Analysis On Leaf Nutrition And Fruit Quality Of ‘Honeycrisp’ Apple And Soil Fertility Under Different Fertilization Treatments

Apple is one of the most important temperate fruit trees in the world,and apple production plays an important role in fruit production all over the world.China is the largest apple production country in the world,but the phenomenon of excessive application of chemical fertilizer and insufficient input of organic fertilizer is widespread in apple production,which leads to poor quality and low fertility of orchard soil,resulting in insufficient nutrition supply for apple tree,and furtherly affecting the yield and quality of apple.In this study,5-year-old ’Honeycrisp’ apple was used as the materials,and the method of strip-furrow fertilization was adopted to set up three different fertilization schemes: organic fertilizer substitution for chemical fertilizer,combined application of commercial organic fertilizer and combined application of different organic fertilizers.The changes of the growth and nutrition level of leaves,fruit quality and nutrition level of soil were analyzed to study the effects of different organic fertilizers,chemical fertilizer and their combination with microbial fertilizer and soil conditioners on leaf nutrition,fruit quality of ’Honeycrisp’ apple and soil fertility.The aim was to provide a basis for effective fertilization techniques for apple orchards in arid areas,which would be to reduce chemical fertilizer and increase efficiency and soil improvement,and to promote the implementation of "zero growth of chemical fertilizer" plan.The following main results were obtained through 2 consecutive years of testing and analysis:(1)Effects of organic fertilizer substitution for chemical fertilizer on leaf nutrition,fruit quality of ‘Honeycrisp’ appleand soil fertility.Compared with chemical fertilizer(CK),commodity organic fertilizer + 1/2 chemical fertilizer(T1),sheep manure(T2),Sheep manure + 1/2 chemical fertilizer(T3)and Peat +1/2 chemical Fertilizer(T4)increased SPAD value,thickness,fresh weight,dry weight and nutrient element content of leaves.T2 treatment had the best effects on increasing the nutrient element content of leaves.The fruit weight of T2 and T4 was higher,and the fruit shape index of T4 was better.T2 treatment significantly increased the soluble solid content by 11.79% and 9.81%,and the solid-to-acid ratio by 23.20% and 47.64%,respectively in 2years,but there was no significant difference between T2 and T4.T2 treatment increased the calcium content of fruits significantly.The substitution of organic fertilizer for chemical fertilizer decreased p H value of soil and increased soil nutrient levels.It showed that the application of organic fertilizer could promote the growth and development of apple trees,improve fruit quality and enhance soil fertility generally.In general,T2 treatment had the best effects.(2)Effect of combined application of commercial organic fertilizer leaf nutrition,fruit quality of ‘Honeycrisp’ apple and soil fertility.Compared with chemical fertilizer(CK),commercial organic fertilizer + microbial fertilizer + 1/2 chemical fertilizer(T5),commercial organic fertilizer + Rongdimei + 1/2chemical fertilizer(T6)and commercial organic fertilizer + fulvic acid + 1/2 chemical fertilizer(T7)all improved the leaf nutrition and fruit quality.Among these treatments,the soluble solid content of T7 was highest,which were increased by 5.90% and 10.43%respectively in 2 years.The fruits of T6 were coloured better.Commercial organic fertilizer combined with microbial fertilizer or soil coditioners reduced p H value of soil,increased organic matter content of soil and improved soil fertility.Among these treatments,T5 increased the organic matter content of soil significantly,and T7 increased the content of available nitrogen,phosphorus and potassium in soil of 0-40 cm significantly.It showed that commercial organic fertilizer combined with microbial fertilizer or soil coditioners could promote the growth of leaves,improve fruit quality,and increase nutrient element levels in soil effectively.Overall,T7 treatment had the best effects.(3)Effects of combined application of different organic fertilizer with fulvic acid,Rongdimei and microbial fertilizer on leaf nutrition,fruit quality of ‘Honeycrisp’ apple and soil fertility.Compared with chemical fertilizer(CK),commercial organic fertilizer + fulvic acid +Rongdimei + 1/2 chemical fertilizer(T8),commercial organic fertilizer + microbial fertilizer + fulvic acid + Rongdimei + 1/2 chemical fertilizer(T9)and peat + microbial fertilizer + fulvic acid + Rongdimei + 1/2 chemical fertilizer(T10)promoted the growth of leaves,fruit quality and soil nutrient accumulation to different degrees.Among these treatments,the fruits of T8 had the largest fruit weight,higher fruit shape index,the highest soluble solid content and lower titratable acid content,and the calcium content of fruits of every treatment was increased.The different combinations improved the physical and chemical properties of soil obviously.In 2 years,compared with CK,the organic matter content in soil of 0-20 cm of T10 was increased by 22.49% and 30.81%,respectively.The organic matter content showed a decreasing trend with the siol depth,which was 0-20 cm >20-40 cm > 40-60 cm.T8 treatment had the best effects on increasing the amount of nitrogen,phosphorus and potassium of soil,and the content of available nitrogen,phosphorus and potassium in soil of 0-20 cm were increased more,compared with CK.It showed that reducing chemical fertilizer and increasing organic fertilizers and soil conditioner could improve the physical and chemical properties of soil and soil fertility to a certain extent.Thereby,this enhanced apple tree’s nutrition and promoted fruit quality.Overall,T8 treatment was the best fertilization scheme.