineated by the Ministry of Agriculture and Rural Affairs.This area belonging to the Three Gorges reservoir is one of the most important ecologically sensitive areas in China.Therefore,the synchronizing local agricultural production with ecological environment is crucial.To solve the problem of water and soil loss,nutrient leaching from soil in this area,low fertilizer utilization rate and high ecological environment risk and screen an optimal fertilizer reduction and soil fertility measures,the effects of different fertilizer reduction measures on citrus tree and soil nutrient changes,tree nutrient utilization,fruit quality and yield were studied by field experiment with 27-year-old Satsuma mandarin orange and 7-year-old Lane late navel orange.It provides the basis and technical support for the citrus fertilizer reduction,quality improvement and industrial sustainable development in the Three Gorges reservoir area.The main results obtained are as follows:1.Farmer conventional fertilization is harmful to the improvement of fruit quality: In the Lane late navel orange,the peel brightness and the coloring intensity in farmer conventional fertilization were significantly reduced;In Satsuma mandarin orange,not only the color quality is deteriorated,but also the total soluble solid content and Vc content of the fruit are significantly reduced.Applying the citrus special fertilizer developed by this subject can promote the accumulation of nutrients in citrus leaves.Even if the total amount of NPK nutrients is reduced by 25% compared with the farmer conventional fertilization,the fruit quality tends to increase.Moreover,in Satsuma mandarin orange orchard with higher background fertility,its output increased by 19.28%,but in the Lane late navel orange orchard,the yield decreased by 8.61%.2.Planting green manure light leaf scorpion on the basis of applying citrus special fertilizer with 25% reduction of NPK total nutrient content significantly improved soil physical properties: The capillary porosity was significantly reduced,the venting porosity was significantly improved,and the loss of available NPK in the soil was reduced.Although the available NPK content in the soil decreased significantly during the period of rapid growth of green manure,the leaf nutrient of this treatment still had an upward trend.The yield and quality of this treatment showed an upward trend in both varieties.3.The application of water-soluble fertilizers with a 25% or even 50% reduction in total NPK nutrients of farmer conventional fertilization increased the fruit yield by 12.55% and 11.13%,respectively.The quality also had an increasing trend,especially the single fruit weight were significantly increased by 8.67% and 12.41% compared with the farmer conventional fertilization.The fertilizer efficiency in the two treatments was fast,and the leaf nutrients increased significantly in May,which was beneficial to the rapid accumulation of nutrients in the early stage,But the available nutrient content of the soil decreased rapidly.4.Judging from the dynamic changes in different treatments of leaves and soil nutrients,the fruit preferentially obtain the required NPK nutrients from the leaves,and the final leaf nutrient level is related to the soil supply level.There was no significant difference in the amount of total NPK nutrients between different fertilization treatments,but there was a significant or extremely significant positive correlation between nutrients.