Effect Of Different Fertilization Schemes On Soil Fertility And Fruit Quality Of Kiwifruit

The phenomenon of unreasonable fertilization of kiwifruit orchards is common in China.Some orchards are over-fertilized with the idea of "high input,high return",resulting in excessive accumulation of soil nutrients,which is not conducive to tree fruiting.At the same time,due to the poor fertility of some orchards,the blind application of a single type of fertilizer not only fails to improve soil fertility effectively,but also results in low soil nutrient utilization and reduced fruit yield and quality.There are no comprehensive studies on the effects of different fertilization schemes on soil physicochemical properties,microbial community composition and fruit yield and quality in kiwifruit orchards.The Wuhan Botanical Garden of the Chinese Academy of Sciences conducted a field trial with different organic fertilizer ratios and different nitrogen,phosphorus and potassium ratios on the Danjiangkou kiwifruit site since autumn 2018,using the early-ripening kiwifruit variety ’Donghong’ and the late-ripening variety ’Jinyan’ as trial materials.The field trials were conducted at the Danjiangkou kiwifruit base.On this basis,this paper investigates the effects of different fertilization schemes on soil physicochemical properties,microbial community structure and fruit yield quality in kiwifruit orchards and the analysis of their rules,with a view to providing data to support scientific fertilization of kiwifruit.The main results were as follows:（1）The results of different organic fertilizer percentage application（787,400 and200 kg/mu of organic rapeseed cake fertilizer for T1,T2 and T3 programs,respectively）on soil ground strength and fruit quality in kiwifruit orchards showed that soil organic matter,total nitrogen,alkaline nitrogen,ammonium nitrogen,nitrate nitrogen,fast-acting phosphorus,total potassium,fast-acting potassium,boron,copper,iron,sulfur and zinc were the lowest after fruit harvesting with pure organic fertilizer（T1 program）,and the lowest overall soil fertility.The number of soil fungal ASVs and Alpha index of the pure organic fertilizer regimen also increased significantly,and the relative abundance of some beneficial bacteria such as RB41,Steroidobacter,Lysobacter,and Plectosphaerella was higher,and the average ’Donghong’ and ’Jinyan’ kiwifruit The average yield of ’Dong hong’ and ’Jinyan’ kiwifruit plants reached 28.82 kg and 23.85 kg,which were 47.79%and 25.94% higher than the other two fertilization programs,respectively.The two varieties of kiwifruit from the pure organic fertilizer program had superior fruit hardness,soluble solids content,soluble sugar content,solid to acid ratio,sugar to acid ratio,vitamin C and other major quality indicators.The results showed that the application of pure organic fertilizer promoted the uptake of soil nutrients and improved the soil microbial community structure of ’Donghong’ and ’Jinyan’ fruit trees,thus significantly improving the yield and quality of kiwifruit fruits.（2）The effects of fertilization with different NPK ratios（1:0.6:1,0.63:0.75:1 and1.45:0.91:1 for T4,T5 and T6,respectively）on soil strength and fruit quality of kiwifruit orchards showed that: the soil organic matter,fast-acting phosphorus,alkaline nitrogen,ammonium nitrogen,nitrate nitrogen and other elements in ’Donghong’ were the lowest after fruit harvesting with inorganic fertilizer（T4）at the appropriate NPK ratio.’Donghong’ and ’Jinyan’ kiwifruit soils had the lowest overall fertility,with ’Donghong’soils having the lowest organic matter,fast-acting phosphorus,alkaline nitrogen,ammonium nitrogen,nitrate nitrogen,copper,iron,manganese,sulfur and zinc elements,while ’Jinyan’ soil has the relatively lowest content of total phosphorus,total potassium,fast-acting potassium,ammonium nitrogen,zinc and other elements.The fruit quality of kiwifruit was relatively the best in the T4 scheme,where the average plant yield of’Donghong’ kiwifruit was up to 19.93 kg,34.48% higher than the T6 scheme,and the average plant yield of ’Jinyan’ kiwifruit was 18.90 kg,which was 47.54% and 40.94%higher than the other schemes.Under the T4 scheme,the main quality indicators such as soluble solids content,soluble sugar content,solid-acid ratio,sugar-acid ratio and dry matter percentage of kiwifruit fruit of both varieties were relatively optimal,and the relative abundance of beneficial microorganisms such as Nitrospira,RB41,Subgroup₁0and Mortierella in the soil was also higher.The results showed that the application of fertilizers at an appropriate N:P:K ratio（1:0.6:1）promoted the uptake and utilization of soil nutrients and regulated the microbial community structure,and significantly improved the yield and main quality indicators of ’Jinyan’ and ’Donghong’ kiwifruits.